Texas Winter 2011-2012...

[Turtle]

Wow the new 18Z has shown some snow for me along I-20 east texas.Though admittedly it's only .01 or so, but to see snow in the forecast within 5 days is pleasing.

[Kelarie]

This is out of Shreveport, there is a brief blurb about a light mix Tuesday.

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Area Forecast Discussion
Issued by NWS Shreveport, LA

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000
FXUS64 KSHV 012204
AFDSHV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
404 PM CST THU DEC 1 2011

.DISCUSSION...
CLOUDS COMING IN OVER THE WESTERN HALF OF THE CWA AT THIS TIME...A
TAD LATE TO HELP THE FORECAST VERIFY TEMPERATURE WISE ANYWAY. THE
BIG 1027 MB IS OVER E TN AND IS STILL KEEPING OUR WIND A BIT MORE
EASTERLY WITH SOUTHEAST DEVELOPING OVERNIGHT AS IT CONTINUES TO
DRIFT EASTWARD. MEANWHILE...DEW POINTS ARE ON THE INCREASE WITH
LOW 50S NOW IN MUCH OF TEXAS...THUS THE LOW DECKS. RIGHT NOW
EXPECTING PARTLY CLOUDY CONDITIONS THROUGH THE NIGHT...BUT BROKEN
DECKS COULD MAKE FOR A WARMER NIGHT OVER TEXAS ANYWAY. ANOTHER
CHILLY START OUT EAST FOR US WITH FAIR SKIES EXPECTED OVERNIGHT.
IN THE SHORT TERM...MODELS LIKE A SLIGHT CHANCE OF LIGHT RAIN DURING
FRIDAY FOR TX/OK...BUT THE REAL DEAL WILL STILL UNFOLD AHEAD OF
THE COLD FRONT DURING LATE SATURDAY. THIS COLD FRONT IS PLOWING IN
THE PANHANDLES RIGHT NOW. MAV BLENDED INTO TEMPS WHICH MAY BE TOO
COOL TOMORROW IF CLOUDS GET FARTHER EASTWARD THAN CURRENTLY
EXPECTED.

THE EXTENDED FORECAST IS NOW A BIT MORE IRONED OUT WITH HIGHER
POPS AND STILL THE TRANSITION FROM SHOWERY...TO RAINY. ISOLATED
THUNDERSTORMS STILL POSSIBLE RIGHT ALONG THE FRONT. ANY BOWING
SEGMENTS LATE SATURDAY AND OVERNIGHT COULD BEAR WATCHING...BUT A
BIGGER CONCERN MAY FOR SOME MINOR FLOODING INTO NEXT WEEK AS THE
RAIN CONTINUES WITH A SECOND UPPER IMPULSE MOVING OVER THE PLAINS.
MEX GUIDANCE IS QUITE REASONABLE AND LIKEWISE HAS BEEN BLENDED
INTO EXTENDED TEMP GRIDS. GFS IS FASTER ON CLEARING...WHILE EURO
LINGERS PRECIP INTO EARLY TUESDAY...WHICH WOULD BE COLD ENOUGH FOR
A MIX AFTER MIDNIGHT MAINLY NORTH OF I-20. NO PROBLEMS AS AMOUNTS
WILL BE LIGHT AND THE GROUND STILL TOO WARM

[gboudx]

Larry Cosgrove

http://www.examiner.com/weather-in-hous ... ts_article

...
If the various schemes verify, sleet could make a brief appearance in the Houston northern suburbs on Monday. And cities such as Dallas and Abilene could have enough mixed precipitation to create driving and power line issues.

[iorange55]

You know it is winter time again when you hear "ground is too warm."

[Turtle]

Even the Houston NWS is thinking about the wintry precip!!!!

THE RAIN SHOULD TAPER OFF MONDAY NIGHT INTO TUESDAY AS COOLER AIR MOVES INTO THE
REGION. AT THIS TIME IT APPEARS THAT THE RAIN WILL MOVE OUT OF THE
REGION BEFORE THE TEMPERATURE PROFILE WOULD BE SUPPORTIVE OF ANY
WINTRY PRECIPITATION...ALTHOUGH A FEW MODELS SUGGEST THAT THERE
COULD BE A BRIEF PERIOD OF MIXED PRECIPITATION ACROSS OUR FAR
NORTHERN COUNTIES. GIVEN THAT THIS IS A LOW PROBABILITY OUTCOME
AND FAIRLY FAR INTO THE FORECAST PERIOD IT WILL NOT BE REFLECTED
IN THE CURRENT FORECAST PACKAGE.

[Rgv20]

Corpus also mentions the remote possibility of some wintry precip...

MONDAY NIGHT/EARLY TUESDAY...LIGHT RAIN/SHOWERS
LIKELY TO PERSIST BASED ON GFS ISENTROPIC LIFT/LOW CONDENSATION
PRESSURE DEFICITS AT 300K...YET GRADUALLY DECREASE FROM WEST TO
EAST. RECALL HWR THAT THE GFS IS FASTER. THE SLOWER ECMWF SUGGEST
PCPN THROUGH TUESDAY. HWR WILL FCST THE PCPN TO END OVER THE CWA BY
12Z TUESDAY. THE GFS PROGS 06-12Z TUESDAY 1000-850MB AND 850-700MB
THICKNESS VALUES CLOSE TO A FREEZING RAIN SCENARIO...ESPECIALLY OVER
THE CNTRL/WRN CWA. WL FCST MIN TEMPS TUESDAY IN THE MID/UPPER 30S
HWR WET BULB TEMPS MAY CONTRIBUTE TO A BRIEF PERIOD OF ICE PELLETS.
THE CONFIDENCE IN FREEZING/FROZEN PCPN IS VERY LOW AT THIS TIME AND
THUS WILL NOT FCST SUCH.

[Jarodm]

Anybody see the latest nam, deff came in colder. Im not sure this is ones going to be a bust for us in north Texas, also check out what nws just wrote in it's update

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
841 PM CST THU DEC 1 2011

.UPDATE...
1035+ MB SURFACE HIGH IS DEVELOPING IN THE PLAINS AS LARGE AREA
OF 3 HOUR PRESSURE RISES OF 3-4MB IS ONGOING. THIS IS HELPING TO
PROPEL A FRONT SOUTHWARD...WHICH IS NOW ENTERING THE NW CWA. AIR
MASS BEHIND THIS FRONT IS NOT PARTICULARLY COLD...BUT IS CERTAINLY
MORE DENSE THAN THE THE AIR MASS OVER NORTH TEXAS. BELIEVE THE
FRONT IS GOING TO MOVE FARTHER SOUTH AND HANG AROUND A LITTLE
LONGER TOMORROW THAN THE PREVIOUS FORECAST INDICATED AND HAVE
LOWERED HIGH TEMPS 5-10 DEGREES WEST OF I-35. FRONT WILL BE THE
DIVIDING LINE BETWEEN COLD AND DAMP WITH TEMPS IN THE 40S AND 50S
AND HUMID WITH TEMPS IN THE 60S. LIGHT SHOWERS AND DRIZZLE WILL
BE POSSIBLE MAINLY BEHIND THE FRONT. HIGH TEMPS FOR MOST LOCATIONS
TOMORROW WONT OCCUR UNTIL LATE IN THE DAY WHEN THE FRONT
RETREATS...AND THUS WITH ONLY A CURSORY GLANCE OF THE FORECAST ARE
DECEPTIVELY WARM. LOCATIONS NORTHWEST OF A PARIS TO DALLAS TO
TEMPLE LINE SHOULD PREPARE FOR A BRISK AND CHILLY DAY TOMORROW.

[Rgv20]

It's interesting that the GFS has been trending toward a slower solution with the 500mb upper low but not as slow as the Euro....maybe the rain will stick around as temps fall below freezing Monday Night-Tuesday Morning in central and eastern Texas?? Trying to forecast in winter time in Texas is a headache!!

[iorange55]

GFS 00Z is certainly interesting......

[Ntxw]

GFS is kind of on the boat now too. Everything seems to point at the third and final energy that rounds the base of the trough is going to provide enough lift in the cold air west, central, and north Texas for maybe some sort of ice/sleet/snow rain combo. It will be close, lets hope the trends continue. Maybe the crazy Canadians aren't crazy after all.

Now we just need that southern stream vort max to strengthen a little and try to pull the slug of moisture back for a comma head! LOL one can wish

Edit: just as I say that the GFS does it over NE Texas but looks dry for now

[Jarodm]

oh man this is getting very intresting, sunday night monday and tuesday i think north texas has a chance of winter. However it looks like ice and sleet would likely be the main precip and snow towards the end. Hopefully models continue to come in colder.

[orangeblood]

GFS is kind of on the boat now too. Everything seems to point at the third and final energy that rounds the base of the trough is going to provide enough lift in the cold air west, central, and north Texas for maybe some sort of ice/sleet/snow rain combo. It will be close, lets hope the trends continue. Maybe the crazy Canadians aren't crazy after all.

Now we just need that southern stream vort max to strengthen a little and try to pull the slug of moisture back for a comma head! LOL one can wish

The Euro has been hinting at that sort of scenario for the past few runs....it's trying to form a closed low somewhere across the southern plains - it can't pin point exactly where though. It appears that there will be enough upper level energy available to develop into a fairly decent winter storm across Texas early next week and confidence level is increasing as we get closer to the weekend. Trends like a stronger Canadian high pressure coming down the plains, energy hanging back across the southwest, Texas winter weather analogs matching the forecasted upper level chart and snow pack increasing across the central plains all favor winter weather across some parts of Texas early next week. It's way too early to pin point exact locations but right now I'd say northwest of a San Angelo to Waco to Tyler line odds are increasing for winter precip.

A trend we don't want is for the models to start hanging the upper level energy back for too long.....

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.

[Turtle]

Hmm 0Z GFS doesn't look as good for wintry precip. Right now I'm thinking we will get only rain. Then again it was like a 5% chance of wintry precip.

This is for I-20 east of Tyler though. I don't know about other areas in TX.

[Longhornmaniac8]

Stupid question:

What is a cutoff low?

[Ntxw]

The Euro has been hinting at that sort of scenario for the past few runs....it's trying to form a cut off low somewhere across the southern plains - it can't pin point exactly where though.

GFS has been so biased with forming cutoff lows too far north this fall via northern stream energy, that should've been a flag right there. I should've known given what it was trying to do last week with the big southeast cutoff low first placing it into the lakes. I think the models have been too weak with this feature and finally putting it together closer to the event. Since this should be the last in the series, I have faith it won't hang back long.

[Longhornmaniac8]

And wow, that Wundermap is pretty cool! GFS 00Z run has Austin right on the boundary from hour 96 through hour 114. Some of it is forecast as liquid, and some as a mixture. Knowing our luck, it's going to be all liquid!

So basically the question isn't if it's cold enough, but if the moisture will hold back long enough?

[orangeblood]

Stupid question:

What is a cutoff low?

It's an area of low pressure that has a distinct center of cyclonic circulation which is completely encircled by one or more height contour lines - the system affecting the southern Rockies currently is a cut off low pressure system that eventually will open up and get caught up in the westerly flow. It gets its name due to it normally being "cut off" from the main westerly flow and usually moves relatively slowly.

[Ntxw]

Canadian is looking better trying to wind up the system as it crosses the southern plains. Looking more like it's own moisture feature this run vs leftovers from previous shortwaves. Might develop a comma head as it treks if this run was to verify.



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[orangeblood]

[quote="Ntxw"]Canadian is looking better trying to wind up the system as it crosses the southern plains. Looking more like it's own moisture feature this run vs leftovers from previous shortwaves. Might develop a comma head as it treks if this run was to verify.

Yeah, it looks like this could be a somewhat prolonged event lasting longer than 24 hours....with shortwave energy rounding the base of the trough sometime on Monday and then the main system moving through on Tuesday. Very interesting and somewhat unexpected event unfolding but still way too early to pinpoint exact locations.

[Ntxw]

So far through 87 hours, Euro is developing snow all over west Texas moving into north Texas/Oklahoma, and more than just a light wintry mix. Good slug of moisture forming a deformation band from the SW. What a turn of events tonight...it will be very close.