Texas winter wx thread (2009-2010)

[Ntxw]

JB is pounding the idea of a snowstorm with I-40 to I-20 axis late this week.

[wxman57]

Well, I'm encouraged in that the models seem to be converging on a single solution for next Thu-Fri now, and at least the GFS is NOT making a very common mistake with such a pattern. The pattern that they're all converging on is a southern stream shortwave moving across Texas. Though some models have it passing farther north, others farther south, they all have a feature of similar strength now.

It's a common setup for another West Gulf Low (WGL). This one doesn't look strong, just your run-of-the-mill WGL bordering on just a wave. Such lows will drive significant moisture inland across Texas/Louisiana as they develop, producing widespread stratiform precipitation. The precipitation shield is where the models often have trouble. Since the source of the moisture will always be the Gulf of Mexico, the heaviest precipitation is confined to coastal counties with diminishing amounts inland. Remember last week that the models had heaviest precipitation across north TX and OK? Now, at least the GFS and ECMWF shift the heavier precip down south. That means the areas with the coldest air get the least precipitation. It's a reasonable solution.

So I'm beginning to trust the GFS a bit more with its latest solution. I ran some meteograms (below). Moderate lower-level warm advection across coastal sections of Texas should mean that we'll see a cold rain down here (temps in the upper 30s or so). Might be a few sleet pellets when the precip is coming to an end as the low moves off to the east on Friday. Farther north in Dallas, very little precip is indicated, but temps are cold enough for at least some frozen precip. West to Austin looks like more cold rain, a bit colder than in Houston, but mostly rain. Could be a bit of sleet mixed in, Portastorm, as the precip winds down on Friday.

I'm becoming more confident that we won't see a significant winter storm in Texas with this event because the airmass is just a tad too warm. It's a close call, though, and I certainly wouldn't rule out some significant winter weather in Texas yet with the event 4-5 days away. The low could form north of the Gulf, and that would mean more moisture farther north.

Dallas-Ft. Worth 00Z GFS Meteogram


Austin 00Z GFS Meteogram


Houston 00Z GFS Meteogram

[gboudx]

Thanks for the update 57. The DFW NWS has added some rain/sleet mix for Thursday night. As is typical, timing will be the biggest factor, and also luck. I find it best to not buy into any solution until I look outside and see it falling.

I suspect you won't be posting any updates after 5pm today. Enjoy!

[Ntxw]

I'm not greedy wxman I'll take an inch or two. I don't like the shut down the entire city type winter weather.

[wxman57]

Thanks for the update 57. The DFW NWS has added some rain/sleet mix for Thursday night. As is typical, timing will be the biggest factor, and also luck. I find it best to not buy into any solution until I look outside and see it falling.

I suspect you won't be posting any updates after 5pm today. Enjoy!

Yeah, I'll be busy after 5pm. Been a Saints fain since 1967 (10 years old) and have been waiting a few years for this. Invited 6-7 people over to watch the game and all were going out of town this weekend (one had a death in the family). So I'll watch it alone on my big HD TV.

As for JB's posting, the winter precip "farther south of I-20 " part he talked about was to the east of Texas (MS/AL/GA). Depth of cold air across central to southeast Texas looks questionable for frozen precip, particularly in my area.

[Ntxw]

Thanks for the update 57. The DFW NWS has added some rain/sleet mix for Thursday night. As is typical, timing will be the biggest factor, and also luck. I find it best to not buy into any solution until I look outside and see it falling.

I suspect you won't be posting any updates after 5pm today. Enjoy!

Yeah, I'll be busy after 5pm. Been a Saints fain since 1967 (10 years old) and have been waiting a few years for this. Invited 6-7 people over to watch the game and all were going out of town this weekend (one had a death in the family). So I'll watch it alone on my big HD TV.

As for JB's posting, the winter precip "farther south of I-20 " part he talked about was to the east of Texas (MS/AL/GA). Depth of cold air across central to southeast Texas looks questionable for frozen precip, particularly in my area.

Well he said mostly within 100 miles south of I-20 which I don't think fits in with s\e Texas. The models never really showed cold air that deep down that way much even the GFS had a warming period in it's most radical solutions.

I hope your saints win!

[Portastorm]

As always Wxman57, your professional insights are greatly appreciated!

So I guess we need to be looking at several things, if I understand you correctly:

1) Strength and track of the upper level trough progged to move across the state

2) Location of surface cyclogenesis in the Gulf

Seems like a common theme this winter for those of us in south Texas. Thanks to you, I did run my own meteogram for AUS after the 0z GFS rolled out and saw the same thing. Temps very close to the magic 32-degree mark ... maybe a bit warmer ... but understanding we have a lot of model runs between now and Wednesday.

[srainhoutx]

We will need to see how the Monday-Tuesday storm plays out as well. There sure is a lot of Upper Energy diving S behind the PV in the Plains. I think we are far from a lock with this pattern and things could become rather fluid as the week unfolds IMHO.

[TrekkerCC]

I'm not greedy wxman I'll take an inch or two. I don't like the shut down the entire city type winter weather.

Well, a inch or two of snow is city stopping weather in DFW area. Realistically, I'm just hoping that we get a little wintry precip next Thurs/Friday. The NAM is showing possible wrap around snow-flurries on Monday night like we saw a few weeks ago, and so some may get lucky again, even if we don't get anything next Thursday/Friday.

[Ntxw]

We will need to see how the Monday-Tuesday storm plays out as well. There sure is a lot of Upper Energy diving S behind the PV in the Plains. I think we are far from a lock with this pattern and things could become rather fluid as the week unfolds IMHO.

I agree with you, even though the details on the GFS further out is rather not so trustworthy, it does have a trend of parading systems in the southern tier of the nation.

Thing to note, the system possibly effecting Texas later in the week is going to be a monster off the California coast. Anyone heading that way should get a heads up.

[srainhoutx]

RE the 12Z GFS...RECON data from the G-IV flight is included...

NCEP Operational Status Message
Sun Feb 7 14:52:38 2010 GMT
NOUS42 KWNO 071450
ADMNFD

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS CAMP SPRINGS MD
1447Z SUN FEB 07 2010
NO MEXICAN REPORTS WERE RECEIVED FOR THE GFS EITHER. BUT IN
ANY CASE THE NCEP MODEL CYCLE IS RUNNING SMOOTHLY AND IS ON
TIME.
12Z GFS RAOB RECAP...
RECON A/C REPORT IN SUPPORT OF WSR...
16 DROPSONDES WERE RECEIVED FROM THE NOAA G-IV FROM THE
WESTPAC REGION.
CWD IN EFFECT UNTIL 02/08/12Z.
$$
WOOLDRIDGE/SDM/NCO/NCEP

[Portastorm]

Looking at the 12z GFS (through 144 hrs) and, more specifically, at the 500mb level ... the 12z appears to be a little slower, deeper, and a little bit further south (honest!) with the upper level storm than the 0z run.

[txagwxman]

Looking at the 12z GFS (through 144 hrs) and, more specifically, at the 500mb level ... the 12z appears to be a little slower, deeper, and a little bit further south (honest!) with the upper level storm than the 0z run.

And much stronger with the low...oh my...but it is the GFS and it is 4-5 days away.

If that verifies there will be snow in central TX...thickness are 540-546 underneath the upper-level low, 850 mb 0C over CLL/ACT/AUS.

[srainhoutx]

Looking at the 12z GFS (through 144 hrs) and, more specifically, at the 500mb level ... the 12z appears to be a little slower, deeper, and a little bit further south (honest!) with the upper level storm than the 0z run.

And much stronger with the low...oh my...but it is the GFS and it is 4-5 days away.

If that verifies there will be snow in central TX...thickness are 540-546 underneath the upper-level low, 850 mb 0C over CLL/ACT/AUS.

I was keeping my mouth shut so I wouldn't have to pull Portastorm back from the ledge again. Trending in the right direction though.

[Portastorm]

I love you guys ... always looking out for me!

Nah, I've been through enough rodeos to know it could all change tonight with the 0z run. But I must admit that if we see this kind of thing 24 hours from now, I might have to issue a FIELD GOALS WITH LUCY watch.

[msstateguy83]

morning guys iam pretty busy up here this morning could someone give me a play by play of what the gfs says for my area for the later in the week
storm let me guess more snow for me??

edit: i know one thing i wanna see a little sun someday lol this weather is getting old very very quickly have not had a full day with
sun in i dont know how many days

[wxman57]

12Z GFS is in, and there are differences from 00Z and 06Z. However, I think that those differences may be going in the wrong direction, accuracy-wise. I'd mentioned that 00Z and 06Z GFS weren't making a common error of positioning the max moisture well inland. It appears the 12Z GFS may be making that mistake. The 12Z GFS has much more moisture in the Austin-Dallas area than the previous 2 runs. It would be unusual for a frontal wave/low in the Gulf to have so much heavy precip that far inland, so I am suspect of the 12Z GFS in that respect.

Airmass-wise, the temps projected are about the same as earlier runs. Marginal for frozen precip across Texas where most of the precip will likely fall. Where temps may be cold enough for frozen precip (Wichita Falls), very little precip is indicated.

Here are the 12Z Meteograms. Looks like cold rain for the coast and lesser amounts of cold rain mixed with sleet farther inland. Again, I don't buy the precip amounts in these 12Z meteograms for Dallas and Austin areas. I think they're overdone.

Houston (IAH)


Austin (AUS)


Dallas - Ft. Worth (DFW)


Wichita Falls (SPS)

[Ntxw]

I'm liking how the EC looks so far! Just need to trend wetter! GRR

[txagwxman]

12z ECMWF now deeper and 540 thickness is near ACT/CLL/AUS line Thu afternoon.

[wxman57]

12z ECMWF now deeper and 540 thickness is near ACT/CLL/AUS line Thu afternoon.

Are you getting a more detailed ECMWF than is available online? I can see only one chart per day, so I can't see anything but 12Z charts for each day.

I do see that the 12Z GFS has the 540 thickness and 0C 850mb isotherm farther south at 96 and 120hrs - but not until after the precip has ended.