Texas Winter 2011-2012...

[iorange55]

A colder pattern for whom is the relevant question. The same questionable model (GFS) that's predicting the monster surface high in western Canada never lowers 500 mb heights at 30 degrees north in Texas beyond 570. It's a flat pattern that pushes the really cold air towards the Great Lakes, not Texas.

For much of the country. I am not looking at the GFS 300+ plus hours out for details. There are a lot of different factors that go into arctic fronts, sometimes it's very shallow air. Again, all I am saying is that a colder pattern for much of the country looks to be in the works. A few pro mets have been hinting at the same thing, so it is not some "insane" thing to say. And, it's not that evil word ****casting.

Cheers.

[austinrunner]

I thought we were talking about Texas weather.

In any event, the forecast 500 mb pattern for this year is far different from 1983 and 1989.

[Ntxw]

The forecast 500 mb pattern for this year is far different from 1983 and 1989.

Maybe so but that was not the point, the emphasis of my post was that it is possible to get cold air even though heights do not show it.

[austinrunner]

Ah, but the 500 mb pattern does always show it, in some form or fashion.

[Brandon8181]

That's really stretching the facts to say that a GFS prediction for early January 2011 had much to do with the cold outbreak one month later.

I really think what is being said is that the models tend to be "trending" colder, which is absolutely correct. Not exactly saying that is going to happen. It is just being said that the models are trending colder..

[austinrunner]

Climatology trends colder, too, through middle to late January.

Where did the monster 1070 mb western Canadian high pressure system go? It's not in the latest GFS model run, which is hardly surprising.

[Portastorm]

David Tolleris (known in some weather forum circle shorthand as "DT") of Wxrisk.com lays out a nice discussion about what he sees for the next month or so and winter finally arriiving for much of the nation.

http://www.wxrisk.com/

[wxman57]

Ah, but the 500 mb pattern does always show it, in some form or fashion.

That would be an incorrect statement. With Arctic outbreaks, the 500mb pattern is often a very poor indicator of surface temps. I have charts in my file cabinet from some big outbreaks in the past. Quite often, the 500 mb pattern would be for a large, deep upper low located well to the W or NW of TX (over Utah in 1993) with strong SW winds aloft across Texas. Of course, the MRF model at that time saw this upper flow and drove the Arctic air northward into OK/KS, but the Arctic air just flowed south into the Gulf, despite the 500mb pattern.

A much better indicator (than the 500mb flow) of potential cold in Texas is the source region of the cold air. If it's not cold to our north, then it's not going to get extremely cold down here.

[wxman57]

It appears that the models have backed away from indicating any chance of snow down here (in TX) next week. Euro, Canadian and GFS are all farther north with the upper low and with higher thickness values more indicative of cold rain than snow. GFS and Euro have surface temps well above freezing (40s-50s) all across TX next Mon-Wed as the upper low passes. Given the airmass in place, that seems more reasonable. I think we'll have to wait for the last week or so of January to have a chance at some much colder air here.

[Rgv20]

FWIW the 0zECMWF Ensemble Control Run is showing a massive Arctic outbreak reaching Texas by mid month. It's forecasting 850mb temperatures close to -20C for North Texas and the -10C isotherm very close to deep South Texas!

[wxman57]

FWIW the 0zECMWF Ensemble Control Run is showing a massive Arctic outbreak reaching Texas by mid month. It's forecasting 850mb temperatures close to -20C for North Texas and the -10C isotherm very close to deep South Texas!

I'm looking at the 00Z Euro ensemble run 850mb temps and that run has temps above normal across TX at 850mb with the exception of a brief period where 850mb temps are 2-5C below normal next Wed-Fri. I see 0C temps forecast for just south of the Red River next Thursday, but no -10 to -20C temps anywhere near Texas in the ensemble run. Closest -20C over the next 360 hrs is in central Canada. Coldest I see in south TX in the ensemble run is +6 to +7C.

Where would one find this "Ensemble Control Run"?

[austinrunner]

A much better indicator (than the 500mb flow) of potential cold in Texas is the source region of the cold air. If it's not cold to our north, then it's not going to get extremely cold down here.

And if it's very cold to our northwest, there's no guarantee it's going to become very cold in Texas. Time and again, very cold air in northwest Canada has never reached Texas because the 500 mb pattern was not conducive for it to migrate here. Contrary to what's often said on this board, cold, dense air does not have a mind of its own.

[Big O]

FWIW the 0zECMWF Ensemble Control Run is showing a massive Arctic outbreak reaching Texas by mid month. It's forecasting 850mb temperatures close to -20C for North Texas and the -10C isotherm very close to deep South Texas!

I'm looking at the 00Z Euro ensemble run 850mb temps and that run has temps above normal across TX at 850mb with the exception of a brief period where 850mb temps are 2-5C below normal next Wed-Fri. I see 0C temps forecast for just south of the Red River next Thursday, but no -10 to -20C temps anywhere near Texas in the ensemble run. Closest -20C over the next 360 hrs is in central Canada. Coldest I see in south TX in the ensemble run is +6 to +7C.

Where would one find this "Ensemble Control Run"?

Accuweather PPV.

[Rgv20]

FWIW the 0zECMWF Ensemble Control Run is showing a massive Arctic outbreak reaching Texas by mid month. It's forecasting 850mb temperatures close to -20C for North Texas and the -10C isotherm very close to deep South Texas!

I'm looking at the 00Z Euro ensemble run 850mb temps and that run has temps above normal across TX at 850mb with the exception of a brief period where 850mb temps are 2-5C below normal next Wed-Fri. I see 0C temps forecast for just south of the Red River next Thursday, but no -10 to -20C temps anywhere near Texas in the ensemble run. Closest -20C over the next 360 hrs is in central Canada. Coldest I see in south TX in the ensemble run is +6 to +7C.

Where would one find this "Ensemble Control Run"?

It's from Accuweather Pro...This is the description that they give it "Control run of the 51 member ECMWF Ensemble Predition System. This is NOT an ensemble mean"

Never the less it looks like it is way over done with the cold air!

[aggiecutter]

I thought we were talking about Texas weather.

In any event, the forecast 500 mb pattern for this year is far different from 1983 and 1989.

Say what????

Ensembles forecasted 500mb anomalies for Mid January 2012 vs December 1983.

https://twitter.com/#!/BigJoeBastardi/s ... 56/photo/1

[wxman57]

The ensemble mean isn't indicating any massive cold outbreak into Texas late next week. The most extreme ensemble member has an 850mb temp in Dallas of -17C on the 16th of January, but the mean at that time is +5C. The operational Euro is cooler than the ensemble mean next Tue-Thu. I don't see anything labeled an ensemble control run in the WSI Energycast model suite we get. What is it?

[wxman57]

It's from Accuweather Pro...This is the description that they give it "Control run of the 51 member ECMWF Ensemble Predition System. This is NOT an ensemble mean"

Never the less it looks like it is way over done with the cold air!

Hmm, it doesn't appear to match any of the ensemble runs or the operational run.

[wxman57]

I thought we were talking about Texas weather.

In any event, the forecast 500 mb pattern for this year is far different from 1983 and 1989.

Say what????

Ensembles forecasted 500mb anomalies for Mid January 2012 vs December 1983.

https://twitter.com/#!/BigJoeBastardi/s ... 56/photo/1

Another thing evident in the comparison is that temps in western Canada are 25-30C warmer now than they were in 1983 before the Arctic air spilled south. You can see the past 850mb temps on the Penn State ewall site:

http://www.meteo.psu.edu/~gadomski/NARR/1983/us1222.php

[Ntxw]

On a side note, since it's such a fun mentioned site and interesting to study here's the direct link to the PSU reanalysis page for all who wishes to see how weather was in the past (at least till 1979)

http://www.meteo.psu.edu/~gadomski/NARR/index.html

[Portastorm]

On a side note, since it's such a fun mentioned site and interesting to study here's the direct link to the PSU reanalysis page for all who wishes to see how weather was in the past (at least till 1979)

http://www.meteo.psu.edu/~gadomski/NARR/index.html

Nice link, Ntxw! Thanks for that. Now when we have these mild periods of winter, we can go back and re-live our favorite Arctic outbreaks or winter storms!