Circulation Hell Discussion Delayed

“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

Because of preparations for the 24 February GWO workshop in Boulder, I am unable to post a “decent” discussion this weekend. I will attempt to do one ~27 February. A “quickie” is given after the SST links.

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 18)

http://www.cdc.noaa.gov/map/images/sst/sst.long.time.gif

The global circulation is well entrenched in a quasi-stationary La-Nina state. In the WB (2009) GWO sense, the current El-Viejo characteristics are similar to this time last year. Global relative AAM is ~2 standard deviations below the R1 data climatology, and zonal mean easterly wind flow anomalies dominate the subtropical atmospheres. Processes involving fast Rossby wave energy dispersions (RWDs), AAM transports and the surface torques are contributing to what may be ~20-30 day variations of the GWO tilted toward the La-Nina attractor in phase space. In fact, the latter have recently caused some disruption to the tropical convective forcing.

Impacts from the recent major SSW onto the troposphere continue to linger. Please remember that the dynamics responsible for the upward propagation of tropospheric wave energy leading to the SSW were linked to poorly understood non-linear feedbacks (multiplicative noise?). These issues go back to the “rogue MJO” event previously discussed. An important point is to be careful over interpreting “causes and effects”, especially when data sets and sample sizes are limited (food for the Rottweiler!). In any case, blocking structures continue across the Northern Hemisphere polar latitudes, and the zonal mean storm track has been shifting south (to ~35N) during the last couple of weeks.

With variations, a loose superposition of phases 3-5 of the snr 250mb psi composite anomaly plots are probable to characterize the global circulation for at least the next several weeks. Tropical convective forcing is also probable to reorganize ~120E as well. Regionally, a continuation of progressive troughs impacting the western USA then shifting into the Plains is likely. Weather ramifications should be understood. Should the storm track continue to shift south against climatology, even portions of the dry southern High Plains may get needed precipitation going into boreal spring. Overall, I think it is fair to offer the weather across the USA lower 48 states spring 2009 will have some similarities to 2008. The latter includes the possibility of an active Plains severe local storm season.

I trust the expertise of the appropriate meteorological agencies to alert the public of additional weather hazards worldwide. There have been some recent notable events.

Appendix

The formal announcement for the 24 February 2009 one-day (~830am-530pm MST) workshop on the WB (2009) GWO has been released through various mailing lists, and is available on the ESRL/PSD GSDM web link.

Links to CPC and PSD ENSO discussions, and a new experimental forecast technique involving a coupled LIM approach (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 awaiting publication in MWR. A pdf of an in press version can be downloaded from the following link:

http://www.cdc.noaa.gov/map/clim/wb08_revised_final.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 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, and unscientific!

I will attempt to post “something” ~27 February 2009.

Ed Berry