Sudden Stratospheric Warming Coming

[Black Hole]

A great write up found here: https://www.aer.com/.../climate-weather/arctic-oscillation/
Some tidbits:

" It would seem to me with the sister vortex predicted to be displaced over Northwestern Canada, should favor cold temperatures across western North America with mild temperatures upstream over eastern North America. However the Global forecast System (GFS) during and immediately after the PV Disruption is predicting above normal temperatures for western North America and normal to below normal temperatures in the Eastern US. The European Centre for Medium Range Forecast (ECMWF) has been predicting warmer temperatures for the Eastern US. I receive little ECMWF data but from what I can tell the ECMWF has actually shifted colder close to the GFS forecast. Models are challenged by stratosphere-troposphere coupling and I expect volatility in the model forecasts and they could migrate to a cold western North America/warm eastern North America pattern in future model runs.

 

For those who read the blog what I write next might shock you so please take a seat. I see little reason to attribute a general warm west/cold east pattern to the behavior of the stratospheric PV. Instead the cycling of the Madden Julian Oscillation through phases 7 and 8 are consistent with a warm west/cold east pattern and maybe it is the MJO that is most contributing to the GFS predicted pattern for next week. I have also been discussing in the blog that we are approaching the period of the winter when persistence is strongest. And if there is one persistent pattern this winter it has been the warm and dry conditions in the Western US and maybe regardless of remote forcings the persistence is too great to overcome, helped in part by the warm sea surface temperatures off the US West Coast. Again regardless, I expect model forecasts be volatile in the coming weeks.

 

...

 

As I discussed in the impacts section,  I expect the tropospheric response from the significant PV disruption to be a major influence on the tropospheric NH circulation from four to possibly six weeks, which takes us through the end if winter.  The initial impact that I expect is to persist the cold temperatures across northern Eurasia including Europe with possible mild temperatures in eastern North America and colder temperatures in western North America.  Though perhaps MJO forcing and persistence may offset these induced pattern from the stratospheric PV."

 

[Front Ranger]

Hope!

[Guest happ]

Thanks Black Hole. This quote isn't encouraging, however.

 

 "And if there is one persistent pattern this winter it has been the warm and dry conditions in the Western US and maybe regardless of remote forcings the persistence is too great to overcome, helped in part by the warm sea surface temperatures off the US West Coast. Again regardless, I expect model forecasts be volatile in the coming weeks."

[Dan the Weatherman]

The warm and dry conditions in the western U.S. this year has almost been a permanent feature this season it seems.

[Phil]

Thanks Black Hole. This quote isn't encouraging, however.

 

"And if there is one persistent pattern this winter it has been the warm and dry conditions in the Western US and maybe regardless of remote forcings the persistence is too great to overcome, helped in part by the warm sea surface temperatures off the US West Coast. Again regardless, I expect model forecasts be volatile in the coming weeks."

Well, +NAO/warm EPAC/expanded Hadley Cell can almost be thought of as a single system, IMO.

 

Theoretically, this SSW could mark the beginnings of a legitimate shake-up.

[Guest happ]

Well, +NAO/warm EPAC/expanded Hadley Cell can almost be thought of as a single system, IMO.

 

Theoretically, this SSW could mark the beginnings of a legitimate shake-up.

 

So if El Nino # 2 is in the future than SoCal could get rain this summer like 2015!

[Dan the Weatherman]

So if El Nino # 2 is in the future than SoCal could get rain this summer like 2015!

 

I think that is a possibility. I certainly think something just has to give eventually to bring us a chance of rain at some point in the future. I find it impossible that this ridiculously resilient dry pattern can go on forever.

 

Hopefully this SSW event provides the shake up in the pattern that is so desperately needed. This dry pattern that has been consistently (too much in my opinion) setting all sorts of records for warmth mostly in CA really did begin in earnest during the 2012-13 season when the last SSW occurred, although 2011-12 was drier than average as well.

[Phil]

Posted in the other thread, but omg y’all. This follow-up shot is still kinda clown range but it fits the periodicity.

 

That little swirl over North America is what’s left of the PV.

 

[Black Hole]

The event is underway in earnest with big time warming going on. There is also an official split in the PV with the dominant vortex over Canada now at 10 hPa and lowering.  

[Phil]

http://www.atmos.albany.edu/student/hattard/realtime/u_65N_10hpa.png

[Black Hole]

http://www.atmos.albany.edu/student/hattard/realtime/u_65N_10hpa.png

Perhaps minimizing at 3 sigma below normal or more. 

[Phil]

Perhaps minimizing at 3 sigma below normal or more.

It’s pretty astounding to see a wind reversal last 2+ weeks up @ 10mb. As modeled, it will be record breaking in terms of duration, and perhaps intensity as well.

[Black Hole]

4 sigma deviations according to Michael Ventrice at 10 mb. 

[Phil]

Well..this event definitely shook things up! I’m seeing a number of low-cusp frequency changes taking place.

[Dan the Weatherman]

Well..this event definitely shook things up! I’m seeing a number of low-cusp frequency changes taking place.

 

Are any of these changes going to help California in terms of rainfall and snowfall before this season is over? It has been colder in CA this week, but precip has been very light and rather spotty as there has been a lack of moisture given the inland track of recent storms.

[Black Hole]

Are any of these changes going to help California in terms of rainfall and snowfall before this season is over? It has been colder in CA this week, but precip has been very light and rather spotty as there has been a lack of moisture given the inland track of recent storms.

The trough position will shift far enough west this week (and less progressive) so that you should get a couple of systems to produce decent rain even in southern Cal. 

[Black Hole]

The SSW definitely gave the system a kick. The massive west coast ridge is no more. 

[Dan the Weatherman]

The SSW definitely gave the system a kick. The massive west coast ridge is no more. 

 

Maybe the west in general will have a more active late winter and spring period overall, compared with what we have experienced so far this winter. It is definitely looking better for rainfall in Socal this upcoming week, since the ridge has finally been displaced enough.