Texas winter wx thread (2009-2010)

[Weatherdude20]

http://radar.weather.gov/radar.php?rid=fws

[JenBayles]

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1017 PM CST THU DEC 3 2009

...SIGNIFICANT SNOWFALL EXPECTED ACROSS SOUTHEAST TEXAS ON FRIDAY...

.AN UPPER LEVEL TROUGH OF LOW PRESSURE COUPLED WITH AN INCREASE
IN MOISTURE AND UNSEASONABLY COLD TEMPERATURES WILL SET THE STAGE
FOR PERIODS OF SNOW ACROSS THE AREA FRIDAY. ACCUMULATIONS OF 1 TO
3 INCHES ARE EXPECTED.

TXZ178-179-199-200-212>214-227-237-238-041230-
/O.UPG.KHGX.WS.A.0002.091204T1200Z-091205T0600Z/
/O.NEW.KHGX.WS.W.0001.091204T1600Z-091205T0200Z/
BRAZORIA-CHAMBERS-FORT BEND-GALVESTON-HARRIS-LIBERTY-MONTGOMERY-
POLK-SAN JACINTO-WALLER-
INCLUDING THE CITIES OF...ALVIN...ANAHUAC...ANGLETON...
BROOKSHIRE...CLEVELAND...COLDSPRING...CONROE...CORRIGAN...
DAYTON...FREEPORT...FRIENDSWOOD...GALVESTON...HEMPSTEAD...
HOUSTON...HUMBLE...KATY...LAKE JACKSON...LEAGUE CITY...LIBERTY...
LIVINGSTON...MISSOURI CITY...MONT BELVIEU...ONALASKA...PASADENA...
PEARLAND...PRAIRIE VIEW...RICHMOND...ROSENBERG...SHEPHERD...
SUGAR LAND...TEXAS CITY...THE WOODLANDS...TOMBALL...WILLIS...
WINNIE
1017 PM CST THU DEC 3 2009

...WINTER STORM WARNING IN EFFECT FROM 10 AM TO 8 PM CST FRIDAY...

THE NATIONAL WEATHER SERVICE IN HOUSTON/GALVESTON HAS ISSUED A
WINTER STORM WARNING FOR SNOW...WHICH IS IN EFFECT FROM 10 AM TO
8 PM CST FRIDAY. THE WINTER STORM WATCH IS NO LONGER IN EFFECT.

SNOW IS EXPECTED TO DEVELOP ACROSS THE AREA BEGINNING LATE MORNING
FRIDAY...AND BECOME MODERATE TO HEAVY DURING THE AFTERNOON HOURS.
THE SNOW WILL PERSIST UNTIL EARLY EVENING BEFORE ENDING. TOTAL
SNOW ACCUMULATIONS OF 1 TO 3 INCHES...WITH ISOLATED TOTALS OF 4
INCHES...ARE EXPECTED ACROSS THE INLAND COUNTIES AND THE NORTHERN
PORTIONS OF THE COASTAL COUNTIES. TOWARD THE IMMEDIATE
COAST...THE PRECIPITATION WILL BEGIN AS RAIN AND NOT CHANGE TO
SNOW UNTIL LATE AFTERNOON. AS A RESULT...SLIGHTLY LOWER
ACCUMULATIONS ARE ANTICIPATED THERE. THE PRECIPITATION IS EXPECTED
TO END ACROSS THE WARNING AREA BETWEEN 6 AND 8 PM. SOME ROADWAYS...
ESPECIALLY ON BRIDGES AND OVERPASSES ARE LIKELY TO BECOME ICY
FRIDAY EVENING AS TEMPERATURES FALL WELL BELOW FREEZING.

IN ADDITION TO THE SNOW...THE COMBINATION OF GUSTY WINDS AND COLD
TEMPERATURES WILL RESULT IN WIND CHILL READINGS IN THE 20S FRIDAY
AFTERNOON AND EVENING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING FOR HEAVY SNOW MEANS WINTER WEATHER
CONDITIONS ARE EXPECTED OR OCCURRING. SIGNIFICANT AMOUNTS OF SNOW
ARE FORECAST.

MELTING AND REFREEZING OF WATER ON ROADWAYS...ESPECIALLY BRIDGES
AND OVERPASSES...WILL CREATE PATCHES OF BLACK ICE. THIS TYPE OF
ICE IS VIRTUALLY INVISIBLE ON THE ROAD SURFACE...AND CAN CAUSE YOU
TO LOSE CONTROL OF YOUR CAR.

[r22weiss]

AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1004 PM CST THU DEC 3 2009

.DISCUSSION...
PER SFC ANALYSIS THE SECONDARY SURGE OF COLDER AIR NOW APPEARS TO
BE SPREADING INTO SE TX. VERY DRY/COLD AIRMASS LOCATED TO OUR
NORTH WITH SFC DEWPOINTS DOWN TO THE LOWER TEENS ACROSS OKLAHOMA
AND WEST TX AND SINGLE DIGITS IN THE PANHANDLE. 850 MB ANALYSIS
SHOWS THAT THE ZERO DEGREE ISOTHERM IS ALREADY LINED UP ALONG I-10...
WITH LCH SHOWING A TEMP OF ZERO AND DRT SHOWING A TEMP OF -2.
THIS IS ACTUALLY A BIT COLDER THAN THE 00Z NAM INITIALIZED.


that the freezing line at 850 is already along I-10 is huge. Once the precip starts in the morning, evaporative cooling will begin and the sfc temps will fall alowing for the rain to change to snow late tomorrow morning/early afternoon.

[wxgirl69]

Looks like things are starting to get crazy for South East Texas

[CYCLONE MIKE]

AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1004 PM CST THU DEC 3 2009

.DISCUSSION...
PER SFC ANALYSIS THE SECONDARY SURGE OF COLDER AIR NOW APPEARS TO
BE SPREADING INTO SE TX. VERY DRY/COLD AIRMASS LOCATED TO OUR
NORTH WITH SFC DEWPOINTS DOWN TO THE LOWER TEENS ACROSS OKLAHOMA
AND WEST TX AND SINGLE DIGITS IN THE PANHANDLE. 850 MB ANALYSIS
SHOWS THAT THE ZERO DEGREE ISOTHERM IS ALREADY LINED UP ALONG I-10...
WITH LCH SHOWING A TEMP OF ZERO AND DRT SHOWING A TEMP OF -2.
THIS IS ACTUALLY A BIT COLDER THAN THE 00Z NAM INITIALIZED.


that the freezing line at 850 is already along I-10 is huge. Once the precip starts in the morning, evaporative cooling will begin and the sfc temps will fall alowing for the rain to change to snow late tomorrow morning/early afternoon.

R22, in your opinion how does that translate to us over here in south LA. Could we also be looking at colder than forecast temps as well?

[zaqxsw75050]

FWIW, 6z NAM = Where is the snow for Houston?

[southerngale]

FWIW, 6z NAM = Where is the snow for Houston?

I don't know, but yesterday's 06Z NAM did the same thing, but then it came back on the next run.

[zaqxsw75050]

FWIW, 6z NAM = Where is the snow for Houston?

I don't know, but yesterday's 06Z NAM did the same thing, but then it came back on the next run.

Yeah... It is just a 6Z run... no need to panic over it.

[r22weiss]

AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1004 PM CST THU DEC 3 2009

.DISCUSSION...
PER SFC ANALYSIS THE SECONDARY SURGE OF COLDER AIR NOW APPEARS TO
BE SPREADING INTO SE TX. VERY DRY/COLD AIRMASS LOCATED TO OUR
NORTH WITH SFC DEWPOINTS DOWN TO THE LOWER TEENS ACROSS OKLAHOMA
AND WEST TX AND SINGLE DIGITS IN THE PANHANDLE. 850 MB ANALYSIS
SHOWS THAT THE ZERO DEGREE ISOTHERM IS ALREADY LINED UP ALONG I-10...
WITH LCH SHOWING A TEMP OF ZERO AND DRT SHOWING A TEMP OF -2.
THIS IS ACTUALLY A BIT COLDER THAN THE 00Z NAM INITIALIZED.


that the freezing line at 850 is already along I-10 is huge. Once the precip starts in the morning, evaporative cooling will begin and the sfc temps will fall alowing for the rain to change to snow late tomorrow morning/early afternoon.

R22, in your opinion how does that translate to us over here in south LA. Could we also be looking at colder than forecast temps as well?

since the bulk precip doesn't look to start there until after it does in the Houston area, i think the current forecast of mid to late afternoon where snow looks to mix in is good.

[Portastorm]

As of 6:20 am, radar returns in west central Texas are encouraging ... the snow, whatever we get, should begin here around 8 or 9 am. The entire swath continues to chug eastbound.

[serenata09]

30 degrees in downtown Dallas. Dewpoint and Humidity slowly rising. Hopefully we can squeeze at least a few flakes out of this again.

[jeff]

TD down into the lower 20's N sections of SE TX. TD trends have been falling at all sites since midnight...coastal sites may have a little aharder time

[Portastorm]

For the record here at Austin-Mabry

4 am - air temp 39, dewpoint 21
5 am - 38/21
6 am - 37/23

[ROCK]

Jackson and Wharton counties already reporting sleet...

[srainhoutx]

Morning e-mail from Jeff...

Moderate to heavy snow will develop over the region today



Significant accumulations are likely producing an unprecedented winter storm event for coastal TX.



Winter Storm Warning has been expanded to include all SE TX counties.



Discussion:

Factors are well on their way to producing a historic snow event for SE TX and metro Houston today. Radar is rapidly filling in as mid and low level moisten and saturate to the surface while surface and 850mb cold air advection of arctic air mass is in progress. Light rain in being reported at our SW county stations and Port Aransas is reporting a mixture at this time…although I am not sure this ASOS site is getting it correct since Port Lavaca or no other sites are reporting SN or SN/RA mix. Strong lift is incoming across SC TX and this will be the trigger to get things going. Models pegging away at meso scale banding features setting up across our central zones this afternoon dumping heavy snowfall rates. In fact dynamics and lift may be strong enough to produce the extremely rare thundersnow across our central and coastal tier zones given convective look of radar images out of CRP. With all said will go with 100% snow for all US 59 corridor counties and then 80% either side of those counties as confidence is now at that level.



Temperatures:



Will crater temperatures during the day today and bottom them out in the low to mid 20’s Saturday morning. This will be a hard and killing freeze with many areas at or below freezing for 10-12 hours. Snow cover will only allow minor warming on Saturday and will cut highs only into the upper 30’s. Areas of heavy snow accumulation may remain snow covered into Sunday morning and area bridges and overpasses will be slow to recover.



Accumulations:



NW Counties (Walker, Polk, San Jacinto, Brazos, Grimes, Washington, Burleson, Madison):

Accumulations of 1-2” this afternoon. Expect a mainly light to at times moderate snow event in this area.



Montgomery, Waller, Austin, Liberty, Harris, Fort Bend, Wharton, Colorado:

This is where the greatest snow will likely fall with moderate to at times heavy snow banding favored along US 59. Expect everything to go over the snow by noon and then begin to accumulate by early to mid afternoon. Rates may approach 1” under the meso scale banding reducing visibilities down to 1/8 or ¼ of a mile. Widespread accumulations of 2-4” is likely with isolated totals of 6” possible under meso scale bands. Significant impacts to travel are likely both on the ground and in the air.



Coastal tier counties (Victoria/Calhoun –Chambers):

Light rain developing with begin to mix and then change to all snow by early to mid afternoon. May see meso scale banding develop in these counties also. Will go with 1-2” SW counties up to 1-3” Brazoria County and possibly higher over Galveston/Chambers counties.



Impacts:



This will be a high impact event both for surface and air travel.



Snowfall rates this afternoon will greatly hinder air travel as aircraft will require vigorous de-icing operations. Reduced visibilities and extremely low ceiling will stack up taxi-way delays and may require aircraft to return to gates for multiple rounds of de-icing as snow accumulates on the control surfaces. Not sure IAH or HOU will be able to keep the runways clear given the possible heavy snow bands being generated.



With air temperatures falling to freezing early this afternoon…initial snowfall will melt and then begin to freeze as a glaze of ice on area bridges and overpasses. As snow continues…it will accumulate on top of this sheet of ice producing very hazardous to near impossible travel conditions. Heavy snow bands will produce rates high enough to cover surface streets producing near impossible travel especially on any inclined ramps. Will be needing heavy sanding operations, but the size and intensity of the event is going to quickly overwhelm available resources…best bet is to be where you are going to be 1-2 hours after the snow begins at your destination location.



***If anyone down in the Matagorda Bay area could send me an update if the precip. is reaching the ground and if it is liquid or frozen…thanks***



Will provide frequent updates today…





Winter Weather Radar

http://www.intellicast.com/National/Rad ... imate=true

[joshskeety]

Told ya'll.. Best Virga storm of all time for west Texas..

Not one snowflake....

[joshskeety]

Although San Angelo did get an inch this morning... Makes up for Abilene getting 2 inches the other day and San Angelo not getting anything...

[JenBayles]

I know the radar says otherwise, but were getting light sleet mixed with a few snowflakes here in Bear Creek. I thought it was supposed to be later!!

[goCoogs]

Snow and rain in the Westchase district right now.

[natlib]

San Angelo still getting some light snow at 8:20. 1 to 2 inches on the ground and a little more than 2 inches in spotty southern parts of the city. Roads are slushy but not bad. All in all a beautiful start to winter.