Texas/MX Obs And Discussion Thread.

[Srain]

Got down to 39 this morning. Still looking ahead for a shallow Arctic boundary to slide through for Thanksgiving.

[msp]

absolutely perfect day. nice breeze and 80F.

[Flexo]

Looks like our handy dandy models are pointing toward our first classic blue norther of the season around Thanksgiving... The Euro is a little slower and warmer with the front, and the GFS is naturally colder and faster... For instance, the 12z GFS has Dallas in the 30s Thanksgiving morning with temps in the upper 60s and 70s in the Houston area. Front plows on through with some storms, and we drop like a rock into the 30s Thanksgiving night from temps near 80 earlier in the day. Freezing temps are then felt the next night. Euro is a day slow and not quite as cold... 12z Euro holds energy back a bit in the SW, then finally ejects the shortwave eastward. The system is further north than the GFS thanks to a stronger SE ridge, so the cold air push isn't as strong.

Either way, Turkey Day should (hopefully) be interesting around here

[Srain]

Looks like our handy dandy models are pointing toward our first classic blue norther of the season around Thanksgiving... The Euro is a little slower and warmer with the front, and the GFS is naturally colder and faster... For instance, the 12z GFS has Dallas in the 30s Thanksgiving morning with temps in the upper 60s and 70s in the Houston area. Front plows on through with some storms, and we drop like a rock into the 30s Thanksgiving night from temps near 80 earlier in the day. Freezing temps are then felt the next night. Euro is a day slow and not quite as cold... 12z Euro holds energy back a bit in the SW, then finally ejects the shortwave eastward. The system is further north than the GFS thanks to a stronger SE ridge, so the cold air push isn't as strong.

Either way, Turkey Day should (hopefully) be interesting around here

The 12Z Euro was down right cold, today. I wouldn't be surprise to see a storm track across the Panhandle with this set. That Blue Norther will be racing S.

HPC:

...AFTERNOON UPDATE...

LASTEST CMC REMAINS SIMILAR HOLDING THE MAIN FULL LATITUDE TROF

WELL WEST OF OTHER MODEL SOLUTIONS WHILE THE 12Z GFS IS MORE

PROGRESSIVE THAN ITS 06Z RUN. A MINOR COMPROMISE IN TIMING USED

FOR DAYS 6 AND 7 WED/THU WITH ERN CONUS FRONTAL TIMING BETWEEN

PRIOR HPC PRELIM PROGS AND LASTEST 12Z GFS AS 12Z GFS ENS MEANS

REMAIN CLOSER TO THE SLOWER FRONTAL TIMING AND MID LEVEL TROF

PROGRESSION OF THE 06Z GFS RUN. LATEST 12Z ECMWF MUCH SLOWER THAN

ITS PRIOR RUN AND HAS CONSIDERABLE MORE DIGGING OF THE TROF TO THE

LEE OF THE ROCKIES. THIS WAS ACCOUNTED FOR BY USING A LAGGED

AVERAGE FORECAST AND THE 06Z GFS FOR MORNING PRELIMS AND THIS

AFTERNOONS FINALS....HOWEVER WE COULD STILL BE FAST CONSIDERING

THE SLOWER CMC AND NOW MUCH SLOWER ECMWF. CERTAINLY DOES NOT

INCREASE CONFIDENCE. THE 06Z GFS USED EARLIER REMAINS A REASONABLE

COMPROMISE AT THIS TIME.

[msp]

upper 30s looking possible here tonight. already feels quite nippy outside.

saturday game time looks nice at least. party sunny with a high in the low to mid 70s falling into the 60s by kickoff.

[Srain]

Had a low of 35 this morning. A nice warmup ahead of next weeks Arctic Air is ahead as well as a chance of some severe storms before the boundary sweeps S. It certainly appears one of the strongest 'Blue Northers' we've seen in a long time is shaping up for mid week. Those 80's temps dropping to upper 30's/low 40's are going to feel like a shock to the old system.

[msp]

looks like we managed 38F this morning.

maybe a second, reinforcing blast of cold air by the weekend too

VERY IMPRESSIVE UPPER RIDGE BUILDING ACROSS THE WESTERN U.S. WITH DOWNSTREAM TROUGHING THROUGH THE MISSISSIPPI VALLEY SETTING THE STAGE FOR ANOTHER ROUND OF COOL/CHILLY AND DRY AIR NEXT WEEKEND WITH A SLOW WARM UP ON SUNDAY.

[Srain]

Taking a look at some of the afternoon discussions coming in, it appears that some of the WFO's are buying the magnitude of the Arctic Air and their discussions reflect that...

Houston/Galveston...

RAIN CHANCES

INCREASE WEDNESDAY NIGHT AND THURSDAY AS A COLD FRONT CROSSES THE

AREA. SHOWERS WILL FOCUS ON THE FRONT WED NIGHT AND EARLY

THURSDAY. ISENTROPIC UPGLIDE BEHIND THE FRONT LOOKS STRONGER NOW

SO WILL KEEP CLOUDS AND RAIN CHANCES GOING INTO THURSDAY NIGHT.

SOUTHEAST TEXAS WILL LIE IN A RIGHT REAR QUAD THURSDAY WHICH

SHOULD PROVIDE ADDITIONAL LIFT. ECMWF AND GFS ARE IN PRETTY GOOD

AGREEMENT NOW SO CONFIDENCE IS GROWING THAT THANKSGIVING DAY WILL

BE MUCH COOLER WITH PERIODS OF VERY LIGHT RAIN. THE UPPER LEVEL

TROUGH AXIS CROSSES EAST TEXAS THURSDAY NIGHT AND SKIES SHOULD

CLEAR FRIDAY MORNING.

Dallas/Ft Worth...

THE PRIMARY FORECAST CHALLENGE CONCERNS THE STRONG MIDWEEK COLD

FRONT. UPPER LEVEL ANALYSIS THIS MORNING DEPICTS THE POLAR VORTEX

OVER THE CANADIAN ARCTIC ARCHIPELAGO WITH STRONG RIDGING ACROSS

THE GULF OF ALASKA. MODELS ARE IN GOOD AGREEMENT THAT THE POLAR

VORTEX WILL LUMBER SOUTHWARD OVER THE NEXT COUPLE DAYS AND REACH

ALBERTA SUNDAY NIGHT BEFORE HEADING EAST. IN RESPONSE TO THE

DYNAMICS ALOFT...THE SURFACE AIR MASS OVER WESTERN CANADA WILL

UNDERGO ANTICYCLOGENESIS WITH A SURFACE HIGH BUILDING TO NEAR

1040MB AND TEMPERATURES COOLING WELL BELOW 0. THIS DENSE ARCTIC

AIR MASS WILL INITIALLY BE HELD AT BAY ACROSS THE NW US...BUT AS A

PIECE OF THE UPPER TROUGH EJECTS EASTWARD BY MIDWEEK...THE FLOOD

GATES WILL OPEN AND COLD AIR WILL PLUNGE SOUTHWARD WEDNESDAY. GFS

FRONTAL TIMING IS THE FASTEST OF THE MODELS AND IS FAVORED. SINCE

MODEL AGREEMENT IS GOOD AND THE EVOLUTION OF THE UPPER LEVEL

PATTERN IS CLIMATOLOGICALLY FAVORED FOR STRONG COLD FRONTS IN OUR

AREA...WILL NOT BE SHY ABOUT PUTTING FORECAST TEMPS WELL BELOW THE

MEX MOS AND CLOSE TO RAW OUTPUT FROM THE GFS/ECMWF. THIS MEANS

TEMPS SHOULD FALL WEDNESDAY NIGHT INTO THE 30S AREA WIDE. TEMPS ON

THANKSGIVING WILL STRUGGLE TO WARM APPRECIABLY WITH COLD ADVECTION

CONTINUING AND HIGHS REMAINING IN THE 40S. 12Z GFS/ECMWF/GFES

ARE SHOWING THE MAIN TROUGH AXIS HANGING BACK AND NOT CLEARING THE

AREA UNTIL THURSDAY EVENING. THIS MAY RESULT IN CLOUD COVER WITH

ISENTROPIC LIFT NEAR AND ABOVE 700 MB THURSDAY WITH HIGHS POSSIBLY

COLDER THAN CURRENTLY FORECAST. HOWEVER...CLEARING SKIES AND

LIGHT WINDS ARE EXPECTED THURSDAY NIGHT WITH LOWS FALLING INTO THE

20S AND LOW 30S AREA WIDE. SINCE THE UPPER LEVEL PATTERN BECOMES

SOMEWHAT PROGRESSIVE...THE VERY COLD AIR WILL NOT HANG AROUND

TOO LONG AND EXPECT A GRADUAL WARMING TREND NEXT WEEKEND.

Norman, OK...

THE EXTENDED FORECAST /MONDAY AND BEYOND/ HAS NOT BEEN CHANGED BY THIS

SHIFT...EXCEPT FOR LOADING NEW GUIDANCE DEW POINT GRIDS BEYOND THE

EXPECTED MID WEEK COLD FRONTAL PASSAGE. MED RANGE MODELS SHOW VERY

SIMILAR TIMING OF THE COLD AIR INTRUSION ANTICIPATED TO ARRIVE ON

WEDNESDAY. MODEL FORECASTS VARY WIDELY REGARDING HOW QUICKLY OUR

TEMPERATURES WILL WARM UP FOLLOWING THANKSGIVING DAY.

Midland/Odessa...

MEANWHILE...THE NORTHWESTERN U.S.

UPPER TROUGH WILL MIGRATE EASTWARD INTO THE ROCKIES AND PLAINS

STATES DURING THE MIDDLE OF THE UPCOMING WEEK. THIS SYSTEM WILL

ALSO DEEPEN AND SEND A TROUGH AXIS ACROSS OUR REGION ON THURSDAY.

WITH THIS SYSTEM...WE EXPECT SOME BIG CHANGES IN OUR TEMPERATURES

LATE NEXT WEEK. AT THE PRESENT...IT APPEARS A STRONG COLD FRONT

WILL MOVE INTO THE AREA WEDNESDAY NIGHT OR EARLY THURSDAY MORNING.

ARCTIC AIR WILL MOVE IN BEHIND THE COLD FRONT...LIKELY SENDING

TEMPERATURES WELL BELOW NORMAL ON THANKSGIVING DAY AND FRIDAY. THE

CURRENT FORECAST ACCOUNTS FOR THE ABOVE SCENARIO WELL AND THE ONLY

CHANGES MADE TO THE FORECAST WERE TO DECREASE HIGH TEMPERATURES ON

THURSDAY AND FRIDAY. 850MB TEMPERATURES MAY VERY WELL REMAIN AT OR

BELOW 0C ON THURSDAY. IF THIS TREND CONTINUES...TEMPERATURES WILL

NEED TO BE LOWERED AGAIN.

[msp]

Taking a look at some of the afternoon discussions coming in, it appears that some of the WFO's are buying the magnitude of the Arctic Air and their discussions reflect that...

nasty forecast already for CLL. high of 58F turkey day with a low of 36F that night. we may get real close to a good frost if the clouds can clear out.

at least the following week looks to get back to near 70F.

it'll be fun to watch the thermal gradient across the state. could be from 80F in the south to 20s in the panhandle.

[Srain]

Good morning. The chatter in the morning discussions from various WFO's continue the downward trend in temps...

Houston/Galveston...

THE FORECAST GETS A LITTLE MORE INTERESTING WED NIGHT THROUGH THE

THANKSGIVING WEEKEND. THE MAIN UPPER LOW WITH THE TROUGH OVER THE

ROCKIES MOVES INTO THE PLAINS. THE GFS/ECMWF/CANADIAN ARE STILL

HAVING A TOUGH TIME DETERMINING THE TIMING OF WHEN THE TROUGH

MOVES INTO THE PLAINS WITH THE ECMWF/CANADIAN TRENDING SLOWER. AS

A RESULT...THESE MODELS ARE SLOWER WITH THE COLD FRONTAL PUSH.

GFS REMAINS CONSISTENT WITH BRINGING THE FRONT THROUGH WED NIGHT

AND OFF THE COAST BY THU MORNING. THE ECMWF SEEMS TO BE ABOUT 6

HRS SLOWER THAN THE GFS WITH THE FRONTAL PASSAGE. AS SUCH...I

WILL KEEP WITH THE GOING FORECAST THINKING AND STICK CLOSER TO

THE GFS FOR THE FORECAST. POPS OF 40 PERCENT LOOK REASONABLE

RIGHT NOW ESPECIALLY GIVEN TIMING DIFFERENCES IN THE FRONT.

POSSIBLE THAT POPS COULD GO HIGHER IF THESE FORECAST TRENDS

CONTINUE.

THE THANKSGIVING HOLIDAY DOES LOOK TO BE COLDER AND WET FOR SE

TX. IT IS NOT OUT OF THE QUESTION THAT TEMPS MAY NOT REACH THE

50S WITH CLOUD COVER AND LINGERING RAIN. FOR NOW THE FORECAST

WILL KEEP TEMPERATURES A FEW DEGREES BELOW GFS GUIDANCE IN

ANTICIPATION OF A DOWNWARD TREND IN TEMPS. MODELS DO HINT AT POST

FRONTAL RAINBANDS SETTING UP THAT CORRESPOND NICELY TO

FRONTOGENESIS AND TEMP GRADIENT AT 850MB. THE FORECAST WILL KEEP

MENTION OF RAIN ON THANKSGIVING WITH DRIER CONDITIONS FOR FRIDAY.

THE CLOUD COVER MAY BE AN ISSUE IN FORECASTING FRI MORNING LOW

TEMP AS CLOUDS MAY BE SLOW TO CLEAR OUT ESPECIALLY ALONG THE

COAST. IT IS POSSIBLE THAT NEXT SATURDAY MORNING COULD BE COLDER

THAN FRIDAY BUT STILL SOME TIME TO WORK OUT THOSE DETAILS.

OVERALL...TEMPS SHOULD BE BELOW NORMAL FOR THE END OF NEXT WEEK

WHICH WILL BE IN CONTRAST TO THE ABOVE NORMAL TEMPERATURES

EXPECTED THE NEXT FEW DAYS.

Dallas/Ft Worth...

ATTENTION THEN TURNS TO THE ARRIVAL OF COLDER AIR DURING MIDWEEK.

00Z ANALYSIS REVEALS SURFACE TEMPERATURES IN THE MINUS 20 DEGREE

RANGE UNDERNEATH THE POLAR VORTEX IN NORTHERN CANADA. EXPECT THIS

COLD AIR TO SLOWLY MOVE SOUTH OVER THE NEXT FEW DAYS UNTIL A SHORT

WAVE TROUGH MOVES THROUGH THE UPPER FLOW...ALLOWING FOR THE COLD

AIR TO MOVE SOUTHWARD. MEDIUM RANGE GUIDANCE CONTINUE TO AGREE ON

THE GENERAL PATTERN...ALLOWING FOR A 1040 HIGH TO MOVE SOUTHWARD

ALONG THE FRONT RANGE OF THE MOUNTAINS. ONCE THE COLD AIR BEGINS

TO RUSH SOUTHWARD...EXPECT FOR THE COLD AIR TO REACH THE RED RIVER

TUESDAY EVENING AND CONTINUE TO MOVE ACROSS THE AREA THROUGH THE

THANKSGIVING HOLIDAY. AREAS THAT HAVE NOT SEEN FREEZING

TEMPERATURES YET THIS SEASON COULD EASILY SEE A FREEZE BY

THANKSGIVING MORNING OR FRIDAY MORNING.

Austin/San Antonio...

RAIN CHANCES WILL PEAK WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING

ASSOCIATED WITH THE APPROACH AND PASSAGE ON A STRONG COLD FRONT. THE

COLD FRONT WILL SWEEP ACROSS THE REGION WEDNESDAY NIGHT SETTING THE

STAGE FOR A COLD AND BLUSTERY THANKSGIVING DAY.

THANKSGIVING DAY WILL BE COLD AND WINDY WITH POST-FRONTAL CLOUDINESS

AND PATCHY LIGHT RAIN. THE COMBINATION OF STRONG CAA...CLOUDY TO

MOSTLY CLOUDY SKIES AND LIGHT STRATIFORM PCPN WILL RESULT IN

AFTERNOON HIGHS RANGING FROM THE UPPER 40S NORTH TO LOWER 60S

SOUTHWEST.

LIGHT STRATIFORM PCPN WILL END THURSDAY AFTERNOON WITH CLEARING SKIES

THURSDAY NIGHT AS THE UPPER LEVEL TROF AXIS MOVES EAST OF OUR CWFA.

TEMPERATURES OVER THE HOLIDAY WEEKEND WILL BE BELOW NORMAL. HIGHS

WILL BE IN THE UPPER 50S TO LOWER 60S WITH LOWS IN THE 30S...20S

ACROSS THE HILL COUNTRY FRIDAY MORNING.

THIS FCST IS BASED ON A BLEND OF THE GFS/ECMWF...THE GEM IS THE

OUTLIER WITH A LATER FROPA. WILL GO ABOVE GFS MOS FOR HIGHS

WEDNESDAY GIVEN THE WEST TO SOUTHWEST WIND COMPONENT IN THE

BOUNDARY LAYER. WILL GO SLIGHTLY BELOW GFS MOS FOR HIGHS THURSDAY

BASED ON THE DOWNWARD TEMPERATURE TREND OF SUCCESSIVE MODEL RUNS.

Norman, OK...

AFTER BEING IN DECENT AGREEMENT ON THE TIMING OF THE STRONG COLD

FRONT FOR MIDWEEK... THE LATEST GFS/ECWMF RUNS ARE DIVERGING ONCE

AGAIN. THE GFS PUSHES THE FRONT THROUGH ALL OF THE CWA BY 18Z

WED... WHILE THE ECMWF... WHICH IS ABOUT 12 HOURS SLOWER... STILL

HAS IT BACK IN NW KS... A MUCH SLOWER SOLUTION FROM PRIOR ECMWF

RUNS. THE TIMING DIFFERENCES RELATE TO HOW QUICKLY EACH OF THE

MODELS MOVE THE UPPER TROUGH MOVES EAST INTO THE PLAINS. AT THIS

POINT... WILL STILL TREND WITH THE FASTER GFS UNTIL WE SEE A FEW

MORE SUBSEQUENT MODEL RUNS.

Lubbock...

A LOW AMPLITUDE SHORTWAVE TROUGH IS RESOLVED IN THE MODELS EJECTING

FROM THE WESTERN U.S. SYNOPTIC TROUGH MONDAY. THIS FEATURE WILL BRING

ANOTHER MINOR DECREASE IN HEIGHTS/THICKNESSES AND DAYTIME TEMPS...BUT

MAXIMA WILL STILL WARM SOME 5-8 DEGREES ABOVE NORMAL. A WEAK FRONTAL

BOUNDARY ALSO WILL SAG SOUTHWARD OVER THE SOUTHERN PLAINS IN THE WAKE

OF THIS FEATURE TUESDAY...BUT NO SENSIBLE WEATHER IMPACTS ARE EXPECTED.

ATTENTION THEN TURNS TOWARD THE ANTICIPATED STRONG FROPA WEDNESDAY...

WITH SUBSEQUENTLY COOLER TEMPERATURES ON THANKSGIVING. THE AIRMASS

NOW CENTERED AT 75 DEGREES N/127 DEGREES W...CURRENTLY CHARACTERIZED

BY -30 DEGREE AIR...WILL BE DISLODGED SOUTHWARD ACROSS WESTERN CANADA

AND INTO THE INNER MOUNTAIN WEST/GREAT BASIN BY TUESDAY. ALTHOUGH THE

AIRMASS WILL MODIFY SIGNIFICANTLY...IT WILL BE PUSHED OVER THE NORTHERN/

CENTRAL ROCKIES AND SOUTHWARD THROUGH THE PLAINS BY MID WEEK AS A NOTABLE

WAVE EJECTS FROM THE WESTERN CONUS UA TROUGH. A SUBSTANTIAL PORTION

OF THIS AIRMASS IS PROGGED TO FILTER OVER THE SOUTHERN PLAINS IN THE

WAKE OF A WEDNESDAY FROPA...AS THE PARENT 1040MB SURFACE HIGH REMAINS

ENTRENCHED OVER THE GREAT BASIN. THIS SHOULD SUPPORT A NOTABLE COOL

DOWN WITH TEMPERATURES 10-15 DEGREES BELOW SEASONAL VALUES BY THURSDAY...

BUT PROGGED DRY PROFILES AND NEAR FULL INSOLATION MAY HELP TO ACTIVELY

MODERATE THE AIRMASS AND PREVENT SUB-MOS DAYTIME TEMPERATURES.

If the Euro is correct, we may well see another shot of chilly air toward the end the month...

[bubba hotep]

Looks to be great timing for this cold shot! Always feels so much more like the holidays when it is cold.

[TXWXCHX]

Wow - excellent info roundup! Thank you for working so hard on it...

Having remembered Texas Thanksgivings past, I'll play it safe and won't rule out a "Cold Turkey Surprise" for the weekend... I wonder if there's any chance with this system for frozen precip? I know it doesn't look like it now, but there is moisture involved and for some reason many models don't handle freezing precipitation well in North/Central Texas.

[Srain]

The 12Z GFS still suggests a Wednesday evening Arctic frontal passage. Of note is a robust shortwave lagging to our W that will keep precip chances going into Thanksgiving Day with a very chilly airmass in place and strong gusty winds...

[Srain]

HPC:

12Z DETERMINISTIC MODELS: THE GFS HAS EXCELLENT CONTINUITY OVER

THE CONUS DAYS 3-5 BUT BECOMES A FAST OUTLIER THEREAFTER WITH THE

NEXT TROF OFF THE PACIFIC COAST. IT MARKEDLY FLATTENS THE

DOWNSTREAM PATTERN OVER THE CONUS FROM CONTINUITY FOR NEXT

FRI/SAT. THESE CONTINUITY CHANGES APPEAR EXCESSIVE.

MEANWHILE THE UKMET/CANADIAN PLAY UP A SRN SPOKE OF ENERGY WELL

BEHIND THE MAIN THANKSGIVING GREAT LAKES LOW...WITH THE

CANADIAN/UKMET HAVING DECENT CONTINUITY FOR THIS SRN STREAM

FEATURE. BOTH THE UKMET AND ESPECIALLY THE CANADIAN ARE SLOWER TO

BRING THE MAIN RIDGE INTO THE ROCKIES EARLY NEXT WEEKEND. THE NEW

12Z ECMWF ...LIKE THE CANADIAN AND UKMET...IS PLAYING UP A STRONG

LOBE OF VORTICITY SWINGING THRU THE SWRN STATES ON THANKSGIVING

DAY. IF CORRECT...THE ECMWF SOLUTION OPENS THE DOOR FOR THE FRONT

TO RETARD ACROSS THE GULF COAST REGION THU/FRI...ACCOMPANIED BY A

BAND OF OVERRUNNING PCPN N OF THE FRONT.

ONE MAIN WEATHER FEATURE DURING THE MEDIUM RANGE PERIOD WILL BE

THE AMPLIFIED TROF/SURFACE SYS CROSSING THE NE CORNER OF THE

CONUS DURING DAY 5...THANKSGIVING. THIS PARTICULAR SYSTEM WILL

BRING DECENT COOLING WELL DOWN INTO THE GULF STATES IN ITS WAKE. N

OF THE MAIN SURFACE LOW TRACK...A GOOD SWATH OF SYNOPTIC SNOWFALL

WED WILL BE FOLLOWED BY LAKE EFFECT SNOW AND BLUSTERY WINDS THU

INTO MUCH OF FRI. UPPER RIDGING IS THEN EXPECTED NEXT WEEKEND OVER

THE ROCKIES AND PLAINS AHEAD OF THE NEXT LARGE SCALE PACIFIC TROF.

A COMPLICATION IN THE FORECAST IS THAT BEHIND THE ABOVE MENTIONED

SYS... THE NEW UKMET/CANADIAN/ECMWF LEAVE ENOUGH ENERGY BEHIND

OVER THE SRN PLAINS FRI DAY 6 TO SUPPORT A FLAT WAVE WITH

OVERRUNNING PCPN ALONG THE W GULF COAST. WHILE EARLIER DOWNPLAYING

THIS WAVE DEVELOPMENT....IT APPEARS MORE LIKELY....NOW THAT THE

12Z/20 ECMWF HAS A WAVY SCENARIO ACROSS THE GULF STATES FRI-SAT. I

WOULD OFFER MODERATE CONFIDENCE THAT SOME KIND OF WAVE WITH

OVERRUNNING PCPN WILL OCCUR BETWEEN THU AND SAT ALONG THE GULF

COAST.

[Srain]

The afternoon discussions are a bit late due to the 12Z model output and coordination between various WFO's regarding how they want to handle the differences...

Houston/Galveston...

THE GREATEST FORECAST CHALLENGE REMAINS IN THE TIMING OF A COLD

FRONT WHICH WILL PASS THROUGH OUR REGION LATE IN THE WEEK. THE GFS HAS

BEEN CONSISTENT IN BRINGING THIS FRONT THROUGH THE REGION LATE

WEDNESDAY AND OFF THE COAST EARLY THURSDAY. THE ECMWF...WHICH HAD BEEN

TRENDING SLIGHTLY SLOWER...IS NOW A FULL 24 HRS LATER WITH THE

FRONTAL PASSAGE IN THE LATEST MODEL RUNS. FOR NOW...WILL TREND THE

FORECAST TOWARDS THE MORE CONSISTENT GFS TIMING...ALTHOUGH THIS

MAY CHANGE OVER THE NEXT FEW DAYS DEPENDING UPON RUN TO RUN

CONSISTENCY AND ALSO THE INPUT OF SHORTER RANGE FORECAST MODELS.

REGARDLESS OF WHICH SOLUTION IS CORRECT...MUCH COOLER AND WETTER

CONDITIONS ARE EXPECTED BY LATE IN THE WEEK FOR ALL OF SOUTHEAST

TEXAS.

Dallas/Ft Worth...

STRONG MIDWEEK COLD FRONT REMAINS THE PRIMARY FORECAST CHALLENGE.

ARCTIC AIR IS POOLING IN WESTERN CANADA AS A BROAD LONGWAVE TROUGH

DEVELOPS ACROSS THE ROCKIES. THE ARCTIC AIR WILL REMAIN BOTTLED UP

ACROSS THE NW CONUS UNTIL A STRONG VORT LOBE SWINGS INTO THE

NORTHERN PLAINS ON WEDNESDAY. ONCE THIS OCCURS THE COLD AIR WILL

SURGE DOWN THE PLAINS INTO THE REGION. MODELS WERE IN A LITTLE

BETTER AGREEMENT ON THE EVOLUTION/TIMING OF THE PRIMARY 500 MB

FEATURES YESTERDAY...AND NOW SOME DIFFERENCES ARE APPEARING. THE

GFS IS THE FAST OUTLIER WITH THE EJECTION OF THE NORTHERN PLAINS

TROUGH AND THUS HAS THE FRONT INTO NORTH TEXAS AROUND NOON

WEDNESDAY...BUT THIS IS 12-24 HOURS FASTER THAN THE OTHER MODELS.

ALTHOUGH I BELIEVE THE 500 MB HEIGHT FORECAST FROM THE GFS IS IN

ERROR...ARCTIC AIR HAS A TENDENCY TO ARRIVE EARLY...SO AM STILL

LEANING TOWARD THE FASTER TIMING OF THE FRONT. HAVE RAISED HIGHS

WEDNESDAY INTO THE 70S SINCE THERE IS REASONABLE CONFIDENCE THE

FRONT WILL NOT ARRIVE UNTIL AFTER PEAK HEATING. BUT DUE TO LOW

CONFIDENCE WILL STAY CLOSE TO MEX MOS FOR WED NIGHT LOWS...BUT IF

THE GEM/ECMWF/NOGAPS ARE INDEED CORRECT WITH THE SLOWER FRONTAL

TIMING...THESE VALUES MAY BE TOO COOL. EITHER WAY...FRONT SHOULD

BE THROUGH BY THANKSGIVING DAY...AND TEMPS LOOK LIKE THEY WILL

STAY IN THE 40S WITH COLD ADVECTION CONTINUING THROUGH THE DAY.

THERE WERE HINTS IN THE MODELS YESTERDAY THAT THE MAIN UPPER

TROUGH AXIS WOULD HANG BACK AND NOT CLEAR THE AREA UNTIL THURSDAY

EVENING. ALL OF THE GUIDANCE CONTINUES TO SEEMINGLY TREND IN THIS

DIRECTION TODAY...WITH THE UPPER TROUGH AXIS LOOKING SHARPER AND

MORE POTENT. SOME OF THE GEM AND GFS MODEL ENSEMBLES ACTUALLY

CLOSE OFF A LOW AT THE BASE OF THE TROUGH OVER THE DESERT SW. THE

INTENSIFICATION OF THE TROUGH AXIS APPEARS TO BE RELATED TO A

TROPOPAUSE FOLDING EVENT AS A STRONG RIDGE OVER THE WESTERN

PACIFIC PUSHES ONSHORE. STRATOSPHERIC AIR IS HIGH IN POTENTIAL

VORTICITY...AND DETERMINING JUST HOW MUCH OF THIS AIR DESCENDS IS

IMPOSSIBLE AT THIS POINT. HOWEVER THE POSSIBILITY EXISTS THAT THE

LAGGING DISTURBANCE WILL INDUCE ENOUGH OF A DYNAMIC RESPONSE TO

RESULT IN ISENTROPIC LIFT OVER THE AREA THURSDAY. THE LOW LEVEL

AIR MASS WILL BE FAIRLY DRY...BUT SATURATION ALOFT AND SOME

ELEVATED INSTABILITY ARE INDICATED IN THE VARIOUS SOLUTIONS. WILL

SHOW A LOW CHANCE OF A VERY COLD RAIN THURSDAY OVER THE CENTRAL

AND SOUTHEAST HALF OF THE AREA.

Norman, OK...

UPPER TROUGH LIFTS OUT FROM THE INTERMOUNTAIN W INTO THE N PLAINS

SUN-MON... JUST ENOUGH TO NUDGE THE SFC FRONT S FROM KS INTO AT

LEAST N OK MON NIGHT INTO TUE. WE HAVE DRAWN A FAIRLY SIGNIFICANT

N-TO-S GRADIENT IN THE HIGHS TUESDAY... AS FAR N OK MAY STRUGGLE

TO REACH THE 50S WHILE THE S CWA WARMS INTO THE 70S. THIS IS A

CONTINENTAL/CANADIAN AIR MASS N OF THE FRONT... AND SO THE USUAL

CONCERNS WILL APPLY IN TERMS OF HOW FAR S THE COLD AIR WILL GET

AND HOW LONG IT WILL LINGER. IN GENERAL COLDER IS USUALLY BETTER

IN THESE CASES... AND SOMETIMES NONE OF THE MODELS GIVE THE COLD

AIR ENOUGH RESPECT. WHICH LEADS US INTO WEDNESDAY - THE TOUGHEST

PART OF THE FORECAST.

IT IS CERTAIN THAT THE AREA WILL BE PLUNGED INTO THE GRIPS OF THE

COLDEST AIR SO FAR THIS SEASON BY WED NIGHT AND THANKSGIVING DAY...

BUT THE MODELS ARE AT ODDS ON HOW FAST IT WILL GET HERE. AGAIN...

THE MORE AGGRESSIVE AND FASTER SOLUTIONS USUALLY WORK OUT BETTER IN

THESE CASES... BUT NONE OF THE MED-RANGE MODELS OR ENSEMBLES HAVE

EXACTLY BEEN POSTER CHILDREN FOR CONSISTENCY LATELY. OPERATIONAL GFS

REMAINS ON THE MORE AGGRESSIVE END OF THE SPECTRUM... BRINGING IN

THE COLD AIR HARD AND FAST WEDNESDAY MORNING... BUT ENSEMBLE MEMBERS

REPRESENT THE ENTIRE SPECTRUM OF SOLUTIONS. THESE INCLUDE THE MUCH

WARMER ECMWF. WE ARE VERY LEARY OF THE ECMWF IN THIS SITUATION...

ONE OF THE FEW SCENARIOS WHERE TRUST ISSUES ARISE WITH THE ECMWF.

THAT AND THE HIGHLY-VARIABLE AND INCONSISTENT SOLUTIONS THE ECMWF

HAS OFFERED IN GENERAL OVER THE PAST 3-4 DAYS LEADS US TO LEAN MORE

TOWARD THE GFS AND A NASTIER DAY WEDNESDAY IN TERMS OF WIND AND

COLD. WE WOULD LIKELY GO EVEN COLDER THAN OUR CURRENT MAX-T GRIDS

WEDNESDAY... BUT FOR THE REASONING OFFERED BY NEIGHBORING OFFICES IN

FAVOR OF THE WARMER ECMWF. IN ANY EVENT... COLD AIR WILL COME IN ON

STRONG WINDS BY WED NIGHT AND TEMPERATURES WILL REACH THEIR LOWEST

LEVELS SO FAR BY THANKSGIVING MORNING IN MOST AREAS. WIND CHILLS LIKELY

TO BE IN THE SINGLE DIGITS AND TEENS OVER MOST OF THE AREA...

POSSIBLY NEAR ZERO IN NW OK.

San Angelo...

UPPER LEVEL WEST-SOUTHWEST FLOW WILL BRING DRY WEATHER AND ABOVE

NORMAL TEMPERATURES EARLY NEXT WEEK. HIGHS WILL BE IN THE 70S...WITH

LOWS IN THE 40S AND 50S. LOOKS LIKE A MAJOR CHANGE IS IN STORE

MIDDLE TO LATE NEXT WEEK AS FIRST ARCTIC AIRMASS OF THE SEASON

ARRIVES. CURRENT NORTHERN HEMISPHERE SURFACE MAP INDICATES AN

ARCTIC AIRMASS MOVING SOUTH ACROSS THE NORTHWEST TERR WITH

TEMPERATURES OF -15 TO -25. THIS VERY COLD AIR WILL MOVE SOUTH

INTO THE NORTHERN ROCKIES AND NORTHERN PLAINS EARLY THIS

WEEK...AND THEN BLAST SOUTH ACROSS THE PLAINS TUESDAY AND

WEDNESDAY WITH THE HELP OF A STRONG UPPER SHORT WAVE TROF MOVING

ACROSS THE NORTH CENTRAL US. THE ARCTIC FRONT WILL ARRIVE IN THE

TEXAS PANHANDLE WEDNESDAY MORNING...AND BE LOCATED JUST NORTH OF

BROWNSVILLE BY THURSDAY MORNING. EXPECT GUSTY NORTH WINDS BEHIND

THE FRONT WEDNESDAY NIGHT AND THURSDAY. NO DOUBT THIS AIRMASS WILL

BE MODIFIED SOME...HOWEVER MUCH COLDER TEMPERATURES ARE

EXPECTED...WITH HIGHS THANKSGIVING DAY IN THE 40S...POSSIBLY EVEN

COLDER. THE COLDEST NIGHT WILL BE THURSDAY...WITH LOWS FRIDAY

MORNING IN THE UPPER TEENS TO LOWER 20S. GOING WITH A LOW OF 20 AT

SAN ANGELO ON FRIDAY MORNING(11/26). THE KSJT RECORD LOW FOR THIS

DATE IS 19 SET IN 1993. TEMPERATURES WILL REMAIN BELOW NORMAL

FRIDAY AND SATURDAY...BUT SLOWLY MODIFY. ALSO...WILL REMAIN DRY

FOR THE NEXT 7 DAYS.

Austin/San Antonio...

THE GFS SHOWS A COLD FRONT ENTERING THE CWA AROUND 0Z ON THURSDAY

WHILE THE ECMWF BRINGS IT THROUGH AROUND 18Z ON THURSDAY. STAYED

CLOSER TO THE GFS WITH A FROPA BETWEEN 0Z AND 6Z ON THURSDAY AS

BOTH MODELS ARE STARTING TO CONVERGE ON TIMING.

OVERRUNNING BEHIND THE FRONT WILL CAUSE CLOUDY SKIES AND LIGHT RAIN

FOR THURSDAY BEFORE A SHORTWAVE TROUGH MOVES THROUGH TO BRING CLEARER

SKIES. THE TROUGH WILL PROVIDE A REINFORCING SHOT OF COLD AIR

INTO THE AREA HELPING OVERNIGHT LOW TEMPERATURES DROP TO NEAR

FREEZING ALONG THE ESCARPMENT AND BELOW FREEZING IN THE HILL

COUNTRY FOR FRIDAY MORNING. TOWARDS THE WEEKEND...WEAK RIDGING

WILL ALLOW TEMPERATURES TO REBOUND SLIGHTLY AS RETURN FLOW SETS UP.

Lubbock...

AS FOR THE SURGE OF COLD AIR MIDWEEK...GFS REMAINS CONSISTENT

WHILE ECMWF HAS BACKED OFF ABOUT 12 HOURS. HOWEVER...HISTORY

SUGGESTS A MORE AGGRESSIVE TIMING ESPECIALLY CONSIDERING LACK OF

STRONG CLOSED LOW TO THE WEST WHOSE LOW LEVEL WARM ADVECTION MIGHT

COUNTERACT COLD AIR. IN THIS CASE THERE DOES NOT APPEAR MUCH TO

KEEP THE DENSITY CURRENT FROM RACING SWD AND WILL MAINTAIN TIMING

FROM PREVIOUS FCST. COOL SFC HIGH TO SETTLE OVER THE AREA LATE

WEDNESDAY NIGHT AND THURSDAY WITH EASILY THE COLDEST TEMPS OF THE

SEASON.

[somethingfunny]

HOWEVER THE POSSIBILITY EXISTS THAT THE

LAGGING DISTURBANCE WILL INDUCE ENOUGH OF A DYNAMIC RESPONSE TO

RESULT IN ISENTROPIC LIFT OVER THE AREA THURSDAY. THE LOW LEVEL

AIR MASS WILL BE FAIRLY DRY...BUT SATURATION ALOFT AND SOME

ELEVATED INSTABILITY ARE INDICATED IN THE VARIOUS SOLUTIONS. WILL

SHOW A LOW CHANCE OF A VERY COLD RAIN THURSDAY OVER THE CENTRAL

AND SOUTHEAST HALF OF THE AREA.

Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God Oh God!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

They're getting me started early this year.

edit: "Central half"?

[ticka1]

Recognize a few names posting here on the Texas forum. Looking forward to the winter blast here in SE Texas for Thanksgiving. Gonna be alot of COLD black friday shoppers out!!!

[Flexo]

When is the forecast truly certain?

NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX

407 AM CST SUN NOV 21 2010

...UNCERTAIN FORECAST FOR THANKSGIVING HOLIDAY...

.DISCUSSION...

YESTERDAY MORNING IT WAS NOTED THAT THE ECMWF AND CANADIAN MODELS

WERE SLOWER WITH MOVING AN UPPER LEVEL LOW ACROSS THE N PLAINS MID

WEEK WHICH CAUSED THEM TO HAVE A LATER COLD FRONTAL PASSAGE FOR

SE TX. THE GFS HAS COME MORE IN SYNC WITH THE ECMWF/CANADIAN

SOLUTIONS SO THERE WERE MAJOR CHANGES TO THE FORECAST FOR THE

THANKSGIVING HOLIDAY. MORE ON THIS LATER...

INCREASING GULF MOISTURE WILL CONTINUE TO SUPPORT LOW CLOUDS AND

PATCHY FOG ACROSS SE TX THIS MORNING. THIS HAS LED TO MILD

MORNING LOW TEMPS IN THE 60S. CLOUDS SHOULD SCATTER OUT ENOUGH

FOR DAY TIME HEATING TO INCREASE TEMPS INTO THE UPPER 70S TO NEAR

80 FOR MAX TEMPS. THESE CONDITIONS ARE LIKELY TO CONTINUE THROUGH

THE MIDDLE OF THE WEEK.

UPPER LEVEL PATTERN HAS BECOME A BIT MORE AMPLIFIED WITH UPPER AIR

ANALYSIS SHOWING A DEEPENING LOW OVER N CALIFORNIA THIS MORNING.

THIS LOW SHOULD MOVE OUT INTO THE PLAINS MONDAY WITH ANOTHER DEEP

LOW MOVING SOUTH INTO THE INTER-MOUNTAIN WEST BY MON NIGHT. THIS

WILL KEEP A MEAN LONG WAVE TROUGH IN PLACE OVER THE WESTERN HALF

OF THE U.S. THROUGH WED. WED THROUGH THUR THIS SECOND UPPER LOW

WILL MOVE ACROSS THE N PLAINS WHICH WILL SUPPORT A SIGNIFICANT

COLD FRONT WITH A DRY/COLD CANADIAN AIRMASS BEHIND IT. IT IS THIS

FRONT THAT HAS BEEN TROUBLESOME TO FORECAST DUE TO THE LACK OF

UPPER LEVEL SUPPORT. LATEST GFS/ECMWF SEEM TO SHOW A MORE

FAVORABLE PATTERN FOR A COLD FRONT PUSH LATE THUR INTO FRI AS THE

TROUGH AXIS PUSH ACROSS THE PLAINS. THIS MEANS THE FRONT SHOULD

ENTER SE TX THU AFTERNOON QUITE POSSIBLY WITH A LINE OF

SHOWERS/THUNDERSTORMS ALONG IT. INSTABILITY APPEARS TO BE LIMITED

AT THIS TIME AND NOT SUPPORT AN ORGANIZED SEVERE THREAT. WHILE I

HAVE LITTLE CONFIDENCE IN WHEN THE FRONT WILL ACTUALLY PUSH

THROUGH SE TX...I AM CONFIDENT THAT SHOWERS/THUNDERSTORMS WILL

ACCOMPANY THE FRONT SO I INCREASED POPS BASED ON THE CONSENSUS OF

GFS/ECMWF FRONTAL TIMING. POPS WERE BUMPED UP TO 50 PERCENT AND

WILL NOT GO HIGHER UNTIL FRONTAL TIMING IS NAILED DOWN WITH LATER

MODEL RUNS. THE COLD FRONT WILL BE STRONG ENOUGH SO THAT TEMPS

WILL DROP BEHIND THE FRONT DURING THE AFTERNOON TIME FRAME AND

OVERNIGHT. COLDER AIRMASS SHOULD BE IN PLACE ON FRI WITH MAYBE

SOME LINGERING POCKETS OF RAIN. CLEARING SHOULD OCCUR DURING THE

DAY FRI WITH MOST OF SE TX HAVING MIN TEMPS IN THE 30S FOR SAT

MORNING. SFC RIDGE WILL BE IN CONTROL FOR MUCH OF NEXT WEEKEND AND

ALLOW FOR A DRY FORECAST.

IN SUMMARY...THE FORECAST IS ONE OF EXTREMES WITH ABOVE NORMAL

TEMPS TO START AND BELOW NORMAL TEMPS IN THE EXTENDED RANGE.

FRONTAL TIMING WILL CONTINUE TO BE A FORECAST CHALLENGE FOR

THURSDAY SO PEOPLE TRAVELING FOR THE THANKSGIVING HOLIDAY NEED

TO KEEP INFORMED ABOUT THE LATEST FORECAST CHANGES.

39

[Srain]

Good morning. Well the overnight guidance threw another wrinkle in the forecast for Thanksgiving Day due to the slow ejection of our Upper Air feature from the Intermountain West portrayed by guidance. I do suspect that the models are under estimating the strength of the dense cold air and may be as much as 24 hour off on their timing of frontal passage in our area, if not a bit more. The other concern is the severe weather that may well be associated with the Arctic Boundary. Severe weather parameters look to be shaping up for parts of TX and will need to be monitored the next couple of days. I wouldn't be surprised to see some major forecasting busts as well and in reading some of the discussions this morning one can almost sense some frustration from forecasters. Past experience tells me that the front will be sharp and faster than progged by models. Interesting days ahead.

[TrekkerCC]

Good morning. Well the overnight guidance threw another wrinkle in the forecast for Thanksgiving Day due to the slow ejection of our Upper Air feature from the Intermountain West portrayed by guidance. I do suspect that the models are under estimating the strength of the dense cold air and may be as much as 24 hour off on their timing of frontal passage in our area, if not a bit more. The other concern is the severe weather that may well be associated with the Arctic Boundary. Severe weather parameters look to be shaping up for parts of TX and will need to be monitored the next couple of days. I wouldn't be surprised to see some major forecasting busts as well and in reading some of the discussions this morning one can almost sense some frustration from forecasters. Past experience tells me that the front will be sharp and faster than progged by models. Interesting days ahead.

I agree - this cold front looks very fascinating. It appears like the Dallas Cowboys fans might be coming out to the game while a cold rain is occurring or developing, and it is incredible to see how a strong Texas cold front drops temperatures 20 to 30 degrees within a hour or a few hours. I know climatology would argue against a snowy Texas winter (La Nina), but I hope we beat the odds and the right elements come together sometime this fall or winter.

[Srain]

Afternoon discussion highlights from across TX/OK...

Houston/Galveston...

MODELS NOW APPEAR TO BE SOLIDIFYING AROUND A LATER FRONTAL

PASSAGE...KEEPING UNSEASONABLY WARM CONDITIONS IN PLACE THROUGH AT

LEAST THE BEGINNING OF THANKSGIVING DAY. AS MOISTURE INCREASES THE

POTENTIAL FOR SHOWERS WILL BE PROGRESSIVELY GREATER AS WE HEAD

TOWARDS MID WEEK. MODEL SOUNDINGS SUGGEST THE POTENTIAL FOR

THUNDERSTORMS ON WEDNESDAY...BUT THEY APPEAR TO BE TOO AGGRESSIVE

IN ERODING THE FAIRLY STRONG CAP ACROSS THE REGION. WILL INCLUDE

MENTION OF ISOLATED THUNDER BUT EXPECT THAT MOST AREAS WILL ONLY

SEE STREAMER SHOWERS UNDERNEATH THE CAP.

COLD FRONT NOW APPEARS TO ARRIVE LATE IN THE DAY ON

THANKSGIVING...BRINGING A CHANCE FOR THUNDERSTORMS AND MUCH COOLER

AIR TO THE REGION. DESPITE SOME LINGERING CLOUDINESS BEHIND THE

FRONT EXPECT THAT THE NORTHERN HALF OF THE REGION SHOULD SEE

TEMPERATURES FALL INTO THE UPPER 30S BY FRIDAY MORNING. SATURDAY

MORNING WILL BE EVEN COOLER...WITH MOST INLAND AREAS IN THE 30S

AND THE NORTHER HALF OF THE AREA SEEING BRIEF PERIODS BELOW

FREEZING. TEMPERATURES WILL BEGIN TO WARM BY SUNDAY AS ONSHORE

FLOW DEVELOPS IN RESPONSE TO A DEEPENING SURFACE LOW ACROSS THE

PLAINS.

Norman, OK...

OTHERWISE TEMPERATURES WILL BE THE BIG CHALLENGE THIS WEEK. STRONG

SURFACE FRONT IS NOW ACROSS CO/KS... AND ALL INDICATIONS ARE THAT IT

WILL REMAIN TO OUR N THROUGH MONDAY. THUS AT LEAST ONE MORE MILD-

TO-WARM DAY ON MONDAY. UPPER LOW NOW OVER NV WILL OPEN UP AND MOVE

NE INTO THE N PLAINS... AND THERE WILL BE ENOUGH SFC PRESSURE

RISES IN ITS WAKE TO NUDGE THE FRONT BACK S INTO THE AREA MON

NIGHT AND TUE. HOW FAR S IS HARD TO ASSESS... BUT THIS IS A

REASONABLY-POTENT COLD AIR MASS WITH 20Z TEMPS STILL BELOW ZERO

IN MT. THE TENDENCY USUALLY IS FOR THIS KIND OF COLD AIR TO MOVE S

MORE FREELY THAN IS OFTEN INDICATED BY THE MODELS... AND THEN TO

BE MORE STUBBORN TO LEAVE ONCE IT ARRIVES. THIS WAS SEEN THIS

MORNING IN PARTS OF NW OK WHERE IT TOOK DIURNAL MIXING TO FINALLY

SWEEP IT OUT WELL AFTER 12Z. FOR THIS FORECAST WE WILL GO WITH THE

FLOW... NO PUN INTENDED... AND KEEP THE LOWS MON NIGHT AND THE

HIGHS TUE WITHIN TOLERANCE OF NEIGHTBORING VALUES. BUT WATCHING

WHAT IS HAPPENING TODAY IN THE CENTRAL HIGH PLAINS - DENVER FELL

FROM THE 50S INTO THE 20S IN 2 HRS THIS MORNING WHEN THE FRONT

SLIPPED S - THERE REMAINS A LOT OF CAUTION AND SKEPTICISM HERE AS

TO WHETHER ANY OF THE MODELS ARE GOING TO HAVE A REALLY GOOD

HANDLE ON THIS FRONT. WOULD NOT BE SURPRISED TO HAVE 70S CLOSE TO

40S SOMEWHERE IN THE CWA ON TUESDAY.

SIMILAR DOUBTS PERSIST TUE NIGHT AND WED... BUT LATEST MODEL TRENDS

SHOW THE GFS TRENDING TOWARD THE ECMWF AND A SLOWER ARRIVAL OF THE

COLD-AIR INVASION WED NIGHT. THUS WE ARE COMPELLED TO FOLLOW THE

CONSENSUS AND WARM WEDNESDAY UP CONSIDERABLY FROM WHAT WE HAD

YESTERDAY. IT NOW APPEARS THAT THE ABRUPT TRANSITION FROM

UNSEASONABLY MILD TO BRUTAL COLD MORE LIKELY WILL TAKE PLACE LATE

WED NIGHT INTO THANKSGIVING MORNING... RATHER THAN DURING THE DAY

OR EVENING WEDNESDAY. AS SUCH WE ALSO WILL BACK OFF A LITTLE ON

THE LOWS WED NIGHT... BUT THU AND THU NIGHT CONTINUE TO LOOK VERY

COLD WITH WIND CHILLS DROPPING INTO THE TEENS AND SINGLE DIGITS.

TEMPS MAY STRUGGLE TO REACH THE 40S ON THANKSGIVING. GRADUAL

MODIFICATION OF TEMPS IS LIKELY GOING INTO NEXT WEEKEND AS UPPER

FLOW PATTERN FLATTENS OUT AND COLD AIR SLOWLY MODIFIES WITH S

WINDS RETURNING.

Lubbock...

.LONG TERM...

MAIN ISSUE CONTINUES TO BE TIMING OF COLD ARCTIC AIR MASS INTO THE

FCST AREA. 12Z MODEL RUNS CONTINUE TO DELAY ENTRY WITH BOTH THE

ECMWF AND GFS BRINGING THE FRONT INTO THE NRN ZONES BETWEEN 06Z

AND 12Z THURSDAY. PROGGED POSITION OF THE FRONT AT 00Z THURSDAY

ON THE WRF-NAM WOULD SUPPORT SIMILAR TIMING WITH 06Z DGEX IN

SUPPORT. RELEASE OF THE COLD AIR DEPENDENT ON EJECTION OF UPPER

LEVEL SHORT WAVE TROUGH ACROSS THE NRN PLAINS...SO UNCERTAINTY

STILL FAIRLY LARGE BUT WILL PUSH FRONT BACK CLOSER TO THIS TIMING.

AS A RESULT WILL HAVE TO PUSH HIGH TEMPS WEDNESDAY UP CONSIDERABLY

AS WELL AS NUDGE WEDNESDAY NIGHT LOWS UP SOME.

OTHERWISE PREVIOUS FCST LOOKS TO BE IN GOOD SHAPE WITH WARM AND

BREEZY CONDITIONS PERSISTING TUESDAY /AND LOOKING LIKE INTO

WEDNESDAY AS WELL/ WITH THE COLDEST DAY BEING THURSDAY IN THE

POST-FRONTAL ENVIRONMENT. FRIDAY MAY NOT BE AS WARM AS PREVIOUSLY

ANTICIPATED GIVEN SLOWER ENTRANCE OF THE COLD AIR...BUT IMPORTANT

TO NOTE THAT IT DOES NOT LOOK LIKE AN EXTENDED STAY FOR THE ARCTIC

AIR MASS WITH SHORT WAVE RIDGING ALOFT TAKING SWIFT AIM ON THE

CENTRAL PART OF THE CONUS AND WINDS VEER TO SW.

Dallas/Ft Worth...

MEDIUM RANGE MODEL GUIDANCE IS IN GOOD AGREEMENT TODAY REGARDING

THE EVOLUTION OF THE UPPER LEVEL PATTERN ACROSS THE NW CONUS

DURING THE NEXT FEW DAYS. COLD AIR WILL REMAIN BOTTLED UP IN

WESTERN CANADA AND THE NW CONUS UNTIL THE UPPER TROUGH ACROSS THE

NORTHERN ROCKIES EJECTS OUT INTO THE PLAINS. THIS IS FORECAST TO

OCCUR SLOWER THAN FORECAST YESTERDAY AND THUS THE COLD FRONT LOOKS

ABOUT 12 HOURS SLOWER AS WELL. THIS WILL PUT THE FRONT INTO NORTH

TEXAS THURSDAY MORNING...WITH HIGHS OCCURRING IN THE MORNING AND

TEMPERATURES FALLING INTO THE 40S DURING THE DAY. THE FRONTAL

PASSAGE WILL BETTER COINCIDE WITH LIFT FROM THE UPPER TROUGH AND

THUS THE CHANCE OF RAIN ALSO LOOKS BETTER ALONG AND JUST BEHIND

THE FRONT THURSDAY.

SKIES SHOULD CLEAR FROM NW TO SE THURSDAY EVENING WITH COLD

ADVECTION CONTINUING INTO THE NIGHT. RADIATIONAL COOLING WILL BE

LIMITED A BIT BY CONTINUING NORTHERLY WINDS...BUT STILL TEMPS ARE

EXPECTED TO REACH THE MID 20S TO LOWER 30S ACROSS THE AREA BY

FRIDAY MORNING. BETTER RADIATIONAL COOLING WILL OCCUR FRIDAY

NIGHT. RAPID MODIFICATION OF THE AIR MASS OCCURS BY NEXT WEEKEND

THANKS TO THE INCREASINGLY PROGRESSIVE UPPER LEVEL PATTERN.

San Angelo...

.LONG TERM...

UPPER LEVEL WEST-SOUTHWEST FLOW WILL BRING DRY WEATHER AND ABOVE

NORMAL TEMPERATURES THROUGH MIDDLE OF THIS WEEK. HIGHS WILL MAINLY

BE IN THE 70S...WITH LOWS IN THE 40S AND 50S...LOWER 60S SOUTHEAST

CWFA WEDNESDAY MORNING. LOOKS LIKE MAJOR CHANGE IN STORE LATE THIS

WEEK AS FIRST ARCTIC AIRMASS OF THE SEASON ARRIVES. CURRENT

NORTH AMERICAN SURFACE MAP INDICATES AN ARCTIC AIRMASS ACROSS THE

NORTHWEST TERR WITH TEMPERATURES OF -15 TO -25. THIS VERY COLD AIR

WILL MOVE SOUTH INTO THE NORTHERN ROCKIES AND NORTHERN PLAINS FOR

THE FIRST PART OF THIS WEEK...AND THEN BLAST SOUTH ACROSS THE

CENTRAL AND SOUTHERN PLAINS WEDNESDAY AND THURSDAY...WITH THE HELP

OF A STRONG UPPER LEVEL SHORT WAVE TROF MOVING ACROSS THE CENTRAL

US. THE GFS AND ECMWF MODELS HAVE BACKED OFF A DAY ON MOVING THE

COLD AIR INTO WEST CENTRAL TEXAS. THE ARCTIC FRONT WILL ARRIVE IN

THE TEXAS PANHANDLE WEDNESDAY EVENING...AND BE LOCATED ACROSS

SOUTH AND SOUTHEAST TEXAS THURSDAY MORNING. EXPECT GUSTY NORTH

WINDS BEHIND THE FRONT LATE WEDNESDAY NIGHT AND THURSDAY. NO DOUBT

THE AIRMASS WILL BE MODIFIED SOME...HOWEVER COLDER TEMPERATURES

ARE EXPECTED...WITH HIGHS THANKSGIVING DAY IN THE 40S ACROSS THE

BIG COUNTY TO THE LOWER 60S ALONG THE I-10 CORRIDOR. THE COLDEST

TEMPERATURES WILL BE THURSDAY NIGHT AND FRIDAY NIGHT...WITH LOWS

IN THE UPPER TEENS AND 20S. A FEW SHOWERS WILL BE POSSIBLE ACROSS

THE HEARTLAND AND NORTHWEST HILL COUNTRY ON WEDNESDAY.

Austin/San Antonio...

THE THANKSGIVING DAY FRONT IS EXPECTED TO HAVE VERY LITTLE

MODIFICATION FROM THE CANADIAN ORIGIN...MEANING THE COLDEST AIR SO

FAR THIS SEASON AND VERY DRY DEW POINTS. SOME LIGHT OVERRUNNING

MOISTURE AND CLOUDS ARE POSSIBLE...BUT THE MOISTURE AND CLOUDS

WERE TONED DOWN SLIGHTLY FROM WHAT THE GFS BASED GUIDANCE HAD.

COOL AND DRY WEATHER SHOULD CONTINUE THROUGH SATURDAY NIGHT...WITH

POSSIBLY A RETURN OF GULF MOISTURE AND DRIZZLE FOR NEXT SUNDAY

MORNING.

Corpus Christi...

.LONG TERM (TUESDAY THROUGH SUNDAY)...CONCUR WITH THE GFS/ECMWF THAT

A SERIES OF DISTURBANCES WILL MOVE ACROSS THE PLAINS EARLY IN THE

PERIOD WITH A MAJOR UPPER TROUGH MOVG ACRS THE PLAINS THURSDAY/

FRIDAY. THIS TROUGH WILL ALLOW VERY COLD AIR TO ENTER TEXAS. MUCH OF

THE POLAR AIR (BASED ON THE POLAR JET) WILL REMAIN NORTH OF CWA/MSA.

YET...SHALLOW (GFS THETA/THETA-E CROSS SECTIONS) COLD AIR WILL ENTER

THE CWA/MSA THURSDAY NIGHT. OWING TO INCREASING MSTR/INSTABILITY

AHEAD OF THE FRONT...WILL MAINTAIN PREVIOUS FCST OF SHOWERS FOR

TUESDAY/WEDNESDAY...THEN SHOWER/ISOLATED THUNDER ACTIVITY NEAR/ALONG

THE FRONT. AFTER FROPA...MUCH COLDER CONDITIONS EXPECTED WITH SCA

(POSSIBLY GALE) CONDITIONS OVER THE WATERS. OWING TO THE VERTICAL

EXTENT OF THE FRONT...AND BASED ON GFS/ECMWF ISENTROPIC

PATTERN...ANTICIPATE ISENTROPIC LIFT OVER THE CWA/MSA...ESPECIALLY

BY SATURDAY AND CONTINUING SUNDAY. WILL RETAIN FCST OF LIGHT

STRATIFORM RAIN OVER PORTIONS OF THE AREA FRIDAY. YET WILL NOT

INTRODUCE PCPN SATURDAY/SUNDAY OWING TO UNCERTAINTY REGARDING

CONDENSATION PRESSURE DEFICITS. COLDEST MIN TEMPS EXPECTED SATURDAY

WITH READINGS IN THE 30S OVER MUCH OF THE CWA. LOWERED MAX TEMPS

SATURDAY/SUNDAY OWING TO THE EXPECTATION OF COLD AIR TRAPPED UNDER

FRONTAL INVERSION/MOSTLY CLOUDY SKIES.

Brownsville...

.LONG TERM /6 AM TUESDAY THROUGH SUNDAY/...

THE PERIOD WILL BEGIN WITH WARMTH MORE TYPICAL OF SEPTEMBER AND

EARLY OCTOBER THAN MID NOVEMBER...BUT END WITH SHARPLY COLDER

TEMPERATURES AS THE WELL ADVERTISED COLD FRONT IS NOW COMING INTO

FOCUS IN THE DAY 4/5 PERIOD. RESIDENTS WITH THANKSGIVING WEEKEND

PLANS WILL NEED A VARIETY OF CLOTHING TO COVER EVERYTHING FROM

SUMMER LIKE HEAT TO WINTER LIKE WIND CHILL.

FOR TUESDAY...DEEP SOUTH TEXAS WILL SEE A SLIGHT REPRIEVE IN THE

WINDY CONDITIONS AS SURFACE TROUGH/FRONT WELL TO OUR NORTH SHIFTS

TOWARD THE OHIO VALLEY AND EASTERN SEABOARD...LEAVING A WEAKER

PRESSURE GRADIENT IN PLACE. THE MORNING WILL DAWN OVERCAST...AND

THE LIGHTER WINDS ESPECIALLY ACROSS THE BRUSH COUNTRY THROUGH THE

KING RANCH MAY ALLOW THE CEILING TO FALL BELOW 400 FEET...CAUSING

PATCHY `FUZZY` FOG IN THESE AREAS. THE CLOUD COVER WILL CONTINUE

THE WARM TEMPERATURES BUT MORNING RISES WILL BE LESS THAN THOSE

TODAY AND MONDAY.

BY AFTERNOON...CONSIDERABLE CLOUDS WILL REMAIN IN MANY

AREAS...WITH SOME PARTIAL SUNSHINE FROM WESTERN HIDALGO/BROOKS

COUNTY TO THE RIO GRANDE PLAINS. MODEL SOUNDINGS ACROSS THE LOWER

VALLEY SHOW ONLY A FEW BREAKS IN THE AFTERNOON SO EXPECT

TEMPERATURES TO BE A HAIR LOWER THAN ON MONDAY IN ALL AREAS.

THE REPRIEVE FROM THE WIND ENDS QUICKLY TUESDAY NIGHT AS LOW LEVEL

JET REDEVELOPS WITH THE APPROACH OF AN EVEN STRONGER TROUGH INTO

THE GREAT PLAINS AS MICRO-RIDGE ALOFT SLIDES EAST AND

SOUTHWESTERLY FLOW FROM THE GREAT BASIN NORTHEAST TO TEH UPPER

MISSISSIPPI VALLEY AIDS SURFACE DEVELOPMENT. THE WINDS AND

REMAINING CLOUD COVER WILL BRING ANOTHER WARM NIGHT AS LOWS LIKELY

STAY ABOVE 70 FOR ALL BUT THE BRUSH COUNTRY.

WINDY AND VERY WARM WEDNESDAY AS 1003 MB LOW IN THE LEE OF THE

SIERRA MADRE FOCUSES THE STRONG SOUTHERLIES. MAY GET CLOSE TO

TOUCHING WIND ADVISORY CONDITIONS...BUT FOR NOW HAVE CAPPED AT 24

KNOTS BETWEN 18 AND 21Z. 1000-500 MB THICKNESSES REACHING 579

DECAMETERS COMBINED WITH INCREASING SUNSHINE AS DRIER AIR ALLOWED

TO MIX THROUGH THE COLUMN AND HIGH TEMPERATURE RECORDS MAY BE

THREATENED IN A NUMBER OF LOCATIONS. FOR NOW HAVE CAPPED AT 90 IN

THE WESTERN LOWER VALLEY...MID TO UPPER 80S ELSEWHERE.

WEDNESDAY NIGHT MAY BE THE WARMEST OF ALL IN THE LOWER VALLEY WITH

A WARM STARTING POINT AND CONTINUED MIXING IN PERSISTENT GRADIENT

NEAR THE COAST. BECOMING MORE CONFIDENT FOR GREAT OUTDOOR

THANKSGIVING WITH WINDS BEGINNING TO DROP JUST A LITTLE AS TROUGH

AXIS SLIDES ACROSS THE REGION WITH A GOOD DEAL OF SUNSHINE FOR

MUCH OF THE DAY AFTER PERHAPS STRATUS REFORMING EARLY. HAVE RAISED

TEMPERATURES TO NEAR 90 ONCE AGAIN...AND IT COULD BE HOTTER STILL

THOUGH LATE NOVEMBER SUN ANGLE SHOULD MITIGATE TOO MUCH HEATING

DESPITE REGION BEING IN THE WARMEST ZONE IN THE COLL AHEAD OF THE FRONT.

GFS AND ECMWF IN GOOD AGREEMENT WITH STRONG COLD...YES

COLD...FRONT SWEEPING FROM NORTH TO SOUTH ACROSS DEEP SOUTH TEXAS

BETWEEN MIDNIGHT AND 3 OR 4 AM. OF COURSE THAT TIMING WILL LIKELY

CHANGE A LITTLE OVER THE NEXT THREE DAYS...BUT CONFIDENCE

INCREASING BASED ON OTHER MODEL SOLUTIONS AS WELL INCLUDING THE

CANADIAN GEM AND NOGAPS. GFS RAW 2 M TEMPERATURES PLUMMET

PRODIGIOUSLY BY DAYBREAK...AND COMBINED WITH 15 TO 25 MPH WINDS IT

WILL FEEL LIKE 35 TO 40 IN MANY AREAS TO BEGIN `BLACK FRIDAY`.

AS FOR THAT DAY ITSELF...ANY LIGHT SHOWERS UNDER LOW CLOUDS WILL

QUICKLY END BUT CEILINGS WILL CONTINUE FOR THE BALANCE OF THE DAY

SOUTH/EAST WITH SOME CLEARING NORTH AND WEST BEFORE SUNSET. RAW

GFS TEMPERATURES REMAIN IN THE 40S TO LOW 50S...AND IF CLOUDS ONLY

LIFT RATHER THAN DISSIPATE THESE COULD BE VERY CLOSE TO DAYTIME

HIGHS. FOR NOW...HAVE JUST NUDGED VALUES INTO THE MID AND UPPER

50S SOUTHEAST AND RISEN FROM THE LOWER 40S INTO THE LOWER 50S

ELSEWHERE. HIGHS WILL LIKELY OCCUR BETWEEN MIDNIGHT AND DAYBREAK.

AS THE UPPER TROUGH ASSISTING THE FRONT SWINGS EAST...LOW AND MID

LEVEL FLOW REMAINS NORTH TO WEST BEFORE 850-700 MB FLOW GOES

VARIABLE AND EVENTUALLY MORE EASTERLY (850) INTO SATURDAY. ONCE

AGAIN...THIS SIGNIFIES ANOTHER RELATIVELY DRY FRONTAL PASSAGE WITH

QUICK CLEARING BEHIND IT ESPECIALLY NORTH OF THE VALLEY. DEW

POINTS WILL FALL INTO THE 20S AND 30S FRIDAY...SO ANY LIGHT RAIN

WILL QUICKLY DRY UP.

A CHILLY NIGHT FRIDAY NIGHT AS THE HIGH SETTLES IN. GFS/ECMWF

HINTING AT SOME MID AND HIGH CLOUDS BUT SHOULDN`T BE ENOUGH TO

KEEP TEMPERATURES FROM FALLING TO SOME OF THEIR LOWEST READINGS OF

THE SEASON SATURDAY MORNING.

CONDITIONS RECOVER OVER THE WEEKEND...THOUGH SATURDAY MAY REMAIN

COOL-ISH ESPECIALLY IF AFTERNOON CLOUDS ARRIVE UNDERNEATH THE

INVERSION. SUNDAY LOOKS NOW LIKE A CLEAN FINISH TO THE

WEEKEND...THOUGH SUNSHINE WILL BE DIMMED BY IN AND OUT

STRATOCUMULUS AS SOUTHEAST FLOW RETURNS AND TEMPERATURES REBOUND

BACK TO SEASONAL LEVELS.

[msp]

surprisingly warm out there now. 80F with a nice breeze. maybe low to mid 80s tomorrow.

i do welcome back these lows in the high 60s, though. makes going to class early in the morning a lot nicer.

[Srain]

Good Morning Folks. So where's this Arctic Air that all the chatter has been about? Let's look up in Canada. IR Imagery is showing the dense Arctic Air spilling S now into Western Canada...

A storm system is taking shape near British Colombia heading S along the Pacific NW and will swing into the Intermountain West today into tomorrow bringing the cold Arctic lobe S. Temps are expected to be in the -20's along with wind-chill indices in the -30 to -40 range in Great Fall, MT. Now that is some mighty cold air. When will that modified air get here? I suspect that when we wake up on Thanksgiving morning that cold air will already be well into TX nearing the northern reaches of SE TX late morning/mid day and off the Coast by early evening. What will be the old shock to the system will be the rapid drop in temps. When we have been in the 80’s for high temps and upper 60’s for lows, a 20+ degree drop in an hour or so will likely occur. While this was never expected to be the coldest air we’ve seen in TX, it is a pretty big change. Heck, we haven’t seen a blue norther like this in a while. So enjoy the warmth of the early week and the weather change there after. Oh, and for those attending the UT/Texas A&M game in Austin on turkey day, bring that warm coat and be ready for a chilly light rain and gusty northerly winds.

[msp]

Good Morning Folks. So where's this Arctic Air that all the chatter has been about? Let's look up in Canada. IR Imagery is showing the dense Arctic Air spilling S now into Western Canada...

A storm system is taking shape near British Colombia heading S along the Pacific NW and will swing into the Intermountain West today into tomorrow bringing the cold Arctic lobe S. Temps are expected to be in the -20's along with wind-chill indices in the -30 to -40 range in Great Fall, MT. Now that is some mighty cold air. When will that modified air get here? I suspect that when we wake up on Thanksgiving morning that cold air will already be well into TX nearing the northern reaches of SE TX late morning/mid day and off the Coast by early evening. What will be the old shock to the system will be the rapid drop in temps. When we have been in the 80’s for high temps and upper 60’s for lows, a 20+ degree drop in an hour or so will likely occur. While this was never expected to be the coldest air we’ve seen in TX, it is a pretty big change. Heck, we haven’t seen a blue norther like this in a while. So enjoy the warmth of the early week and the weather change there after. Oh, and for those attending the UT/Texas A&M game in Austin on turkey day, bring that warm coat and be ready for a chilly light rain and gusty northerly winds.

it'll definitely be some real cold air.

but after a day like today, it's welcome. we hit 84/66 at 2pm. feels like what i consider august.

continual rain chances through friday, but nothing looks especially likely. nothing so far today, though we had some overcast skies before.

[Flexo]

but after a day like today, it's welcome. we hit 84/66 at 2pm. feels like what i consider august.

lol

oh, you northies

[msp]

lol

oh, you northies

y'all have screwed me up. 84/66 still feels gross but now 50s can feel uncomfortable too. i'm becoming a weather wuss.

74/69 now... may not dip below 70F tonight

[Srain]

Nice temp gradiant across TX this morning in response to the first shortwave. This front will waffle across TX until the much stronger Arctic Boundary arrives lated Wednesday/early Thursday...

[msp]

77/70 here. mostly cloudy. record for today is 84F. we may hit it if we get enough sun.

but t-showers between here and houston. looks like these popcorn cells will drift north over time.

[Flexo]

77/70 here. mostly cloudy. record for today is 84F. we may hit it if we get enough sun.

but t-showers between here and houston. looks like these popcorn cells will drift north over time.

Looks like the record was tied at 3 pm

IAH's record is 85 for today, but it doesn't look like we'll make it

GFS indicates Houston's first freeze of the season possible saturday morning... That would be a bit earlier than normal

[msp]

Looks like the record was tied at 3 pm

IAH's record is 85 for today, but it doesn't look like we'll make it

GFS indicates Houston's first freeze of the season possible saturday morning... That would be a bit earlier than normal

looks like we hit 86F intrahour

...RECORD HIGH TEMPERATURE SET AT COLLEGE STATION...

A RECORD HIGH TEMPERATURE OF 86 DEGREES WAS SET AT COLLEGE STATION TODAY.

THIS BREAKS THE OLD RECORD OF 84 SET IN 2005.

and iah managed to tie it

A RECORD HIGH TEMPERATURE OF 85 DEGREES WAS SET AT HOUSTON

INTERCONTINENTAL TODAY. THIS TIES THE OLD RECORD OF 85 SET IN 1973.