Texas winter wx thread (2009-2010)

[HockeyTx82]

Gfs actually is warmer than previous. I'm starting to question the move to the new Gfs a few weeks back.

Warmer in regards to what and where?

[Ntxw]

Gfs actually is warmer than previous. I'm starting to question the move to the new Gfs a few weeks back.

Warmer in regards to what and where?

Still cold just not as cold as the other runs and further east. My trust on the gfs is very low. To me it seems very conservative compared to the other global models since the switch and jumps on the other bandwagons after vs the way it was before which was see crazy things in advance and tone down later.

[iorange55]

Let's not panic here, comparing it to the 12z run it's not THAT much warmer, or that much further east. Just a slight jog on both plus it is the GFS this is what it does. Forecast still looks good to me.

[Ntxw]

Let's not panic here, comparing it to the 12z run it's not THAT much warmer, or that much further east. Just a slight jog on both plus it is the GFS this is what it does. Forecast still looks good to me.

I'm not questioning the cold at all, I guess i'm picking out the logistics (or lack of depends on how you see it) of our "new\improved" GFS =P

[iorange55]

Let's not panic here, comparing it to the 12z run it's not THAT much warmer, or that much further east. Just a slight jog on both plus it is the GFS this is what it does. Forecast still looks good to me.

I'm not questioning the cold at all, I guess i'm picking out the logistics of our new\improved GFS =P

My post was directed towards a post that apparently was just deleted, lol. Figures.

[HockeyTx82]

Let's not panic here, comparing it to the 12z run it's not THAT much warmer, or that much further east. Just a slight jog on both plus it is the GFS this is what it does. Forecast still looks good to me.

I'm not questioning the cold at all, I guess i'm picking out the logistics of our new\improved GFS =P

My post was directed towards a post that apparently was just deleted, lol. Figures.

Yeah, I was thinking out loud, posted, then was like that was stupid.....

[wxgirl69]

GFS does predict a fair bit of mid-level moisture on Friday (575mb to 400mb), but it has quite dry air in the lower 5000-7000 ft. So, I agree, could see some snow aloft but not reaching the ground Friday.

Will we still see snow and or is it tooooo high and will melt before it ever becomes visible to the human eye..

[weatherguy425]

whether it comes to fruiton or not, it does appear a decent amount warmer...

[wxgirl69]

What is Viagra???? OOPS!!! I mean Virga... LOL

[HockeyTx82]

What is Viagra???? OOPS!!! I mean Virga... LOL

From Wikipedia.... http://en.wikipedia.org/wiki/Virga

In meteorology, virga is an observable streak or shaft of precipitation that falls from a cloud but evaporates before reaching the ground.[1] At high altitudes the precipitation falls mainly as ice crystals before melting and finally evaporating; this is usually due to compressional heating, because the air pressure increases closer to the ground. It is very common in the desert and in temperate climates. In North America, it is commonly seen in the Southern United States and the Canadian Prairies.

[iorange55]

The ECMWF 0z run looks to continue the cold. Lol it's almost as if its boring to say now cause we've been watching this for so long now, but I can't wait to feel what 13 degrees feels like. Haven't really been in that cold of an airmass before.

[Ntxw]

Anything under 25 to me is the same. By then I'm too numb to really feel much at all whether it's 15 or 0 lol. I think this has been the best consensus run by the models that I have ever seen for winter. I'm glad that we finally get to experience winter at it's best (or worst depending on how you see it). We really have been spoiled the past decade or so with such relatively mild winters.

[srainhoutx]

Saw some slight changes on the overnight runs. Darn CMC is still suggesting some post frontal moisture in the Friday time frame. Even the EC had a bit of a different look at the 500mb level with a strung out WSW to ENE S/W mess. I just wonder if some surprises aren't ahead in guidance the next couple of days. We will see.

[Portastorm]

The one thing about the GFS that is not making sense to me is how quickly it erodes the Polar airmass and displaces it via a more progressive flow by the weekend. If this airmass is as dense and stout as advertised, it ain't going anywhere anytime soon. I have seen this happens over the years where these airmasses stick around longer than originally thought.

I'm not suggesting the entire weekend will be bitter cold or anything ... but I'm skeptical of seeing some of these forecast highs in the 50s by Sunday.

Meanwhile, I concur with all the thoughts posted already on the slightly warmer GFS runs and the subtle Euro and CMC changes. Given that we're 48 hours out from the event, unless the 12z runs have some pleasant surprises for us, I'm thinking we need to pack our bags and check out of the "Maybe We'll Get Snow from This Front" Hotel and move along.

[srainhoutx]

Morning e-mail from Jeff...

Major Arctic air outbreak heading for TX.



Long duration sub-freezing temperatures expected Thursday PM – Saturday PM.



Preparations to protect plants, pipes, and pets/livestock should be completed by Wednesday evening.



Discussion:

A taste of what is to come this morning with widespread lows in the upper 20’s and lower 30’s with nearly all locations except the coast and deep urban heat core at or below freezing…these will be our highs come Friday. This current polar high will shift eastward today allowing temperatures to recover to near 50 (still 12 degrees below average) by mid afternoon under mainly sunny skies. Clouds will rapidly increase tonight with a chance of light to moderate rain developing on Wednesday in a warm air advection regime prior to the arctic front. Highs on Wednesday will reach the mid to upper 50’s and this will be the warmest we will see for the 4 days.



All eyes turn toward the north late Wed PM into early Thursday as powerful arctic surface high pressure plows down the plains and roars through TX on its way to deep interior Mexico. Heart of the arctic air mass over NW Canada is on the move this morning under the influence of a 1045mb high which will build to over a 1054mb high by this time tomorrow as it enters the northern Rockies. Arctic frontal boundary will plunge southward at 40-50mph down the plains entering TX late Wednesday and pushing off the coast early Thursday morning. Will start the day Thursday near 40 and fall from that point under very strong cold air advection regime. Impressive surface pressure rises will result in very strong NW winds of 20-35mph with 40mph gust forcing wind chills into the 20’s and upper teens by Thursday afternoon. Freezing line will march southward under the cold air advection and reach I-10 by mid afternoon and the coastal regions by 600pm. Will see upper to mid 20’s N of I-10 by early evening with strong N winds continuing with wind chills falling into the lower teens and possible single digits over our northern and western counties.



Hard Freeze Warning will be required with criteria being greatly exceeded (at or below 25 for 2 hours). Onset of sub-freezing air mass N of I-10 will be around 300pm Thursday and do not expect temperatures to rise back above freezing until some point mid afternoon Saturday and only for a few hours. S of I-10, 16-20 hours of sub-freezing temperatures can be expected with highs on Friday only in the mid 30’s for a few hours.



Coldest night will be Friday night/Saturday morning as impressive arctic high settles over TX…entire state including deep south TX and the coast will fall below freezing. GFS raw plots show dewpoints falling to as low as -5F at IAH Friday afternoon suggesting an incredibly dry surface layer. With strong high pressure overhead, nearly clam winds, and a highly chilled/frozen top soil layer…the little heat we gain Friday will be lost quickly and with such low dewpoints a rapid temperature fall can be expected. Will go with mid-upper 10’s north of a line from Hempstead to The Woodlands to Liberty, 18-22 from Victoria to Sugar Land to IAH, 21-25 from Port Lavaca to Bay City to Angleton and 28-30 along the beaches including Galveston Island. Record low for IAH is 19 Saturday AM and this may be tied or broken. Will probably need to go with the middle teens at Conroe with a favorable cold air drainage pattern in the valley around Lake Conroe…could even go a little colder at this location.



Temperatures N of I-10 may be at or below freezing for 48-60 hours resulting in the potential for freezing and bursting of exposed pipes outside of homes and within exterior facing walls and attics.



As far as any frozen precipitation goes, any light rain will end fairly quickly behind the arctic front as very dry air settles in. May see a 1-2 hour window for a rain/sleet mix Thursday morning, but surface temperatures will still be above freezing. Could see a better shot at frozen precipitation over deep south TX Thursday night/Friday AM as a short wave tracks over that region, but this should remain south of our region. Bridges and overpasses should completely dry prior to the onset of freezing temperatures Thursday afternoon….but any prolonging of the rainfall slightly later on Thursday could result in some icing if roads are not completely dry…given the extremely dry air mass on its way I would suspect this will be a non issue and any minor ice that does form will quickly sublimate.



Preparations:


Protect pipes along the exterior of the house and within exterior walls. Open cabinet doors along outside facing walls to help prevent pipes from freezing. Disconnect outside water hoses and cover faucets. Turn off outdoor sprinkler systems.



As far as plants go…the best bet it to bring indoors what you can. For those plants in the ground heavy irrigation today and Wednesday and then multiple layers of cover will help, but with temperatures as low as forecast and for the duration only so much can be done and many tropicals will not survive this event. Forecasted lows are below the hardiness of many of the palms and citrus that grow in our area, and best bet is to try and save the roots/trunk wrapping them heavily with coverings. Strong north winds will be felt Thursday into early Friday morning so make sure to properly secure coverings. Advection freeze as we will see late Thursday into Friday is worse than the radiative freeze we will see Saturday AM as the concept of covering plants and providing a greenhouse effect does not work well with strong surface winds helping to remove the heat rising from the ground. Additionally, very low dewpoints will rapidly dry vegetation making them more susceptible to damage…deep watering today and Wednesday will be very important.



Pets/livestock should be protected during this event. With wind chills forecasted into the lower teens and single digits prolonged exposure to such conditions could be dangerous. Move livestock into protected areas and provide a source of water…many lakes and stock ponds will be frozen over by Friday morning and will remain frozen until Sunday afternoon.



Lows so far this morning:

IAH: 29

Hobby: 30

Sugar Land: 27

Tomball: 27

Conroe: 23

Huntsville: 23

Victoria: 30

Palacios: 30

Bay City: 32

Port Arthur: 25

Wharton: 32

College Station: 26

Brenham: 27

La Grange: 29

Giddings: 27

Austin Bergstrom: 21

[Roxy]

my poor, poor plumeria and orange tree.

[attallaman]

Morning e-mail from Jeff...

Major Arctic air outbreak heading for TX.



Long duration sub-freezing temperatures expected Thursday PM – Saturday PM.



Preparations to protect plants, pipes, and pets/livestock should be completed by Wednesday evening.



Discussion:

A taste of what is to come this morning with widespread lows in the upper 20’s and lower 30’s with nearly all locations except the coast and deep urban heat core at or below freezing…these will be our highs come Friday. This current polar high will shift eastward today allowing temperatures to recover to near 50 (still 12 degrees below average) by mid afternoon under mainly sunny skies. Clouds will rapidly increase tonight with a chance of light to moderate rain developing on Wednesday in a warm air advection regime prior to the arctic front. Highs on Wednesday will reach the mid to upper 50’s and this will be the warmest we will see for the 4 days.



All eyes turn toward the north late Wed PM into early Thursday as powerful arctic surface high pressure plows down the plains and roars through TX on its way to deep interior Mexico. Heart of the arctic air mass over NW Canada is on the move this morning under the influence of a 1045mb high which will build to over a 1054mb high by this time tomorrow as it enters the northern Rockies. Arctic frontal boundary will plunge southward at 40-50mph down the plains entering TX late Wednesday and pushing off the coast early Thursday morning. Will start the day Thursday near 40 and fall from that point under very strong cold air advection regime. Impressive surface pressure rises will result in very strong NW winds of 20-35mph with 40mph gust forcing wind chills into the 20’s and upper teens by Thursday afternoon. Freezing line will march southward under the cold air advection and reach I-10 by mid afternoon and the coastal regions by 600pm. Will see upper to mid 20’s N of I-10 by early evening with strong N winds continuing with wind chills falling into the lower teens and possible single digits over our northern and western counties.



Hard Freeze Warning will be required with criteria being greatly exceeded (at or below 25 for 2 hours). Onset of sub-freezing air mass N of I-10 will be around 300pm Thursday and do not expect temperatures to rise back above freezing until some point mid afternoon Saturday and only for a few hours. S of I-10, 16-20 hours of sub-freezing temperatures can be expected with highs on Friday only in the mid 30’s for a few hours.



Coldest night will be Friday night/Saturday morning as impressive arctic high settles over TX…entire state including deep south TX and the coast will fall below freezing. GFS raw plots show dewpoints falling to as low as -5F at IAH Friday afternoon suggesting an incredibly dry surface layer. With strong high pressure overhead, nearly clam winds, and a highly chilled/frozen top soil layer…the little heat we gain Friday will be lost quickly and with such low dewpoints a rapid temperature fall can be expected. Will go with mid-upper 10’s north of a line from Hempstead to The Woodlands to Liberty, 18-22 from Victoria to Sugar Land to IAH, 21-25 from Port Lavaca to Bay City to Angleton and 28-30 along the beaches including Galveston Island. Record low for IAH is 19 Saturday AM and this may be tied or broken. Will probably need to go with the middle teens at Conroe with a favorable cold air drainage pattern in the valley around Lake Conroe…could even go a little colder at this location.



Temperatures N of I-10 may be at or below freezing for 48-60 hours resulting in the potential for freezing and bursting of exposed pipes outside of homes and within exterior facing walls and attics.



As far as any frozen precipitation goes, any light rain will end fairly quickly behind the arctic front as very dry air settles in. May see a 1-2 hour window for a rain/sleet mix Thursday morning, but surface temperatures will still be above freezing. Could see a better shot at frozen precipitation over deep south TX Thursday night/Friday AM as a short wave tracks over that region, but this should remain south of our region. Bridges and overpasses should completely dry prior to the onset of freezing temperatures Thursday afternoon….but any prolonging of the rainfall slightly later on Thursday could result in some icing if roads are not completely dry…given the extremely dry air mass on its way I would suspect this will be a non issue and any minor ice that does form will quickly sublimate.



Preparations:


Protect pipes along the exterior of the house and within exterior walls. Open cabinet doors along outside facing walls to help prevent pipes from freezing. Disconnect outside water hoses and cover faucets. Turn off outdoor sprinkler systems.



As far as plants go…the best bet it to bring indoors what you can. For those plants in the ground heavy irrigation today and Wednesday and then multiple layers of cover will help, but with temperatures as low as forecast and for the duration only so much can be done and many tropicals will not survive this event. Forecasted lows are below the hardiness of many of the palms and citrus that grow in our area, and best bet is to try and save the roots/trunk wrapping them heavily with coverings. Strong north winds will be felt Thursday into early Friday morning so make sure to properly secure coverings. Advection freeze as we will see late Thursday into Friday is worse than the radiative freeze we will see Saturday AM as the concept of covering plants and providing a greenhouse effect does not work well with strong surface winds helping to remove the heat rising from the ground. Additionally, very low dewpoints will rapidly dry vegetation making them more susceptible to damage…deep watering today and Wednesday will be very important.



Pets/livestock should be protected during this event. With wind chills forecasted into the lower teens and single digits prolonged exposure to such conditions could be dangerous. Move livestock into protected areas and provide a source of water…many lakes and stock ponds will be frozen over by Friday morning and will remain frozen until Sunday afternoon.



Lows so far this morning:

IAH: 29

Hobby: 30

Sugar Land: 27

Tomball: 27

Conroe: 23

Huntsville: 23

Victoria: 30

Palacios: 30

Bay City: 32

Port Arthur: 25

Wharton: 32

College Station: 26

Brenham: 27

La Grange: 29

Giddings: 27

Austin Bergstrom: 21

Good gawd, look at that book report.

[CaptinCrunch]

NWS FTW TX

DRY AND STABLE NORTHWEST FLOW ALOFT WILL REMAIN OVER NORTH TEXAS
TODAY. SURFACE HIGH PRESSURE WILL MOVE EAST OF THE REGION TODAY
AND ALLOW A SOUTH/SOUTHEASTERLY WIND TO RETURN. HOWEVER...LOW
LEVEL MOISTURE WILL NOT RETURN UNTIL WEDNESDAY IN RESPONSE TO A
DEEPENING SURFACE LOW OVER WEST TEXAS. WARM AIR ADVECTION WILL SET
UP WEDNESDAY AND RESULT IN WARMER TEMPERATURES...ESPECIALLY IN THE
SOUTH AND SOUTHWEST ZONES.

A STRONG ARCTIC COLD FRONT SHOULD CROSS THE RED RIVER AROUND 6 PM
AND MOVE THROUGH ALL OF NORTH TEXAS BEFORE SUNRISE THURSDAY. SOME
LIGHT RAIN MAY ACCOMPANY THE COLD FRONT...ESPECIALLY EAST OF
INTERSTATE 35. MODELS CONTINUE TO GENERATE PRECIP IN THE COLD AIR
EVEN THOUGH INSENTROPIC SECTIONS INDICATE INCREASING MOIST
DOWNGLIDE BEHIND THE FRONT. HAVE OPTED TO MENTION A SLIGHT CHANCE
OF LIGHT FREEZING RAIN OR SNOW FOR A BRIEF TIME AFTER
MIDNIGHT...GENERALLY NORTH OF A HILLSBORO TO CANTON LINE. ANY
PRECIP THAT FALL SHOULD BE VERY LIGHT AND NO SIGNIFICANT
ACCUMULATIONS OF ANY KIND ARE EXPECTED. THE PRECIPITATION SHOULD
SHUT DOWN QUICKLY AS MUCH DRIER AND STABLE AIR MOVE IN BEHIND THE
FRONT. TEMPERATURES THURSDAY MORNING WILL RANGED FROM THE TEENS IN
THE NORTHWEST TO THE MID 30S IN THE SOUTHEAST AND LITTLE IF ANY
WARMING IS EXPECTED THROUGH THE DAY THURSDAY. A STRONG NORTH WIND
WILL PREVAIL BEHIND THE FRONT AND RESULT IN WIND CHILL VALUES IN
SINGLE DIGITS IN SOME LOCATIONS. THE SKY WILL CLEAR THURSDAY NIGHT
AND ALLOW FOR STRONG RADIATIONAL COOLING. WIND SPEEDS WILL REMAIN
IN THE 10 TO 15 MPH RANGE THURSDAY NIGHT AND RESULT IN WIND CHILL
VALUES BELOW 0 IN MANY LOCATIONS.

THE ARCTIC AIRMASS WILL REMAIN IN PLACE FRIDAY AND TEMPERATURES
SHOULD REMAIN BELOW FREEZING ACROSS THE ENTIRE REGION EVEN THOUGH
THE SUN WILL BE OUT. SATURDAY NIGHT WILL BE COLD AGAIN WITH MOST
LOCATIONS IN THE TEENS. A BIT OF A WARMUP IS EXPECTED SATURDAY AND
SUNDAY AS AN UPPER LEVEL RIDGE BUILDS IN FROM THE WEST. ANOTHER
REINFORCEMENT OF COLD AND DRY AIR WILL ARRIVE MONDAY NIGHT...BUT
NO PRECIP IS EXPECTED.

[txagwxman]

"with the middle teens at Conroe with a favorable cold air drainage pattern in the valley around Lake Conroe…could even go a little colder at this location."

There is no cold air drainage around Lake Conroe...CXO just radiates like mad (open sky, open field), similar to Magnolia which one Davis weather station was 22F this morning. In fact temps around Lake Conroe are warmer.

[Portastorm]

No hope shown by the 12z NAM for wintry precip fun later this week.

That's it ... I'm calling it for winter in Austin. Winter = Cancel.