Texas Winter 2014-2015

[Rgv20]

Looks like the 12zUKMET wants to eject the upper level low out of the Desert South West a bit faster than the GFS and ECMWF

12zUKMET 500mb forecast valid for Wednesday Morning.



12zGFS Ensembles 500mb forecast valid for Wednesday Morning...All of the GFS Ensembles agree on a cut off upper level low in the Desert South West but the exact placement of the low is still a bit problematic.

[TheProfessor]

The GEFS is extremely wet too, It has 1.5-2 inches of what would be liquid precip for the Eastern half of Texas, including the DFW area, if that were to verify as all frozen precip it could very well rival last year's ice storm.

[CYCLONE MIKE]

So why are all the models now showing the cold air running into a brick wall and not making it any further south than north Texas then shooting east?

This is a common fault of the GFS and it does it every winter. See Ntxw's note above about why the model does this. Arctic or Polar air always, always, always comes down the leeside of the Rockies into the Southern Plains if the high cell comes into Montana. The only thing that would change that is a screaming Pacific jet stream which we don't have right now.

Portastorm nice try,but until CYCLONE MIKE has snow and ice covering his yard and home he's gonna continue to talk down the upcoming weather event.

Nah. I live in south LA and no matter what long range forecasters, analogs, and models say I don't think we will see anything close this winter to like what we have experienced in the past. Even with our ice episodes we had around here last year. Have to see it to believe, and not talking long range gfs maps

[orangeblood]

We're beginning to enter the NAM strike zone for evaluating the Arctic Air next week....it now has the Arctic HP building to an eye-popping 1059 in Alberta on Sunday evening with sub-zero temps crossing the border into North Dakota. Once that high begins in trek south, there won't be much to stop it particularly in the lower levels!

[TeamPlayersBlue]

Wow that is impressive. That big of a high-pressure will definitely bring extreme cold to be area. How does the snow cover look in the planes? The only comparison I can think of with a high that big is from 1983 or 89 but I don't know what the snow cover was like during those years. On the NWS Twitter page today they talk about the Christmas eve snowstorm for us in Southeast Texas. The upper level low was positioned south of Big Bend in northern Mexico for that event. As long as the upper level low digs in South enough to really get lots of Pacific moisture and feed it into the state I think many of us can be happy with what plays out.

For the Christmas eve event in 2000 for the forecast sounding showed lots of below freezing air throughout the entire column except at around 9000 feet were it was maybe 1°C this was out of Corpus Christi. I'm not sure if the air will be that cold in the upper levels of the atmosphere as with this event

[Ntxw]

JMA too has 1058+. There's amazing agreement of an intense HP cell on all the guidance as they have trended stronger. I'm interested to see if they will show something beyond 1060+ at some point cause thats when you get to the elite tier of HP systems (1962, 1983, 1989 etc) as we get closer and better model resolution.

1983 had 1060mb high sitting in Montana on the 23rd if Im not mistaken.

[TexasF6]

Apologies on the url, shack is not working for me but...WOW

http://contours.hamweather.net/contours ... points.png

[orangeblood]

JMA too has 1058+. There's amazing agreement of an intense HP cell on all the guidance as they have trended stronger. I'm interested to see if they will show something beyond 1060+ at some point cause thats when you get to the elite tier of HP systems (1962, 1983, 1989 etc) as we get closer and better model resolution.

Plus check out how asinine the models look dissipating the HP so quickly once it gets into the southern plains...the Euro takes it from 1050 in Kansas on Wednesday to 1028 in Texas in less than 24 hours. It's unfathomable an Arctic HP that strong would crater so quickly!! Only explanation is it not being able to handle to southwest flow aloft.

Also, the Euro reloads at the end of week with even colder Arctic Air, this time straight out of the North Pole. With snowpack even greater across the plains, that one could have some records accompany it!! I couldn't draw a better synoptic pattern for winter weather across the southern plains the next couple of weeks.

[SouthernMet]

Another great discussion from Cavanaugh..

[TeamPlayersBlue]

JMA too has 1058+. There's amazing agreement of an intense HP cell on all the guidance as they have trended stronger. I'm interested to see if they will show something beyond 1060+ at some point cause thats when you get to the elite tier of HP systems (1962, 1983, 1989 etc) as we get closer and better model resolution.

1983 had 1060mb high sitting in Montana on the 23rd if Im not mistaken.

1064 I think.

[Ntxwx]

Another great discussion from Cavanaugh..

Except for the part when he says all the precip on 2nd might fall as rain..

[aggiecutter]

Since this is in the <5 day time frame, I am becoming a little bit optimistic that something significant might happen next week.

[Ntxw]

Another great discussion from Cavanaugh..

Except for the part when he says all the precip on 2nd might fall as rain..

It was a great discussion. I will refer to modification to orangeblood and srain's post. Another Alaskan ridge is in the offing as height fields remain high over the EPO on most if not all guidance. Euro actually shows snow breaking out as the trof kicks out over Nw, Nc, and Ne Texas. Has a few inches for DFW

[TexasF6]

Since this is in the <5 day time frame, I am becoming a little bit optimistic that something significant might happen next week.

[aggiecutter]

Shreveport AFD is buying into something significant late next week:

".THE MOISTURE BEGINS TO DEEPEN NEW YEAR/S DAY AND THEREAFTER
AHEAD OF SHORTWAVE ENERGY THAT WILL EJECT AHEAD OF A CLOSED LOW OVER
THE DESERT SW/NEAR THE CA COAST...WHICH MAY RESULT IN A CHANCE OF A
WINTRY MIX OVER THE NRN HALF OF THE REGION JUST BEYOND THE EXTENDED
RANGE."

[Portastorm]

Another great discussion from Cavanaugh..

Yes it was quite fascinating. I was particularly interested by his comments about surface temperatures and how the SW cutoff low is supposed to be disconnected by the polar westerlies and how that might impact P-types.

The guy is amazing.

[TheProfessor]

It looks like the 18z PGFS wants to challenge last years Ice storm, it shows about 3 inches of what looks to be sleet for most of the Metroplex and 6 inches around the I-35 corridor and west.

[wxman57]

Wxman57 has posted this before but when you have a trof/storm in the southwest models tend to think it pumps ridging ahead of it and creates a block holding up the very cold air to the north of the boundary and warm to the south. But what they often mistake is low level cold bullies it's way south regardless in spite of with such strong HP and and dense air damming up against the Rockies. They will get colder, much colder a 1030+HP in the state of Texas usually results in subfreezing days for DFW in the past.

The EPO forecasts of late go anywhere from -3 to -5SD. Don't disregard that index, it rarely fails.

That is precisely what we have to watch for in this case. I think that the models are not depicting the shallow Arctic air well across Texas next week. I think that the sub-freezing air will penetrate farther south than the GFS and Euro are indicating. Thus the freezing/frozen precip risk may be farther south than today's model runs indicate.

[Rgv20]

Just read the forecast discussion out of Dallas all I have to say is WOW.......Below is the 12zECMWF Ensemble Means 500mb forecast for New Years Day, Basically the Upper Level Low is giving the Euro and other model fits. The darker the Purple color the more uncertainty within the Ensembles

[TeamPlayersBlue]

Ahhhhh didn't know that with the darker purple, thanks!


Look at that storm the PGFS has. Geez that would be nuts.