February Pattern and Storm Discussion

[Brick Tamland]

Just saw this from WxSouth on facebook. Hope we can get that Southern Greenland block back.

 

 

 

Last nights 10 day models showed a feature not yet seen in North America this Winter...a strong Southern Greenland Block. If you've followed weather, you'll recall the last strong blocking in southern Greenland was around the Sandy timeframe and has been mostly absent since. This and some other features is why the Southeast has had such a warm Winter (headed for a top ten warmest again--maybe top ...5). But GFS and ECMWF both are showing a block in Southern Greenland and hold it there. Only time will tell if that occurs, right now I'd say odds are very low it does based on how this Winter has gone, but it could. Each day now the sun is stronger and the average temps are going up, and this time fram would be late February when the averages are climbing rapidly. But *IF* this block occurs in southern Greenland, and works to eastern Canada, combined with that closed upper low in eastern Canada, this would force storms south, as well as cold, so the Eastern US would have to watch for possible Winter storms. So Winter might not be over, just yet, esp. for Va/KY northward. It would take a major block further south to get the colder air (cold enough for snow) in the Deep South at this point. We'll see if the models hold on to this look in future runs or it's just another tease...Getting the block in southern Greenland will be crucial. Without it, expect more of the same, and thunderstorms/severe weather will be paying the Southeast a visit more and more over the next few weeks.

 

[CarolinaCrusher2000]

The 12z would be great if it verified. https://www.facebook.com/TomSkilling?ref=stream

[franklin NCwx]

Fresh of the 12z gfs ensembles

 

 

 

 

[tnweathernut]

Fresh of the 12z gfs ensembles

I am really liking the look of the NAO on the Euro.  Deeply going negative would be a great thing.  It could help salvage this winter for some.  Hope it comes to fruition and glad to see the GFS ensembles backing it up.

[superjames1992]

You know, that February 26th-27th fantasy storm on the GFS would be the nine-year anniversary of 2/26/04.  And it affects the same areas.  It's a sure-fire guarantee!

 

At least some fantasy storms are showing up in the long range.  Maybe we'll get another shot before it's all over.

[burgertime]

Euro is showing a big CAD signal @210 with lots of moisture incoming.  1036 high was parked in Canada with a 1032 sitting in south NY but it flips to a 1032 and head north. Should we call this the Bob storm? 

[burgertime]

By 228 there is a weak CAD signal...fun little run probably has a 1% chance of verifying. 

[tarheelwx]

By 228 there is a weak CAD signal...fun little run probably has a 1% chance of verifying. 

Can't see 228, but at 216 there was a weak lp over s GA which if it moved off the coast, would help to lock in cold surface temps.

TW

 

edit - than at 240 there's a 997 lp off of NJ.  Looked like a miller b with typical ptype issues over the cad areas.  Not showing a big snowstorm on the 12 z run.

TW

[griteater]

Can't see 228, but at 216 there was a weak lp over s GA which if it moved off the coast, would help to lock in cold surface temps.

TW

 

edit - than at 240 there's a 997 lp off of NJ.  Looked like a miller b with typical ptype issues over the cad areas.  Not showing a big snowstorm on the 12 z run.

TW

 

You got it...verbatim on SV, the Euro is freezing rain or freezing rain to rain in NC foothills, W & NW piedmont

[franklin NCwx]

You got it...verbatim on SV, the Euro is freezing rain or freezing rain to rain in NC foothills, W & NW piedmont

It looks like some wierd early miller B. The op euro has one heck of a -nao at this time.

 

 

 

 

 

[tnweathernut]

It's hard to see this making it to Chicago with such a -NAO in place.

[franklin NCwx]

Very stormy pattern showing up with a nice block!

 

 

 

 

 

[FLO]

Very stormy pattern showing up with a nice block!

Trying to learn. What is a block and how do I read that? TIA!

[franklin NCwx]

On the map I posted ( the top left one) look at Greenland. Do you see the lines pointing north towards the pole? Now here is another easier to read map. You can see the red color ( higher heights) over Greenland and eastern Canada. This is known as a block. This will help to keep storms on a more southerly track. This also helps in keeping arctic high pressures locked into eastern Canada over Hudson Bay area or just to the west. This will give us a cold air source. Do you remember Dec 2010 and Jan 2011? That was all from a west based -nao.

 

 

 

 

 

 

 

 

 

[burgertime]

Can't see 228, but at 216 there was a weak lp over s GA which if it moved off the coast, would help to lock in cold surface temps.

TW

 

edit - than at 240 there's a 997 lp off of NJ.  Looked like a miller b with typical ptype issues over the cad areas.  Not showing a big snowstorm on the 12 z run.

TW

 

Sorry I didn't mean to imply a huge snow storm or anything. Just seeing a nice high up there was fun to look at. 

[Cold Rain]

It's hard to see this making it to Chicago with such a -NAO in place.

That ultra big -PNA will kill us unless the block is super strong and remains in place and the 50/50 remains locked in. At 240, you can already see the block shifting east and the 50/50 too. Consequently, the big 1044 HP in perfect position over the Lakes at 192 translates waaaay up into NE Canada by 240.

It's going to be exceptionally hard to pull off a suppressed storm track with the kind of -PNA the Euro is showing.

[franklin NCwx]

I got this from ORH-wxman. This map says it all. Look at the blocking over the Davis Straits

 

 

 

 

 

 

 

 

The most negative PNA December on record was December 2010:

 

 

 

 

 

 

 

 

Here were the temperature anomalies that month:

 

 

[superjames1992]

Isn't late February a little late for a major ZR event, going by climo?  Then again, climo doesn't suggest that early December would be a favorable time for ZR and look what happened in December 2002.

[tarheelwx]

Isn't late February a little late for a major ZR event, going by climo?  Then again, climo doesn't suggest that early December would be a favorable time for ZR and look what happened in December 2002.

Yes.  But not out of the question.

TW

[GaWx]

Isn't late February a little late for a major ZR event, going by climo?  Then again, climo doesn't suggest that early December would be a favorable time for ZR and look what happened in December 2002.

 

 In Atlanta, it is late but not too late. The highest concentration there is in late Jan. There have been a few in early Feb. and NONE 2/10-3/1! However, there have been three in March with one (1971) as late as 3/25! That one was a big snow in NE GA and surely was big snow in W NC/upstate SC.

[superjames1992]

 In Atlanta, it is late but not too late. The highest concentration there is in late Jan. There have been a few in early Feb. and NONE 2/10-3/1! However, there have been three in March with one (1971) as late as 3/25! That one was a big snow in NE GA and surely was big snow in W NC/upstate SC.

 

Interesting find regarding 3/25/71.  Looks like upstate SC got a big one out of that one.  Clemson got 10"!

 

http://www.dnr.sc.gov/climate/sco/ClimateData/cli_table_snow_events_historical.php

 

According to the Gainesville Times, Helen, GA got 11" from that one, too.

 

I'd love to see a late March snowstorm.  It would melt fast, which would suck, but just seeing an extreme weather event like that would be awesome.

 

Of course, personally, I'd like to see the April 1903 (?) event repeat again when Raleigh got 10" of snow in early April.  I'd also love seeing another April 19, 1983 (!!!) when Raleigh got 2" or so of snow (nothing here, though, IIRC).

 

I also read an article once that stated that Raleigh saw non-accumulating flurries in early May 1940, though I really don't know if that's true or not.

[SnowNiner]

That ultra big -PNA will kill us unless the block is super strong and remains in place and the 50/50 remains locked in. At 240, you can already see the block shifting east and the 50/50 too. Consequently, the big 1044 HP in perfect position over the Lakes at 192 translates waaaay up into NE Canada by 240.

It's going to be exceptionally hard to pull off a suppressed storm track with the kind of -PNA the Euro is showing.

 

I agree with this.  The -NAO would have to be REALLY strong to pull off the cold against the -PNA.  Yes, that's what happened in 2010 but I think the -NAO was just that strong.  I do not think it's going to be that strong this year.  I continue to think we stay normal to maybe a bit slightly below.  Not saying there's no more shot, but I'm not expecting anything. 

[GaWx]

 Not only is this weekend continuing to look like either a nonevent or a very minor event for just about all of the SE (outside the mountains at least) wintry precip.-wise, the intensity of the cold air this weekend is not looking as strong as it did on many of those very cold Euro and especially GFS runs that were suggesting high teens at KATL. Of course, that's no surprise at all and was pretty much expected based on the recent past/GFS cold bias. This just increases the chance that the coldest of this winter will be in March at KATL and at other SE US locations, which would go along well with the warm early winter analogs that I've been following.

[RockyKnob]

Interesting find regarding 3/25/71.  Looks like upstate SC got a big one out of that one.  Clemson got 10"!

 

http://www.dnr.sc.gov/climate/sco/ClimateData/cli_table_snow_events_historical.php

 

According to the Gainesville Times, Helen, GA got 11" from that one, too.

 

I'd love to see a late March snowstorm.  It would melt fast, which would suck, but just seeing an extreme weather event like that would be awesome.

 

Of course, personally, I'd like to see the April 1903 (?) event repeat again when Raleigh got 10" of snow in early April.  I'd also love seeing another April 19, 1983 (!!!) when Raleigh got 2" or so of snow (nothing here, though, IIRC).

 

I also read an article once that stated that Raleigh saw non-accumulating flurries in early May 1940, though I really don't know if that's true or not.

I was a young child growing up in Western North Carolina then.  I THINK this is the storm where my mother, grandmother and I left Atlanta and drove through the storm but when we got to Lenoir, there was absolutely nothing but sunshine.  I remember no one believing my mother and grandmother that we'd been in a snowstorm coming  back. 

[Cold Rain]

Not only is this weekend continuing to look like either a nonevent or a very minor event for just about all of the SE (outside the mountains at least) wintry precip.-wise, the intensity of the cold air this weekend is not looking as strong as it did on many of those very cold Euro and especially GFS runs that were suggesting high teens at KATL. Of course, that's no surprise at all and was pretty much expected based on the recent past/GFS cold bias. This just increases the chance that the coldest of this winter will be in March at KATL and at other SE US locations, which would go along well with the warm early winter analogs that I've been following.

You may very well end up being right about the cold March. But I'm curious as to what physical mechanisms you see that will allow that to happen. The -NAO does look to go negative, which is good (will it last the next 6 weeks?), but the Pacific still looks horrible as far as the eye can see and has been the bane of our winter so far. Also, the coldest air appears to be setting up shop on the other side of the pole. If that migrates back over here, which it will probably need to do in order to support a cold end to winter, it will take some time for that to occur.

I'm just wondering what we should be looking for in the modeling that will lead to the cold March. As always, thanks for your contributions and research that you share with us!

[franklin NCwx]

You may very well end up being right about the cold March. But I'm curious as to what physical mechanisms you see that will allow that to happen. The -NAO does look to go negative, which is good (will it last the next 6 weeks?), but the Pacific still looks horrible as far as the eye can see and has been the bane of our winter so far. Also, the coldest air appears to be setting up shop on the other side of the pole. If that migrates back over here, which it will probably need to do in order to support a cold end to winter, it will take some time for that to occur.

I'm just wondering what we should be looking for in the modeling that will lead to the cold March. As always, thanks for your contributions and research that you share with us!

I wonder what the enso was in those years also what the nao values too. Jb said and I remember reading it somewhere too, that the nao has the greatest effect in February and March. The euro ensembles continue to bring a west based -nao into strongly negative territory.

[franklin NCwx]

This weekend's fail forms a nice 50/50.

[GaWx]

You may very well end up being right about the cold March. But I'm curious as to what physical mechanisms you see that will allow that to happen. The -NAO does look to go negative, which is good (will it last the next 6 weeks?), but the Pacific still looks horrible as far as the eye can see and has been the bane of our winter so far. Also, the coldest air appears to be setting up shop on the other side of the pole. If that migrates back over here, which it will probably need to do in order to support a cold end to winter, it will take some time for that to occur.

I'm just wondering what we should be looking for in the modeling that will lead to the cold March. As always, thanks for your contributions and research that you share with us!

 

 You're welcome! My feeling about a good bit higher than average chance at a cold stretch somewhere within late Feb-mid March (which would most likely be most intense during a 1-2 week long period and could easily be the coldest 1-2 week stretch this winter...you don't need anything close to a wall to wall cold March to allow this to happen) is strictly based on past analogs of winters that were also warm much of the winter due to a lack of physical mechanisms allowing for those winters to get cold. The mechanisms obviously changed to allow for cold late. So, the suggestion is that there's a good chance for the current mechanisms to change, just as they did for the analog winters, to allow for the coldest stretch in the SE US to be between late Feb. and mid March.The specifics of those mechanism changes aren't important at this still early stage. I didn't get into that much detail and some of those winters are back far enough such that some of the indices that we follow aren't even known.

 

You need to keep in mind that the very mediocre medium range modeling barely reaches into March right now and it is changing so much from run to run for late Feb.! There are indications that the NAO may finally go negative...we'll see...but that obviously would be a big help if it persists. I've already made several posts that hopefully have convinced you that the forecasted MJO. which is not even that reliable in the first place, and only barely reaches early March, hardly matters as far as cold chances are concerned. I don't care if it is in phases 4-6 through early March. The blizzard of 3/1993, which was accompanied by the coldest of that winter for many, was during the "warm" phase 4. The big snow of early March of 2009 was also during phase 4. The big snows of 3/1983 and 3/1980 were when the MJO was within the COD. So, none of the major March winter storms since 1974 were even within the "favorable phases". I urge you to not read much into the MJO for these purposes. I do think it has been overhyped in recent years for its forecasting help in the SE US. It is only a tool, not a crystal ball. In this case, it isn't even much of a tool.

 

Regarding where the coldest air sets up shop: 1) On what are you basing it not being be on our side of the pole? Keep in mind the weakness of medium range modeling. 2) Even if it does stay on the other side, that doesn't mean the SE US can't have a quite cold period. 

 

Edit: none of the analogs were during El Nino. (3/1983 is not one of my analogs.)

[Cold Rain]

You're welcome! My feeling about a good bit higher than average chance at a cold stretch somewhere within late Feb-mid March (which would most likely be most intense during a 1-2 week long period and could easily be the coldest 1-2 week stretch this winter...you don't need anything close to a wall to wall cold March to allow this to happen) is strictly based on past analogs of winters that were also warm much of the winter due to a lack of physical mechanisms allowing for those winters to get cold. The mechanisms obviously changed to allow for cold late. So, the suggestion is that there's a good chance for the current mechanisms to change, just as they did for the analog winters, to allow for the coldest stretch in the SE US to be between late Feb. and mid March.The specifics of those mechanism changes aren't important at this still early stage. I didn't get into that much detail and some of those winters are back far enough such that some of the indices that we follow aren't even known.

You need to keep in mind that the very mediocre medium range modeling barely reaches into March right now and it is changing so much from run to run for late Feb.! There are indications that the NAO may finally go negative...we'll see...but that obviously would be a big help if it persists. I've already made several posts that hopefully have convinced you that the forecasted MJO. which is not even that reliable in the first place, and only barely reaches early March, hardly matters as far as cold chances are concerned. I don't care if it is in phases 4-6 through early March. The blizzard of 3/1993, which was accompanied by the coldest of that winter for many, was during the "warm" phase 4. The big snow of early March of 2009 was also during phase 4. The big snows of 3/1983 and 3/1980 were when the MJO was within the COD. So, none of the major March winter storms since 1974 were even within the "favorable phases". I urge you to not read much into the MJO for these purposes. I do think it has been overhyped in recent years for its forecasting help in the SE US. It is only a tool, not a crystal ball. In this case, it isn't even much of a tool.

Regarding where the coldest air sets up shop: 1) On what are you basing it not being be on our side of the pole? Keep in mind the weakness of medium range modeling. 2) Even if it does stay on the other side, that doesn't mean the SE US can't have a quite cold period.

Edit: none of the analogs were during El Nino. (3/1983 is not one of my analogs.)

Quick post to say thanks for the response. Got to do the family thing for a while, but I'll get back to you in a couple hours.

[dsaur]

 Not only is this weekend continuing to look like either a nonevent or a very minor event for just about all of the SE (outside the mountains at least) wintry precip.-wise, the intensity of the cold air this weekend is not looking as strong as it did on many of those very cold Euro and especially GFS runs that were suggesting high teens at KATL. Of course, that's no surprise at all and was pretty much expected based on the recent past/GFS cold bias. This just increases the chance that the coldest of this winter will be in March at KATL and at other SE US locations, which would go along well with the warm early winter analogs that I've been following.

I'm counting it if it gets below freezing, and the highs don't get past 41 or 42, lol.  If it does, or beats that then I'll say Goofy got the cold.  But if it weakens anymore, it will just be the same cold nights and warm days I've seen all winter.  I sure hope it comes in colder than it's looking now, so I can keep hope for another.  Just have to break the ice, finally, after 3 years.  It's like coming back from 20 down...that go ahead point can be so hard to get, but once you get it, they tend to pile up, and winning in overtime counts   T