Texas Winter 2014-2015

[Portastorm]

ECMWF 12/8 0000z shows: The 500mb low will intensify as it passes over Texas Sunday night and Monday, with almost a 3 standard deviation anomaly from normal. It's accompanied by a wide area of below freezing 850mb temperatures north of a Del Rio to Corpus Christi line. Snow is now forecast for Amarillo, with surface temps below freezing, and Lubbock, with temps slightly above freezing. A rain event everywhere else, with about 1.8 inches for Dallas, 0.8 for Austin, and 0.7 for Houston, and over 2.0 for Texarkana.

I'd be curious what the 1000mb-850mb levels are progged for as that bottom 6,000 feet of the atmosphere can often spell the difference between rain and snow. We can and have seen snow in Texas with surface temps above freezing if the column of air above a locale is cold enough. Conversely we can see rain falling on locales below freezing at the surface. All depends on how the air column is set up, temperature-wise. As wxman57 has taught us in previous winters that the 0-degree isotherm at 850mb isn't always a guarantee of snow falling.

[Nairobi]

Unlikely to have snow at the surface if 2m temperatures are above 40. When the precip cuts off, the ECMWF is predicting:

Abilene 36 Mon afternoon
Amarllo 28 Mon afternoon (snow)
Austin 52 Mon morning
Corpus Christi 60 Mon morn
Dallas 41 Tue morning
Fort Stockton no rain at all
Houston 57 Mon afternoon
Lubbock 34 Mon afternoon (snow)
Midland 39 Mon morning
San Antonio 54 Mon morning
Texarkana 43 Tue afternoon
Waco 41 Tue morning
Wichita Falls 39 Mon afternoon

This storm can be seen in the Pacific east of Russia. It's not one of those that are purely model-predicted at this point.

[Ntxw]

Assuming the model(s) is correct a week out right Portastorm? I mean since when is the surface progs nailed to the tee that long out, all subject to change. Not long ago I believe there wasn't much to talk about, storm? What storm? Pattern change?

[srainhoutx]

Unlikely to have snow at the surface if 2m temperatures are above 40.

Temperatures at the 500mb level are expected to be very cold in the -10 to -15+ range. Sleet is certainly possible beneath the cold core upper low. At this range I would be very cautious regarding the potential dynamics/temperature gradients associated with this feature until in enters the RAOB network and is sufficiently sampled.

[Ralph's Weather]

ECMWF 12/8 0000z shows: The 500mb low will intensify as it passes over Texas Sunday night and Monday, with almost a 3 standard deviation anomaly from normal. It's accompanied by a wide area of below freezing 850mb temperatures north of a Del Rio to Corpus Christi line. Snow is now forecast for Amarillo, with surface temps below freezing, and Lubbock, with temps slightly above freezing. A rain event everywhere else, with about 1.8 inches for Dallas, 0.8 for Austin, and 0.7 for Houston, and over 2.0 for Texarkana.

I'd be curious what the 1000mb-850mb levels are progged for as that bottom 6,000 feet of the atmosphere can often spell the difference between rain and snow. We can and have seen snow in Texas with surface temps above freezing if the column of air above a locale is cold enough. Conversely we can see rain falling on locales below freezing at the surface. All depends on how the air column is set up, temperature-wise. As wxman57 has taught us in previous winters that the 0-degree isotherm at 850mb isn't always a guarantee of snow falling.

I am going to be paying close attention to the 850 temps as that will be the tell for what the precip types will be. I have seen these lows produce good snow when surface temps were progged to be way warm. I am going to review a storm from about this time in 2008 I think to see how it compares, I was in College Station at the time and we got a good 3 or so inches overnight.

[Nairobi]

12/8 06Z operational GFS says at precip cutoff time for 500, 850, and 925 meter temps:

Austin -18, 10, 17
Amarillo -20, 3, 8
Dallas -20, 9, 15
Lubbock -19, 2, 7

[srainhoutx]

I am going to be paying close attention to the 850 temps as that will be the tell for what the precip types will be. I have seen these lows produce good snow when surface temps were progged to be way warm. I am going to review a storm from about this time in 2008 I think to see how it compares, I was in College Station at the time and we got a good 3 or so inches overnight.

That particular December bowling ball cold core upper low brought snow across Metro Houston as well. Some locations on the E side near Pasadena/Channelview/La Porte recorded nearly 6-8 inches of snow and it closed the Fred Hartman Bridge between La Porte and Baytown as well as the 610 E Loop and East Belt Bridges over the ship channel.

[Tireman4]

Here is the thing. I could be way off. I am just a historian, but this is what I have learned over the years with Srain, Ntxw, Wxman57 and others...models do not handle cold air well at all. I think we saw this in November. They just do not. I have seen it time and time again. Lots of times, Wxman 57 and Srain say...the models say some things but gut feelings finish the final deduction. Also, models say many things ( remember the Cat 5 in the Gulf earlier this past week...LOL), but sending up balloons also add to the equation. This will be an exciting Winter. Hold on to your hats, they may get blown away.

[Nairobi]

Temps got to freezing in that one. This next storm is progged to be much warmer at the surface for Houston.

[Ralph's Weather]

I am surprised I remembered the timing of that storm so well. If the Euro pans out a similar situation could occur under the path of the upper low. Or maybe the GFS will win out and there will be nothing at that time.

[Ralph's Weather]

Temps got to freezing in that one. This next storm is progged to be much warmer at the surface for Houston.

It seems like just about every storm is progged to be warmer than it turns out to be.

[Ntxw]

There's also another baja low in the medium to longer range on ensembles. Cutoff lows barrage? It wouldn't be unusual with Nino climo

[Portastorm]

GFS says at precip cutoff time for 500, 850, and 925 meter temps:

Austin -18, 10, 17
Amarillo -20, 3, 8
Dallas -20, 9, 15
Lubbock -19, 2, 7

Which GFS? The operational or ensembles? If op, which run? Please clarify.

[Portastorm]

Assuming the model(s) is correct a week out right Portastorm? I mean since when is the surface progs nailed to the tee that long out, all subject to change. Not long ago I believe there wasn't much to talk about, storm? What storm? Pattern change?

Exactly! So much can (and probably will) change. IMO, the important thing here is that we will be dealing with a major cold-core low. We all know what those can do in Texas in wintertime. Whether snow or rain, it's going to provide a relatively major impact to Texas weather.

[srainhoutx]

There's also another baja low in the medium to longer range on ensembles. Cutoff lows barrage? It wouldn't be unusual with Nino climo

The longer range ensemble mean are very suggestive of the pattern transitioning to one that is rather stormy and colder for our Region. The Aleutian low retrogrades W allowing heights to build along the W Coast. The sub tropical jet remain very active throughout the period with a 120+ knot jet max over Northern Mexico, Southern New Mexico and Texas. Generally lower pressures are situated along the NW and Northern Gulf Coast into the SE United States and up the Eastern seaboard. As many of the long range energy Mets as others have eluded to, this is a very typical weak Nino pattern and is known to throw many a curve ball for even the most seasoned forecaster.

[Ralph's Weather]

Here is the thing. I could be way off. I am just a historian, but this is what I have learned over the years with Srain, Ntxw, Wxman57 and others...models do not handle cold air well at all. I think we saw this in November. They just do not. I have seen it time and time again. Lots of times, Wxman 57 and Srain say...the models say some things but gut feelings finish the final deduction. Also, models say many things ( remember the Cat 5 in the Gulf earlier this past week...LOL), but sending up balloons also add to the equation. This will be an exciting Winter. Hold on to your hats, they may get blown away.

The mid November one and even the late November one were cases of dense Arctic air pushing south faster and further than the models predict. This potential mid December upper low will be cold from the upper levels being advected down via precipitation. Arctic air intrusions are typically much easier to predict days in advance as you can watch what is happening upstream at the surface. These closed upper lows tend to offer surprises when they interact with the Gulf moisture which allows the cold above to be brought down. The opposite often happens with moisture and Arctic fronts because the cold is at the surface and precip brings down warm air from above.

[Ralph's Weather]

GFS says at precip cutoff time for 500, 850, and 925 meter temps:

Austin -18, 10, 17
Amarillo -20, 3, 8
Dallas -20, 9, 15
Lubbock -19, 2, 7

Which GFS? The operational or ensembles? If op, which run? Please clarify.

Either the GFS is lost or it will be the big winner, I think most expect it to give in to the other models. These systems are some of the most fun to forecast as the models will likely never get a good handle on what will happen.

[Tireman4]

GFS says at precip cutoff time for 500, 850, and 925 meter temps:

Austin -18, 10, 17
Amarillo -20, 3, 8
Dallas -20, 9, 15
Lubbock -19, 2, 7

Which GFS? The operational or ensembles? If op, which run? Please clarify.

Either the GFS is lost or it will be the big winner, I think most expect it to give in to the other models. These systems are some of the most fun to forecast as the models will likely never get a good handle on what will happen.

How many times have we seen the GFS spin up a snowstorm for Houston then have it take it back then spin it up again. That far out one week or two weeks......my gracious. Remember the GFS models back around 2006-2008...LOL

[Ralph's Weather]

How many times have we seen the GFS spin up a snowstorm for Houston then have it take it back then spin it up again. The far out...my gracious. Remember the GFS models back around 2006-2008...LOL

It is pretty embarrassing that the primary American model puts out such an inferior product to the Euro. I think the update to the GFS will help, but it seems to still lag behind the ECMWF. Though in the case of the mid month storm I expect all models to struggle.

[TeamPlayersBlue]

I am going to be paying close attention to the 850 temps as that will be the tell for what the precip types will be. I have seen these lows produce good snow when surface temps were progged to be way warm. I am going to review a storm from about this time in 2008 I think to see how it compares, I was in College Station at the time and we got a good 3 or so inches overnight.

That particular December bowling ball cold core upper low brought snow across Metro Houston as well. Some locations on the E side near Pasadena/Channelview/La Porte recorded nearly 6-8 inches of snow and it closed the Fred Hartman Bridge between La Porte and Baytown as well as the 610 E Loop and East Belt Bridges over the ship channel.

I remember it very very well. It happened twice that year. Both cold core lows and both were not predicted AT ALL. December 10th 2008 for one and the other was Feb 2009 i think.

It was in the low 40's as the cold core approached and temps fell with the snow