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

6 comments:

Captain Climate said...

It would be terrible not to have at least 1 comment :>)

If the AAM Bear strikes now could it raise the odds of Polar Bears roaming the east in the winter?

We are historic climatic times (in terms of power of observation). Thanks Ed for sharing your insight with us.

Unknown said...

I think an AAM bear would increase the odds of a cold Western winter if it were to persist. It's pretty interesting to see a nice burst of trade winds in progress across a good part of the equatorial Pacific! The subsurface sea temperatures aren't that impressively warm in the Western equatorial Pacific either.

Is Mother Nature going to go for the ENSO upset?

Jim

Captain Climate said...

I will try to do better with writing in a way that avoids my statements being misunderstood.

IF (big IF) an El Nino is going to have any long distance running ability into winter ... Then it would be good for the AAM bear to roam some in the summer and fall so that a higher AAM regime could build a foundation under it (less volatility).

A decent ENSO event is hard to come by in a Cold PDO. Oddly enough the low AAM/Cold PDO years of the 60's averaged colder in the east and featured snowfall consistency. (Source CDC). Probably related for propensity for high latitude blocking (-NAO) but another formula for cooling to march south.

Therefore my statement maybe could have been worded, "If the AAM Bear strikes now, could it raise the odds of an El Nino Bull Run this winter?"

I hope that helps. My own opinion is struggling with an emotional desire for an El Nino but logically there are reasons to believe that the atmosphere might not be ready to maintain some momentum through our winter yet...

Unknown said...

Ok...that makes more sense. The 1960s certainly were interesting. There were some fabulously wicked winters in both the West and the East. That decade also featured some winters that had El Nino with negative PDO. Winters with that combo often favor cold in the NW, but can be quite unpredictable.

The amount of uncertainty concerning next winter at this point is about as high as it gets. I have seen some comments on weather forums about the liklihood of a 2002-03 repeat. In my opinion this is nothing like 2002.

Ed Berry said...

All,

Thank you for the comments and dialog. I just posted a discussion. You are all correct that the ENSO situation is unclear. There are an endless number of scientific issues that I did not/cannot discuss. There had better be additional WWBs and anomalous surface westerlies across the entire equatorial Pacific Ocean is El-Nino is going to amplify. The current resurgence of the trades around the Dateline does not help.

Ed

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