January Pattern and Storm Discussion II

[DaculaWeather]

If this does set up like its forecast to does that open the door for Alberta Clippers? Serious question...haven't seen a strong clipper in a while!

Are you talking the immediate forecast or long term. Strong SSW events will send waves straight down the east side of the Rockies and around the base of the cold, generally in the north and east Gulf, just south of the panhandle of Florida (according to the maps I saw, I'll post those in a while), and then back up the coast. Exactly where is decided when the PV decides where it wants to go. 

[tnweathernut]

Looking at CPC's PNA ensemble this morning shows it going positive about the time the models show it going cold. Also, the AO is going in the tank. The NAO looks relatively neutral. Looks like a cold set-up for the upper south. From what I can tell, if that pattern were to take hold(keeping in mind their have been many false positives this winter), looks like the northern stream energy would dominate most of the time. However, the tendency for the past many months is to transport moisture into the TN Valley - Robert has mentioned this continually. Could(stress could) be a very good set-up for the southern Apps if the cold can establish itself. Normally, I am a -NAO person in terms of looking for winter storms in this area. Right now, I believe the +PNA will have to do the heavy lifting if we are to get snow. If this happens, I think Robert's ideas for winter would be validated. The only thing that bothers me is that somewhere during the middle of last winter, i remember thinking it was going to get very cold. Could very well be a winter where temps are well above normal(we just logged a +20 @ KTRI) and snow goes normal. Looks like a potentially wild pattern if the models verify.

This SSW is nothing like last year. This one appears to be a rare event. Last years was a lot different and what cold did come from it was sent to the other side of the globe...... I have been on the cold train for over a week now for around the 20th going forward, but this actually looks like it could be a lot more than any of us could have imagined just a few short weeks ago!

[DaculaWeather]

EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD

957 AM EST SAT JAN 12 2013

VALID 12Z TUE JAN 15 2013 - 12Z SAT JAN 19 2013

USED THE 00Z/12 ECMWF FOR DAYS 3 THROUGH 5 ACROSS THE CONTIGUOUS

UNITED STATES, AND THE 00Z/12 ECENS MEAN FOR DAYS 6 AND 7 TO

MITIGATE THE UNCERTAINTY IN SYNOPTIC DETAILS INHERENT TO THAT TIME

RANGE. WHERE THE EUROPEAN CENTRE GUIDANCE DIFFERS FROM THE GFS AND

GEFS MEAN--MAINLY WITH THE TIMING OF THE PRIMARY ARCTIC WAVE

CROSSING SOUTHERN CANADA DAY 4--IT IS SUPPORTED BY THE GEM GLOBAL

AND UKMET. THE PATTERN IS SLOWING EVOLVING, WITH A FILLING OF THE

SOUTHWEST TROUGH, A WEAKENING OF THE SOUTHEAST RIDGE, AND A MORE

DOMINANT NORTHERN STREAM ALONG THE CANADIAN BORDER. THE BIGGEST

SLUG OF SYNOPTIC MOISTURE IS EXPECTED TO EJECT ACROSS THE

APPALACHIANS, MID ATLANTIC, AND CAROLINAS EARLY IN THE PERIOD.

SNOW OR SOME ICE IS ANTICIPATED ON THE NORTHERN EDGE OF THIS

PLUME, MOST LIKELY FROM THE CENTRAL APPALACHIANS TO THE NORTHERN

MID ATLANTIC REGION. THE WEST AND NORTH CENTRAL STATES WILL BE

QUITE DRY IN THE NEW FLOW REGIME, WITH THE DEEP SOUTH VULNERABLE

TO ANOTHER WAVE LATER IN THE PERIOD. THE HEART OF THE ARCTIC AIR

IS STILL SLATED TO BE CONTAINED NORTH OF THE CANADIAN BORDER,

THOUGH IT WOULD NOT TAKE MUCH AMPLIFICATION OF ANY GIVEN NORTHERN

STREAM WAVE TO TAP SOME OF THAT AIRMASS INTO THE NORTHERN TIER OF

STATES EAST OF THE CONTINENTAL DIVIDE.

CISCO

[burgertime]

I will say this about the storm next weekend, the GFS keeps slowly trending towards keeping that s/w out west just a little stronger each run and slightly less sheered out. Still not gonna cut it on the 12z. 

[Stovepipe]

Over the next week or two, I believe you'll see some radical changes in the teleconnection indcies as well as the model depiction of what's going to happen. These are extremely strong changes happening in the upper atmosphere and this could very well be a historic SSW that is occurring. The best I can tell, the strongest SSW recorded was in 1977 and we are approaching that strength with this one. Here's a summary of that event:

 

1977_strat_warming.png

 

Fascinating.  I really appreciate your posts on this subject.

[oconeexman]

Are you talking the immediate forecast or long term. Strong SSW events will send waves straight down the east side of the Rockies and around the base of the cold, generally in the north and east Gulf, just south of the panhandle of Florida (according to the maps I saw, I'll post those in a while), and then back up the coast. Exactly where is decided when the PV decides where it wants to go.

Hey Steve I was talking long range over the next 4 weeks. Clippers have always fascinated me for some reason. Thanks for all the start goodies and other stuff you've brought to the site...never knew the how much effect it had on our weather!

[DaculaWeather]

Warmings occur all the time in the winter, but most are very minor and have little to no effect on the weather at the surface, much like the one we had last year. We just happen to have a grand one this year! 

 

One study looked at events from 1955 to 1980 and there were only 11 Major events that covered 400 days. The shortest duration was 20 days and the longest was 50 days. 

[burgertime]

12z brings the mother load of cold air into the heartland in the LR. -20's for highs across North/South Dakota. 

[BullCityWx]

12z brings the mother load of cold air into the heartland in the LR. -20's for highs across North/South Dakota. 

 

and that 240 frame is pretty interesting, especially given how cold the parent source of the high is.

[burgertime]

and that 240 frame is pretty interesting, especially given how cold the parent source of the high is.

 

Yes too bad it's 240 lol. You know that would be an epic storm if it had that look.

[BullCityWx]

And then there's the snow event showing up for Brownsville out into the central gulf..lol.

[burgertime]

GFS keeps most of the south under freezing from 252 - 348

[eyewall]

Not much to look at on the 12z GFS. The cold doesn't look all that robust for the Southeast. I see primarily temps in the normal range (which of course is a 25 degree drop from what we may see today). Looking out to 192 hours there is nothing impressive out there in terms of arctic blasts and/or wintry weather for most.

[burgertime]

And then there's the snow event showing up for Brownsville out into the central gulf..lol.

 

This run has possible snow in NOLA

[WilkesboroDude]

GFS keeps most of the south under freezing from 252 - 348

 

Guessing that will shunt the storm track way south...

[burgertime]

Not much to look at on the 12z GFS. The cold doesn't look all that robust for the Southeast. I see primarily temps in the normal range (which of course is a 25 degree drop from what we may see today). Looking out to 192 hours there is nothing impressive out there in terms of arctic blasts and/or wintry weather for most.

 

Fantasy or not the LR is kind of jaw dropping. 

[BullCityWx]

Not much to look at on the 12z GFS. The cold doesn't look all that robust for the Southeast. I see primarily temps in the normal range (which of course is a 25 degree drop from what we may see today). Looking out to 192 hours there is nothing impressive out there in terms of arctic blasts and/or wintry weather for most.

 

Dude, are you sure we're seeing the same maps?

[packbacker]

Seems we can't get the cold within 10 days, it's not till after day 11 where the cold makes it way to the SE. 

[burgertime]

Dude, are you sure we're seeing the same maps?

 

Well it is pretty boring out to 192. 

[WilkesboroDude]

Dude, are you sure we're seeing the same maps?

 

He is referring out to 192.

[packbacker]

Dude, are you sure we're seeing the same maps?

 

I imagine, like most, that after day 8 on the GFS Op run is fairly worthless.  I am overstating this a bit, but I agree, let's see what the ensembles show.

[burgertime]

Seems we can't get the cold within 10 days, it's not till after day 11 where the cold makes it way to the SE. 

 

The GFS has not had this kind of look in the past two winters like at all. I'm not concerned with that argument, just my opinion. Obviously 12z will not verify but it shows that the models are picking up something big happening. Euro as well keeps hinting that a big arctic outbreak is coming. 

[BullCityWx]

I imagine, like most, that after day 8 on the GFS Op run is fairly worthless.  I am overstating this a bit, but I agree, let's see what the ensembles show.

 

Time will tell but this is 3 runs out of 4 with a major arctic outbreak. All of the other medium range models agree with this arctic outbreak, too.

[BullCityWx]

[BullCityWx]

A little clarification on the 0z Euro from last night. If you look at the extracted data, HKY starts the storm at 39/24 with an 850 temp of -2.The 850's at hickory only warm up to .1 for the next frame. I have no idea how cold the rest of the column is but I think you can certainly see why such a snowy solution showed up overnight.

[packbacker]

Time will tell but this is 3 runs out of 4 with a major arctic outbreak. All of the other medium range models agree with this arctic outbreak, too.

 

Yep, we will see, I do think it will get really cold, but it might not be until February, who knows, after all this is a day 11+ OP run of the GFS run we are talking about.

[eyewall]

I am not discounting an arctic outbreak beyond 192 and that is clearly seen on the op run in fantasy land but I don't put much stock in that when we are talking 10 days out. We will see what the ensambles have to offer for those time frames.

[packbacker]

Well I guess the good news on the GEFS, is that is wetter on day 6-7, but of course its not cold enough for anything wintery, and for a cold biased model that's not good....

 

[BullCityWx]

I am not discounting an arctic outbreak beyond 192 and that is clearly seen on the op run in fantasy land but I don't put much stock in that when we are talking 10 days out. We will see what the ensambles have to offer for those time frames.

 

I figured that's what you meant

[DaculaWeather]

He's been remarkably correct so far: http://www.americanwx.com/bb/index.php/topic/37584-2012-13-winter-medium-range-discussion/page-15#entry1990638