SE TX/SW LA Winter WX - 2011-2012

[JenBayles]

Plants, pets and pipes first. Eggnog, adult beverages and S2K second. Unfortunately.

[Flyinman]

I get the pleasure of driving to Beaumont and back tomorrow. We are going to attempt to leave early and get back before noon. I will let you all know what we experience on the road.

[jasons2k]

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE LAKE CHARLES LA
345 AM CST THU DEC 3 2009

...AN UNSEASONABLE SNOWFALL EXPECTED FRIDAY EVENING...

And so there it is - NWS LCH becomes the first office guilty of calling this an "unseasonable" event in December - the meteorological winter.

[srainhoutx]

HGX Update...

1036 AM CST THU DEC 3 2009

.DISCUSSION...
SURFACE HIGH PRESSURE IS BUILDING INTO TEXAS . COLD AIR ADVECTION
CONTINUES WITH TEMPERATURES STILL IN THE 40S. CLOUDS HAVE BEGUN TO
INCREASE OVER CENTRAL TEXAS AND HAVE MODIFIED THE SKY GRIDS TO
ACCOUNT FOR AN INCREASE CLOUD COVER THIS AFTERNOON. TEMP FORECAST
LOOKS ON THE MARK SO NO CHANGES THERE.

THE BIG QUESTION IS WHAT WILL HAPPEN ON FRIDAY. THERE IS A GROWING
CONSENSUS THAT THE DEEPER MOISTURE WILL REMAIN CONFINED TO AREAS
CLOSER TO THE COAST. THE NAM HAS COME IN CLOSER TO THE ECMWF/CAN
WITH THE BULK OF THE PRECIP OFFSHORE. ALL THE MODELS ARE NOW IN
GOOD AGREEMENT WITH THE SPEED OF THE UPPER TROUGH AND HAVE TRENDED
TOWARD THE FASTER ECMWF. THE GFS...WHICH HAS BEEN EXTREMELY
CONSISTENT SINCE 12Z MONDAY...IS VERY AGGRESSIVE WITH MOISTURE.
HOWEVER THE GFS MOIST AXIS HAS NOW SHIFTED SOUTH TOWARD THE COAST.
WILL NOT MAKE A MAJOR CHANGE AT THIS TIME AS WE AWAIT THE
ECMWF...BUT FEEL THE WINTER STORM WATCH/WARNING WILL NEED TO BE
SHIFTED SOUTH. NOT SURE THERE WILL BE ENOUGH MOISTURE OVER THE
NORTH TO WARRANT ANYTHING MORE THAN A FEW FLURRIES. THE GFS IS
ALSO NOT AS COLD IN ITS THERMAL PROFILE SO THE CHANGEOVER TO SNOW
COULD ALSO BE DELAYED A BIT. IF THE GFS IS CORRECT...A SWATH OF
2-4 INCHES OF SNOW WILL BE POSSIBLE OVER THE CITY OF HOUSTON. IF
THE NAM AND OTHER GLOBAL MODELS ARE CORRECT...LIGHT RAIN AND SNOW
WITH LITTLE OR NO ACCUMULATIONS. WHAT A RIDE...STAY TUNED! 43

[srainhoutx]

GFS snowfall outlook...

http://204.2.104.196/gfs/CONUS_GFS0P5_S ... W_42HR.gif

[JenBayles]

Just once I'd like to see a NWS met voice a personal opinion in addition to discussing the models. Sure, models are great tools, but IMHO an informed, intuitive, experienced and educated "guess" from a professional can be just as valid if not moreso than a computer model. Is it just me?

[southerngale]

Some interesting information regarding official snow statistics for SE TX & SW LA from NWS LCH.


Snow Climatology for Southeast Texas & Southwest Louisiana

[wxman57]

Here's a good site with a close up of SE TX accumulated snow forecast by the latest GFS:

http://wxcaster.com/gis-gfs-snow-overla ... TIONID=HGX

I don't recall ever seeing better dynamics for snow forecast by the models in my 30 years here in Houston. Don't see how we'll escape at least a dusting. And if the GFS is right, some quite significant amounts.

[lrak]

Thanks wxman57, it looks like CC TX is right on the edge...

[Flyinman]

Any update on the timing of all of this? I have heard and read it can begin as early as tomorrow morning but mostly tomorrow afternoon is the focus. I am really trying to beat all the weather as I know people will be driving crazy.

[wxman57]

Thanks wxman57, it looks like CC TX is right on the edge...

Afraid so, look:
http://wxcaster.com/gis-gfs-snow-overla ... TIONID=CRP

[wxman57]

Any update on the timing of all of this? I have heard and read it can begin as early as tomorrow morning but mostly tomorrow afternoon is the focus. I am really trying to beat all the weather as I know people will be driving crazy.

Cold rain may start 7am-8am, maybe some sleet at first. Rain changes to snow by 11am-1pm. Snow lasts until 6pm-8pm then ends. Maybe some thunder snow mid afternoon. Roads start to get dangerous by 2-3pm, so be home by noon.

[Ivanhater]

Does that map go to the Central Gulfcoast wxman?

[srainhoutx]

Afternoon Update fom Jeff..Major Changes...

All models have trended wetter and colder for the Friday event.

Will likely need a Winter Storm Warning for metro Houston and all US 59 corridor counties this afternoon and possible upgrade for the coastal counties also.
Winter Weather Advisory issues for all of C and SC TX.

Discussion:

Moisture advection noted on the visible images out of central Texas moving up the Rio Grande while powerful short wave dips into the southern Rockies. Impressive lift comes to bear over the region starting by mid morning Friday and really cranks into gear by noon. Profiles show a frozen profile all the way down to Hobby and Victoria by noon Friday with a rapid change to all snow north of this line and change to all snow to the coast by mid afternoon. GFS strongly supports a 60-80 mile wide banded heavy snow axis roughly 60 miles either side of US 59 with significant surface accumulations possible. 12Z GFS model pounds the US 59 corridor with 4-6 inches of accumulation. Trend has been a southward shift in the snowfall axis and the heaviest totals may in fact end up over the coastal counties and first inland tier counties. Starting to look very similar to the historic 2004 Christmas Eve event where the moisture near the coast meets the cold air..although not expecting a foot of snow and a version more to the northeast than in 2004.
Accumulations:

Austin to College Station to Huntsville:

Will be lowering totals in this region as focus is shifting southward. A dusting to 2” is possible starting early Friday morning.

Columbus to Conroe to Lake Livingston:

This area should be on the north side of the heavier snow band with accumulations of 1-4 inches possible. Should see onset of snow by early to mid morning with accumulations by late morning as temperatures fall to freezing.

US 59 from Victoria to Liberty Co including metro Houston:

Will be upping accumulations into the 2-4” range across this area including metro Houston with some areas possibly picking up 6”. Will onset snow between 1000am and noon Friday and continue into early evening. May need to add moderate and heavy snow with visibilities tanking to below 1/4th of a mile at times in heavy snow bands. Could see up to 1” per hour of accumulation. Given the possible increased snowfall rates…not only bridges, but surface streets may become issues by Friday afternoon as surface temperatures fall to and below freezing.

Coastal Counties:

Will need to add accumulation to the coastal counties given the latest data with 1-2” likely including the beaches. Will see snow onset before noon in the Victoria area and spread NE up the coast by early afternoon. May need to go even higher on the accumulation in this region if the models continue to trend southward.

Freeze Warning:

Other change was to add a freeze warning to all counties for Friday into mid morning Saturday. Will be lowering temperatures into the mid to upper 20’s by Saturday morning. Freezing and sub-freezing temperatures are expected for 10-12 hours across the region…this will be an advection freeze leading to greater impact to vegetation as ground warmth will be stripped away.

Actions:

TXDOT, Harris County Toll Road Authority, and all county Precincts are applying de-icing agent to area freeways and connector ramps and preparing to sand bridges and overpasses.

Travel will become increasingly hazardous during the day on Friday and should be avoided if possible after snow begins to fall as elevated surfaces glaze over and then accumulate slush.

[PTrackerLA]

Wxman got a link for snowfall for southern LA?

[Flyinman]

Wxman, thanks for the update. Yes I am now seeing the changes and I agree better be homw by noon. Thanks again.

[lrak]

Any update on the timing of all of this? I have heard and read it can begin as early as tomorrow morning but mostly tomorrow afternoon is the focus. I am really trying to beat all the weather as I know people will be driving crazy.

Cold rain may start 7am-8am, maybe some sleet at first. Rain changes to snow by 11am-1pm. Snow lasts until 6pm-8pm then ends. Maybe some thunder snow mid afternoon. Roads start to get dangerous by 2-3pm, so be home by noon.

If you got room my 5 yr old boy and I will travel your way, he keeps asking "when is it going to snow Daddy?"

[Jag95]

Wxman got a link for snowfall for southern LA?

http://wxcaster.com/gis-gfs-snow-overlays.htm

[southerngale]

Any update on the timing of all of this? I have heard and read it can begin as early as tomorrow morning but mostly tomorrow afternoon is the focus. I am really trying to beat all the weather as I know people will be driving crazy.

Cold rain may start 7am-8am, maybe some sleet at first. Rain changes to snow by 11am-1pm. Snow lasts until 6pm-8pm then ends. Maybe some thunder snow mid afternoon. Roads start to get dangerous by 2-3pm, so be home by noon.

If you got room my 5 yr old boy and I will travel your way, he keeps asking "when is it going to snow Daddy?"

If he doesn't have room, book a hotel and make a mini-vacation out of it. Just leave today so you don't have to travel in it tomorrow. And if it all falls apart, there's lots to do in Houston. There's even an outdoor ice skating rink now.

[wxman57]

Does that map go to the Central Gulfcoast wxman?

It goes all across the country, just pick a blue square:
http://wxcaster.com/gis-gfs-snow-overlays.htm