SE TX/SW LA Winter WX - 2011-2012

[pwrdog]

Houston IAH is at 42 with a 27 dew point..

The temp just 15 miles NW of Houston IAH in Conroe is 39 with a dewpoint of 24..

West houston airport is 40 with a dew point of 25..

Downtown Houston is at 42 with a 29 dew point..

Lower dew points seem to be moving in pretty fast from the north and west....

Change over should happen quickly, I would think... For north and west houston ...

The corpus radar is showing moderate to heavy rain moving NE towards Houston..

The lower dewpoints near Houston should eat into that rain but start the temps dropping soon... It should also be strong enough to saturate all the levels..

Light sleet is now being reported in the western edge of the rain heading towards Houston..

[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

[Portastorm]

Well good luck today SE TX/SW LA friends ... hope you get everything that is advertised!

[ROCK]

Well good luck today SE TX/SW LA friends ... hope you get everything that is advertised!

Port, your making us feel bad....I will save a snowball in the freezer for you. Next time I am in Austin I will bring it up....

[Portastorm]

Well good luck today SE TX/SW LA friends ... hope you get everything that is advertised!

Port, your making us feel bad....I will save a snowball in the freezer for you. Next time I am in Austin I will bring it up....

You're a good guy ROCK!

Since we're upstream from y'all, I will keep you posted as snow starts here. We're supposed to get up to an inch and if we do, that's pretty amazing at any stretch since it is only Dec. 4th. But I'll be cheering for a four-alarm, massive, you-have-to-be-kidding-me snowstorm for your area today!

[Air Force Met]

That's an old article. I actually read it in the paper a couple of days ago...think it was Wednesday's?

Yup, I found out its from wednesday.But I wanted to highlight the comments from Bastardi that are comical.

Yeah...but no truer words have ever been spoken (at least about the weather guy)

[wxman57]

One of our meteorologists is reporting it's sleeting in Richmond (SW side of Houston) at 7am.

[Air Force Met]

One of our meteorologists is reporting it's sleeting in Richmond (SW side of Houston) at 7am.

The radar signature looks like sleet. That's some heafty DBZ given the IR cloud tops...

[wxman57]

Sleet just west of Bellaire, too (near west side of Houston).

[brunota2003]

One of our meteorologists is reporting it's sleeting in Richmond (SW side of Houston) at 7am.

The radar signature looks like sleet. That's some heafty DBZ given the IR cloud tops...

I second that...look at all the reds and oranges south of Houston and west of Galveston! Most definitely all ice (that doesnt necessarily mean it is all hitting the ground as ice, if it is even hitting the ground at all).

[srainhoutx]

Update @7:AM from Jeff...

Getting numerous reports of sleet from Austin and Fort Bend counties under radar bright band region with dbz nearing 55 over Matagorda and Brazoria counties. Just got a phone call of sleet in Rosenberg and anther call from East Bernard.



Surface dewpoints crashing into the lower to mid 20’s will allow heavy mid level based precipitation to wet bulb the surface temperatures to near or below freezing a few hours after the precipitation begins along and N of I-10 where mid 20 dewpoints are already in place.



Surface profiles are still too warm to support snow…but arctic air is building into the region helping to cool this column…sleet reports suggest snow aloft is melting on the way down and near surface layer is still warm too deep to support SN to the surface. Things will be changing very quickly this morning!



Interesting to note saturation of the lower layers as brought dewpoints at Wharton and Victoria above freezing…change over may take long along the coast as additional dry air must be brough southward to evaporate and cool the air temperature. Feel dewpoints are low enough along and N of US 59 to bring the air temp. to freezing 3-4 hours after preip. begins.

[srainhoutx]

From Jeff...

Getting numerous reports of sleet changing to snow over Fort Bend and Austin counties.



Surface temperatures remain above freezing so no accumulation at this time.



Should see snow into SW Harris County shortly.



IP reported at TMC and Bellaire



Just got a report of SN in Bellaire.

[ROCK]

rain mixed with Snow in Pearland.....heavy snow.....

[wxman57]

Rain mixed with big snowflakes here SE of Hobby Airport near 45 south and Fuqua.

[vbhoutex]

Radar shows you in the heaviest precipitation area attm. Not surprising to hear and now see on the tube in Rosenberg. With temp now 34f and falling pretty quickly I expect the changeover to begin soon in most areas showing precipitation. Wxman popped in while I was posting.

[ROCK]

I am in moderate snow fall now rain slowly changing over.....not much rain left really.....taking video....

[goCoogs]

SSnow and rain in the Westchase District right now at Richmond and the Beltway.

[srainhoutx]

Light snow in NW Harris County. Lift increasing SE of Austin as S/W approaches from the W. Radar from Austin...

http://radar.weather.gov/radar.php?rid= ... 1&loop=yes

[vbhoutex]

Changeover to snow has begun in Spring Branch. Nothing heavy yet just some flakes mixed in with temp at 33f.

[Diva]

C'mon snow.....keep on moving east!! Pretty please?! We're sitting here anxiously waiting in Orange County.