February 1-5, 2011 Arctic Blast/Winter Storm Discussion

[Andrew]

Look at the vertical profile from the 12z GFS. That is impressive but at the same time impossible to get any moisture out of:

[TexasMetBlake]

I am shocked that nobody has commented on the zones. HGX already had temps down to 23 for a forecast low next Thursday Night. Folks, that is a STRONG indication that we have wicked cold on the way and the likely hood of those temps being too warm is becoming more of a reality. For the far southern zones in the DFW CWA, they have a low of 16 for Hearne and a high of 35. So there could be BIG changes in the forecast ahead....especially since now the models are coming into strong agreement of severe cold across the area--especially with -11 isotherms showing up over Houston.

[Andrew]

I am shocked that nobody has commented on the zones. HGX already had temps down to 23 for a forecast low next Thursday Night. Folks, that is a STRONG indication that we have wicked cold on the way and the likely hood of those temps being too warm is becoming more of a reality. For the far southern zones in the DFW CWA, they have a low of 16 for Hearne and a high of 35. So there could be BIG changes in the forecast ahead....especially since now the models are coming into strong agreement of severe cold across the area--especially with -11 isotherms showing up over Houston.

Yea I was just about to comment on that. I kinda expect the Euro to drop down in temps next run. I felt like it had to high of surface temps for such a low 850mb temp. It is going to be interesting to say the least. Can't wait for the 18z GFS (that's a first).

[Mr. T]

MADE SOME CHANGES TO THE TEMPS IN THE EXTENDED PACKAGE. ARCTIC
FRONT SHOULD PUSH THRU THE REGION TUE MORNING AND OFF THE COAST
AROUND NOON. EXPECT ANOTHER ROUND OF SHRA/TSTMS AHEAD OF THIS
FRONT. GFS CAME IN MUCH COLDER THAN EARLIER RUNS AND SIMILAR TO
WHAT THE CANADIAN AND ECMWF WERE SHOWING A COUPLE DAYS AGO (H85
TEMPS -7C TO -11C BY THURS MORNING, LOWS IN THE TEENS AND RAW
SOUNDING FCST HIGHS NEAR FREEZING NORTH). DID LOWER TEMPS A
CATEGORY OR SO - GENERALLY A 4 WAY BLEND BETWEEN OUR OLD FCST, RAW
GFS, RAW ECMWF AND MEX NUMBERS. LOOKING LIKE THE THE NORTHERN HALF
OF THE REGION WILL SEE A HARD FREEZE WED AND THURSDAY NIGHTS AND
POSSIBLY FURTHER SOUTH IF TEMPS EVENTUALLY NEED FURTHER DOWNWARD
ADJUSTMENT. THANKFULLY CHANCES OF WINTERY PRECIP LOOK EXTREMELY LOW
AT THIS TIME. GRADUAL WARMING TREND SHOULD BEGIN LATE NEXT WEEK AS
THE SFC HIGH MOVES OFF TO THE EAST. 47

[TexasMetBlake]

Dallas:

THE CONFIDENCE IN THE MONDAY NIGHT AND TUESDAY FORECAST IS NOW
INCREASING AS THERE IS GENERALLY GOOD AGREEMENT IN THE MEDIUM
RANGE GUIDANCE. AN UPPER LEVEL TROUGH IS FORECAST TO INTENSIFY
ACROSS THE NORTHERN ROCKIES SUNDAY NIGHT INTO MONDAY AS IT DROPS
SOUTH. AN UPPER LOW THAT IS CURRENTLY OFF THE PACIFIC COAST WILL
ROTATE AROUND THE PERIPHERY OF THIS TROUGH AND RAPIDLY MOVE
THROUGH TEXAS EARLY TUESDAY. STRONG FORCING/LIFT COMBINED WITH
PLENTIFUL MOISTURE AND INSTABILITY WILL CREATE WIDESPREAD SHOWERS
AND A FEW STORMS MONDAY NIGHT AND TUESDAY. MEANWHILE AN ARCTIC
AIR MASS WITH A 1050+ MB SURFACE HIGH WILL BE BUILDING ACROSS
WESTERN CANADA AND HEADING SOUTH.

THE FORECAST CHALLENGE CONTINUES TO BE THE POSITION AND STRENGTH
OF THE COLD FRONT EARLY TUESDAY...AND THE FASTER GFS/NAM ARE
PREFERRED. AS PRECIPITATION BEGINS TO FALLS INTO SUBFREEZING
AIR...A CHANGE OVER TO FREEZING RAIN AND SLEET WOULD OCCUR. MODELS
HAVE COME INTO ALIGNMENT WITH OUR PREVIOUS FORECAST AND WE WILL
KEEP THE FREEZING RAIN LINE FROM COMANCHE TO WAXAHACHIE TO SULPHUR
SPRINGS. HOWEVER THIS LINE MAY BE ADJUSTED FARTHER SOUTH IF
CONFIDENCE CONTINUES TO INCREASE ON AN EARLY FRONTAL PASSAGE. WHAT
IS BECOMING MORE CERTAIN IS THAT SOME SIGNIFICANT ACCUMULATIONS OF
ICE AND SLEET AFFECTING TRAVEL ARE POSSIBLE ACROSS OUR NW ZONES
EARLY TUESDAY. THIS REGION SHOULD HAVE SURFACE TEMPS IN THE MID-
UPPER 20S BEFORE PRECIP ENDS. TOO SOON TO NAIL DOWN EXACT AMOUNTS
BUT WE SHOULD GET A BETTER IDEA BY TOMORROW. PRECIPITATION SHOULD
RAPIDLY COME TO AN END FROM WEST TO EAST EARLY TUESDAY AFTERNOON
WITH STRONG DOWNGLIDE AND SUBSIDENCE BEHIND THE SHORTWAVE...BUT
SOME LINGERING SNOW FLURRIES MAY OCCUR NORTH OF I-20 INTO EVENING.

ASIDE FROM THE WINTER PRECIP...THE BIG STORY FOR EVERYONE IS GOING
TO BE THE VERY COLD AIR AND STRONG WINDS. GFS IS FINALLY ON
BOARD WITH A COLD SOLUTION SIMILAR TO ECMWF/CANADIAN AND IT GIVES
US THE CONFIDENCE TO FURTHER LOWER OUR TEMPERATURES FOR MID-LATE
WEEK. THE UNUSUAL SOUTHWARD MOVEMENT OF THE UPPER TROUGH IS
EXCEPTIONALLY FAVORABLE TO DRIVE ARCTIC AIR INTO OUR REGION. 850MB
TEMP ANOMALIES APPROACH 4 STANDARD DEVIATIONS BELOW NORMAL OVER
WEST TEXAS...AND THIS IS SHAPING UP TO BE SOME OF THE COLDEST
AIR OUR REGION HAS SEEN IN AT LEAST A COUPLE YEARS. ADDING INSULT
ARE WINDS THAT WILL BE BLOWING AT 20-30 MPH AND GUSTY TUESDAY WITH
WIND CHILLS BELOW 0 NORTH OF I-20 AS TEMPS FALL INTO THE TEENS
TUESDAY NIGHT. BRISK NORTH WINDS WILL CONTINUE INTO WEDNESDAY
WITH THE SURFACE HIGH STAYING TO OUR NW AND DO NOT BELIEVE TEMPS
WILL MAKE IT ABOVE FREEZING IN OUR AREA FOR HIGHS. CONTINUED
COLD ON THURSDAY WITH MODELS SUGGESTING THE HIGH BUILDING IN OVER
US ON THURSDAY NIGHT FOR SOME BETTER RADIATIONAL COOLING. BELIEVE
THE MODELS ARE TOO QUICK TO WARM US UP AT THE END OF THE WEEK AND
WILL KEEP TEMPS COOL INTO NEXT WEEKEND. THERE IS VIRTUALLY NO
AGREEMENT IN FORECAST UPPER LEVEL PATTERNS NEXT WEEKEND...AND THUS
IT IS TOO EARLY TO SPECULATE ON PRECIPITATION POTENTIAL. WILL KEEP
POPS AT 10 PERCENT AND SHOW INCREASING CLOUDS.

[BiggieSmalls]

I like the sound of that! Should be interesting being that it is Superbowl Week in Dallas. Expect lots of complaining from our visitors, just like when Atlanta had their ice storm during Superbowl week in 2000 (i think).

[sambucol]

Is it time now to make preps for a hard and extended freeze? Is this similar to January 2010 or is this airmass colder?

[srainhoutx]

Is it time now to make preps for a hard and extended freeze? Is this similar to January 2010 or is this airmass colder?

It's time, sambucol. Tonight and tomorrow through at least late morning look damp. A brief reprieve on Monday before more showers/storms develop later on Monday evening until the front passes. I feel comfortable enough to advise folks that the cold is coming and as we can see there is model agreement to that fact. The NWS offices will likely ramp up Special Weather Statements/Hazardous Weather Outlooks tomorrow morning and those areas that may well see wintry precip, Winter Storm Watches/Advisories will likely also be issued tomorrow AM. Just my hunch, so take it for what it's worth.

[losmabies]

Thanks to everyone for the insights. It is just still disappointing that we will finally have the cold weather to support some sort of wintery weather and there is no moisture to be found.

Again - thanks to all those who help explain things to newbies like me.

[srainhoutx]

As expected, SWS are going up across TX...

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN ANGELO TX
410 PM CST SAT JAN 29 2011

TXZ049-054-064>066-071>073-076>078-098-099-113-114-127-128-139-
140-154-155-168>170-301100-
FISHER-NOLAN-STERLING-COKE-RUNNELS-IRION-TOM GREEN-CONCHO-
CROCKETT-SCHLEICHER-SUTTON-HASKELL-THROCKMORTON-JONES-SHACKELFORD-
TAYLOR-CALLAHAN-COLEMAN-BROWN-MCCULLOCH-SAN SABA-MENARD-KIMBLE-
MASON-
INCLUDING THE CITIES OF...ROTAN...ROBY...SWEETWATER...
STERLING CITY...ROBERT LEE...BRONTE...BALLINGER...WINTERS...
MERTZON...SAN ANGELO...EDEN...OZONA...ELDORADO...SONORA...
HASKELL...THROCKMORTON...WOODSON...STAMFORD...ANSON...HAMLIN...
ALBANY...ABILENE...CLYDE...BAIRD...CROSS PLAINS...COLEMAN...
BROWNWOOD...BRADY...SAN SABA...MENARD...JUNCTION...MASON
410 PM CST SAT JAN 29 2011

...CHANCE OF ICE AND SNOW MONDAY NIGHT INTO TUESDAY...
...MUCH COLDER TEMPERATURES THIS WEEK...

ALTHOUGH THERE REMAINS A GREAT DEAL OF UNCERTAINTY ABOUT THE
AMOUNTS OF ICE AND SNOW THAT MAY FALL ACROSS WEST CENTRAL TEXAS
MONDAY NIGHT AND TUESDAY...THERE IS A POTENTIAL FOR HIGH ENOUGH
ACCUMULATIONS TO CREATE DANGEROUS TRAVEL CONDITIONS ACROSS
PORTIONS OF THE AREA. IN ADDITION...WIND CHILL READINGS BELOW ZERO
WILL BE POSSIBLE ON TUESDAY AND WEDNESDAY. THIS PROLONGED COLD WILL
CREATE HAZARDOUS CONDITIONS FOR LIVESTOCK AND OUTDOOR PETS.
EXPOSED PIPES MAY FREEZE AND BURST IF THEY ARE NOT PROPERLY INSULATED.

A STRONG UPPER LEVEL STORM SYSTEM WILL MOVE ACROSS THE SOUTHWESTERN
UNITED STATES ON MONDAY. AT THE SAME TIME A CANADIAN AIR MASS WILL
BE MOVING SOUTH INTO THE CENTRAL US. THIS COLD AIR MASS WILL
APPROACH WEST CENTRAL TEXAS DURING THE EARLY MORNING HOURS ON
TUESDAY AND PERSIST THROUGH THE REST OF THE WEEK.

THE UPPER LEVEL STORM SYSTEM AND THE COLD FRONT BRING
PRECIPITATION ACROSS WEST CENTRAL TEXAS MONDAY NIGHT. AFTER
MIDNIGHT...THE RAIN WILL LIKELY CHANGE OVER TO SLEET AND SNOW AS
THE COLDER AIR MASS MOVES INTO THE AREA. THE WINTRY PRECIPITATION
WILL END DURING THE DAY ON TUESDAY.

GIVEN THE UNCERTAINTY WITH BOTH THE TIMING OF THE STORM SYSTEM AND
THE FRONT...ADJUSTMENTS WILL BE MADE TO THE FORECAST AS WE GET
CLOSER TO THE EVENT. STAY TUNED TO NOAA WEATHER RADIO...YOUR LOCAL
TV AND RADIO...AND OUR NATIONAL WEATHER SERVICE WEB PAGE FOR
UPDATES.

[cristina99]

you never know - mother has been known to surprise us - and I'm talking about winter precip - not getting warmer. I hope!! Wouldn't mind a dusting of snow.

[Andrew]

We could see this happening again too:

[srainhoutx]

One more post before I head out for the evening, but thought is was worth mentioning. San Angelo afternoon discussion does a great job explaining the potential problems in the forecast ahead. While we are not in San Angelo, a faster front arrival and a slower progression of the Upper Low could mean a whole different situation regarding sensible weather across the area...


.LONG TERM...
IT WILL TURN VERY COLD BY THE MIDDLE OF NEXT WEEK...WITH THE
CHANCE OF SOME WINTRY PCPN TUESDAY. CURRENT SURFACE MAP HAS A LARGE
ARCTIC AIRMASS ACROSS NORTHERN CANADA AND NORTHWEST TERRITORIES...WITH
SURFACE TEMPS OF -20 TO -35. ALSO...GOOD CROSS POLAR UPPER LEVEL
FLOW WILL HELP TRANSPORT THE ARCTIC AIR SOUTH ACROSS MUCH OF THE
CONUS NEXT WEEK. THE POSSIBILITY OF WINTRY PCPN LIES WITH AN UPPER
LEVEL LOW THAT IS LOCATED OF THE PACIFIC NORTHWEST COAST.

ONE MORE VERY WARM DAY MONDAY...WITH HIGHS IN THE MID 60S TO MID
70S. THEN THE BOTTOM DROPS OUT AS ARCTIC COLD FRONT WILL MOVE SOUTH
ACROSS WEST CENTRAL TEXAS MONDAY NIGHT AND WILL PROBABLY BE SOUTH OF
THE I-10 CORRIDOR BY 15Z TUE. THE NAM AND EC MODELS ARE INDICATING
THE FRONT MOVING FASTER...WHICH IS PROBABLY A GOOD BET.
TEMPERATURES WILL SLOWLY FALL INTO THE 20S AND 30S TUESDAY. VERY
COLD AIR WILL POUR SOUTH ACROSS THE CWFA TUESDAY AND WEDNESDAY.
THIS WILL PROBABLY BE THE COLDEST TEMPERATURES SO FAR THIS SEASON.
THE MODELS ARE ALSO INDICATING A DEEP COLD AIRMASS WITH 850 MB
TEMPS BETWEEN -10 AND -15 DEG C TUESDAY AND WEDNESDAY. GOING WITH
LOWS IN THE THE LOWER TO MID TEENS TUESDAY NIGHT AND WEDNESDAY
NIGHT AND HIGHS ONLY 25 TO 35 WEDNESDAY...AND IN THE 30S THURSDAY.
ALSO...NORTH WINDS OF 15 TO 25 MPH AND GUSTY MAY PRODUCE WIND
CHILLS OF 0 TO -5 ACROSS THE BIG COUNTRY TUESDAY AND WEDNESDAY
...WITH SINGLE DIGITS ACROSS THE REST OF THE AREA. A SLIGHT
MODERATION IN TEMPERATURES IS EXPECTED BY NEXT WEEKEND.

AS THE ARCTIC FRONT MOVES SOUTH MONDAY NIGHT...AND UPPER LEVEL
LOW(CURRENTLY OF THE PACIFIC NORTHWEST COAST) WILL SWING SOUTH
INTO THE SOUTHERN ROCKIES...AND THEN NORTHEAST ACROSS THE SOUTHERN
PLAINS. ITS GOING TO BE RACE BETWEEN THE MUCH COLDER TEMPERATURES
AND UPPER LEVEL SUPPORT. LOOKS LIKE THE PCPN WILL START AS RAIN
MONDAY EVENING...WITH THE POSSIBILITY OF AN ISOLATED TSTM OR TWO.
AS THE ARCTIC AIR ARRIVES...THE PCPN WILL CHANGE TO SLEET AND SNOW
ACROSS THE BIG COUNTRY AFTER 06Z TUE. FURTHER SOUTH...EXPECT FZRA
AND SLEET ACROSS THE CONCHO VALLEY AND HEARTLAND AFTER 12Z TUE.
THERE IS STILL A LOT OF UNCERTAINTY ON WINTER PCPN AMOUNTS. IF
THE UPPER LEVEL SYSTEM IS DELAYED ANOTHER 6 TO 12 HOURS...THE
CHANCES INCREASE FOR A SIGNIFICANT WINTER WEATHER EVENT ON
TUESDAY...INCLUDING THE POTENTIAL OF DANGEROUS TRAVEL CONDITIONS
DUE TO ENOUGH ICE ACCUMULATION. FOR NOW...WILL END THE PCPN BY
00Z WED.

RESIDENTS OF WEST CENTRAL TEXAS SHOULD KEEP UP ON THE LATEST
INFORMATION FOR THIS DEVELOPING WINTER WEATHER SITUATION. WILL
ISSUE AND SPS FOR THE AFTERNOON FORECAST PACKAGE.

[cristina99]

simple terms please - i am still learning how to read these forecasts. "sensible" weather - don't let me down - or do you mean winter precip

[wxman57]

simple terms please - i am still learning how to read these forecasts. "sensible" weather - don't let me down - or do you mean winter precip

That forecast discussion was for way out in west Texas, not here. We're not expecting any winter precipitation in Houston.

[biggerbyte]

Nothing has changed for our area. Confirmation for us is just a day or two off, and there are some things to watch for between now and then that could alter current thinking on temps. Right now, it just looks like some of the same temp ranges we have already seen. Precip. is in question, but even that currently looks cold wet, but not frozen. Current forecast from the NWS will reflect these statements as well.

A word of caution. This is a developing situation. There is wiggle room, and changes in both temp and precip. forecasts are possible right down to a day or two before. I urge everyone to just pay attention and prepare for worse scenario. If the situation changes, it could be in a big way. Teens would be easily met in our area, with evolving possibilities, that if at the right times, could be frozen.

Sunday and Monday will be telling.

[Andrew]

Nothing has changed for our area. Confirmation for us is just a day or two off, and there are some things to watch for between now and then that could alter current thinking on temps. Right now, it just looks like some of the same temp ranges we have already seen. Precip. is in question, but even that currently looks cold wet, but not frozen. Current forecast from the NWS will reflect these statements as well.

A word of caution. This is a developing situation. There is wiggle room, and changes in both temp and precip. forecasts are possible right down to a day or two before. I urge everyone to just pay attention and prepare for worse scenario. If the situation changes, it could be in a big way. Teens would be easily met in our area, with evolving possibilities, that if at the right times, could be frozen.

Sunday and Monday will be telling.

These are prob going to be the coldest temps of the year and possibly colder than last year.

[TexasMetBlake]

Yes, last year's temps are in jeopardy.

2010 Lows: (from top of my head)

IAH: 20
CXO (Conroe): 15
ACT (Waco) 8
Sugar Land: 16
Hooks: 16
CLL (College Station): 18

IF the bottom falls out, we COULD see:

IAH: 16-18
CXO: 12-15
ACT: 8-10
SL: 14-17
Hooks: 14-16
CLL: 15-18

[biggerbyte]

You could very well be right..

We'll see!!!

I'm certainly ready for a wow factor. If someone can send me some snow on Wednesday. Lol

[cisa]

I keep hoping I'll ck in and someone will have a snowy forecast. sigh! We live in hope.