Texas Winter 2014-2015

[Rgv20]

12zECMWF Ensemble Mean progged 500mb patter as we head to the new year still unchanged from previous runs.

December 29 Monday Morning


December 31 Wednesday Morning

[Portastorm]

The Portastorm Weather Center happily wishes all of you a Happy Winter Solstice! Special wintry/frosty thoughts for wxman57.

[JDawg512]

Happy Winter Solstice to all!!!

[Ntxw]

GFS now has low 40s at the surface, very cold aloft below 0 to -2C at 850mb and thickness at or below 540 for Tuesday in W/NW, NC, and NE Texas Tuesday into Weds. Very strong deepening storm over our heads. I wouldn't be shocked if this became a changeable, difficult forecast the next 48-72 hours.Soundings from the GFS dendritic growth is very good in a deep layer, the caveat is the model has the air near the surface above freezing.

[aggiecutter]

GFS now has low 40s at the surface, very cold aloft below 0 to -2C at 850mb and thickness at or below 540 for Tuesday in W/NW, NC, and NE Texas Tuesday into Weds. Very strong deepening storm over our heads. I wouldn't be shocked if this became a changeable, difficult forecast the next 48-72 hours.Soundings from the GFS dendritic growth is very good in a deep layer, the caveat is the model has the air near the surface above freezing.

18z GFS says snow for the Dallas-Ft. Worth metroplex on Tuesday:

[SouthernMet]

Yup for the 1st time now gfs had caught on, & sref trended colder. (nam still has sfc temps above freezing fwiw)

dendrict growth zone looks solid on the sref too.

[Ntxwx]

Im not too familiar with TwisterData.. The 00z GFS shows snow accumulations again for DFW but the NAM & others don't? I thought it was suppose to stay in the upper 30's...

[weatherdude1108]

HAPPY WINTER SOLSTICE everyone!!

[Ralph's Weather]

Tuesday could be a lot like the mid Nov snow with a light band moving from between Midland and the Panhandle east across North Texas and into Northeast Texas. The models are finally picking up on it, but it is very doubtful they have this small system figured out yet. It has been over a month since our last chance for snow so I am sure we will all be watching this closely.

[Ntxwx]

Tuesday could be a lot like the mid Nov snow with a light band moving from between Midland and the Panhandle east across North Texas and into Northeast Texas. The models are finally picking up on it, but it is very doubtful they have this small system figured out yet. It has been over a month since our last chance for snow so I am sure we will all be watching this closely.

How is the GFS showing snow accumulations with surface temps in the 40's?

[Ralph's Weather]

How is the GFS showing snow accumulations with surface temps in the 40's?

Not sure will have to study it in the morning, I did see sub freezing temps at 850mb on there.

[TeamPlayersBlue]

Well all the models certainly lost the cold air. Interesting. Also, i think a while back the models saw this HUGE cutoff low that the GFS and Euro are seeing. Kind of interesting.

[Ntxwx]

Can I get a Pro met, or someone knowledgeable that can explain to me why this won't happen tomorrow? http://www.twisterdata.com/index.php?pr ... hive=false

[Ralph's Weather]

Can I get a Pro met, or someone knowledgeable that can explain to me why this won't happen tomorrow? http://www.twisterdata.com/index.php?pr ... hive=false

Def not a pro, but this is a very intriguing situation. All models show 850mb temps around or below freezing, but they show surface temps around 40. The models vary on precip qpf with the GFS being the heaviest so that could be why it is showing snow. Seems like a situation where if the precip comes down heavy we could get wet snow flakes and otherwise just light rain.

[srainhoutx]

Can I get a Pro met, or someone knowledgeable that can explain to me why this won't happen tomorrow? http://www.twisterdata.com/index.php?pr ... hive=false

The surface column is projected to be too dry up to about 5000 feet. Now that said it is possible some light flurries could make it to the surface. Each model run has trended stronger with the shortwave in the Southern Rockies and as seen in the Northern and Central Mountains of New Mexico, Winter Weather Advisories were changed to Winter Storm Warnings and the Panhandles of Texas/ Oklahoma have issued Special Weather Statements regarding some potential for light snow.

[Portastorm]

Can I get a Pro met, or someone knowledgeable that can explain to me why this won't happen tomorrow? http://www.twisterdata.com/index.php?pr ... hive=false

Def not a pro, but this is a very intriguing situation. All models show 850mb temps around or below freezing, but they show surface temps around 40. The models vary on precip qpf with the GFS being the heaviest so that could be why it is showing snow. Seems like a situation where if the precip comes down heavy we could get wet snow flakes and otherwise just light rain.

As stated in the morning AFD out of DFW, the middle and lower levels of your airmass will be too dry to support the nutty amounts the 6z GFS is showing. It also looks like the 6z run is progging a strong vortmax down the back side of the trough when the air column (if it was mostly or entirely saturated) would support snow temperature wise. While it's exciting to see, I wouldn't count on it if I were you.

Now ... tonight ... if short range models like the SREF and the HRRR are showing this, that's a different story.

[Ralph's Weather]

This is when mets make their money. The most likely scenario is 40s and light rain, but then again leading up to this forecasts have been calling for 50s. If the lower levels can moisten and this storm is as strong as some models are indicating we could see mid 30s and snow with a forecast of 50s and rain.

[wxman57]

How is the GFS showing snow accumulations with surface temps in the 40's?

The answer is that the algorithm in the GFS for differentiating rain from snow accumulations is probably not capturing this setup properly. The 6Z GFS (same run pointed out above with 1" snow) is forecasting temps in the mid to upper 40s tomorrow at the surface and temps aloft (850mb / 5000ft) approaching freezing as the precip ends.



But look at the plot of the projected upper-air pattern during the precip (below). While the temperature from the surface to around 5000 ft is ABOVE freezing, the temperature above 5000 ft (850mb) is all below freezing. And look where the red & green lines (temp & dewpoint) are touching above 850mb. That's where the precip is falling from (700mb/10,000ft to 400mb). The GFS is forecasting the precip to fall as snow from about 10,000-15,000ft up and make it to the ground AND accumulate. Of course, with surface temps in the mid 40s any snow reaching the ground would immediately melt. It's going to be difficult for any snow to reach the ground there in Dallas with such warm temps in the lower 5000 ft. But it's not impossible to see some snow flurries with temps in the mid 40s.

[TeamPlayersBlue]

So nat gas futures are down almost 8% today, i think alot of people saw the models drop the cold air yesterday, i hope that the models catch onto them again

[Ralph's Weather]

So nat gas futures are down almost 8% today, i think alot of people saw the models drop the cold air yesterday, i hope that the models catch onto them again

I am sure they will. Sometimes I think the models like to toy with us. Next week should be cold, but nothing that we don't see most years. The snow potential is what could make it memorable. I remember a widespread 4-6" snow storm on New Year's night about 15 years ago across North and Northeast Texas.