Thursday, February 12, 2009

Update from the Depths of Circulation 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 the following.

This discussion simply extends what was posted on 7 February. There is little overall change to the global SSTs. Roughly minus 1C anomalies continue across all Nino regions, and the warmest SSTs persist around New Guinea with totals ~30C. Please see links below. (note the initial projection) (link 18)

The global ocean-land-atmosphere dynamical system can be summed up as a solidly quasi stationary La-Nina state. While individual components may not be overly robust, working in cooperation the character of the global circulation is not much different than about a year ago. An important exception is that impacts from the SSW continue on the Northern Hemisphere troposphere (discussed in past postings). From a research and speculative point of view, a “stable equilibrium of sorts” involving the dynamical processes explained by the WB (2009) measure of the GWO may be going on.

Tropical convective forcing has drifted slightly farther west to ~0/120E extending from the central Indian Ocean to just east of Australia. Any MJO signal is very weak. The ~1.5 sigma projection in octant 5 of WH (2004) phase space retaining ENSO is an artifact of the computation methodology. In contrast to late December 2008 into January, an eastward propagating signal is unlikely for at least the next 1-2 weeks.

Global relative AAM has crept up to ~1 standard deviation below the R1 data climatology (through 10 February). Contributions have included the surface torques and, indirectly, the eddy transports. The latter does not have a global signal, but can strongly contribute to the zonal mean. In fact, flanked by zonal mean sinks, there has been a well-defined source ~40N for about the last week. A response has been for some intensification of the zonal mean Northern Hemisphere polar jet, with a slight southward shift. However, there is little change to the pattern of anomalous midlatitude ridges characteristic of the positive phase of a Branstator (2002) circumglobal teleconnection (with strong interhemispheric symmetry) as discussed in the 7 February posting.

The WB (2009) GWO is currently doing a slow orbit shifted toward the La-Nina attractor in phase space. I do think global AAM tendency will become negative allowing the circuit to continue. A loose superposition of GWO phase 3 and MJO phases 4-5 of the snr 250mb psi and OLRA composite anomaly plots still best characterizes the global circulation and tropical rainfall. This includes the central North Pacific Ocean ridge with downstream progressive troughs impacting the west coast into the lower 48 states. I think this situation will continue for at least the next 2 weeks, and perhaps well into boreal spring. With synoptic variations (ex., low amplitude ridge across the central states at times), weather ramifications should be well understood. I trust the expertise of the appropriate meteorological agencies to alert the public of additional weather hazards worldwide (there has been an increase).


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. If you have not already done so, please send an email confirmation of your attendance asap.

Links to CPC and PSD ENSO discussions:

The following are links to information about the stratosphere and other nice monitoring tools: (new stratosphere link!)

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:

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:

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!

Discussions continue to be very difficult to publish given shift work and preparations for the GWO workshop. I will attempt to post “something” ~20-21 February 2009.

Ed Berry


JordanWeather Forecasters Team said...

Hi Ed,
Its Moh'd Al-Shaker again from the Middle East (Jordan).

Last week, we had a very strong low pressure system, exactly on Tuesday/Wednesday 10-11/2/2009.

This low pressure track was northern African Coast (rare for this time), so the warm front brought temperatures about 25c in Amman (14c Above the daily average), and in the second day we had a very severe weather, with drastic and dramatic drop on the temperatures, and it was in Amman just 10c. Very heavy rain, with strong thunderstorms, large hail reported mostly everywhere in Jordan, and Snow fell above 1200meters (we have mountains in Jordan above 1400meters, while Amman average heights is 850meters AMSL).

Also, as this low pressure was very deep, strong gale force winds blow before the entering of the cold front causing wild dust storms in Jordanian deserts, and later on these dust stroms gatherd to be a large one, hitting northern Saudi Arabia and all the Gulf areas with visibility down to 0 in those areas.

NWP is pointing something very nice next week especailly on next Friday, and I think it's something could be major, I'm still monitoring, and I'll keep you update. But, still our (Middle East) problem for this year causing the drought is the "inactive" Atlantic, because if any acitivty will establish in the Atlantic the high pressure over Western Europe will get stronger pushing the wave towards eastern Europe and also the Middle East.
I have a question, do you think that the atlantic could carry some activtiy in the next weeks, and what is your thoughts about the european regions?

I will be your reporter here always :)
Thanks Ed,
Yours Moh'd Al-Shaker

Ed Berry said...

Hello Moh'd

Thank you for staying in touch including the update on your weather. I think the dust storm your referred to was mentioned in the latest WMO news including Doha, Qatar (?). The satellite imagery has shown some impressive storms tracking across the Mediterranean Sea for at least the past several days.

The recent SSW continues to impact the troposphere, constructively interfering with La-Nina (in this case). I think the global circulation is in a relatively coupled quasi-stationary La-Nina base state.

Unlike a year ago, the eastern tropical Atlantic SSTs are not excitingly warm (totals generally <29C). Hence I would not expect a lot of tropical forcing there (very intense in that region a year ago; Atlantic El-Nino?).

The gist is you folks should see more of the same the next couple of weeks, keeping in mind the unpredictable synoptic details. A full latitude ridge may wobble ~20W with the downstream trough axis ~20E. Storms should dig into the Mediterranean then head east toward your region. Tied to La-Nina, the most robust trough-ridge-trough pattern is likely to become established from Asia to North America, with a weaker response across the Atlantic Ocean sector. It would not surprise me to see the storm track remain anomalously south in your region going into March.

Take care,

Greg said...

Just wanted to say thank you for the continued updates. I know you take time out of your busy schedule to keep some of us up to date with the state of our atmospheric patterns.

Ed Berry said...

Hi Greg,

Thank you for the comment! I hope at some point our information can be shared much more efficiently.