“The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
Best regards,
Ed Berry
Thursday, July 09, 2009
This is the End
Best regards,
Ed Berry
Friday, July 03, 2009
Brief Update on a Bearish Atmosphere
"The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
Time constraints preclude a complete discussion. In fact, at this point that may be case for at least the rest of this summer. The 6 June 2009 posting has all relevant links. I will attempt another short writing the weekend of 11-12 July.
SSTs across the equatorial Pacific Ocean basin remain above normal, generally ~0.5-1C, with localized greater magnitudes west of South America. Additionally, latest TAO buoy data of 5-day averaged ocean surface waters indicate that the 29C isotherm on the equator is at about 165W, the farthest east in at least 2 years. Further, there is a separate warm anomaly along and just west of the Dateline with totals in excess of 30C. However, the subsurface anomalies in this region, while deep (~200m), are only plus 1-2C. I can easily attribute much of the central Pacific Ocean warming to strong interactions with the extratropics, including the weakened trades and actual westerlies.
The wind and convective signals are seemingly wanting to drift away from the EL-Nino attractor in WB (2009) GWO phase space (see ALL plots). Total AAM including the mass (earth) term through 30 June has dropped to more than 1 sigma below the R1 data climatology. Contributing processes include the following. As part of a dynamic response to interhemispheric meridional symmetry of zonal mean zonal wind anomalies, zonal mean low pressure anomalies are present ~35N and 45S. There has also been strong frictional dissipation of intense westerly wind flows across the Southern Hemisphere storm track regions. Should total AAM departures become comparable to that observed during this past January and February, my concerns of an El-Nino "false alarm" for the weather-climate dynamical system will be significantly raised.
Finally, responding to the global wind signals while also part of complex feedback processes (interactions with baroclinic wave packets, RWDs, etc.), strong tropical convective forcing has returned to the North Indian Ocean as well as the Eastern Hemisphere monsoon systems. A weaker but important region of convection is also present ~0/160E. Hence our nemesis of 2 areas of tropical forcing is back (other global regions understood). Furthermore, there has been some westward shifting of these regions of enhanced tropical rainfall, especially across the Indian Ocean. Which will dominate going into boreal autumn?; stay tuned. The bottom line is that the global wind and convective signals continue to lead the SSTs (broken record), and the ENSO situation is unclear (will stochastic forcing have giveth then taketh away?).
A loose superposition of the snr plots for GWO/MJO phases 8-1-2 (considering synoptic variations) still depict the global atmosphere for all fields. I suspect that will be true the rest of the summer, including the USA July trough-ridge-trough pattern possibly transitioning to more of a western trough and southeast states ridge situation during August.
Ed Berry
Saturday, June 27, 2009
The Rottweiler Returns – Atmospheric Correction???
“The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
Time constraints (and scientific/efficiency considerations) continue dictate for these discussions to be scaled back. The 6 June posting has relevant links, and there is no need to be redundant.
Short and simple, starting in March and “maturing” during April and May, the global ocean-land-atmosphere dynamical system has shifted toward a weak El-Nino base state. The phase space plots depicting the WH (2004) measure of the MJO and WB (2009) measure of the GWO clearly show this. That is, a general displacement toward octants 7-8. The GWO projection has been “weaker” because of complicated issues involving the dynamics of the earth-atmosphere AAM budget including zonal mean contributions. Remember that the WB (2009) GWO is a global dynamical measure of the circulation as opposed to the empirical and equatorially confined WH (2004) MJO.
SST anomalies across the entire equatorial Pacific Ocean basin including the Nino regions are positive, including ~plus 1C and greater east of 160W. Further, the 29C isotherm is well to the east of the Dateline (see TAO and other plots). However, the subsurface anomalies across the west Pacific are not that robust, only ~plus 1-2C down to around 200m. In any case, this basin-wide warming of the Nino SSTs is a response to the global circulation (more said below), and our weak El-Nino is already (and has been) impacting global weather including the USA. Additionally, as discussed previously, the evolution to get to where we are at (in phase space) has been impacting global weather since December 2008 (recall the GWO driven “cheap” MJOs).
My “punch line” for today is that, in general, the global circulation, as part of a complex forcing-response-feedback “loop”, has been leading the SSTs since about boreal autumn 2006 (see previous posts). The latter includes projections on the “beloved” ONI and other measures such as the PDO. I am concerned this is still going on, perhaps working with the seasonal and annual cycles (there are reasons).
Since about mid-May, anomalous zonal mean westerly wind flows have been shifting off the equator into the subtropical and midlatitude atmospheres, with the largest magnitudes across the winter Southern Hemisphere (greater than 10m/s at 200mb). Frictional dissipation due to interactions with tropical forcing (including a recent weak MJO; e.g., WWBs) and midlatitude eddies led to a strong negative global frictional torque by mid-June. Updated through 24 June the there is a clustered negative global mountain torque of roughly minus 20 Hadleys. The point is this is an example of a negative global friction-mountain torque index cycle linked to atmospheric processes including tropical forcing (GWO 8-1). Global relative AAM has decreased to near the R1 data climatology, and tropical convection has become re-established ~10N/90E, good news for the Indian monsoon system. Will this tropical forcing coherently propagate into the west Pacific Ocean during the next few weeks? Stay tuned.
Like the recent behavior of the financial markets, we have seen an “AAM correction”. However, is this simply a subseasonal variation destructively interfering with El-Nino, or is a process beginning that not only could weaken EL-Nino this upcoming boreal autumn, but perhaps bring a La-Nina situation boreal winter 2009-10? The answer is unclear, and careful daily rigorous monitoring is critical. Hopefully at some point the atmosphere and the financial markets will become decoupled!
Animations of upper tropospheric daily mean vector wind fields do show that anomalous subtropical and midlatitude ridges have returned (bearish). Loosely, phases 1-2 of the both the MJO and GWO 250mb psi composite anomaly plots represent the global atmosphere. Responding to the weakening of the North Pacific Ocean jet, the warm ridge in place across the south central and southeastern states last week is retrograding. That behavior is consistent with a brief excursion toward phases 3-5. However, with low confidence, I think another loop in GWO/MJO phase spaces displaced toward octants 7-8-1 is probable during the next 1-3 weeks. As seen from the snr composites, temperature anomalies across the lower 48 states are very sensitive in this region of phase space (as is numerical model predictability skill). My own thought is the intense heat may be focused across the south central states the rest of this summer, with increasing probabilities of northeastward expansions during August. I will try to write a short posting 3 July.
Ed Berry
Time constraints (and scientific/efficiency considerations) continue dictate for these discussions to be scaled back. The 6 June posting has relevant links, and there is no need to be redundant.
Short and simple, starting in March and “maturing” during April and May, the global ocean-land-atmosphere dynamical system has shifted toward a weak El-Nino base state. The phase space plots depicting the WH (2004) measure of the MJO and WB (2009) measure of the GWO clearly show this. That is, a general displacement toward octants 7-8. The GWO projection has been “weaker” because of complicated issues involving the dynamics of the earth-atmosphere AAM budget including zonal mean contributions. Remember that the WB (2009) GWO is a global dynamical measure of the circulation as opposed to the empirical and equatorially confined WH (2004) MJO.
SST anomalies across the entire equatorial Pacific Ocean basin including the Nino regions are positive, including ~plus 1C and greater east of 160W. Further, the 29C isotherm is well to the east of the Dateline (see TAO and other plots). However, the subsurface anomalies across the west Pacific are not that robust, only ~plus 1-2C down to around 200m. In any case, this basin-wide warming of the Nino SSTs is a response to the global circulation (more said below), and our weak El-Nino is already (and has been) impacting global weather including the USA. Additionally, as discussed previously, the evolution to get to where we are at (in phase space) has been impacting global weather since December 2008 (recall the GWO driven “cheap” MJOs).
My “punch line” for today is that, in general, the global circulation, as part of a complex forcing-response-feedback “loop”, has been leading the SSTs since about boreal autumn 2006 (see previous posts). The latter includes projections on the “beloved” ONI and other measures such as the PDO. I am concerned this is still going on, perhaps working with the seasonal and annual cycles (there are reasons).
Since about mid-May, anomalous zonal mean westerly wind flows have been shifting off the equator into the subtropical and midlatitude atmospheres, with the largest magnitudes across the winter Southern Hemisphere (greater than 10m/s at 200mb). Frictional dissipation due to interactions with tropical forcing (including a recent weak MJO; e.g., WWBs) and midlatitude eddies led to a strong negative global frictional torque by mid-June. Updated through 24 June the there is a clustered negative global mountain torque of roughly minus 20 Hadleys. The point is this is an example of a negative global friction-mountain torque index cycle linked to atmospheric processes including tropical forcing (GWO 8-1). Global relative AAM has decreased to near the R1 data climatology, and tropical convection has become re-established ~10N/90E, good news for the Indian monsoon system. Will this tropical forcing coherently propagate into the west Pacific Ocean during the next few weeks? Stay tuned.
Like the recent behavior of the financial markets, we have seen an “AAM correction”. However, is this simply a subseasonal variation destructively interfering with El-Nino, or is a process beginning that not only could weaken EL-Nino this upcoming boreal autumn, but perhaps bring a La-Nina situation boreal winter 2009-10? The answer is unclear, and careful daily rigorous monitoring is critical. Hopefully at some point the atmosphere and the financial markets will become decoupled!
Animations of upper tropospheric daily mean vector wind fields do show that anomalous subtropical and midlatitude ridges have returned (bearish). Loosely, phases 1-2 of the both the MJO and GWO 250mb psi composite anomaly plots represent the global atmosphere. Responding to the weakening of the North Pacific Ocean jet, the warm ridge in place across the south central and southeastern states last week is retrograding. That behavior is consistent with a brief excursion toward phases 3-5. However, with low confidence, I think another loop in GWO/MJO phase spaces displaced toward octants 7-8-1 is probable during the next 1-3 weeks. As seen from the snr composites, temperature anomalies across the lower 48 states are very sensitive in this region of phase space (as is numerical model predictability skill). My own thought is the intense heat may be focused across the south central states the rest of this summer, with increasing probabilities of northeastward expansions during August. I will try to write a short posting 3 July.
Ed Berry
Saturday, June 20, 2009
Delayed - Part II
“The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
Please see links from the 6 June posting for current information. I am hopeful that time will allow me to present a more formal discussion next weekend, ~27 June. Whatever the case, the subseasonal dog (Rex the Rottweiler) is always watching!
The global ocean-land-atmosphere dynamical system remains tilted toward a weak El-Nino base state. Per WB (2009) measure of the GWO, the latter has particularly been the case since about mid-May. Having a contribution from frictional dissipation (negative global frictional torque) of anomalous zonal mean westerly wind flows propagating poleward into the midlatitude atmospheres, there is an on-going superimposed GWO/MJO 8-1 transition. In WB (2009) GWO and WH (2004) MJO phase spaces, the latter is probable to appear as another relatively minor orbit displaced toward octants 7-8-1. Phases 8-1 of the snr plots nicely depict the current global weather-climate system.
The equatorial Pacific Ocean basin is generally ~plus 0.5-1.0C warmer than normal. One important monitoring issue will be to see how much of an impact the recent strongest west Pacific WWB in roughly 2 years (~10-15m/s anomalies) has upon the thermocline during the next 1-2 months.
One regional scale response has been a convectively active Western Hemisphere, favoring deep tropical moisture transport into the central USA. I think the notion of most models to show retrogression of the trough-ridge-trough pattern across the lower 48 states during the next couple of weeks is reasonable. The latter is consistent with a brief circuit through phases 2-5 of the snr composites. By later week-2 into week-3, there may be a period of ridging around the west coast suggesting a "cool/wet trough" across the central and eventually portions of the eastern states. On average, phases 7-8 of the snr composites may best represent the global atmosphere the rest of boreal summer.
Ed Berry
Friday, June 12, 2009
Delayed - Part I
“The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
As I typed on 6 June, my next discussion will not be until the weekend of 26-28 June. The global circulation is weakly tilted toward El-Nino; however, there are some mixed signals involving the weather-climate dynamical system. While tropical convective forcing "hangs back" across the region of Indonesia, a superimposed MJO signal is emerging into the Western Hemisphere. Perhaps there will be another loop in WH (2004) phase space during the next few weeks displaced toward octant 7. The WB (2009) measure of the GWO maintains its weak projection, given the recent persistent positive ~1 sigma global AAM anomaly (R1 data climatology) and minimal time tendency. Simply put, analogous to the current financial markets the GWO is moving sideways. Will this continue the remainder of boreal summer 2009?
A mixture of the snr composite anomaly plots for MJO phases 7-8 and GWO phases 8-1 loosely depicts the global atmosphere. With variations, this situation may continue going well into July. Interestingly, anomalous upper tropospheric anticyclones are starting to dominate the Southern Hemisphere subtropical atmosphere (austral winter), arguably bearish. Stay tuned!
Please see links from the 6 June posting for real-time infomation, and email me/post comments if you have questions.
Ed Berry
As I typed on 6 June, my next discussion will not be until the weekend of 26-28 June. The global circulation is weakly tilted toward El-Nino; however, there are some mixed signals involving the weather-climate dynamical system. While tropical convective forcing "hangs back" across the region of Indonesia, a superimposed MJO signal is emerging into the Western Hemisphere. Perhaps there will be another loop in WH (2004) phase space during the next few weeks displaced toward octant 7. The WB (2009) measure of the GWO maintains its weak projection, given the recent persistent positive ~1 sigma global AAM anomaly (R1 data climatology) and minimal time tendency. Simply put, analogous to the current financial markets the GWO is moving sideways. Will this continue the remainder of boreal summer 2009?
A mixture of the snr composite anomaly plots for MJO phases 7-8 and GWO phases 8-1 loosely depicts the global atmosphere. With variations, this situation may continue going well into July. Interestingly, anomalous upper tropospheric anticyclones are starting to dominate the Southern Hemisphere subtropical atmosphere (austral winter), arguably bearish. Stay tuned!
Please see links from the 6 June posting for real-time infomation, and email me/post comments if you have questions.
Ed Berry
Saturday, June 06, 2009
New, or No “Bull” Atmosphere?
“The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
Please keep in mind the ESRL/PSD GSDM web link, below, while reading this discussion. Also, part-1 of a paper detailing the WB (2009) measure of the GWO has been published in MWR. See Appendix to download a copy.
http://www.cdc.noaa.gov/map/clim/gsdm.composites.shtml
The following are links for SST details. Loosely, positive SST anomalies dominate all equatorial ocean basins, with magnitudes ~1-2C. The warmest tropical waters are across the west central and northwest Pacific, as well as portions of the central Indian Ocean, where totals are in excess of 30C. The equatorial basin from ~140E to the west coast of South America is slightly warmer than climatology; however, per latest TAO buoy data not continuously greater than plus 0.5C. Roughly plus 1-3C anomalies were observed at depth along the less than normal sloped equatorial Pacific Ocean thermocline.
The causes for the observed warming across the Nino regions since about last March are complicated and subtle, and require additional careful detailed rigorous scientific analysis. In any case, I again remind the readers that ENSO is a global phenomenon involving all tropical ocean basins as part of the coupled ocean-land-atmosphere dynamical system. For instance, an argument could be made for an equatorial Atlantic Ocean basin-wide warm event during the past few months. A similar situation played a significant role during early 2008, perhaps reinforcing the on-going strong La-Nina at that time. During boreal autumn 2006, an exceptionally warm Indian Ocean contributed not only to shutting down El-Nino, but tilting the weather-climate system toward La-Nina.
As discussed below, the weather-climate system is tipping toward El-Nino. However, serious scientific issues are present (most cannot be addressed here), and the “truth may be told” during the upcoming boreal autumn. Maybe we need a “Rottweiler watch”!
http://www.wmo.int/pages/prog/wcp/wcasp/enso_update_latest.html
http://iri.columbia.edu/climate/ENSO/currentinfo/technical.html
http://www.pmel.noaa.gov/tao/jsdisplay/
http://www.cdc.noaa.gov/forecast1/IndoPacific.frcst.html (note the initial projection)
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/index.primjo.html (link 19)
http://www.cdc.noaa.gov/map/images/sst/sst.long.time.io.gif
For the time being, the wind and convective signals are generally in sync. Full disk satellite imagery presents a large region of moist tropical forcing centered ~15N/120-140E, extending from about southern India into the west central Pacific Ocean. Contributing to this rainfall has been some re-invigoration of the regional monsoon systems. Various animations and Hovmoller plots show there has been a coherent eastward shift of the tropical forcing with the circulation for about the last couple of weeks. Prior to that a lot of complicated “high frequency stuff” related to the two “stochastically (GWO) driven MJOs” dominated (see past discussions).
Anomalous twin upper tropospheric anticyclones dominate the west Pacific Ocean centered ~140E, and well defined Rossby wave energy dispersions (RWDs) arc from these features into both hemispheres. For example, keeping in mind seasonal issues, anomalous extratropical ridges are currently present in the higher latitudes near the coasts of both Americas. There is reasonable symmetry between the Northern and Southern Hemispheres, including anomalous zonal mean easterly wind flow propagating poleward well into the extratropics (supporting higher latitude ridges) while westerlies shift into the subtropics. In some sense, a negative phase of a Branstator (2002) circumglobal teleconnection of anomalous subtropical and midlatitude cyclones is present, not seen in quite a while.
Through 5 June with/without the interannual component, there is a good 1 sigma projection of the MJO in octant 6 of WH (2004) phase space, after yet another “loop”. Regardless of the details and the large circuit this past April, there has been a decided tendency for the MJO signal to be shifted toward octants 6-8, approximately the El-Nino attractor. Looping and recent weak projections understood, the same can also be said for the WB (2009) measure of the GWO. This is all in sharp contrast to a year ago. A general superposition of MJO phases 6-7 with GWO phases 8-1 of the snr 250mb psi composite anomaly plots represents the global atmosphere. The GWO phases do a much better job of capturing the role of the extratropical response to tropical forcing, in addition to the AAM transport and topographic dynamics.
Updated through 4 June tropospheric global relative AAM is greater than 1 sigma above the R1 data climatology, the highest since last boreal autumn. Putting aside important details (meteorologically and financially), I continue to find it rather intriguing how “close” the trends of the time series for both global AAM and the DJIA are! Unlike hopefully for the financial markets, is this latest “bull run of AAM” done? I suspect this AAM peak is going to be checked by the oncoming GWO 8-1 transition (correction?).
The anomalous subtropical zonal mean westerly wind flows shifting into the midlatitudes per above are coming down to the surface, leading to a negative global frictional torque of ~10 Hadleys. A negative global mountain torque may soon follow. This may/may not contribute to a large negative global AAM tendency (for reasons); however, the notion of a GWO 8-1 evolution is reasonable for the next 1-2 weeks. Per snr composites, the likely synoptic response for the USA is western and central states troughs as part of an active west-southwest flow storm track across the Plains. In fact, working with the MJO, this situation has been expected for at least the past 3 weeks.
More generally, latest animations and other tools suggest to me the interannual component, eastward shifted from the boreal 2008-09 cold season, may be starting to dominate the weather-climate system. That is, going into summer I think the global circulation may (confidence continues low) persist in a situation shown by a superposition of phases 6-7 for both the GWO and MJO snr 250mb psi composite anomaly plots centered on 15 July, while relatively rapid GWO 8-1 “corrections” occur. This is different than what I was writing 1-2 months ago, thinking at that time a weakening La-Nina base state, as opposed to a shift toward an El-Nino, was probable. Again, the jury is still out whether this trend will amplify going into northern winter.
Please see the composites for weather impacts. Generally, during JJA for the lower 48 states, cooler than normal temperatures may focus on the west coast and northern Plains/Upper Mississippi Valley at times while anomalous heat extends from the southern Plains into portions of the Deep South periodically. There may also be episodes of exceptional MCS activity concentrated on the north central into the central Plains states. Notice that our composites also suggest the continuation of an increased risk for low pressure/cyclonic systems in the region of the Gulf of Mexico and Caribbean. This implies that hybrid systems as opposed to true tropical cyclones may become a bigger issue during at least this summer in those areas and adjacent locations.
Appendix
All presentations from the 24 February 2009 GWO workshop are available via anonymous ftp. If you have not received information on how to retrieve these, let me know. There was excellent attendance at this day-long event, and feedback was strongly positive. We are working VERY HARD to mainstream this effort. The support is very much appreciated!
Links to CPC and PSD ENSO discussions, and a new experimental forecast technique involving a coupled LIM (3rd link below):
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml
http://www.cdc.noaa.gov/people/klaus.wolter/MEI/
http://www.cdc.noaa.gov/forecasts/clim/
The following are links to information about the stratosphere and other nice monitoring tools:
http://ds.data.jma.go.jp/tcc/tcc/products/clisys/index.html
http://code916.gsfc.nasa.gov/Data_services/met/ann_data.html
The following is a link to NCEP model verifications (surf around for lots more):
The following is a link discussing recent global weather and related events:
http://www.wmo.ch/pages/mediacentre/news/index_en.html
These are probabilistic statements. We are working on an opportunity to arise for us soon to allow our dedicated GSDM web page effort to mature, expediting objectively and accountability. This web page effort will hopefully include an objective predictive scheme for the GWO with hindcast measures.
The WB (2007) paper on the GSDM has been published in the February issue of MWR. The first of a two-part paper, where WB formally introduces the GWO (WB (2009)), is now published in the May issue of MWR, and be can be downloaded from the following link:
http://ams.allenpress.com/archive/1520-0493/137/5/pdf/i1520-0493-137-5-1601.pdf
In addition to the subseasonal snr composite anomaly plots, we would like near real-time discussions with “weather maps” to become a routine part of the ESRL/PSD GSDM web site sometime soon. Part-2 of our GWO paper will discuss the latter. We want to emphasize notions such as global-zonal mean-regional scale linkages as well as forcing-response-feedback (with subsequent interactions) relationships. An important purpose is to provide a dynamical weather-climate linkage framework to evaluate the numerical models in a sophisticated manner as part of a complete subseasonal (and any time scale) forecast process, in addition to a climate service for all users. Relying on the numerical models alone is a cookbook, extremely unscientific, and makes Rex the Rottweiler VERY angry! My next complete discussion will not be until the weekend of 26-28 June. Hopefully I will be able to post brief updates in the interim.
Ed Berry
Please keep in mind the ESRL/PSD GSDM web link, below, while reading this discussion. Also, part-1 of a paper detailing the WB (2009) measure of the GWO has been published in MWR. See Appendix to download a copy.
http://www.cdc.noaa.gov/map/clim/gsdm.composites.shtml
The following are links for SST details. Loosely, positive SST anomalies dominate all equatorial ocean basins, with magnitudes ~1-2C. The warmest tropical waters are across the west central and northwest Pacific, as well as portions of the central Indian Ocean, where totals are in excess of 30C. The equatorial basin from ~140E to the west coast of South America is slightly warmer than climatology; however, per latest TAO buoy data not continuously greater than plus 0.5C. Roughly plus 1-3C anomalies were observed at depth along the less than normal sloped equatorial Pacific Ocean thermocline.
The causes for the observed warming across the Nino regions since about last March are complicated and subtle, and require additional careful detailed rigorous scientific analysis. In any case, I again remind the readers that ENSO is a global phenomenon involving all tropical ocean basins as part of the coupled ocean-land-atmosphere dynamical system. For instance, an argument could be made for an equatorial Atlantic Ocean basin-wide warm event during the past few months. A similar situation played a significant role during early 2008, perhaps reinforcing the on-going strong La-Nina at that time. During boreal autumn 2006, an exceptionally warm Indian Ocean contributed not only to shutting down El-Nino, but tilting the weather-climate system toward La-Nina.
As discussed below, the weather-climate system is tipping toward El-Nino. However, serious scientific issues are present (most cannot be addressed here), and the “truth may be told” during the upcoming boreal autumn. Maybe we need a “Rottweiler watch”!
http://www.wmo.int/pages/prog/wcp/wcasp/enso_update_latest.html
http://iri.columbia.edu/climate/ENSO/currentinfo/technical.html
http://www.pmel.noaa.gov/tao/jsdisplay/
http://www.cdc.noaa.gov/forecast1/IndoPacific.frcst.html (note the initial projection)
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/index.primjo.html (link 19)
http://www.cdc.noaa.gov/map/images/sst/sst.long.time.io.gif
For the time being, the wind and convective signals are generally in sync. Full disk satellite imagery presents a large region of moist tropical forcing centered ~15N/120-140E, extending from about southern India into the west central Pacific Ocean. Contributing to this rainfall has been some re-invigoration of the regional monsoon systems. Various animations and Hovmoller plots show there has been a coherent eastward shift of the tropical forcing with the circulation for about the last couple of weeks. Prior to that a lot of complicated “high frequency stuff” related to the two “stochastically (GWO) driven MJOs” dominated (see past discussions).
Anomalous twin upper tropospheric anticyclones dominate the west Pacific Ocean centered ~140E, and well defined Rossby wave energy dispersions (RWDs) arc from these features into both hemispheres. For example, keeping in mind seasonal issues, anomalous extratropical ridges are currently present in the higher latitudes near the coasts of both Americas. There is reasonable symmetry between the Northern and Southern Hemispheres, including anomalous zonal mean easterly wind flow propagating poleward well into the extratropics (supporting higher latitude ridges) while westerlies shift into the subtropics. In some sense, a negative phase of a Branstator (2002) circumglobal teleconnection of anomalous subtropical and midlatitude cyclones is present, not seen in quite a while.
Through 5 June with/without the interannual component, there is a good 1 sigma projection of the MJO in octant 6 of WH (2004) phase space, after yet another “loop”. Regardless of the details and the large circuit this past April, there has been a decided tendency for the MJO signal to be shifted toward octants 6-8, approximately the El-Nino attractor. Looping and recent weak projections understood, the same can also be said for the WB (2009) measure of the GWO. This is all in sharp contrast to a year ago. A general superposition of MJO phases 6-7 with GWO phases 8-1 of the snr 250mb psi composite anomaly plots represents the global atmosphere. The GWO phases do a much better job of capturing the role of the extratropical response to tropical forcing, in addition to the AAM transport and topographic dynamics.
Updated through 4 June tropospheric global relative AAM is greater than 1 sigma above the R1 data climatology, the highest since last boreal autumn. Putting aside important details (meteorologically and financially), I continue to find it rather intriguing how “close” the trends of the time series for both global AAM and the DJIA are! Unlike hopefully for the financial markets, is this latest “bull run of AAM” done? I suspect this AAM peak is going to be checked by the oncoming GWO 8-1 transition (correction?).
The anomalous subtropical zonal mean westerly wind flows shifting into the midlatitudes per above are coming down to the surface, leading to a negative global frictional torque of ~10 Hadleys. A negative global mountain torque may soon follow. This may/may not contribute to a large negative global AAM tendency (for reasons); however, the notion of a GWO 8-1 evolution is reasonable for the next 1-2 weeks. Per snr composites, the likely synoptic response for the USA is western and central states troughs as part of an active west-southwest flow storm track across the Plains. In fact, working with the MJO, this situation has been expected for at least the past 3 weeks.
More generally, latest animations and other tools suggest to me the interannual component, eastward shifted from the boreal 2008-09 cold season, may be starting to dominate the weather-climate system. That is, going into summer I think the global circulation may (confidence continues low) persist in a situation shown by a superposition of phases 6-7 for both the GWO and MJO snr 250mb psi composite anomaly plots centered on 15 July, while relatively rapid GWO 8-1 “corrections” occur. This is different than what I was writing 1-2 months ago, thinking at that time a weakening La-Nina base state, as opposed to a shift toward an El-Nino, was probable. Again, the jury is still out whether this trend will amplify going into northern winter.
Please see the composites for weather impacts. Generally, during JJA for the lower 48 states, cooler than normal temperatures may focus on the west coast and northern Plains/Upper Mississippi Valley at times while anomalous heat extends from the southern Plains into portions of the Deep South periodically. There may also be episodes of exceptional MCS activity concentrated on the north central into the central Plains states. Notice that our composites also suggest the continuation of an increased risk for low pressure/cyclonic systems in the region of the Gulf of Mexico and Caribbean. This implies that hybrid systems as opposed to true tropical cyclones may become a bigger issue during at least this summer in those areas and adjacent locations.
Appendix
All presentations from the 24 February 2009 GWO workshop are available via anonymous ftp. If you have not received information on how to retrieve these, let me know. There was excellent attendance at this day-long event, and feedback was strongly positive. We are working VERY HARD to mainstream this effort. The support is very much appreciated!
Links to CPC and PSD ENSO discussions, and a new experimental forecast technique involving a coupled LIM (3rd link below):
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml
http://www.cdc.noaa.gov/people/klaus.wolter/MEI/
http://www.cdc.noaa.gov/forecasts/clim/
The following are links to information about the stratosphere and other nice monitoring tools:
http://ds.data.jma.go.jp/tcc/tcc/products/clisys/index.html
http://code916.gsfc.nasa.gov/Data_services/met/ann_data.html
The following is a link to NCEP model verifications (surf around for lots more):
http://www.cpc.ncep.noaa.gov/schemm/z500ac_wk2_na.html
The following is a link discussing recent global weather and related events:
http://www.wmo.ch/pages/mediacentre/news/index_en.html
These are probabilistic statements. We are working on an opportunity to arise for us soon to allow our dedicated GSDM web page effort to mature, expediting objectively and accountability. This web page effort will hopefully include an objective predictive scheme for the GWO with hindcast measures.
The WB (2007) paper on the GSDM has been published in the February issue of MWR. The first of a two-part paper, where WB formally introduces the GWO (WB (2009)), is now published in the May issue of MWR, and be can be downloaded from the following link:
http://ams.allenpress.com/archive/1520-0493/137/5/pdf/i1520-0493-137-5-1601.pdf
In addition to the subseasonal snr composite anomaly plots, we would like near real-time discussions with “weather maps” to become a routine part of the ESRL/PSD GSDM web site sometime soon. Part-2 of our GWO paper will discuss the latter. We want to emphasize notions such as global-zonal mean-regional scale linkages as well as forcing-response-feedback (with subsequent interactions) relationships. An important purpose is to provide a dynamical weather-climate linkage framework to evaluate the numerical models in a sophisticated manner as part of a complete subseasonal (and any time scale) forecast process, in addition to a climate service for all users. Relying on the numerical models alone is a cookbook, extremely unscientific, and makes Rex the Rottweiler VERY angry! My next complete discussion will not be until the weekend of 26-28 June. Hopefully I will be able to post brief updates in the interim.
Ed Berry
Friday, May 29, 2009
Postponed
“The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
Please see links in the 23 May discussion for real-time and other information. An apparently rapid GWO 7-8-1 transition is occurring as I type, and zonal mean westerly wind flow anomalies are strong in the subtropical atmospheres (~plus 5-7m/s at ~15N/250mb). Loosely, a superposition of phase 5 for the MJO and phases 8-1 of the GWO 250mb snr psi composite anomaly plots depicts the current global circulation. I think the wind and convective signals getting back into sync. That coupling is probable to occur in the region of the west Pacific Ocean during the next few weeks, projecting in octants 6-8 of MJO/GWO phase space, which is on the El-Nino side. Having the expected difficulties, most models are starting to capture a USA synoptic evolution days 5-10 fairly consistent with the atmosphere heading toward these GWO/MJO phases.
As the subtropical westerly wind flow anomalies propagate poleward, relative to climatology the North Pacific Ocean jet will strengthen. Perhaps as part of a more robust coupled GWO/MJO 7-8-1 transition, at some point this jet is likely to come into the western states while collapsing, leaving a trough in its wake. This could lead to a very active southwest flow storm track focusing on the central/northern Plains/Upper Mississippi Valley regions ~mid June. Weather impacts, as well as all the issues with unpredictable timing and other details, are understood.
As compared to a year ago, I am now convinced that some form of an El-Nino is more probable going into the 2009-10 boreal cold season. However, the issues raised in past discussions remain valid, and we need to diligently and rigorously monitor. Will the tropical convective forcing signal finally "get out of Dodge (La-Nina)" and start hanging out in the west Pacific beginning this summer? That is, in contrast to the past 2 Northern Hemisphere cold seasons, be displaced toward octants 6-8 of WH (2004) phase space? Stay tuned.
Ed Berry
Saturday, May 23, 2009
Be Careful Having False Atmospheric Recovery Hopes
“The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
Please keep in mind the ESRL/PSD GSDM web link, below, while reading this discussion.
http://www.cdc.noaa.gov/map/clim/gsdm.composites.shtml
There is little change to the spatial pattern of global SSTs from a week ago. An earlier trade wind surge across the west central
One of the many ENSO issues includes the magnitude of (any) additional warming across the west
http://www.wmo.int/pages/prog/wcp/wcasp/enso_update_latest.html
http://iri.columbia.edu/climate/ENSO/currentinfo/technical.html
http://www.pmel.noaa.gov/tao/jsdisplay/
http://www.cdc.noaa.gov/forecast1/IndoPacific.frcst.html (note the initial projection)
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/index.primjo.html (link 19)
http://www.cdc.noaa.gov/map/images/sst/sst.long.time.io.gif
There is also no change to the painful complexity, including the harsh reality that now is not a good time to be making weather predictions. Tropical convective forcing remains most intense across the
The combination of the winds and convective signals has led to a resurgent MJO signal in WH (2004) phase space, having ~1.5 sigma projection in octant 7 (through 22 May) and somewhat weaker in octant 6 retaining ENSO. The “loop scenario” offered in my 16 May discussion worked out. Phase 6 of the 250mb MJO snr psi composite anomaly plots best describes tropical and even a few extratropical circulation anomalies. My thought has been for this signal to persist in octants 6-8 for a while. However, there may start to be cancellation between the 2 regions mentioned above. Regardless of the projection, I still do expect a signal of tropical forcing to propagate through the
Tropical-extratropical interactions including the MJO and dynamical processes explained by the WB (2009) measure of the GWO have worked to create a recent respectable positive global wind tendency. Through 21 May global AAM tendency was ~plus 20 Hadleys having large zonal mean contributions from the equatorial and subtropical atmospheres. In fact, latest 250mb weekly means are ~3-4m/s. However, albeit shifted northward, 250mb weekly averaged zonal mean easterly wind flow anomalies are ~10m/s around 45-50N, strongly bearish.
Forced by AAM transports (see plots), those poleward and downward propagating anomalous zonal mean easterly wind flows have increased global and zonal mean mountain and frictional torques during the past 7-10 days. That has also contributed to the recent increase in global westerly wind flow with relative AAM near the R1 data climatology. The point from this untangling of the earth-atmosphere AAM budget is that there is finally a greater than 1 sigma projection of the GWO. Through 21 May the signal was in octant 4-5 of phase space. However, I am not at all confident there will be the nice GWO variations in the near future like observed during this past boreal cold season. There may be a weak orbit towards octants 7-8-1; however, hanging around toward phases 3-5 UFN appears probable (weak La-Nina). Phase 4 of the GWO 250mb snr psi composite anomaly plot reasonably describes the current global atmosphere.
Synoptic responses during the past week or so included the zonal mean storm track shifted anomalously poleward over the Northern Hemisphere, continuation of anomalous extratropical ridges (both hemispheres) with low pressure across the subtropics, and Western Hemisphere subtropical jets. Cutting to the chase, I do expect the latter to shift poleward and bring the Northern Hemisphere storm track southward (including the lower 48 states) over the next 2-3 weeks. During roughly days 10-20 a couple of strong progressive troughs across the western into the central states (north of ~35-40 degrees) is still possible should there be some form of GWO 7-8-1 transition. Maybe there is still some hope for project VORTEX!
I am continuing the notion I have had since mid-April about the average synoptic pattern across the
Appendix
All presentations from the 24 February 2009 GWO workshop are available via anonymous ftp. If you have not received information on how to retrieve these, let me know. There was excellent attendance at this day-long event, and feedback was strongly positive. We are working HARD to mainstream this effort. The support is very much appreciated!
Links to CPC and PSD ENSO discussions, and a new experimental forecast technique involving a coupled LIM (3rd link below):
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml
http://www.cdc.noaa.gov/people/klaus.wolter/MEI/
http://www.cdc.noaa.gov/forecasts/clim/
The following are links to information about the stratosphere and other nice monitoring tools:
http://ds.data.jma.go.jp/tcc/tcc/products/clisys/index.html
http://code916.gsfc.nasa.gov/Data_services/met/ann_data.html (new stratosphere link!)
The following is a link to NCEP model verifications (surf around for lots more):
http://www.cpc.ncep.noaa.gov/schemm/z500ac_wk2_na.html
The following is a link discussing recent global weather and related events:
http://www.wmo.ch/pages/mediacentre/news/index_en.html
These are probabilistic statements. We hope that an opportunity will arise for us (soon) to allow our dedicated web page effort to mature, expediting objectively and accountability. This web page effort will hopefully include an objective predictive scheme for the GWO with hindcasts.
The WB (2007) paper on the GSDM has been published in the February issue of MWR. The first of a two-part paper, where WB formally introduce the GWO (WB (2009)), is (still) awaiting publication in MWR. An early on-line release can be downloaded from the following link:
http://ams.allenpress.com/archive/1520-0493/preprint/2008/pdf/10.1175_2008MWR2686.1.pdf
In addition to the subseasonal snr composite anomaly plots, we would like near real-time discussions with “weather maps” to become a routine part of the ESRL/PSD GSDM web site sometime soon. Part-2 of our GWO paper will discuss the latter. We want to emphasize notions such as global-zonal mean-regional scale linkages as well as forcing-response-feedback (with subsequent interactions) relationships. An important purpose is to provide a dynamical weather-climate linkage framework to evaluate the numerical models in a sophisticated manner as part of a complete subseasonal (and any time scale) forecast process, in addition to a climate service for all users. Relying on the numerical models alone is a cookbook, extremely unscientific, and makes Rex the Rottweiler VERY angry! I will not be able to do a complete discussion until the weekend of 5-7 June. Anyway, I need a break from all this atmospheric madness!
Ed Berry
Saturday, May 16, 2009
When Will El-Viejo go back to Hell???
“The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
Please keep in mind the ESRL/PSD GSDM web link, below, while reading this discussion.
http://www.cdc.noaa.gov/map/clim/gsdm.composites.shtml
Very intense tropical convection has substantially cooled total and anomalous SSTs ~1-2C across the equatorial and North Indian Ocean during the past week. Consistent with the seasonal cycle, the 29-30C isotherm has expanded north into much of the Arabian Sea and Bay of Bengal. Interactions with the extratropics have forced well below normal waters centered on the South China Sea (SCS) and the Philippines. SST anomaly magnitudes across the SCS are ~minus 2C with totals less than 28C, not good news for regional monsoon onset.
Finally, for the first time in at least 2-3 years weak (less than 1C) positive anomalies extend all along the equatorial Pacific Ocean basin from ~140E to the coast of South America, with the 29C isotherm still west of the Dateline on the equator. Latest 5-day averaged TAO buoy data continues to show a less than average thermocline slope, and ~plus 1-3C anomalies at depth as a function of the latter. Is there an ENSO signal here especially given the recent stochastic Hell? Stay tuned, and see links below.
http://www.wmo.int/pages/prog/wcp/wcasp/enso_update_latest.html
http://iri.columbia.edu/climate/ENSO/currentinfo/technical.html
http://www.pmel.noaa.gov/tao/jsdisplay/
http://www.cdc.noaa.gov/forecast1/IndoPacific.frcst.html (note the initial projection)
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/index.primjo.html (link 19)
http://www.cdc.noaa.gov/map/images/sst/sst.long.time.io.gif
There is no change to the weather-climate dynamical system involving mixed complicated signals. This is one reason for the relatively weak projections in both the WH (2004) MJO and WB (2009) GWO phase spaces (keeping in mind the details of these measures). Hence the confidence of any subseasonal and longer predictions must be inherently low.
Tropical convective forcing with the MJO did erupt across the Indian Ocean during the last 5-7 days. However, as I expected given the history of this event (see past discussions), the equatorial signal is propagating east very quickly, ~15-20m/s per my own “back of the envelope” calculations. Supportive of the latter is the projection onto convectively coupled Kelvin waves per coherent modes Hovmollers. Full disk satellite imagery suggests there is some consolidation occurring ~120E north of the equator. For reasons that I will only briefly discuss in the following, I think we may be looking at another behavior of tropical forcing having some similarities to this past March-April.
The atmospheric circulation has been drifting back toward La-Nina during the past couple of weeks ("over bought" atmosphere?), related to the tropical forcing but also involving GWO processes as defined in WB (2009). Total (not relative) AAM has dipped to ~1 sigma below the R1 data climatology (through 14 May), with significant contributions coming from the subtropical atmospheres of both hemispheres dominated by anomalous zonal mean easterly wind flows. In fact, latest weekly averages of these anomalous easterlies at 250mb have been greater than 5m/s. Furthermore, there is once again interhemispheric meridional symmetry of zonal mean zonal wind anomalies favoring strong midlatitude ridges. Even though the global signal is weak (competing terms in the AAM budget), phase 3 of the GWO 250mb psi composite anomaly plots reasonably depicts the current tropospheric circulation.
The astute readers will notice that the distribution of zonal mean relative AAM anomalies is similar to early-mid March, including the equatorial positive signal (cyclonic shear in the subtropics). There are also some similarities with the other terms, including the frictional torque and the transports (see plots). A notable difference to me is that there are no anomalous upper tropospheric subtropical troughs in the region of the Dateline. In fact, I could suggest that these troughs have been displaced into the east Pacific with anticyclones around the Dateline/west Pacific Ocean. In other words, the possibility exists that the ENSO background state in the tropics has been shifted east, perhaps as the result of the past 2 stochastically (GWO) driven MJOs. Interestingly, the Australian jet has been anomalously strong the past 1-2 weeks. Are we seeing a forcing-response-feedback loop, and is this the “hard reality” of ENSO transition, should that be the case?
Regardless, my point is I think it is probable the tropical forcing will get established ~0/140E during the next couple of weeks, then perhaps also continue east as a MJO into the Western Hemisphere. The WH (2004) MJO projection may do a “loop inside the magic 1-sigma circle of death”, then come out and "hang around" in octants 7-8 for a while. Remembering that the WB (2009) measure of the GWO is a global dynamical quantity tied to ENSO, its projection may remain relatively weak until the interannual component of the weather-climate system clarifies.
The global circulation may behave as shown by phases 3-5 of the GWO 250mb psi composite anomaly plots during the next couple of weeks. Weeks 3-4 may see a loose GWO/MJO superposition of phases 6-8. At some point during early-mid June a form of at least GWO 7-8-1 transition may be probable. Until we can show maps having several variables with verifiable probabilities, this forecast information will continue to be confusing to many users.
For the USA, with variations that suggests troughs off/around the west coast and the region of the eastern states, with anomalous ridging west of the Mississippi River the rest of this month. Anomalous low pressure in the Gulf of Mexico including the possibility of a hybrid tropical cyclone (Anna?; SSTs are marginal, refer to official forecasts) combined with the above may give the Plains some respite from severe local storms at times. During the first couple weeks of June strong progressive troughs may again shift into the western and central states poleward of ~35-40N. That may (again, very low confidence) lead to the situation I discussed in my 9 May posting.
Appendix
All presentations from the 24 February 2009 GWO workshop are available via anonymous ftp. If you have not received information on how to retrieve these, let me know. There was excellent attendance at this day-long event, and feedback was strongly positive. We are working to mainstream this effort. The support is very much appreciated!
Links to CPC and PSD ENSO discussions, and a new experimental forecast technique involving a coupled LIM (3rd link below):
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml
http://www.cdc.noaa.gov/people/klaus.wolter/MEI/
http://www.cdc.noaa.gov/forecasts/clim/
The following are links to information about the stratosphere and other nice monitoring tools:
http://ds.data.jma.go.jp/tcc/tcc/products/clisys/index.html
http://code916.gsfc.nasa.gov/Data_services/met/ann_data.html (new stratosphere link!)
The following is a link to NCEP model verifications (surf around for lots more):
http://www.cpc.ncep.noaa.gov/schemm/z500ac_wk2_na.html
The following is a link discussing recent global weather and related events:
http://www.wmo.ch/pages/mediacentre/news/index_en.html
These are probabilistic statements. We hope that an opportunity will arise for us (soon) to allow our dedicated web page effort to mature, expediting objectively and accountability. This web page effort will hopefully include an objective predictive scheme for the GWO with hindcasts.
The WB (2007) paper on the GSDM has been published in the February issue of MWR. The first of a two-part paper, where WB formally introduce the GWO (WB (2009)), is (still) awaiting publication in MWR. An early on-line release can be downloaded from the following link:
http://ams.allenpress.com/archive/1520-0493/preprint/2008/pdf/10.1175_2008MWR2686.1.pdf
In addition to the subseasonal snr composite anomaly plots, we would like near real-time discussions with “weather maps” to become a routine part of the ESRL/PSD GSDM web site sometime soon. Part-2 of our GWO paper will discuss the latter. We want to emphasize notions such as global-zonal mean-regional scale linkages as well as forcing-response-feedback (with subsequent interactions) relationships. An important purpose is to provide a dynamical weather-climate linkage framework to evaluate the numerical models in a sophisticated manner as part of a complete subseasonal (and any time scale) forecast process, in addition to a climate service for all users. Relying on the numerical models alone is a cookbook, extremely unscientific, and makes Rex the Rottweiler VERY angry! I am planning on posting a discussion next weekend, 22-24 May.
Ed Berry
Please keep in mind the ESRL/PSD GSDM web link, below, while reading this discussion.
http://www.cdc.noaa.gov/map/clim/gsdm.composites.shtml
Very intense tropical convection has substantially cooled total and anomalous SSTs ~1-2C across the equatorial and North Indian Ocean during the past week. Consistent with the seasonal cycle, the 29-30C isotherm has expanded north into much of the Arabian Sea and Bay of Bengal. Interactions with the extratropics have forced well below normal waters centered on the South China Sea (SCS) and the Philippines. SST anomaly magnitudes across the SCS are ~minus 2C with totals less than 28C, not good news for regional monsoon onset.
Finally, for the first time in at least 2-3 years weak (less than 1C) positive anomalies extend all along the equatorial Pacific Ocean basin from ~140E to the coast of South America, with the 29C isotherm still west of the Dateline on the equator. Latest 5-day averaged TAO buoy data continues to show a less than average thermocline slope, and ~plus 1-3C anomalies at depth as a function of the latter. Is there an ENSO signal here especially given the recent stochastic Hell? Stay tuned, and see links below.
http://www.wmo.int/pages/prog/wcp/wcasp/enso_update_latest.html
http://iri.columbia.edu/climate/ENSO/currentinfo/technical.html
http://www.pmel.noaa.gov/tao/jsdisplay/
http://www.cdc.noaa.gov/forecast1/IndoPacific.frcst.html (note the initial projection)
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/index.primjo.html (link 19)
http://www.cdc.noaa.gov/map/images/sst/sst.long.time.io.gif
There is no change to the weather-climate dynamical system involving mixed complicated signals. This is one reason for the relatively weak projections in both the WH (2004) MJO and WB (2009) GWO phase spaces (keeping in mind the details of these measures). Hence the confidence of any subseasonal and longer predictions must be inherently low.
Tropical convective forcing with the MJO did erupt across the Indian Ocean during the last 5-7 days. However, as I expected given the history of this event (see past discussions), the equatorial signal is propagating east very quickly, ~15-20m/s per my own “back of the envelope” calculations. Supportive of the latter is the projection onto convectively coupled Kelvin waves per coherent modes Hovmollers. Full disk satellite imagery suggests there is some consolidation occurring ~120E north of the equator. For reasons that I will only briefly discuss in the following, I think we may be looking at another behavior of tropical forcing having some similarities to this past March-April.
The atmospheric circulation has been drifting back toward La-Nina during the past couple of weeks ("over bought" atmosphere?), related to the tropical forcing but also involving GWO processes as defined in WB (2009). Total (not relative) AAM has dipped to ~1 sigma below the R1 data climatology (through 14 May), with significant contributions coming from the subtropical atmospheres of both hemispheres dominated by anomalous zonal mean easterly wind flows. In fact, latest weekly averages of these anomalous easterlies at 250mb have been greater than 5m/s. Furthermore, there is once again interhemispheric meridional symmetry of zonal mean zonal wind anomalies favoring strong midlatitude ridges. Even though the global signal is weak (competing terms in the AAM budget), phase 3 of the GWO 250mb psi composite anomaly plots reasonably depicts the current tropospheric circulation.
The astute readers will notice that the distribution of zonal mean relative AAM anomalies is similar to early-mid March, including the equatorial positive signal (cyclonic shear in the subtropics). There are also some similarities with the other terms, including the frictional torque and the transports (see plots). A notable difference to me is that there are no anomalous upper tropospheric subtropical troughs in the region of the Dateline. In fact, I could suggest that these troughs have been displaced into the east Pacific with anticyclones around the Dateline/west Pacific Ocean. In other words, the possibility exists that the ENSO background state in the tropics has been shifted east, perhaps as the result of the past 2 stochastically (GWO) driven MJOs. Interestingly, the Australian jet has been anomalously strong the past 1-2 weeks. Are we seeing a forcing-response-feedback loop, and is this the “hard reality” of ENSO transition, should that be the case?
Regardless, my point is I think it is probable the tropical forcing will get established ~0/140E during the next couple of weeks, then perhaps also continue east as a MJO into the Western Hemisphere. The WH (2004) MJO projection may do a “loop inside the magic 1-sigma circle of death”, then come out and "hang around" in octants 7-8 for a while. Remembering that the WB (2009) measure of the GWO is a global dynamical quantity tied to ENSO, its projection may remain relatively weak until the interannual component of the weather-climate system clarifies.
The global circulation may behave as shown by phases 3-5 of the GWO 250mb psi composite anomaly plots during the next couple of weeks. Weeks 3-4 may see a loose GWO/MJO superposition of phases 6-8. At some point during early-mid June a form of at least GWO 7-8-1 transition may be probable. Until we can show maps having several variables with verifiable probabilities, this forecast information will continue to be confusing to many users.
For the USA, with variations that suggests troughs off/around the west coast and the region of the eastern states, with anomalous ridging west of the Mississippi River the rest of this month. Anomalous low pressure in the Gulf of Mexico including the possibility of a hybrid tropical cyclone (Anna?; SSTs are marginal, refer to official forecasts) combined with the above may give the Plains some respite from severe local storms at times. During the first couple weeks of June strong progressive troughs may again shift into the western and central states poleward of ~35-40N. That may (again, very low confidence) lead to the situation I discussed in my 9 May posting.
Appendix
All presentations from the 24 February 2009 GWO workshop are available via anonymous ftp. If you have not received information on how to retrieve these, let me know. There was excellent attendance at this day-long event, and feedback was strongly positive. We are working to mainstream this effort. The support is very much appreciated!
Links to CPC and PSD ENSO discussions, and a new experimental forecast technique involving a coupled LIM (3rd link below):
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml
http://www.cdc.noaa.gov/people/klaus.wolter/MEI/
http://www.cdc.noaa.gov/forecasts/clim/
The following are links to information about the stratosphere and other nice monitoring tools:
http://ds.data.jma.go.jp/tcc/tcc/products/clisys/index.html
http://code916.gsfc.nasa.gov/Data_services/met/ann_data.html (new stratosphere link!)
The following is a link to NCEP model verifications (surf around for lots more):
http://www.cpc.ncep.noaa.gov/schemm/z500ac_wk2_na.html
The following is a link discussing recent global weather and related events:
http://www.wmo.ch/pages/mediacentre/news/index_en.html
These are probabilistic statements. We hope that an opportunity will arise for us (soon) to allow our dedicated web page effort to mature, expediting objectively and accountability. This web page effort will hopefully include an objective predictive scheme for the GWO with hindcasts.
The WB (2007) paper on the GSDM has been published in the February issue of MWR. The first of a two-part paper, where WB formally introduce the GWO (WB (2009)), is (still) awaiting publication in MWR. An early on-line release can be downloaded from the following link:
http://ams.allenpress.com/archive/1520-0493/preprint/2008/pdf/10.1175_2008MWR2686.1.pdf
In addition to the subseasonal snr composite anomaly plots, we would like near real-time discussions with “weather maps” to become a routine part of the ESRL/PSD GSDM web site sometime soon. Part-2 of our GWO paper will discuss the latter. We want to emphasize notions such as global-zonal mean-regional scale linkages as well as forcing-response-feedback (with subsequent interactions) relationships. An important purpose is to provide a dynamical weather-climate linkage framework to evaluate the numerical models in a sophisticated manner as part of a complete subseasonal (and any time scale) forecast process, in addition to a climate service for all users. Relying on the numerical models alone is a cookbook, extremely unscientific, and makes Rex the Rottweiler VERY angry! I am planning on posting a discussion next weekend, 22-24 May.
Ed Berry
Saturday, May 09, 2009
Time to Punt our Stochastic Football!!!
“The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
Please keep in mind the ESRL/PSD GSDM web link, below, while reading this discussion.
http://www.cdc.noaa.gov/map/clim/gsdm.composites.shtml
Please see links below for global SST details. The largest expanse of warmest ocean waters globally persist across the equatorial and North Indian Ocean, with totals in excess of 30C and anomalies ~plus 1-2C. As is typical prior to monsoon onset, the 30C SST isotherm has been expanding northward into both the Bay of Bengal and Arabian Sea. There has also been warming of the equatorial west central Pacific Ocean, with totals ~30C and roughly plus 1C anomalies.
In general, slightly positive SST anomalies cover the equatorial Pacific Ocean basin and the slope of the thermocline continues to decrease. Anomalous surface westerly wind flows linked to the ongoing MJO has contributed to this evolution. However, for numerous reasons the ENSO situation is unclear and diligent monitoring must continue. For example, if coherent dynamics start to “heat” the equatorial west Pacific substantially during boreal summer into autumn, then I will get impressed about the possibility of transitioning to a warm event. Regardless, subseasonal activity (GWO/MJO, etc.) will continue, and these will impact North America.
http://www.wmo.int/pages/prog/wcp/wcasp/enso_update_latest.html
http://www.pmel.noaa.gov/tao/jsdisplay/
http://www.cdc.noaa.gov/forecast1/IndoPacific.frcst.html (note the initial projection)
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/index.primjo.html (link 19)
http://www.cdc.noaa.gov/map/images/sst/sst.long.time.io.gif
While the general behavior of our weather-climate situation continues to evolve as expected during the past several weeks, many details have become more complicated than I would like. I do think I see “what is going on”; however, I have typed that before and drawn the wrath of Rex the Rottweiler! Somewhat analogous to rolling a backup bowling ball and relying on that to get a Brooklyn strike, I feel my poor USA assessment a week ago for this upcoming week (western USA trough for a period of days) was partly linked to “playing the MJO card” while not being conscientious enough about its initiation. That is, stochastic GWO dynamics forced its initiation during early-mid March around Indonesia (see past discussions), and that forcing appears to have been “taketh away”. This once again demonstrates to me and should also to the rest of the world that it is important to keep in mind the on-going dynamics, and to know better than “play a signal” regardless of its origins (for example). The latter are serious basic research issues, and there is no way I can do justice about those matters here.
WH (2004) plots updated through 7 May show a greater than 1 sigma projection in octant 7 (west Pacific Ocean) of phase space, having done a loop from a week ago. I was expecting phase 8 then 1. In reality, there is no “loop” in the atmosphere. The trace is an artifact of this empirical technique. Animations of upper tropospheric daily mean vector wind anomalies show a well-defined subtropical wave train (SWT) propagating through the Eastern Hemisphere ~30N forced by interactions with the extratropics (sound familiar?). That has disrupted the MJO signal, and the dynamics do involve the WB (2009) measure of the GWO. For example, tied to the SWT (a zonally oriented RWD typical of a GWO response), anomalous upper tropospheric twin anticyclones are returning to Africa and the western Indian Ocean. In other words, and consistent with the past 2008-09 boreal cold season, I offer that the GWO is again driving the MJO. It is clear to me that the extratropics are currently forcing the tropics. Could this kind of behavior be telling us something about where ENSO is going?
Full disk satellite imagery and other tools show that the global signal of tropical convective forcing is somewhat disorganized. However, cutting to the chase, the African Highlands/Gulf of Guinea regions are active, there is Indian Ocean “sputtering” and a convectively coupled Rossby mode is over western Indonesia. It is probable there will be some form of consolidation over much of the Indian Ocean during the next 1-2 weeks. The west Pacific Ocean (loosely) is also somewhat active, and that region may again become a “wild card” UFN (recall our "nemesis"). During weeks 2-3, enhanced rainfall should further consolidate/shift into the region of Indonesia, and the Eastern Hemisphere monsoon systems may also be active at that time. It is uncertain whether or not a “REAL” MJO will initiate during the next several weeks.
As expected, the GWO projection in phase space is improving located in octants 8-1 through 7 May. It is at this point where I can only “hope” readers can start to put things together (need maps!). Tied to the SWT interacting with the MJO signal, etc., a strong negative global friction-clustered mountain torque index cycle is in progress as I type. The latter is contributing to a decent negative global AAM tendency (~20 Hadleys relative to R1 data climatology) with much of the zonal mean contribution coming from the subtropical atmospheres. Stated another way, several circulation features characteristic of La-Nina are returning. A response is that our strong North Pacific Ocean jet is collapsing, one of the reasons all numerical models have been performing poorly (along with me!) for about the past week. Other behaviors include above average easterly wind flows increasing ~25-30N/35S, zonal mean storm tracks shifting anomalously poleward at least across the Northern Hemisphere, and ridges starting to dominate the extratropics.
Summing up so far, could our “May surprise” be a re-emergence of stationary tropical forcing across the Eastern Hemisphere favoring an eventual return to La-Nina? Or, will we finally see the initiation of decent coherent MJOs that could significantly impact the equatorial Pacific? These are only 2 of an infinite number monitoring issues, and stay tuned. I wanted to make a bit of an effort to get readers to gain an even better appreciation of some of the serious real-time scientific matters that are currently (and always) involved spanning wide time and space scales. This is an example of the next level of weather-climate research/monitoring that is needed, and hopefully that will come to fruition via the ESRL/PSD GSDM web page.
As I typed last week, a GWO/MJO 8-1-2 transition is in progress (WH “loop” understood). The 250mb GWO snr psi composite anomaly plot for phase 1 reasonably depicts the current global circulation. One can also argue a loose superposition of MJO phases 1-2 with GWO phase 1. Per above, with reasonable confidence (I hope!), I offer that a superposition of phases 2-3 for both the GWO and MJO 250mb snr plots for psi and other variables is plausible through at least week-2. For the USA, this suggests our familiar synoptic pattern of progressive western and central states troughs increasing the risk of severe local storms across the central and northern Plains/Upper Mississippi Valley. Possible weather globally can also be inferred from the composites, in addition to the expertise of the international centers. There has been some recent increase of global high impact weather.
Afterward, and I think some readers will understand why, I do have some concern (low confidence) that heading into June, with perhaps many episodes through August, that a synoptic pattern typical of ~GWO phase 4 may occur. That is, per 250mb snr psi composite anomaly plots centered ~15 July, USA west and east coast ridges with troughs across the central states into the Great Lakes at times are possible. While there may be periods of cool and wet for the Plains and Great Lakes states, episodes of intense heat may occur particularly west of the Continental Divide.
Appendix
All presentations from the 24 February 2009 GWO workshop are available via anonymous ftp. If you have not received information on how to retrieve these, let me know. There was excellent attendance at this day-long event, and feedback was strongly positive. We are working to mainstream this effort. The support is very much appreciated!
Links to CPC and PSD ENSO discussions, and a new experimental forecast technique involving a coupled LIM (3rd link below):
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml
http://www.cdc.noaa.gov/people/klaus.wolter/MEI/
http://www.cdc.noaa.gov/forecasts/clim/
The following are links to information about the stratosphere and other nice monitoring tools:
http://ds.data.jma.go.jp/tcc/tcc/products/clisys/index.html
http://code916.gsfc.nasa.gov/Data_services/met/ann_data.html (new stratosphere link!)
The following is a link to NCEP model verifications (surf around for lots more):
http://www.cpc.ncep.noaa.gov/schemm/z500ac_wk2_na.html
The following is a link discussing recent global weather and related events:
http://www.wmo.ch/pages/mediacentre/news/index_en.html
These are probabilistic statements. We hope that an opportunity will arise for us (soon) to allow our dedicated web page effort to mature, expediting objectively and accountability. This web page effort will hopefully include an objective predictive scheme for the GWO with hindcasts.
The WB (2007) paper on the GSDM has been published in the February issue of MWR. The first of a two-part paper, where WB formally introduce the GWO (WB (2009)), is (still) awaiting publication in MWR. An early on-line release can be downloaded from the following link:
http://ams.allenpress.com/archive/1520-0493/preprint/2008/pdf/10.1175_2008MWR2686.1.pdf
In addition to the subseasonal snr composite anomaly plots, we would like near real-time discussions with “weather maps” to become a routine part of the ESRL/PSD GSDM web site sometime soon. Part-2 of our GWO paper will discuss the latter. We want to emphasize notions such as global-zonal mean-regional scale linkages as well as forcing-response-feedback (with subsequent interactions) relationships. An important purpose is to provide a dynamical weather-climate linkage framework to evaluate the numerical models in a sophisticated manner as part of a complete subseasonal (and any time scale) forecast process, in addition to a climate service for all users. Relying on the numerical models alone is a cookbook, extremely unscientific, and makes Rex the Rottweiler VERY angry! I am planning on posting a discussion next weekend, 15-17 May.
Ed Berry
Please keep in mind the ESRL/PSD GSDM web link, below, while reading this discussion.
http://www.cdc.noaa.gov/map/clim/gsdm.composites.shtml
Please see links below for global SST details. The largest expanse of warmest ocean waters globally persist across the equatorial and North Indian Ocean, with totals in excess of 30C and anomalies ~plus 1-2C. As is typical prior to monsoon onset, the 30C SST isotherm has been expanding northward into both the Bay of Bengal and Arabian Sea. There has also been warming of the equatorial west central Pacific Ocean, with totals ~30C and roughly plus 1C anomalies.
In general, slightly positive SST anomalies cover the equatorial Pacific Ocean basin and the slope of the thermocline continues to decrease. Anomalous surface westerly wind flows linked to the ongoing MJO has contributed to this evolution. However, for numerous reasons the ENSO situation is unclear and diligent monitoring must continue. For example, if coherent dynamics start to “heat” the equatorial west Pacific substantially during boreal summer into autumn, then I will get impressed about the possibility of transitioning to a warm event. Regardless, subseasonal activity (GWO/MJO, etc.) will continue, and these will impact North America.
http://www.wmo.int/pages/prog/wcp/wcasp/enso_update_latest.html
http://iri.columbia.edu/climate/ENSO/currentinfo/technical.html
http://www.pmel.noaa.gov/tao/jsdisplay/
http://www.cdc.noaa.gov/forecast1/IndoPacific.frcst.html (note the initial projection)
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/index.primjo.html (link 19)
http://www.cdc.noaa.gov/map/images/sst/sst.long.time.io.gif
While the general behavior of our weather-climate situation continues to evolve as expected during the past several weeks, many details have become more complicated than I would like. I do think I see “what is going on”; however, I have typed that before and drawn the wrath of Rex the Rottweiler! Somewhat analogous to rolling a backup bowling ball and relying on that to get a Brooklyn strike, I feel my poor USA assessment a week ago for this upcoming week (western USA trough for a period of days) was partly linked to “playing the MJO card” while not being conscientious enough about its initiation. That is, stochastic GWO dynamics forced its initiation during early-mid March around Indonesia (see past discussions), and that forcing appears to have been “taketh away”. This once again demonstrates to me and should also to the rest of the world that it is important to keep in mind the on-going dynamics, and to know better than “play a signal” regardless of its origins (for example). The latter are serious basic research issues, and there is no way I can do justice about those matters here.
WH (2004) plots updated through 7 May show a greater than 1 sigma projection in octant 7 (west Pacific Ocean) of phase space, having done a loop from a week ago. I was expecting phase 8 then 1. In reality, there is no “loop” in the atmosphere. The trace is an artifact of this empirical technique. Animations of upper tropospheric daily mean vector wind anomalies show a well-defined subtropical wave train (SWT) propagating through the Eastern Hemisphere ~30N forced by interactions with the extratropics (sound familiar?). That has disrupted the MJO signal, and the dynamics do involve the WB (2009) measure of the GWO. For example, tied to the SWT (a zonally oriented RWD typical of a GWO response), anomalous upper tropospheric twin anticyclones are returning to Africa and the western Indian Ocean. In other words, and consistent with the past 2008-09 boreal cold season, I offer that the GWO is again driving the MJO. It is clear to me that the extratropics are currently forcing the tropics. Could this kind of behavior be telling us something about where ENSO is going?
Full disk satellite imagery and other tools show that the global signal of tropical convective forcing is somewhat disorganized. However, cutting to the chase, the African Highlands/Gulf of Guinea regions are active, there is Indian Ocean “sputtering” and a convectively coupled Rossby mode is over western Indonesia. It is probable there will be some form of consolidation over much of the Indian Ocean during the next 1-2 weeks. The west Pacific Ocean (loosely) is also somewhat active, and that region may again become a “wild card” UFN (recall our "nemesis"). During weeks 2-3, enhanced rainfall should further consolidate/shift into the region of Indonesia, and the Eastern Hemisphere monsoon systems may also be active at that time. It is uncertain whether or not a “REAL” MJO will initiate during the next several weeks.
As expected, the GWO projection in phase space is improving located in octants 8-1 through 7 May. It is at this point where I can only “hope” readers can start to put things together (need maps!). Tied to the SWT interacting with the MJO signal, etc., a strong negative global friction-clustered mountain torque index cycle is in progress as I type. The latter is contributing to a decent negative global AAM tendency (~20 Hadleys relative to R1 data climatology) with much of the zonal mean contribution coming from the subtropical atmospheres. Stated another way, several circulation features characteristic of La-Nina are returning. A response is that our strong North Pacific Ocean jet is collapsing, one of the reasons all numerical models have been performing poorly (along with me!) for about the past week. Other behaviors include above average easterly wind flows increasing ~25-30N/35S, zonal mean storm tracks shifting anomalously poleward at least across the Northern Hemisphere, and ridges starting to dominate the extratropics.
Summing up so far, could our “May surprise” be a re-emergence of stationary tropical forcing across the Eastern Hemisphere favoring an eventual return to La-Nina? Or, will we finally see the initiation of decent coherent MJOs that could significantly impact the equatorial Pacific? These are only 2 of an infinite number monitoring issues, and stay tuned. I wanted to make a bit of an effort to get readers to gain an even better appreciation of some of the serious real-time scientific matters that are currently (and always) involved spanning wide time and space scales. This is an example of the next level of weather-climate research/monitoring that is needed, and hopefully that will come to fruition via the ESRL/PSD GSDM web page.
As I typed last week, a GWO/MJO 8-1-2 transition is in progress (WH “loop” understood). The 250mb GWO snr psi composite anomaly plot for phase 1 reasonably depicts the current global circulation. One can also argue a loose superposition of MJO phases 1-2 with GWO phase 1. Per above, with reasonable confidence (I hope!), I offer that a superposition of phases 2-3 for both the GWO and MJO 250mb snr plots for psi and other variables is plausible through at least week-2. For the USA, this suggests our familiar synoptic pattern of progressive western and central states troughs increasing the risk of severe local storms across the central and northern Plains/Upper Mississippi Valley. Possible weather globally can also be inferred from the composites, in addition to the expertise of the international centers. There has been some recent increase of global high impact weather.
Afterward, and I think some readers will understand why, I do have some concern (low confidence) that heading into June, with perhaps many episodes through August, that a synoptic pattern typical of ~GWO phase 4 may occur. That is, per 250mb snr psi composite anomaly plots centered ~15 July, USA west and east coast ridges with troughs across the central states into the Great Lakes at times are possible. While there may be periods of cool and wet for the Plains and Great Lakes states, episodes of intense heat may occur particularly west of the Continental Divide.
Appendix
All presentations from the 24 February 2009 GWO workshop are available via anonymous ftp. If you have not received information on how to retrieve these, let me know. There was excellent attendance at this day-long event, and feedback was strongly positive. We are working to mainstream this effort. The support is very much appreciated!
Links to CPC and PSD ENSO discussions, and a new experimental forecast technique involving a coupled LIM (3rd link below):
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml
http://www.cdc.noaa.gov/people/klaus.wolter/MEI/
http://www.cdc.noaa.gov/forecasts/clim/
The following are links to information about the stratosphere and other nice monitoring tools:
http://ds.data.jma.go.jp/tcc/tcc/products/clisys/index.html
http://code916.gsfc.nasa.gov/Data_services/met/ann_data.html (new stratosphere link!)
The following is a link to NCEP model verifications (surf around for lots more):
http://www.cpc.ncep.noaa.gov/schemm/z500ac_wk2_na.html
The following is a link discussing recent global weather and related events:
http://www.wmo.ch/pages/mediacentre/news/index_en.html
These are probabilistic statements. We hope that an opportunity will arise for us (soon) to allow our dedicated web page effort to mature, expediting objectively and accountability. This web page effort will hopefully include an objective predictive scheme for the GWO with hindcasts.
The WB (2007) paper on the GSDM has been published in the February issue of MWR. The first of a two-part paper, where WB formally introduce the GWO (WB (2009)), is (still) awaiting publication in MWR. An early on-line release can be downloaded from the following link:
http://ams.allenpress.com/archive/1520-0493/preprint/2008/pdf/10.1175_2008MWR2686.1.pdf
In addition to the subseasonal snr composite anomaly plots, we would like near real-time discussions with “weather maps” to become a routine part of the ESRL/PSD GSDM web site sometime soon. Part-2 of our GWO paper will discuss the latter. We want to emphasize notions such as global-zonal mean-regional scale linkages as well as forcing-response-feedback (with subsequent interactions) relationships. An important purpose is to provide a dynamical weather-climate linkage framework to evaluate the numerical models in a sophisticated manner as part of a complete subseasonal (and any time scale) forecast process, in addition to a climate service for all users. Relying on the numerical models alone is a cookbook, extremely unscientific, and makes Rex the Rottweiler VERY angry! I am planning on posting a discussion next weekend, 15-17 May.
Ed Berry
Saturday, May 02, 2009
Atmospheric MAYhem???
“The views expressed are those of the author and do not necessarily represent those of the National Weather Service.”
Please keep in mind the ESRL/PSD GSDM web link, below, while reading this discussion.
http://www.cdc.noaa.gov/map/clim/gsdm.composites.shtml
Please see links below for global SST details. Partially linked to the seasonal cycle, the warmest SSTs globally are across the equatorial
http://www.wmo.int/pages/prog/wcp/wcasp
http://iri.columbia.edu/climate/ENSO/currentinfo/technical.html
http://www.pmel.noaa.gov/tao/jsdisplay/
http://www.cdc.noaa.gov/forecast1/IndoPacific.frcst.html (note the initial projection)
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/index.primjo.html (link 19)
http://www.cdc.noaa.gov/map/images/sst/sst.long.time.io.gif
Per WH (2004) measure and other tools, the moist convective signal with the ongoing strong MJO is propagating through the
Moist tropical convective forcing has already propagated poleward off the equator across the west central Pacific, increasing the tropical cyclone hazard in the region of the
There continues to be the lack of a significant projection in phase space of the WB (2009) measure of the GWO (since ~1 April). Recall (again) that the GWO is a global dynamical measure of the atmosphere, whereas the WH (2004) empirical MJO measure only considers lower and upper tropospheric winds with OLR anomalies within 15 degrees of the equator. From the global perspective, there has been a weakening La-Nina allowing relative AAM to return to about normal per R1 data climatology. In fact, through 30 April relative tropospheric AAM is slightly above normal. Additionally, AAM tendencies have not been large (for reasons), all combining to give the appearance of a weak GWO signal.
However, zonal mean and regional scale GWO components, as well as individual terms of the earth-atmosphere AAM budget have been anything but weak. These include Eastern Hemisphere subtropical wave trains that excited the 2 (stochastically forced "cheap") MJOs in the region of
Regardless of details, a superposition of phase 7 for both the GWO and MJO snr 250mb psi composite anomaly plots best depicts the current global circulation. For example, there has been subtropical transition of
It is relatively clear to me that a GWO/MJO 7-8-1-2 transition is in progress (a.k.a. a low to high zonal eddy wave number transition response across the Northern Hemisphere extratropics). The corresponding snr 250mb psi composite anomaly plots should depict the expected synoptic behavior of the atmospheric circulation over the next few weeks. The probable response for other variables such as anomalous 2m air temperature across
Enhanced moist tropical convective forcing is likely to return to the
Appendix
All presentations from the 24 February 2009 GWO workshop are available via anonymous ftp. If you have not received information on how to retrieve these, let me know. There was excellent attendance at this day-long event, and feedback was strongly positive. We are working to mainstream this effort. The support is very much appreciated!
Links to CPC and PSD ENSO discussions, and a new experimental forecast technique involving a coupled LIM (3rd link below):
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml
http://www.cdc.noaa.gov/people/klaus.wolter/MEI/
http://www.cdc.noaa.gov/forecasts/clim/
The following are links to information about the stratosphere and other nice monitoring tools:
http://ds.data.jma.go.jp/tcc/tcc/products/clisys/index.html
http://code916.gsfc.nasa.gov/Data_services/met/ann_data.html (new stratosphere link!)
The following is a link to NCEP model verifications (surf around for lots more):
http://www.cpc.ncep.noaa.gov/schemm/z500ac_wk2_na.html
The following is a link discussing recent global weather and related events:
http://www.wmo.ch/pages/mediacentre/news/index_en.html
These are probabilistic statements. We hope that an opportunity will arise for us (soon) to allow our dedicated web page effort to mature, expediting objectively and accountability. This web page effort will hopefully include an objective predictive scheme for the GWO with hindcasts.
The WB (2007) paper on the GSDM has been published in the February issue of MWR. The first of a two-part paper, where WB formally introduce the GWO (WB (2009)), is (still) awaiting publication in MWR. An early on-line release can be downloaded from the following link:
http://ams.allenpress.com/archive/1520-0493/preprint/2008/pdf/10.1175_2008MWR2686.1.pdf
In addition to the subseasonal snr composite anomaly plots, we would like near real-time discussions with “weather maps” to become a routine part of the ESRL/PSD GSDM web site sometime soon. Part-2 of our GWO paper will discuss the latter. We want to emphasize notions such as global-zonal mean-regional scale linkages as well as forcing-response-feedback (with subsequent interactions) relationships. An important purpose is to provide a dynamical weather-climate linkage framework to evaluate the numerical models in a sophisticated manner as part of a complete subseasonal (and any time scale) forecast process, in addition to a climate service for all users. Relying on the numerical models alone is a cookbook, extremely unscientific, and makes Rex the Rottweiler VERY angry! I am planning on posting a discussion next weekend, 8-10 May.
Ed Berry
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