Texas winter wx thread (2009-2010)

[Big O]

From this morning's Houston-Galveston AFD:

WE
COULD SEE SOME BRIEF CLEARING OF SKIES BY THURS EVENING. HOWEVER
SOME OF THE PROGS (MAINLY THE CANADIAN...AND NOW THE NAM) REMAIN
CONSISTENT/PERSISTENT WITH THE DEVELOPMENT/PASSAGE OF A DISTURB-
ANCE WHICH COULD PRODUCE SOME PCPN FOR FRI. AND GIVEN THE ARCTIC
AIRMASS WHICH WILL ALREADY IN PLACE THIS MAY WELL BE WINTRY PCPN
IF/WHEN IT OCCURS.

The Canadian no longer forecasts any precip across Texas after about late Thursday morning. Look at the lower right panel of the loop:

http://www.meteo.psu.edu/~gadomski/CMC_0z/cmcloop.html

Just some mid and high-level moisture on Friday, that's all.

It does show precipitation with sub-freezing 850 mb temps over Deep South Texas/Rio Grande Valley at 72h (0z Sat-6:00 p.m. Friday). However, even in that respect it appears to be an outlier.

In addition, at 120h, the European is showing sub-freezing 850mb temps south of the Texas/Mexico border with what appears to be moisture (at the 850 mb level) moving north from the south (Northern Mexico). Then at 144h, the precipitation/moisture engulfs much of the State. If this verifies, northeast, central and perhaps south-east Texas may have precipitation-type issues on Monday or Tuesday. Since I live in the RGV, I wonder what occurs between 120h and 144h with 850mb temperatures and precipitation. Do the 850 mb temperatures remain below freezing and does the moisture continue to move north? Anyone with insights, please chime in.

[orangeblood]

From this morning's Houston-Galveston AFD:

WE
COULD SEE SOME BRIEF CLEARING OF SKIES BY THURS EVENING. HOWEVER
SOME OF THE PROGS (MAINLY THE CANADIAN...AND NOW THE NAM) REMAIN
CONSISTENT/PERSISTENT WITH THE DEVELOPMENT/PASSAGE OF A DISTURB-
ANCE WHICH COULD PRODUCE SOME PCPN FOR FRI. AND GIVEN THE ARCTIC
AIRMASS WHICH WILL ALREADY IN PLACE THIS MAY WELL BE WINTRY PCPN
IF/WHEN IT OCCURS.

The Canadian no longer forecasts any precip across Texas after about late Thursday morning. Look at the lower right panel of the loop:

http://www.meteo.psu.edu/~gadomski/CMC_0z/cmcloop.html

Just some mid and high-level moisture on Friday, that's all.

It does show precipitation with sub-freezing 850 mb temps over Deep South Texas/Rio Grande Valley at 72h (0z Sat-6:00 p.m. Friday). However, even in that respect it appears to be an outlier.

In addition, at 120h, the European is showing sub-freezing 850mb temps south of the Texas/Mexico border with what appears to be moisture (at the 850 mb level) moving north from the south (Northern Mexico). Then at 144h, the precipitation/moisture engulfs much of the State. If this verifies, northeast, central and perhaps south-east Texas may have precipitation-type issues on Monday or Tuesday. Since I live in the RGV, I wonder what occurs between 120h and 144h with 850mb temperatures and precipitation. Do the 850 mb temperatures remain below freezing and does the moisture continue to move north? Anyone with insights, please chime in.

Big O - you need to pay attention to the S/W energy coming down from Canada next week. That will be bringing down another reinforcing shot of cold air and IF that can combine with the energy moving in from the southwest then we could be talking about a statewide winter storm all the way into south Texas. It just all depends on if that energy is going to move northeast or get entrained into the cut-off low forming over Texas. That northern stream energy is the key to getting this storm cold enough to produce winter precip into central and south Texas. Right it appears all of the energy is going to get together and form one big storm.

[jasons2k]

Just an FYI: TXDOT will begin laying down deicing agent this morning across the Houston Metro Area.

Yeah, I could see it on the overpapsses on the Hardy.

[Portastorm]

And the other consideration is the development of a coastal trough ... which almost always occurs in Texas winters when short-wave energy approaches from the west. It has happened EVERY TIME so far this winter. That will also play a role in the type of precip and temps.

[Portastorm]

Incidentally the 12z NAM has finished its run. While at the 850mb level we don't see much hint of precip on Friday, there clearly is 500mb level energy coming down the backside of the trough and shearing out over Texas on Friday. It's also there at the same time at the 700mb level.

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/12/model_l.shtml

The big question is: would that be just a mid-level cloud creator or would it have enough instability to tap into some moisture and squeeze out a few flurries? Given how low the dewpoints will probably be ... my guess is the former.

[wxman22]

Yea next week may be interesting,the last time we had a state wide winter storm was the ice storm of 2007 which affected allmost all of Texas with sleet/Freezing rain/and even snow.It wouldnt suprise me with the current pattern where in, that something like that happens again...It'll be interesting to see how the models trend over the weekend.

[srainhoutx]

Incidentally the 12z NAM has finished its run. While at the 850mb level we don't see much hint of precip on Friday, there clearly is 500mb level energy coming down the backside of the trough and shearing out over Texas on Friday. It's also there at the same time at the 700mb level.

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/12/model_l.shtml

The big question is: would that be just a mid-level cloud creator or would it have enough instability to tap into some moisture and squeeze out a few flurries? Given how low the dewpoints will probably be ... my guess is the former.

Cold core vort max. We have seen surprises with these type systems before. Remember December 2008.

[wxman57]

Canadian does show precipitation with sub-freezing 850 mb temps over Deep South Texas/Rio Grande Valley at 72h (0z Sat-6:00 p.m. Friday). However, even in that respect it appears to be an outlier.

In addition, at 120h, the European is showing sub-freezing 850mb temps south of the Texas/Mexico border with what appears to be moisture (at the 850 mb level) moving north from the south (Northern Mexico). Then at 144h, the precipitation/moisture engulfs much of the State. If this verifies, northeast, central and perhaps south-east Texas may have precipitation-type issues on Monday or Tuesday. Since I live in the RGV, I wonder what occurs between 120h and 144h with 850mb temperatures and precipitation. Do the 850 mb temperatures remain below freezing and does the moisture continue to move north? Anyone with insights, please chime in.

What's your location? I don't think you'll be seeing any precip down there Friday afternoon. Regardless, surface temps should be well above freezing all day Friday into Friday evening. At the very most, what the Canadian model (alone) is indicating would be some possible light rain mixed with sleet.

[Tejas89]

Temps may be the spoiler next week. FTW NWS has the DFW area above freezing all of Monday and Tuesday and just mentions possibility of rain on the back-end of the morning discussion. While we're getting a reinforcing shot of cold air, not anything like tomorrow - Saturday.

[iorange55]

Temps may be the spoiler next week. FTW NWS has the DFW area above freezing all of Monday and Tuesday and just mentions possibility of rain on the back-end of the morning discussion.

They're being very cautious as is always the case, and they did hint that it could be more than just rain. They're following the GFS closely, but if what could happen actually happens then Temps would be a non-issue for the DFW area.

[Big O]

Canadian does show precipitation with sub-freezing 850 mb temps over Deep South Texas/Rio Grande Valley at 72h (0z Sat-6:00 p.m. Friday). However, even in that respect it appears to be an outlier.

In addition, at 120h, the European is showing sub-freezing 850mb temps south of the Texas/Mexico border with what appears to be moisture (at the 850 mb level) moving north from the south (Northern Mexico). Then at 144h, the precipitation/moisture engulfs much of the State. If this verifies, northeast, central and perhaps south-east Texas may have precipitation-type issues on Monday or Tuesday. Since I live in the RGV, I wonder what occurs between 120h and 144h with 850mb temperatures and precipitation. Do the 850 mb temperatures remain below freezing and does the moisture continue to move north? Anyone with insights, please chime in.

What's your location? I don't think you'll be seeing any precip down there Friday afternoon. Regardless, surface temps should be well above freezing all day Friday into Friday evening. At the very most, what the Canadian model (alone) is indicating would be some possible light rain mixed with sleet.

McAllen, Texas

[srainhoutx]

Front is making good progress S fairly quickly. Thru Colorado Springs, CO now.

[CaptinCrunch]

Temps may be the spoiler next week. FTW NWS has the DFW area above freezing all of Monday and Tuesday and just mentions possibility of rain on the back-end of the morning discussion.

They're being very cautious as is always the case, and they did hint that it could be more than just rain. They're following the GFS closely, but if what could happen actually happens then Temps would be a non-issue for the DFW area.

NWS FTW is always on the safe side of things, right now they are gonig with mid 30's for highs on saturday, where I dont see it getting above freezing till sunday at the earliest. As for next week they still have low temps at or below freezing for mon and tues. The big question is will the arctic high really move off as fast as they think it will? If not then they are a few degrees to high on their temps both for highs and lows. Next week does look promissing for some type of winter precip for much of NTX.

Tonight: A chance of rain before 3am, then a slight chance of freezing drizzle. Cloudy, with a low around 24. Windy, with a north northwest wind 5 to 10 mph increasing to between 20 and 25 mph. Winds could gust as high as 35 mph. Chance of precipitation is 40%

If front comes in faster there maybe more frozen precip than what's forecasted at this point. We'll see what happens.

[Ntxw]

12z gfs = not a lot of fun though the 216hr fantasy blizzard is nice to look at

[iorange55]

I wouldn't worry too much about any of the model runs at the moment. Unless of course they're in our favor, lol. Still a long ways to go about a week. Probably won't stick to something till Sunday.

[Ntxw]

I'm not too worried, I haven't really sided with the GFS as of late. EC has been better to me imo. The upper pattern still looks favorable

[srainhoutx]

The pattern is ripe for a lot of opportunities the next couple of weeks. Trends my friends.

[Nederlander]

Yea next week may be interesting,the last time we had a state wide winter storm was the ice storm of 2007 which affected allmost all of Texas with sleet/Freezing rain/and even snow.It wouldnt suprise me with the current pattern where in, that something like that happens again...It'll be interesting to see how the models trend over the weekend.

The pattern is ripe for a lot of opportunities the next couple of weeks. Trends my friends.

It feels like I've been hearing that every week for two months.. I know that snow in Texas is a rare event and its hard to accomplish, but its equally as difficult not to get your hopes up. Especially with the amount of cold temps weve been having. It just seems like the cold temps and the precip cant ever get on the same page.

[Big O]

The pattern is ripe for a lot of opportunities the next couple of weeks. Trends my friends.

The AO is forecasted to rebound, but remain slightly negative, as is the NAO. The PNA is forecasted to decrease, but remain slightly positive. As such and to the extent these forecasts verify, there may be some chances for fun and games during the next week to week-and-a-half. IMHO temperatures will moderate mid-month. This moderation may last 1-2 weeks. However, posters in other forums suggest that we may revert to a cold and stormy pattern later in January or February.

Are you seeing things differently with regard to trends?

[srainhoutx]

The pattern is ripe for a lot of opportunities the next couple of weeks. Trends my friends.

The AO is forecasted to rebound, but remain slightly negative, as is the NAO. The PNA is forecasted to decrease, but remain slightly positive. As such and to the extent these forecasts verify, there may be some chances for fun and games during the next week to week-and-a-half. IMHO temperatures will moderate mid-month. This moderation may last 1-2 weeks. However, posters in other forums suggest that we may revert to a cold and stormy pattern later in January or February.

Are you seeing things differently with regard to trends?

AO will likely only rebound slightly (still in the negative range, just not as deep) The NAO will relax as well as the PNA and a split flow will likely start. This brings the STJ back into play. MJO pulse is nearing the dateline and this tends to enhance the southern stream. The warm up (January thaw if you will) will likely be brief and not much of a warm up at all. AO and NOA will likely tank again setting the stage for what will be an active period. This pattern is not going away anytime soon IMHO.