#4077 Postby Portastorm » Tue Jan 21, 2014 7:30 am
Here is a summary of comments from morning AFDs re: the late-week weather potential into early next week:
Houston/Galveston (HGX):
A STRONG COLD FRONT WILL THEN MAKES IT WAY INTO SOUTHEAST TEXAS
THURSDAY MORNING. THE MAIN LONGWAVE TROUGH AXIS WILL REMAIN OVER
THE UNITED STATES WITH AN OMEGA HIGH SITTING JUST TO THE WEST OF
THE PACIFIC NORTHWEST. A SHORTWAVE WILL RIDE UP AND OVER THE OMEGA
HIGH AND FALL BACK UNDER THE HIGH TO FORM A REX BLOCK. AT THE SAME
TIME A SHORTWAVE WILL PULSE SOUTHWARDS OVER THE GREAT LAKES
SENDING THE SURFACE COLD FRONT SOUTHWARDS. MODELS ARE IN PRETTY
GOOD AGREEMENT ABOUT TEMPERATURES BEHIND THE FRONT. THE GFS...
CANADIAN... EURO... AND NAM ALL HAVE ~1044MB HIGH CROSSING INTO
THE PANHANDLE OF TEXAS EARLY FRIDAY MORNING. WHERE MODELS DISAGREE
ON IS PRECIPITATION. THE 0Z GFS AND ECMWF START THE PRECIPITATION
THURSDAY MORNING AND DON`T END IT UNTIL FRIDAY MORNING. THE PRECIP
LOOKS TO START FIRING DUE TO VERY WEAK ISENTROPIC LIFT... WAA...
AND FROM THE RRQ. AS THE TROUGH AXIS SAGS SOUTHWARDS SO WILL THE
BEST UPPER LEVEL DYNAMICS AND DRY AIR. BOTH THE 6Z NAM AND GFS
HAVE TRENDED TO THE UPPER LEVEL ENERGY PUSHING FURTHER SOUTH ALONG
WITH THE PRECIPITATION. TEMPERATURES WILL APPROACH FREEZING EARLY
FRIDAY MORNING. ALMOST ALL OF OUR CWA LOOKS TO BE NEAR OR BELOW
FREEZING SOMETIME FRIDAY MORNING. THE 0Z GFS SOUNDING FOR KCLL
WOULD SUPPORT RAIN INITIALLY THURSDAY TRANSITIONING TO FREEZING
RAIN AND THEN ICE PELLETS AND FINALLY SNOW FRIDAY MORNING. 850 MB
TEMPERATURES AT KIAH AND KGLS NEVER MAKE IT TO FREEZING AS AT
KCLL. THE GFS AND NAM DO SHOW BOTH KIAH AND KGLS TO BE BELOW
FREEZING AT THE SURFACE THOUGH FRIDAY MORNING. THESE SOUNDING
PROFILES WOULD SUPPORT FREEZING RAIN. AGAIN THE MAIN PROBLEM WILL
BE IF DRIER AIR FORM THE NORTH MAKES ITS WAY SOUTH. THE NEW 6Z NAM
SOUNDINGS SHOW EXTENSIVE DRY AIR MAKING IT INTO THE AREA AT 900MB
AND WOULD SUPPORT NO PRECIP WITH THE BELOW FREEZING TEMPERATURES.
THIS REMAINS A TRICKY EVENT SO PLEASE STAY TUNED.
Austin/San Antonio (EWX):
THE BIG CHALLENGE FOR
THIS THURSDAY NIGHT AND FRIDAY MORNING FORECAST PERIOD IS THE
POSSIBLY WINTRY PRECIPITATION. EXPECT FREEZING RAINS TO AFFECT
PARTS OF THE HILL COUNTRY BEGINNING AROUND 10 PM THURSDAY WHILE
SPREADING ALONG THE I-35 CORRIDOR AROUND AND AFTER MIDNIGHT AND
SOUTH OF HIGHWAY 10 AROUND 2 OR 3 AM TO 8 AM FRIDAY MORNING.
REMEMBER TO PROTECT PETS...PIPES... PEOPLE...AND ANY SENSITIVE
PLANTS WHICH HAVE SURVIVED THE PREVIOUS FREEZES EARLIER THIS
WINTER SEASON AND USE EXTRA CAUTION WHEN DRIVING THURSDAY NIGHT
INTO FRIDAY MORNING. SINCE THE ECMWF MODEL HAS BEEN THE MORE
CONSISTENT FOR THE LAST FEW RUNS...WILL GO WITH IT AND END POPS
EARLY FRIDAY MORNING WITH DRY CONDITIONS PREVAILING THROUGH MONDAY
OF NEXT WEEK.
Brownsville:
WEDNESDAY NIGHT LOOKS TO THE MILDEST NIGHT WITH THE ADVERTISED
ARCTIC FRONT MOVING INTO NORTH TEXAS. THE FRONT IS PROGGED TO
MAKE QUICK PROGRESS MOVING INTO THE CWA AROUND NOON AND MOVE OFF
THE SE COAST BEFORE SUNSET. COLD AIR TO SETTLE IN AND HANG OUT FOR
36 TO 48 HOURS. A BIG SWING IN TEMPERATURES TO OCCUR BETWEEN THU
AND FRI WITH A DROP OF ALMOST 30 DEGREES IN SOME SPOTS. DO NOT
EXPECT ANY TYPE OF FREEZING TEMPERATURES AT THIS TIME ESPECIALLY
FARTHER SOUTH. MID 30S LOOKS ABOUT AS COLD AS IT GET BOTH FRIDAY
AND FRIDAY MORNINGS ACROSS THE NORTHERN AND WESTERN RANCH LANDS.
THE BRISK NORTH WINDS BEHIND THE FRONT THOUGH TO PRODUCE LOW WIND
CHILLS WITH FELL LIKE TEMPS RANGING FROM THE UPPER 20S TO UPPER
30S FRIDAY INTO SATURDAY MORNING. THE SAVING GRACE FROM DAMAGING
FREEZING TEMPS IS THE DEVELOPING STRONG INVERSION AND STRENGTHENING
ISENTROPIC LIFT AS THE MID AND UPPER FLOW INCREASES FROM THE
SOUTHWEST. A COASTAL TROUGH DEVELOPS WITH MODELS PINPOINTING BEST
LIFT AND HIGHEST RAIN CHANCES THURSDAY NIGHT INTO FRIDAY MORNING.
AREAS ALONG EAST OF HIGHWAY 77/69E LOOK TO HAVE THE BEST CHANCES
WITH ALL AREAS REMAINING SHROUDED UNDER A THICK BLANKET OF CLOUDS.
MODELS SUGGESTING UPPER LEVEL WINDS VEERING WEST TO NORTHWEST
BEGINNING FRIDAY AFTERNOON IF TIMING IS CORRECT THIS WILL WEAKEN
AND PUSH THE COASTAL TROUGH EASTWARD LESSON THE CHANCE OF RAIN.
MODELS HAVE BEEN PERSISTENT WITH THIS TIMING AND FORECAST
CONTINUES TO TREND LOWER ON POPS SATURDAY. MAIN QUESTION IS IF
TEMPERATURES RECOVER EVEN WITH A THICK OVERCAST. TOOK A BLEND OF
ALL MODELS WHICH TRENDS ON THE WARMER SIDE OF THE GFS/ECMWF MOS
GUIDANCE. BELIEVE THE STRENGTHENING WESTERLY FLOW TO PUSH THE
ARCTIC HIGH QUICKLY TO THE EAST ALLOWING FOR A FASTER RECOVERY.
RECOVERY CONTINUES SUNDAY AND MONDAY BUT WILL BE SUBTLE WITH SOUTH
TEXAS REMAINING BETWEEN THE DOMINATE EASTERN TROUGH AND WESTERN
RIDGE. MODELS CONTINUE TO HINT AT ANOTHER SHOT OF ARCTIC AIR TO
SURGE SOUTH MAKING ITS WAY INTO THE REGION NEXT TUESDAY
San Angelo:
LONG TERM...
...ARCTIC FRONT HEADS INTO TEXAS WEDNESDAY NIGHT WITH THE POTENTIAL
FOR WINTERY PRECIPITATION THURSDAY AFTERNOON AND NIGHT...
EC AND GFS MODELS CONTINUE TO INDICATE AN ARCTIC AIR MASS COMING OUT
OF WESTERN CANADA ON A MORE SOUTHERLY COURSE (RATHER THAN A
SOUTHEASTERLY DIRECTION) OF THE PREVIOUS MODEL RUNS. WINDS BEHIND TO
SHIFT NORTH IN THE BIG COUNTRY LATE WEDNESDAY AFTERNOON, BUT STRONG
COLD ADVECTION WILL BEGIN WEDNESDAY NIGHT WITH THE FRONT PUSHING
ALONG A SAN ANGELO TO BROWNWOOD LINE AROUND MIDNIGHT WEDNESDAY
NIGHT, AND WELL SOUTH OF I-10 BY THURSDAY MORNING.
HIGHS FOR THE DAY ON THURSDAY WILL BE EARLY MORNING BEHIND THE COLD
FRONT. TEMPERATURES ALONG I-20 SHOULD FALL BELOW FREEZING BY
DAYBREAK THURSDAY WITH TEMPERATURES FALLING BELOW FREEZING ALONG THE
I-10 CORRIDOR IN THE AFTERNOON. BOTH THE GFS AND EC MODELS ARE
WETTER, INDICATING SOME LIGHT WINTERY PRECIPITATION FOR THURSDAY AND
THURSDAY NIGHT. THE GFS INDICATES THIS PRECIPITATION MAINLY IN THE
CONCHO VALLEY, AND AREAS SOUTH AND EAST. THE EC INDICATES WINTER
PRECIPITATION AS FAR NORTH AS I-20. WILL ADD A SLIGHT CHANCE OF
PRECIPITATION FOR THE CONCHO VALLEY AND AREAS SOUTH AND EAST, WHERE
THE MODELS ARE IN AGREEMENT. GFS FORECAST SOUNDING PROFILES ARE
NEARLY ALL BELOW FREEZING BY NOON THURSDAY, WITH SATURATION UP TO
-15 C BY 6 PM THURSDAY. THE FORECAST SOUNDING PROFILE INDICATES A
MIXTURE OF LIGHT FREEZING RAIN, SLEET AND LIGHT SNOW, THOUGH
FREEZING RAIN IS LESS LIKELY THURSDAY NIGHT. MODEL LIQUID AMOUNTS
ARE LIGHT, ON THE ORDER OF A FEW HUNDREDTHS OF AN INCH. WITH SOME OF
THE PRECIPITATION GOING INTO SATURATING OF THE ATMOSPHERIC COLUMN, I
AM KEEPING POPS AT 20 PERCENT AT THIS TIME.
VERY COLD AIR THURSDAY NIGHT, WITH LOWS IN THE TEENS. CLEARING SKIES
EXPECTED FRIDAY AS SOUTHWESTERLY AND WESTERLY WINDS IN THE LOW AND
MID LEVEL MOVE MOISTURE TO THE EAST. SOME HIGH CLOUDS MAY REMAIN
HOWEVER, AND HIGHS ON FRIDAY MAY ONLY REACH 40. A NICE WEEKEND IN
STORE HOWEVER, WITH HIGHS ON SATURDAY AND SUNDAY INCREASING INTO THE
60S. ANOTHER COLD FRONT MAY AFFECT THE REGION NEXT MONDAY, AND COULD
BRING IN ANOTHER MASS OF COLDER AIR FROM CANADA FOR TUESDAY.
Dallas/Fort Worth (FWD):
THE POLAR VORTEX ACROSS EASTERN CANADA WILL BEGIN AMPLIFYING AND
EXPANDING WEST ACROSS THE GREAT LAKES AND NORTHERN TIER OF THE U.S
INTO THE LATE WEEK PERIOD. THIS WILL ASSIST AN ARCTIC FRONT INTO
OUR AREA WEDNESDAY NIGHT WHILE TAPPING INTO SHORTWAVE ENERGY ALOFT
ACROSS WESTERN CANADA AND THE PACIFIC NORTHWEST. THURSDAY WILL BE
WINDY AND COLD WITH WIND CHILLS RANGING FROM THE TEENS AND 20S NORTH
TO THE 30S SOUTH. HIGH TEMPERATURES ON THURSDAY WILL NOT WARM MUCH
MORE THAN THE 30S NORTH TO THE LOWER 40S SOUTH AND THAT MAY EVEN
BE OPTIMISTIC...AS THE ARCTIC AIR DEEPENS READILY THROUGH THE DAY.
THE POLAR VORTEX ALOFT ACROSS THE GREAT LAKES AND NEW ENGLAND WILL
EXPAND WESTWARD ACROSS THE ROCKIES AND RAPIDLY DEEPEN THE COLD
AIRMASS ACROSS THE ENTIRE CWA. APPROACHING SHORTWAVE ENERGY
EMBEDDED WITHIN THE NORTHWEST FLOW ALOFT WILL DEEPEN AN EASTERLY
LOW LEVEL WIND COMPONENT ACROSS CENTRAL TEXAS AND SOUTHWEST TOWARD
THE HILL COUNTRY AND RIO GRANDE PLAIN. SATURATION OF THE THETA-E
SURFACES SHOULD REMAIN SOUTH OF A GOLDTHWAITE...WACO...PALESTINE
LINE. SPOTTY LIGHT WINTRY PRECIPITATION BEGINS THURSDAY AFTERNOON
AND LINGERS INTO EARLY FRIDAY MORNING. SOUNDING ANALYSIS CONCURS
WITH PARTIAL THICKNESS AND TOP DOWN METHODS ON AN INITIAL RAIN...
SLEET AND SNOW MIX ACROSS OUR CENTRAL TEXAS THURSDAY AFTERNOON.
PRECIPITATION LOOKS TO TRANSITION QUICKLY TO A SLEET/SNOW MIX OR
EVEN ALL LIGHT SNOW OR SNOW FLURRIES BY MIDNIGHT FRIDAY. FEEL THE
MIX IS BETTER HERE AS THE ATMOSPHERIC COLUMN BETWEEN 850-700MB
REMAINS BETWEEN 0 AND -5 DEG C. FREEZING RAIN HAS BEEN DISCOUNTED
DUE TO ANY WARM NOSE ALOFT BEING BRIEF AND ELEVATED. AREAS FURTHER
NORTH WILL SEE PLENTY OF DRY AIR ENTRAINMENT AND DO NOT EXPECT
ANYTHING MORE THAN THE CHILLY TEMPERATURES. LOWS WILL PLUMMET INTO
THE TEENS NORTHWEST TO LOWER-MID 20S SOUTHEAST BY FRIDAY MORNING.
ARCTIC HIGH PRESSURE WILL CONTINUE ITS GRIP ON FRIDAY WITH HIGHS
STILL STRUGGLING TO GET INTO THE 30S TO POSSIBLY LOWER 40S
SOUTHWEST. THE BROAD VORTEX ALOFT DOES LOOK TO WEAKEN AND DAMPEN BY
THE WEEKEND AND MAKE THIS ARCTIC INTRUSION A BRIEF ONE. LOW LEVEL
S/SW FLOW WILL RETURN AS SHORTWAVE RIDGING ALOFT TAKES HOLD FOR THE
WEEKEND. HIGHS WILL WARM BACK INTO THE 50S SATURDAY AND INTO THE 60S
ON SUNDAY. THERE ARE SIGNS OF ANOTHER ARCTIC SURGE EARLY NEXT
WEEK...THOUGH THE MODELS CERTAINLY DIFFER ON THE AMPLIFICATION OF
THE EASTERN CONUS VORTEX AND TIMING...WITH THE ECMWF HAVING AN
EARLIER AN ARRIVAL ON MONDAY. THESE DIFFERENCES SHOULD IRON
THEMSELVES OUT AS WE MOVE THROUGH THE WEEK.
Corpus Christi (CRP):
LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)...MOISTURE WILL BE ON THE
INCREASE WED NIGHT AHD OF A STRONG ARCTIC COLD FRONT THAT IS PROGD
TO MOVE THROUGH THE AREA ON THU. BEHIND THE FRONT BY THU
AFTERNOON...COLD...BREEZY/WINDY AND WET CONDITIONS CAN BE EXPECTED.
DYNAMICS/FORCING WILL BE WEAK BUT A SATURATED FCST SOUNDING AND SOME
WEAK ISENTROPIC UPGLIDE INDICATE THAT 30-50 POPS FOR -RA LOOKS
WARRANTED ON THU THROUGH FRI. MAIN CONCERN WILL BE THU NIGHT/FRI
MORNING AS FCST SOUNDINGS FOR THE NRN CWA LOOKS SLIGHTLY CONDUCIVE
FOR FROZEN PRECIP. STILL NOT TOO CONFIDENT IN THIS SCENARIO GIVEN
THE MODELS HAVE VARIED IN JUST HOW MUCH ARCTIC AIRMASS MOVES INTO S
TX. HAVE INTRODUCED A SLIGHT CHC OF LIGHT FREEZING RAIN AND SLEET
FROM COT TO VCT EARLY FRI MORNING. MAIN IMPACT WOULD BE FOR
OVERPASSES AND BRIDGES BEING SUSCEPTIBLE TO ICING. THE OTHER BIG
CONCERN WILL BE WINDS OVER THE COASTAL WATERS. MODELS VARY ON JUST
HOW STRONG THE OFFSHORE FLOW WILL BE THU NIGHT/FRI MORNING...SO WENT
WITH A COMPROMISE WHICH LEADS TO POTENTIAL GALE CONDITIONS. WINDS
DIMINISH THROUGH FRI BUT OVC SKIES AND WET CONDITIONS ARE EXPECTED
TO PERSIST THROUGH THE DAY...KEEPING TEMPS IN THE 40S. GUIDANCE
PROGS FREEZING TEMPS SAT MORNING ACROSS PORTIONS OF THE NRN CWA. FOR
NOW WENT WITH A LIGHT FREEZE ACROSS THE NE CWA SAT MORNING. PRECIP
IS PROGD TO DECREASE FRI NIGHT THRU SAT NIGHT FROM NW TO
SE...THEREFORE FROZEN PRECIP SAT MORNING IS NOT EXPECTED. TEMPS WILL
GRADUALLY WARM THROUGH THE WEEKEND AND INTO MONDAY. SUN/MON SHOULD
SEE DRIER CONDITIONS AND MILD TEMPS.
Shreveport, LA:
LITTLE CHANGE ELSEWHERE DOWN THE ROAD WITH ANOTHER STRONG ARCTIC
FRONT STILL PUSHING DOWN INTO THE FOUR STATE AREA LATE WEEK.
MOISTURE LIMITED...BUT IT STILL LOOKS LIKE SOME TRANSITIONING QPF
WILL UNFOLD OVERNIGHT THURSDAY INTO EARLY FRIDAY. MOSTLY RAIN
CHANGING TO SNOW WITH A GOOD DEPTH OF COLD AIR ENSUING. THE EURO IS
FAIRLY CONSISTENT ON LOCATION OF THE QPF UP TO NEAR I-20...BUT THE GFS
CONTINUES TO TREND FARTHER SOUTH. MUCH MORE SO IN FACT ON THE
LATEST 06Z RUN. WE WILL CONTINUE TO MONITOR WITH STILL LITTLE
AFFECT ON TRAVEL EXPECTED FOR OUR AREA. MAV AND MEX NUMBERS ARE
REASONABLE AND HAVE BEEN BLENDED INTO THE NEXT SEVEN DAYS.
Lake Charles, LA:
FUN PART OF THE FORECAST COMES THURSDAY INTO FRIDAY AS MOISTURE
ALOFT BEGINS TO POOL AND RISE OVER THE ARCTIC AIRMASS SETTLING IN
BEHIND THE FRONTAL BOUNDARY. FORECAST SOUNDINGS AND THICKNESS
PROGS CONTINUE TO INDICATE THE POSSIBILITY OF A WINTRY MIX OF
PRECIP LATE THURSDAY NIGHT INTO FRIDAY MORNING ACROSS ALL BUT
MAYBE THE BEACHES. WOULD BE MORE INCLINED TO GO WITH A WIDESPREAD
WINTER EVENT IF WE HAD A SFC LOW DEVELOP OVER THE WRN GULF AND
SKIRT THE COAST BUT FOR NOW THIS SCENARIO IS NOT PLAYING OUT IN
THE LATEST MODEL RUNS...HOWEVER WILL LEAVE THE WINTER WEATHER IN
THE FORECASTS TO ELIMINATE ANY POSSIBLE PUBLIC CONFUSION ATTM.
REGARDLESS FRIDAY LOOKS VERY COLD WITH HIGHS BARELY IN THE LOWER
40S AND WIND CHILLS IN THE 30S.
BY SATURDAY THE ARCTIC HIGH IS PROGGED TO SETTLE OVER THE WRN GULF
REGION WHICH SHOULD PUSH ANY REMAINING PRECIP WELL INTO THE GULF.
DRY CONDITIONS ARE THEN PROGGED TO LINGER FOR THE REMAINDER OF THE
FORECAST PERIOD AS NRLY FLOW PERSISTS ALOFT AROUND THE ERN CONUS
TROF...AND SFC HIGH PRESSURE DOMINATES AS WELL.
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Any forecasts under my name are to be taken with a grain of salt. Get your best forecasts from the National Weather Service and National Hurricane Center.
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K.
We didn't see you around much last night when we were high-fiving each other about the 0z GFS run. 
