Winter 2014-2015 Pattern Discussion Thread I

[Bevo]

what I took away from the map is yellows in the south, the deeper blues up north. To me, that means the coldest air relative to normal stays up north. Oh, and 99% of the south is in the lightest shade of blue.

 

Do you even weather map bro? I'm kidding. Mostly

 

Even if the SE were in the "white", it would be pretty normal for climo. I seriously can't wrap my head around what people were/are expecting. This isn't Wisconsin or Maine. It never will be. Aside from occasional arctic blasts that penetrate farther south than usual, departures of -8/-9 just don't linger here.

[RONALD B]

Quite the shift on the EPS, no longer dumping the cold in the west, it's spilling east now and is cold for us day 11-15. Trough isn't as deep as GEFS but is nice.

it's a big shift an shall trend there the models sw bias is making it look bad

[dan123]

Quite the shift on the EPS, no longer dumping the cold in the west, it's spilling east now and is cold for us day 11-15. Trough isn't as deep as GEFS but is nice.

Was a little surprised to see that to be honest. Tropical forcing does support what the EPS was saying for the past few days. Maybe it flips back at 12z?

[Srain]

The Pacific pattern is responding to convention W of the dateline. Heights rise across the West Coast and ridge into Alaska and Western Canada. The entire North American jet pattern buckles in response digging a deep trough along and E of the Continental Divide. The blocking regime becomes fully established as the Christmas storm moves E. Watch carefully for a big Winter Storm around New Years Eve that could bring wintry weather across Texas and Louisiana.

[RONALD B]

The Pacific pattern is responding to convention W of the dateline. Heights rise across the West Coast and ridge into Alaska and Western Canada. The entire North American jet pattern buckles in response digging a deep trough along and E of the Continental Divide. The blocking regime becomes fully established as the Christmas storm moves E. Watch carefully for a big Winter Storm around New Years Eve that could bring wintry weather across Texas and Louisiana.

I agree on this a neg epo an so far a neg nao is modeled too. Set in around Christmas ! A real active pattern an cold will make most on here happy I think !

[packbacker]

it's a big shift an shall trend there the models sw bias is making it look bad

 

Hopefully it holds at 12z, it was big shift in one model run. 

 

Was a little surprised to see that to be honest. Tropical forcing does support what the EPS was saying for the past few days. Maybe it flips back at 12z?

 

I thought it was right before and then gradually the cold would shift east but we will see.  The +ENSO/+PDO analogs all point to a cold east, eventually it has to come.

[packbacker]

Looking at the GEFS members, very good consensus on the cold and several have apocalyptic type cold....

 

 

[packbacker]

Good read from Mike V.

https://www.americanwx.com/bb/index.php/topic/45140-ending-out-december-with-a-potential-pattern-change/page-10#entry3195730

[griteater]

Was a little surprised to see that to be honest. Tropical forcing does support what the EPS was saying for the past few days. Maybe it flips back at 12z?

 

Yeah that was a big flip on the Euro Ens to the GFS Ens...let's see if it holds.  It's a fine line in terms of exactly where the Alaska ridging sets up and orients itself.

[tnweathernut]

Yeah that was a big flip on the Euro Ens to the GFS Ens...let's see if it holds.  It's a fine line in terms of exactly where the Alaska ridging sets up and orients itself.

Without a doubt.  Too far west and we deal with ridging.  Too far east and we deal with cold and dry.  Even if these things don't set up in the best place initially, these features typically don't stay in one place so slight movements after they set up and especially before they break down can provide an opportunity or two.

[Brick Tamland]

From Facebook. This is a met with the NC Climate Office.

 

 

Central NC Weather

1 hr · Edited · 

Folks, I'm going to be honest, I'm getting a little excited. The models are looking better and better for the period after Christmas extending into the first week of January. I've been talking about this since October, and it appears it's finally about to be game on. I continue to eye the period roughly from 12/27 to 1/1 for our first real threat for winter weather, and some of the guidance is beginning to pick up on this signal. In the included image, it's the storm showing up over SW Montana on Christmas Eve that will dive southeastward and could be a southern U.S. winter storm threat just after Christmas.

 

Why does this one have potential? The models have come into fairly strong agreement that our Christmas storm is going to rapidly deepen into a major upper and surface low pressure system as it moves into the eastern U.S. This one will be rain for Central NC, but it will also be the mechanism that catapults cold air back into the southeastern U.S. as it drives a strong cold front through behind it.

 

Meanwhile, with a west based, negative NAO in place to the north, it will cause this storm to become trapped over southern Canada, which would in-turn force the next storm system to track much further south and also deliver a continual feed of cold air into our region.

 

It's still a long way out (at least 10 days), but this is going to be the first one we have to watch closely I believe.

[SnowNiner]

Good read from Mike V.

https://www.americanwx.com/bb/index.php/topic/45140-ending-out-december-with-a-potential-pattern-change/page-10#entry3195730

 

"We have seen a significant shift in the ECMWF EPS towards the GFS model package solution, in which the model is now more aggressive with building a western U.S. ridge and deepening and eastern U.S. trough as heights build across the North Pole."

 

GEFS for the win.  Another example of it being a bit better at highlighting pattern changes in the long run.  I am concerned a bit though that the 6Z lost the -NAO toward the end of the run. 

[Southern Track]

I like the look of the indeces today.  It seems to point in the direction of the trend towards a colder eastern part of the country.  I like the look of the sustaining +PNA.

 

[BullCityWx]

Sure looked like something brewing down in Texas on the Euro ENS control run at the end. 

[metwannabe]

When did the control run become the go to model??? It gets mentioned everyday. Does anyone have ANY stats that show its track record

[packbacker]

"We have seen a significant shift in the ECMWF EPS towards the GFS model package solution, in which the model is now more aggressive with building a western U.S. ridge and deepening and eastern U.S. trough as heights build across the North Pole."

 

GEFS for the win.  Another example of it being a bit better at highlighting pattern changes in the long run.  I am concerned a bit though that the 6Z lost the -NAO toward the end of the run. 

 

Yeah, but it's still a good look, IMO...reminds of mid Jan 2003, which was active and cold. 

[griteater]

Super Ensemble analogs are chilly....this is for the period Dec 25-31

 

[packbacker]

Yeah, but it's still a good look, IMO...reminds of mid Jan 2003, which was active and cold. 

 

HAH, and look at the latest day 11 analogs that show up, mid Jan 2003...

 

Edit:  A few other hits in the analogs too, including my all time favorite snow event.

[franklin NCwx]

I very interested in the wave coming under the super bomb next week. Definitely won't have to worry about temps or cutting with that one.

[LithiaWx]

6Z GFS depicted some wrap around flurries for N. GA, and E. TN on x-mas eve.  Also some upslope for the mountains on x-mas eve.  Then the day after x-mas it depicted an overrunning snow event for N.GA and N.AL.  JMO.

 

 

[SnowNiner]

HAH, and look at the latest day 11 analogs that show up, mid Jan 2003...

 

Edit:  A few other hits in the analogs too, including my all time favorite snow event.

 

Good call on the 2003 analog.  No missing -NAO on that map....I think everything is moving along nicely.  This time next week we should be able to start tracking real threats. 

[griteater]

Big bomb on the GFS (like Euro)...that would be some vigorous upslope snows on the backside

[packbacker]

Big bomb on the GFS (like Euro)...that would be some vigorous upslope snows on the backside

 

Looks very pleasant for Xmas eve...not sure my luminaries are going to stay lit.

 

Edit:  This will help with the snowpack.

[LithiaWx]

12Z GFS came in a lot warmer for the after xmas storm.  Still shows some upslope for the mountains on xmas eve and some back side flurries from the bomb over the lakes for E.Tn and N.GA.

[SnowNiner]

12Z GFS came in a lot warmer for the after xmas storm.  Still shows some upslope for the mountains on xmas eve and some back side flurries from the bomb over the lakes for E.Tn and N.GA.

 

Yeah saw that.  Boo GFS.  Hopefully it's a blip.  Everything looks to cut on it through the end of the run.  What happened to the blocking?

 

Edit: Ah, looks like it pinches the western ridge off north of alaska and we lose the +PNA/-EPO.  -NAO is in place though.  Seems like it wouldn't be so cold but the storms shouldn't cut.  Strange run. 

[Southern Track]

Yeah the 6z was a lot better. Hopefully just a one blip run.

[packbacker]

Yeah saw that.  Boo GFS.  Hopefully it's a blip.  Everything looks to cut on it through the end of the run.  What happened to the blocking?

 

Edit: Ah, looks like it pinches the western ridge off north of alaska and we lose the +PNA/-EPO.  -NAO is in place though.  Seems like it wouldn't be so cold but the storms shouldn't cut.  Strange run. 

 

 

Yeah the 6z was a lot better. Hopefully just a one blip run.

 

Anything right after Xmas may track to our NW, but I think as we get close to new years into early Jan will be more favorable for us.  Besides, I would rather have a week or so of cold then get a storm.

[Brick Tamland]

Anything right after Xmas may track to our NW, but I think as we get close to new years into early Jan will be more favorable for us.  Besides, I would rather have a week or so of cold then get a storm.

 

Beggers can't be choosers.

[Jon]

It's great to see posters posting about cold agian, really it makes me not feel so bat **** crazy.

 

Out to going neutral at 156hrs for the NAO/AO for the Euro OP...it's not day 10 anymore guys!

 

 

-EPO how low can you go?

 

 

Other than that I don't have much ammo for this morning/noon whatever time it is.

[Southern Track]

Anything right after Xmas may track to our NW, but I think as we get close to new years into early Jan will be more favorable for us. Besides, I would rather have a week or so of cold then get a storm.

Hopefully the -AO/-NAO will be showing it's early effects.