(New!!) Cold for the Deep South (Models, Maps, Discussion)

[jeff]

Arctic cold front passing through the area currently with temperatures dropping 10-15 degrees.

Cold wet weekend in store for the area with the threat for freezing rain and icing Saturday night across our northern counties.

What a difference a day makes:

Dallas: record high of 85 yesterday (high today 36)

Laredo: high of 100 yesterday (high today 47)

Houston: record high of 81 yesterday (high today 68 this morning, low will be this afternoon or evening)

Arctic front should arrive at the coast in the next few hours with strong cold air advection in progress across the entire area. Upstream temps. have fallen into the mid and upper 30’s across N TX and this should advect southward this afternoon under cloudy skies.

Next big concern is precipitation this weekend with a very cold surface dome. Plethora of watches and advisories being issued across TX in anticipation of a winter storm this weekend. Isentropic pattern (ascent of warm air above the surface cold air) begins in earnest this afternoon and continues through the entire weekend. This will produce periods of rain and widespread clouds for the next several days. Main concern is surface freezing line and its ultimate location Saturday night. This line will dictate where it is liquid and where it is ice. Guidance continues to show lows at or below freezing north of a line from Columbus to Conroe to Livingston Saturday night and this is where light freezing rain may occur. Given there is still a 24 + hour period before the onset of such conditions any advisories and watches are being held until this afternoon, although I would not be surprised if a portion of our area is under a Winter Weather Advisory by Saturday afternoon. Significant icing and sleet is expected across N TX the entire weekend and travel N and NW of SE TX will be extremely difficult.

Forecast (Harris County):



Today:

Cloudy with a 30% chance of light rain. Much colder with temperatures falling into the 40’s. N winds 15-25mph.



Tonight:

Cloudy with a 40% chance of rain. Lows in the upper 30’s. N winds 10-20mph



Saturday:

Cloudy and cold with a 60% chance of rain. Near steady temperatures in the upper 30’s. N winds 10mph



Saturday night:

Cloudy and cold with a 60% chance of rain. Lows in the low to mid 30’s. Rain may change to freezing rain north of a line from Columbus to Hempstead to Livingston. Ice accumulation should be less than 1/10th of an inch.



Sunday:

Cloudy and cold with a 50% chance of rain. Highs in the mid to upper 30’s.

[jeff]

Winter Storm Watch has been issued for that part of N TX north of a line from Temple to Palestine including all of the metro area.

Prolonged freezing rain and sleet event expected this weekend.

Travel will become increasingly difficult after sun set tonight.

What a difference a day can make after a record high of 85 yesterday, temps. will not get out of the 30’s today. Arctic front is well south of the area with a shallow but very cold air mass in place.

The real fun begins this evening as surface temperatures fall to freezing or below and remain there for most of the weekend. Isentropic lifting (or the gradual flow of warm moist air over the cold air at the surface) will produce periods of rain. With temps. at the surface below freezing much of the rain will freeze on contact and produce icing across the area. The cold air dome deepens some Saturday night resulting in a freezing rain and sleet mixture.

Forecast amounts for between 1/10th and 1/4th of an inch over the entire weekend which will make travel nearly impossible. TXDOT has begun deployment of anti-icing agent on area bridges and overpasses and local jurisdictions will conduct sanding operations once the precip. begins. Increased precip. amounts would result in the need for an Ice Storm Warning across the area, as trees and power lines would be in jeopardy of failing under the pressure of the ice.

[cheezyWXguy]

Jeff, do you think there will be an icestorm warning by this afternoon in my area

[cctxhurricanewatcher]

Laredo: high of 100 yesterday (high today 47)


You got to love extremes!

[wxman22]

Jeff with highs in the mid to upper 30's Sunday do you think we may have a chance of frozen precip Sunday to? (The NAM points to this possibility)

[jeff]

Jeff, do you think there will be an icestorm warning by this afternoon in my area

I think any warning will not come until Saturday once it is known how much QPF is happening and expected. Winter Storm Warning is more likley actually.

[jeff]

Jeff with highs in the mid to upper 30's Sunday do you think we may have a chance of frozen precip Sunday to? (The NAM points to this possibility)

Our only real chance of anything besides rain is freezing rain. The depth of the cold air will not be deep enough for snow and not really for sleet either. We will have to closely watch the freezing line as it will determine the icing area. Feel that this line will be somwhere between KCLL and KIAH Sunday morning. It is going to be either 32 or below with icing or 33 and above with rain given the profiles.

[wxman22]

Heres my latest discussion: Looks as though things may get intresting after all around southeast texas as a ARTIC front has pushed halfway through the area. Behind the front there is a 10 deegree drop in temps. Looks like showers should increase starting later on this evening as insotropic lift unfolds. With a shallow dome of cold air in place and pacific moisture overuns the shallow cold air. Saturday looks to be wet with on & off light showers. As tempetures "tumble" down Saturday night things could get intresting as temps may get to freezing in places across the area especcialy the north. With light freezing rain & sleet possible RIGHT NOW it doesnt look like Houston will see any frozen precip but if temps are a little colder than thinking there may be freezing rain in Houston proper.......??????

[weatherrabbit_tx]

feel that line from hempstead to livingston may have to pushed southeastward a bit to include mainly north of I-10, this is a devloping and tricky one this time to try to forecast, my feeling north of I-10, places like hooks(tomball), conroe, maybe even bush intercontinetal in the upper 20s to near 30 ideal for frozen precip.......

[Portastorm]

Temperatures continue to plummet in the greater Austin metro area this morning. I've personally watched the temps in north Austin go from 44 to 40 in 2 1/2 hours. Dew points also dropping and I keep thinking about what AFM said how when evap cooling occurs with light rain how the two numbers meet somewhere in the middle. With dew points in the low 20s and air temp near 40 ... well, freezing's a possibility!

Hill Country temps also continue to fall. Northern Hill Country is now in the middle 30s while places like Fredericksburg are in the mid to upper 30s.

I'm curious how the air temps are reacting as compared to what the models have suggested.

[wxman22]

I know it a computer generated forcast but accuweather does have ICE accumulations.... (also click day 2)

http://wwwa.accuweather.com/winter/maps ... ce&large=0

[wxman22]

8AM SPECIAL WEATHER STATEMENT UPDATE (for southeast Texas):


SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
829 AM CST FRI FEB 17 2006

GMZ330-335-350-355-370-375-TXZ163-164-176>179-195>200-210>214-226-
227-235>238-172200-
MATAGORDA BAY-GALVESTON BAY-
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM-
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM-
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM-
WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM-HOUSTON-TRINITY-
MADISON-WALKER-SAN JACINTO-POLK-BURLESON-BRAZOS-WASHINGTON-GRIMES-
MONTGOMERY-LIBERTY-COLORADO-AUSTIN-WALLER-HARRIS-CHAMBERS-WHARTON-
FORT BEND-JACKSON-MATAGORDA-BRAZORIA-GALVESTON-
INCLUDING THE CITIES OF...CROCKETT...TRINITY...GROVETON...
MADISONVILLE...HUNTSVILLE...SHEPHERD...COLDSPRING...LIVINGSTON...
CORRIGAN...CALDWELL...LAKE SOMERVILLE...COLLEGE STATION...BRYAN...
BRENHAM...NAVASOTA...THE WOODLANDS...CONROE...LIBERTY...
CLEVELAND...DAYTON...COLUMBUS...EAGLE LAKE...WEIMAR...SEALY...
BELLVILLE...HEMPSTEAD...BROOKSHIRE...HOUSTON...PASADENA...
WINNIE...MONT BELVIEU...ANAHUAC...EL CAMPO...WHARTON...
SUGAR LAND...MISSOURI CITY...RICHMOND...ROSENBERG...EDNA...
BAY CITY...PALACIOS...PEARLAND...LAKE JACKSON...ALVIN...
ANGLETON...FREEPORT...GALVESTON...LEAGUE CITY...TEXAS CITY...
FRIENDSWOOD
829 AM CST FRI FEB 17 2006

...STRONG COLD FRONT MOVING THROUGH SOUTHEAST TEXAS THIS MORNING
USHERING IN MUCH COOLER AIR...

A STRONG COLD FRONT IS MOVING THROUGH SOUTHEAST TEXAS THIS MORNING
AND IS EXPECTED TO BE OFF THE COAST LATER THIS MORNING. MUCH COLDER
AIR WILL CONTINUE TO FILTER IN BEHIND THE FRONT RESULTING IN A
RETURN TO MORE WINTER LIKE CONDITIONS FOR THE AREA.

TODAY`S HIGH TEMPERATURES ARE EXPECTED TO OCCUR THIS MORNING.
READINGS WILL FALL THROUGHOUT THE DAY WITH LOWER 40S INLAND AND
LOWER TO MID 50S ALONG THE COAST EXPECTED BY SUNSET. CLOUDY SKIES
AND INCREASING RAIN CHANCES CAN ALSO BE EXPECTED.

FROM TONIGHT AND ON THROUGH THE WEEKEND...CLOUDY SKIES...COLD
TEMPERATURES AND THE CHANCE OF RAIN WILL PERSIST. AT THIS TIME...
PRECIPITATION ACROSS MUCH OF SOUTHEAST TEXAS IS EXPECTED TO BE
ONLY RAIN AS TEMPERATURES REMAIN ABOVE FREEZING. THERE IS A CHANCE
FOR SOME FREEZING RAIN ACROSS THE NORTHERN COUNTIES OF THE AREA...
ROUGHLY ALONG AND NORTH OF A LINE FROM BRENHAM TO HUNTSVILLE TO
TRINITY...SATURDAY NIGHT THROUGH SUNDAY MORNING. COMPUTER MODELS
CONTINUE TO POINT TOWARD THE POSSIBILITY OF EVEN COLDER TEMPERATURES
FURTHER SOUTH THAN IS CURRENTLY FORECASTED. IF THIS TREND
PERSISTS...WINTER WEATHER ADVISORIES MAY EVENTUALLY BE REQUIRED
FOR AREAS FURTHER TO THE SOUTH.

WEEKEND TRAVEL NORTH AND WEST OF SOUTHEAST TEXAS...TOWARD THE RED
RIVER OR THE HILL COUNTRY AREAS...SHOULD BE AVOIDED IF POSSIBLE DUE
TO THE CHANCE OF FREEZING OR FROZEN PRECIPITATION. WINTER WEATHER
ADVISORIES... INCLUDING WATCHES OR WARNINGS...WILL LIKELY BE
ISSUED FOR PORTIONS OF THESE AREAS.

STAY TUNED TO NOAA WEATHER RADIO OR OTHER WEATHER NEWS SOURCES
FOR FURTHER UPDATES ON THIS DEVELOPING WINTER WEATHER EVENT

[wxman22]

Looks like the new 12z NAM brings the frozen precip even closer....


http://www.rap.ucar.edu/weather/model/d ... 24hr72hr30

[aggiecutter]

portastorm, you guys in austin are nearly as cold as Texarkana. We're currently 39. I've seen this happen many times before where the arctic air would first plunge south and then ooze to the east. Even west texas has temps in the mid 20's nearly all the way to mexico. Moisture will be the key to this winter event. Temps are a given even down into the hill country.

http://www.weatherimages.org/data/imag226.html

[Portastorm]

portastorm, you guys in austin are nearly as cold as Texarkana. We're currently 39. I've seen this happen many times before where the arctic air would first plunge south and then ooze to the east. Even west texas has temps in the mid 20's nearly all the way to mexico. Moisture will be the key to this winter event. Temps are a given even down into the hill country.

http://www.weatherimages.org/data/imag226.html

Yes! I have also seen similar events, aggiecutter.

It is 40.5 degrees at my house right now, 9:25 a.m. I also notice that the drizzle and light rain is starting to occur in certain areas of the Hill Country ... a little ahead of schedule.

This is really going to be something all of us in Texas need to watch in real time. Y'all up there look to be in for a nasty freezing event. I hope it's not too devastating for your sake!

[Extremeweatherguy]

wow! look at day 2 on accuweather (Sat). If this is right then ice could surely reach Houston!

http://wwwa.accuweather.com/winter/maps ... 2&site=TXS

[wxman22]

***UPDATE***

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1024 AM CST FRI FEB 17 2006

.UPDATE...
COLD FRONT HAS MADE IT TO THE COAST. AT 16Z...TEMPERATURES HAVE
FALLEN INTO THE MID TO UPPER 40S UP NORTH AND INTO THE MID 50S AT
ALL BUT THE IMMEDIATE COAST NEAR GALVESTON (66 DEGREES). EXPECT
READINGS TO CONTINUE TO SLOWLY FALL THIS AFTERNOON AREAWIDE. RADAR
SHOWS LIGHT RAIN DEVELOPING AND MOVING NORTHWARD ACROSS PORTIONS
OF SOUTHEAST TEXAS. THIS WILL ALSO CONTINUE THIS AFTERNOON.

THERE IS STILL A QUESTION OF WHETHER OR NOT THE NORTHERN PORTIONS
OF SOUTHEAST TEXAS (ANY MAYBE EVEN CENTRAL PARTS OF THE AREA)
MIGHT SEE A MIXTURE OF LIGHT RAIN AND LIGHT FREEZING RAIN SATURDAY
NIGHT/SUNDAY MORNING. 12Z NAM GUIDANCE HAS TEMPERATURES THAT
SUPPORT THIS SCENARIO...BUT AT THE SAME TIME HAS LOWERED ITS POPS.
THE MAV GUIDANCE THAT JUST ARRIVED IS VERY SIMILAR TO THE NAM.
WILL EVALUATE THE NEW MODEL DATA AND ADDRESS THIS POTENTIAL WINTER
WEATHER EVENT IN THE AFTERNOON DISCUSSION.

[jeff]

Winter Storm to impact the state this weekend.



Increasing threat for freezing rain and icing across SE TX this weekend.



Latest model guidance has come in even colder for the Saturday night through Monday morning time frame with the threat for freezing rain being expanded southward. Feel central and northern counties may be under the gun for icing starting Saturday night and into Sunday morning. Although amounts are forecast to be light, even a very small amount of ice can make for hazardous driving conditions.



A Winter Weather Advisory or Winter Storm Watch may be required for locations north of I-10 late today or early Saturday.



Will take a very close look at the prospects for freezing rain and ice this afternoon and send another e-mail before 400pm.

[Portastorm]

The plot thickens ...

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1049 AM CST FRI FEB 17 2006

.UPDATE...UPDATED THE GRIDS THIS MORNING TO ACCOUNT FOR THE
CURRENT CONDITIONS. THE COLD AIR CONTINUES TO SPILL INTO SOUTH
CENTRAL TEXAS AND THE HILL COUNTRY...WHERE TEMPERATURES IN THE
HILL COUNTRY HAVE STARTED FALLING INTO THE MID 30S. TEMPERATURES
WILL CONTINUE TO FALL THROUGHOUT THE DAY. LIGHT PRECIPITATION IS
SHOWING ON RADAR OF WHICH SOME HAS STARTED REACHING THE GROUND.
WILL FOCUS ON ESPECIALLY THE FORECAST FOR TONIGHT AS NEW MODEL
RUNS CONTINUE TO LOWER TEMPERATURES. THERE IS A POSSIBILITY OF
FREEZING PRECIPITATION TONIGHT...ESPECIALLY OVER THE HILL COUNTRY.

[Stormcenter]

Winter Storm to impact the state this weekend.



Increasing threat for freezing rain and icing across SE TX this weekend.



Latest model guidance has come in even colder for the Saturday night through Monday morning time frame with the threat for freezing rain being expanded southward. Feel central and northern counties may be under the gun for icing starting Saturday night and into Sunday morning. Although amounts are forecast to be light, even a very small amount of ice can make for hazardous driving conditions.



A Winter Weather Advisory or Winter Storm Watch may be required for locations north of I-10 late today or early Saturday.



Will take a very close look at the prospects for freezing rain and ice this afternoon and send another e-mail before 400pm.

What about the area around Jackson, MS? Any chance for frozen precip there?