2015-16 Winter Pattern Discussion

[Brick Tamland]

I really think things are going to change starting January, and change in a big way. There's no way it can be this warm in December so often and not have some kind of extreme solution on the other end of the spectrum down the road. The rubber band will snap back and in a big way beginning in January.

[nchighcountrywx]

Joe D'Aleo and Bastardi are still confident in their Jan-Feb forecast and I would not bet against them. While they do have a cold bias, it should be pointed out that the CFSV2 has a warm bias

View Monday's Atmospheric Advenger

Joe makes the case for a cold January to work out, we must look for ridging from Asia over the pole to deliver cold into the East

Go 5:47 in on today's video

Image:

[Bob Chill]

EPS is impressive for how fast it changes from this crap pattern to a potential wintery one...still believe we "relax" again for a couple of weeks in mid-Jan though.

 

Last 3 eps runs have trended higher with heights near the pole. GEFS is definitely the most aggressive there but EPS actually trended towards it last night. Tonight's weeklies will be interesting. Especially week 3. The pattern rolling forward d15 is much different than 0z eps run on thursday. 

 

I could see a relax as well but IMO the definition of "relax" does not mean regressing back to what we saw in Dec. 

[packbacker]

Last 3 eps runs have trended higher with heights near the pole. GEFS is definitely the most aggressive there but EPS actually trended towards it last night. Tonight's weeklies will be interesting. Especially week 3. The pattern rolling forward d15 is much different than 0z eps run on thursday. 

 

I could see a relax as well but IMO the definition of "relax" does not mean regressing back to what we saw in Dec. 

 

You would think someone in the east will finally see atleast a moderate event if this pattern develops as advertised.  A "relax" seems inevitable for mid-Jan, but I am probably getting way ahead of myself, let's get this change inside 10 days :-)

 

CFS is usually not far off from reality when looking at the last few runs for it's upcoming monthly forecast, I sure would like to see it get us to atleast neutral temps.

[BristowWx]

Last 3 eps runs have trended higher with heights near the pole. GEFS is definitely the most aggressive there but EPS actually trended towards it last night. Tonight's weeklies will be interesting. Especially week 3. The pattern rolling forward d15 is much different than 0z eps run on thursday. 

 

I could see a relax as well but IMO the definition of "relax" does not mean regressing back to what we saw in Dec. 

well at that point if you include these four weeks and take another two away a lot of winter has been eaten up.  Would be nice if the relax is just average temps.  tough to be optimistic when the next model run can take it all away but we'll keep the candle lit for now

[snowlover91]

GEFS ensemble meteogram for RDU shows quite well the change to a cooler pattern. Nothing extreme but it's much better than seeing spikes to 80F like we will see this week. By the end of the run it has RDU slightly below normal which is what I would want to see from the mean at this range. I do think the pattern we are transitioning to will have staying power and last through late February. There could be a few days of the pattern "reloading" or relaxing at times with transient warmth (just like we see a few shots of cold air in this warm pattern) but they should be short lived. The CFS is a little worrisome with its predictions but it may be overdoing the warmth quite a bit. The CANSIPS had a much different picture for January as did the UK seasonal. Analogs suggest a cooler January also.

[Jon]

View Monday's Atmospheric Advenger

Joe makes the case for a cold January to work out, we must look for ridging from Asia over the pole to deliver cold into the East

Go 5:47 in on today's video

Image:

Yeah, cross polar flow in a non-blocky pattern gets it going.

 

I'm glad most of the board is optimistic about the future...phew, that was getting depressing for a while, almost ran me off!

[Solak]

‏@NWSRaleigh 2m2 minutes ago

NWS Raleigh Weekly Briefing for Central NC, valid December 21-27, 2015 http://youtu.be/wB84Kela_IA?a

[MichaelJ]

Yeah, cross polar flow in a non-blocky pattern gets it going.

 

I'm glad most of the board is optimistic about the future...phew, that was getting depressing for a while, almost ran me off!

Have to agree with you Jon, I was visiting less ad less because of the depressing nature of comments. Hopefully the transformation weatherbell sees will happen, the sooner (meaning 10-15th of Jan), the better

[downeastnc]

Yeah, cross polar flow in a non-blocky pattern gets it going.

 

I'm glad most of the board is optimistic about the future...phew, that was getting depressing for a while, almost ran me off!

 

Looks at the least to go seasonal around Jan 1, figure there will be warm up and cool downs within that pattern but that at least make highs in the 60+ range the exception and not the rule and maybe get some days with sub 40 highs in here.....and who knows it might even snow some.....generally when extreme patterns change the change extremely so lets hope that by mid to late Jan everyone is harping some record breaking cold/snow.....

[Jon]

Looks at the least to go seasonal around Jan 1, figure there will be warm up and cool downs within that pattern but that at least make highs in the 60+ range the exception and not the rule and maybe get some days with sub 40 highs in here.....and who knows it might even snow some.....generally when extreme patterns change the change extremely so lets hope that by mid to late Jan everyone is harping some record breaking cold/snow.....

It should go that way....The composite of all strong Ninos (n=13) has a clear trend into Feb...this year shouldn't be any different but you never know with wx...clear SE trough for Feb though. With all of the evidence I've seen on snows and flips in either Jan or J-F to a -AO/-NAO regime, it will be hard for this winter not to produce at least average snowfall for most in the SE. With recent developments and optomism in the stratopshere, I see those who were harping on the PV strength a little more optomistic for a SSWE which is good to see...the evidence for SSWE's in Strong El Ninos is there as well.

 

[superjames1992]

There seems to be a misconception that we need some tremendous pattern to get snow, but we don't (at least most of us). Mediocre patterns can produce with good timing, as we've seen before. Obviously, we aren't going to get snow in the current pattern we're in, but this pattern will end eventually.

[superjames1992]

Anyways, looks like we won't be dipping below 45 again for the next seven days. Today is seasonal at around 50, but we barely cool off tonight and then the torch ensues tomorrow. Really warm...

[packbacker]

There seems to be a misconception that we need some tremendous pattern to get snow, but we don't (at least most of us). Mediocre patterns can produce with good timing, as we've seen before. Obviously, we aren't going to get snow in the current pattern we're in, but this pattern will end eventually.

 

Yep, if we can get a bowling ball ULL with the pattern being advertised first week of Jan it could produce.   TX/OK about to cash in big time this weekend on one.

[packbacker]

Anyways, looks like we won't be dipping below 45 again for the next seven days. Today is seasonal at around 50, but we barely cool off tonight and then the torch ensues tomorrow. Really warm...

 

GFS doesn't have RDU going below 50F until Jan1st, LOL.  I recall warm winters but nothing like this, these temps are the norms for late Sept/early October.  

[mackerel_sky]

GFS doesn't have RDU going below 50F until Jan1st, LOL. I recall warm winters but nothing like this, these temps are the norms for late Sept/early October.

My normal high is about 53, so I'm good

[packbacker]

My normal high is about 53, so I'm good

Euro is printing out 5-8" of rain over next 4 days for you. Yikes...

[mackerel_sky]

Euro is printing out 5-8" of rain over next 4 days for you. Yikes...

I guarantee nobody gets over 3" !

[jshetley]

I guarantee nobody gets over 3" !

We may not down here, but someone in the mountains will end up with at least 6 inches of rain by 18z Christmas day. The GFS says the I-85 corridor in SC goes over 3 too, so there's  a chance many of us get 3+. We may also end up with a couple of severe storms too before this event is  done. I'd bet that GSP has much of our area under a Flood or Flash Flood watch by at least tomorrow afternoon.

 

Edit: Well the entire FFC county warning area now has a flood watch. The GSP and Raleigh CWA's should have them issued with in 24 hours.

[snowlover91]

We may not down here, but someone in the mountains will end up with at least 6 inches of rain by 18z Christmas day. The GFS says the I-85 corridor in SC goes over 3 too, so there's  a chance many of us get 3+. We may also end up with a couple of severe storms too before this event is  done. I'd bet that GSP has much of our area under a Flood or Flash Flood watch by at least tomorrow afternoon.

And another big rain event could be on the way for December 31-January 1st timeframe. End of Euro shows this and GFS does as well. Could be some flooding issues with all the rain especially in the mountains.

High resolution models indicate a very summertime type style to the rain with scattered storms forming into a line. Wherever this line/band sets up (sounds like snowstorm talk lol) will see more than 4" imo. Euro has consistently placed this along and west of GSP.

[BristowWx]

And another big rain event could be on the way for December 31-January 1st timeframe. End of Euro shows this and GFS does as well. Could be some flooding issues with all the rain especially in the mountains.

High resolution models indicate a very summertime type style to the rain with scattered storms forming into a line. Wherever this line/band sets up (sounds like snowstorm talk lol) will see more than 4" imo. Euro has consistently placed this along and west of GSP.

would be nice if we could mix in some cold air with that..maybe the upper part of the region could get some winter fun..if that H in Midwest would just press a little more...famous last words

[snowlover91]

would be nice if we could mix in some cold air with that..maybe the upper part of the region could get some winter fun..if that H in Midwest would just press a little more...famous last words

It certainly needs to be watched since the pattern is turning colder and several GFS runs have hinted at some snow during this timeframe. I'll want to see the Euro jump on board, it's done very well this year as usual. The high res version actually has about the same verification score as the regular euro so looks like the upgrade didn't mess things up too much while improving the resolution further. January should be fun with multiple threats to track

[NCSNOW]

What sexy looks like; Copied from another board:

 

[pcbjr]

What sexy looks like; Copied from another board:

 

 

 

And if, if, if were to pan out - just in time to return to work .... 

 

 

but it's about the prettiest damn thing I've seen in a while (wife excluded)

[Solak]

Somebody down South is gonna get wet...

 

[deltadog03]

[Jon]

Updated AO disco from Cohen: https://www.aer.com/science-research/climate-weather/arctic-oscillation

 

Summary

• The AO is currently positive and is predicted to trend negative but still remain near neutral.
• The negative AO trend is reflective of the model forecast of initial low pressure/geopotential heights over the North Atlantic side of the Arctic transitioning to more high pressure/geopotential heights.  The models are predicting that the dominant geopotential height rise will be near Scandinavia and the Barents Kara Seas with downstream troughing over East Asia.  This has significant implications for the strength of the polar vortex in January.
• With high pressure strengthening in the Barents Kara Seas, temperatures should turn cold first across Siberia and Central Asia and then eventually across East Asia.  However for now, blocking across northwest Asia will prevent the westward flow of cold air from Siberia into Europe.
• Models are also predicting rising pressure/geopotential heights across western North America, in part in response to some initial perturbing of the polar vortex.  This will likely result in deepening troughing across eastern North America and a cooling trend in temperatures for the Eastern United States.
• The atmosphere is currently experiencing a pulse of energy transfer from the troposphere to the stratosphere that will last the remainder of the week.  The models are predicting a second pulse during the first week of January and we continue to anticipate even further energy transfer.  This will begin to perturb or disturb the polar vortex starting this week, which will likely peak sometime in January.
• High snow cover and low sea ice this past fall favored a weakening of the polar vortex preferentially in January.  The latest weather model forecasts increase our confidence in a weakening or perturbed polar vortex in January (the GFS more so than the ECMWF and this needs to be closely monitored). Following the polar vortex weakening the negative phase of the AO, cold temperatures and potentially an increase in snowstorms is favored across the Northern Hemisphere mid-latitudes including the Eastern United States, Europe and East Asia.

 

Other interesting highlights:

• It is becoming less of a question if the polar vortex weakens and more of a question of when. However with the polar vortex at or near record strength, much of the energy is currently being deflected.  Still enough energy is absorbed to stretch the polar vortex so as to increase cross-polar flow from Siberia into eastern North America and commence a cooling trend.
• Still, If the energy transfer is not sufficiently strong over the next month or so to weaken the polar vortex, then the winter AO is likely to average positive in the mean and a mild weather pattern will dominate the mid-latitude continents for the remainder of the winter.
• We have been discussing the polar vortex model developed here at AER that predicts the strength of the polar vortex one month in advance.  As we discussed in the blog for the past month, the model was predicting the polar vortex to become disturbed the third week of December, which is predicted by the weather models to occur this week.  The polar vortex model also predicts a similar perturbing of the stratospheric polar vortex in the first week of January, which again is now being predicted by the weather models.  And as we have been discussing, the polar vortex model predicts an even bigger event the second week of January.  As we discussed above the predicted atmospheric circulation is nearly optimal for the vertical transfer of energy from the troposphere to the stratosphere that results in weakening of the polar vortex.  Therefore, based on the polar vortex model and the upcoming atmospheric circulation pattern, we are anticipating more upward pulses of WAFz. If the predicted atmospheric circulation pattern is correct and our expectations of more upward pulses of WAFz is correct, this should be sufficient to force a sudden stratospheric warming (SSW) sometime in January. And if our expectations of a weakened polar vortex verify, this will likely favor an increased likelihood of severe winter weather across the continents of the Northern Hemisphere.
• One ongoing inhibiting background factor is the westerly phase of the quasi-biennial oscillation (QBO) that favors a strong vortex over a weak vortex. If this prevails and our expectations of an active period of WAFz is incorrect, then the polar vortex will strengthen and likely the AO will remain positive and the weather pattern mild for the Eastern United States, Northern and Western Europe and East Asia.  However we are becoming increasingly confident in the first solution of a weakening polar vortex and an increasing bias towards a negative AO.

[Jon]

5-day mean of 500mb from the GEFS looks great, EPS coming around...clear +PNA. Despite no blocking, with that tall of a ridge into W Canada, it can only give you a complimentary deep trough over the eastern seaboard (depending on location it can give you a trough in the central US but as of now the placement looks great to me)...That's enough to give us seasonal temps during this time period and a shot at a storm. Seasonal temps in January is enough for snow. We really don't need to wait for a SSWE to have a chance at snow or a mix of wintry precip, with the perturbed vortex and the +PNA we have a shot. With Cohen's update and the models looking the way they are, I can't see how one isn't excited for January...and January isn't even supposed to be "the month" in Strong El Ninos, that's February. It's interesting, though, these are 5 day ensemble mean heights and the +PNA on both models are impressive...we could have a massive ridge develop during this time period. 

 

The 5-day means are as follows for days 11-16 or 10-15...clear pattern change, whether transient or not, the pattern is changing for the first week of January and not mid or late January, although that's when most are calling for the best pattern (Mid-late Jan into Feb), people say it over and over again...don't need a -AO/-NAO combo or even one or the other for a snowfall event in Strong El Ninos, we just need a pattern that supports one, and this looks like it. I'd rather see this look than a deep PV drop over the SE indicating deep cold, as that will likely not produce snow. 

 

GEFS

 

EPS

EPS Control

 

 

[Brick Tamland]

Everything sounds good to me going into January. Maybe get that -AO and +PNA combo. I don't want that deep cold and dry mess. Just give me enough cold for snow.

Looking back it seems Dec 2011 was like this week, too, with the warm weather. Saw on the Facebook feed that I was talking about wearing short sleeves the week of Christmas then, too. Of course, I don't think a warm December means a bad winter. The weather here can turn on a dime from week to week.

[packbacker]

5-day mean of 500mb from the GEFS looks great, EPS coming around...clear +PNA. Despite no blocking, with that tall of a ridge into W Canada, it can only give you a complimentary deep trough over the eastern seaboard (depending on location it can give you a trough in the central US but as of now the placement looks great to me)...That's enough to give us seasonal temps during this time period and a shot at a storm. Seasonal temps in January is enough for snow. We really don't need to wait for a SSWE to have a chance at snow or a mix of wintry precip, with the perturbed vortex and the +PNA we have a shot. With Cohen's update and the models looking the way they are, I can't see how one isn't excited for January...and January isn't even supposed to be "the month" in Strong El Ninos, that's February. It's interesting, though, these are 5 day ensemble mean heights and the +PNA on both models are impressive...we could have a massive ridge develop during this time period. 

 

The 5-day means are as follows for days 11-16 or 10-15...clear pattern change, whether transient or not, the pattern is changing for the first week of January and not mid or late January, although that's when most are calling for the best pattern (Mid-late Jan into Feb), people say it over and over again...don't need a -AO/-NAO combo or even one or the other for a snowfall event in Strong El Ninos, we just need a pattern that supports one, and this looks like it. I'd rather see this look than a deep PV drop over the SE indicating deep cold, as that will likely not produce snow. 

 

GEFS

http://i.imgur.co.png

 

EPS

http://i.imgur.co.png

EPS Control

http://i.imgur.comxTKtJ.png

Although not ready to spike the football for Jan just yet as I do think the core of the "cold/trough" remains in the SW/plains for January but Feb looks more and more promising. This is following the W-QBO/Lsolar Nino analogs to a tee. 83/88/07 all had events for Jan for RDU, mostly small but events are events! Mtns are super due, they will bust through.