Texas Winter 2012-2013

[somethingfunny]

I turn away from my computer and the models for two days and I come back to see this!!

Is anybody else here going to to Austin for the AMS conference that begins on the 6th?

[horselattitudesfarm]

As per the morning discussion for San Antonio. This seems to follow the GFS model as mentioned in other replies. The dreaded dry-slot is mentioned as a possible player:

"GOOD RAIN CHANCES ARE DEPICTED OVER NORTHERN COUNTIES FOR SUNDAY NIGHT
THROUGH MONDAY EVENING...BUT MODEL RUN-TO-RUN TRENDS CONTINUE TO
SHOW LESS POTENTIAL FOR MEANINGFUL RAINS...ESPECIALLY OVER
SOUTHERN COUNTIES. THE ADJUSTMENTS WITH EACH RUN ARE MORE SUBTLE
SO PERHAPS THIS MEANS THAT RAIN CHANCES WILL NOT DECREASE FURTHER
AS WE GET CLOSER TO THE RAIN EVENT. MOST OF THE ACTIVITY SHOULD BE
SCATTERED LIGHT RAIN SHOWERS...WITH A POSSIBLE BROKEN SQUALL LINE
DEVELOPING OVER EASTERN COUNTIES LATE MONDAY. THE CONVECTION
POSSIBILITY APPEARS TO BE WELL REMOVED FROM STRONGER DYNAMICS TO
THE NORTH...SO WILL PASS ON ADDRESSING ANY THREAT FOR STRONG
STORMS IN THE HWO. THE PRESENCE OF A DRY SLOT IS PROBABLE AROUND
THE BASE OF THE TROUGH LATE MONDAY...LEAVING CENTRAL AND WESTERN
COUNTIES IN A DRYING PATTERN FOR NEW YEARS EVE...FOLLOWED BY A
MODERATE COLD FRONT. AS FOR EVENT TOTAL RAINS SUNDAY THROUGH
MONDAY NIGHT...EASTERN COUNTIES COULD SEE 1/4 TO 3/4 INCH AVERAGES
WITH WESTERN COUNTIES LIKELY TO SEE LESS THAN 1/10 INCH.

[Ntxw]

FW seems to like abandoning the GFS, big change from earlier today

***
.UPDATE...
HIGH CLOUDS ARE INCREASING TO THE SOUTHWEST AND HIGH TEMPS MAY BE
A BIT TOO WARM IN THE SOUTHWEST ZONES. HAVE LOWERED TEMPS A BIT IN
THIS AREA...AND MADE SOME AMENDMENTS TO TONIGHT/S LOWS BASED ON
MORE CLOUD COVER ARRIVING SOONER.

12Z MODEL DATA IS ROLLING IN NOW...AND SOME PRETTY SIGNIFICANT
CHANGES ARE OCCURRING TO THE FORECAST SYNOPTIC PATTERN ACROSS THE
WESTERN HALF OF THE CONTINENT AROUND THE MID-LATE WEEK TIME
FRAME. MAY NEED TO ADD POPS TO THE ENTIRE AREA WEDNESDAY
NIGHT...AND WILL NEED TO INVESTIGATE A POTENTIAL FOR
FREEZING/FROZEN PRECIP AS WELL.

[ROCK]

ok I am crawling out from under my rock for this event. Might have to take a roady up to Austin with the fam if this verifies...when in doubt go with the EURO....I say that because I pretty much hug it during TC season... It does seem the GFS is giving ground to the EURO and CMC solution. Still though you have keep watching the GFS to see if it completly comes around.. Not looking forward to low 30 to 20s around here. I would lose my tropical pool plants again for the 3rd year in a row.... and that makes for a tremendous mess.



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[wxman57]

12Z Euro has more snow across TX than the 00Z.

[Ntxw]

12Z Euro has more snow across TX than the 00Z.

Thanks for the graphic Wxman57. Do you have access to Euro skew T's? I was wondering how much of that in central/north Texas is sleet that euro may be reflecting as snow

[wxman57]

12Z Euro has more snow across TX than the 00Z.

Thanks for the graphic Wxman57. Do you have access to Euro skew T's? I was wondering how much of that in central/north Texas is sleet that euro may be reflecting as snow

Don't have all the data ingesting yet, so I'm not sure what the Euro is looking at when coming up with that snowfall.

[Ntxw]

18z GFS is caving to the Euro. Swath of wintry precip breaking out in West Texas to North Texas with the 850 0c moving south

[Portastorm]

Given what the last few Euro op runs have shown, what the CMC has shown, what the ensembles are now suggesting ... and the trend today of the GFS coming towards the Euro solution, I am completely baffled and scratching my head by the area forecast discussion (below) issued this afternoon by the forecasters at EWX. Why do they refuse to acknowledge the possibility of frozen precip or freezing rain next week? No, I'm asking for snow or freezing rain to be included in the forecast ... but if you're going to reference the Euro in your AFD, at least you might mention the possibility. It's not like only one model run showed winter weather happening. And, you really got to wonder when the neighboring NWSFOs reference it (Fort Worth and Houston/Galveston).

------------
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
320 PM CST SAT DEC 29 2012

.DISCUSSION...
RATHER COOL-CLOUDY...SOMETIMES WET CONDITIONS PREVAILING FOR MUCH
OF THIS FORECAST PACKAGE. THE MEAN TROUGH AXIS REMAINS WEST OF
TEXAS AND A SERIES OF SHORT WAVES TRAVERSE THE AREA IN THE SWLY
FLOW ALOFT. IN ADDITION...AFTER A BRIEF WARM-UP ON MONDAY...A
COLD FRONT PUSHES THRU EARLY TUESDAY WITH A COOL AIRMASS REMAINING
OVER S TX THRU THE REMAINDER OF THE WEEK AND INTO NEXT WEEKEND.
THE ECMWF/GFS IN A LITTLE BETTER CONSENSUS IN THE LONG TERM BY
EJECTING THE UPPER TROUGH/LOW EAST OF THE AREA BY SATURDAY WITH
DRIER CONDITIONS PREVAILING.

CONSIDERABLE MID LEVEL CIRRUS TRAVERSING THE AREA THIS AFTERNOON
AND WILL CONTINUE TO INCREASE/LOWER LATE TONIGHT INTO SUNDAY. LOWS
TONIGHT WILL BE TRICKY AS DEW POINTS REMAIN VERY LOW AND WINDS
WILL BE LIGHTER THAN LAST NIGHT. HOWEVER THICKER CIRRUS COULD RESULT
IN WARMER MINS THAN CURRENTLY FORECAST. OTHERWISE MOSTLY CLOUDY
SUNDAY WITH A INCREASING RAIN CHANCES FROM THE WEST...STARTING
WITH A FEW SPRINKLES OVER THE RIO GRANDE PLAINS AND WESTERN EDWARDS
PLATEAU SUNDAY MORNING...BECOMING MORE WIDESPREAD LIGHT RAIN AND
SHOWERS BY SUNDAY NIGHT INTO MONDAY AND MONDAY NIGHT. COULD SEE
ISOLATED THUNDERSTORMS LATE MONDAY/MONDAY NIGHT OVER THE EASTERN
CWA AS THE LOW LEVEL JET DEVELOPS AHEAD OF AN UPPER LEVEL
DISTURBANCE AND COLD FRONT. RAIN CHANCES SHOULD PUSH MOSTLY SOUTH
OF THE CWA TO NEAR THE COAST ON NEW YEARS DAY...HOWEVER ANOTHER
UPPER AIR DISTURBANCE QUICKLY APPROACHES FROM THE WEST BY
WEDNESDAY. THEREFORE RAIN CHANCES WILL BRIEFLY RETURN TO THE
EASTERN HALF THE CWA AT MID WEEK...TAPERING OFF FROM THE WEST
THURSDAY. WEDNESDAY COULD BE EVEN COOLER THAN CURRENTLY FORECAST
DUE OVERRUNNING MOISTURE/CLOUDS OVER THE COLD AIRMASS NEAR THE
SURFACE.

DRIER CONDITIONS PREVAILING FRIDAY INTO SATURDAY AS A ZONAL FLOW
EVOLVES FOR THE WEEKEND WITH DECREASING CLOUDS AND MORE DIURNAL
VARIATION IN TEMPERATURES.

[Portastorm]

And then we see an outstanding discussion, once again, issued by the gang at NWS Fort Worth. I consider it "outstanding" because they discuss the possibilities and limitations of the models and really lay things out for the reader. Good work, Fort Worth!

----------------------------
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
327 PM CST SAT DEC 29 2012

.DISCUSSION...
WATER VAPOR SHOWS A LARGE UPPER LEVEL LOW OVER CALIFORNIA DIGGING
SOUTH TOWARD BAJA. THE UPPER LOW IS BEGINNING TO TAP INTO SOME
SUBTROPICAL PACIFIC MOISTURE...WHICH WILL BE ARRIVING INTO NORTH
TEXAS TONIGHT AND SUNDAY IN THE FORM OF INCREASING MID-HIGH
CLOUDINESS. THESE CLOUDS WILL IMPEDE OPTIMAL RADIATIONAL COOLING
LATER TONIGHT DESPITE SURFACE WINDS BECOMING LIGHT. HOWEVER LOWS
WILL STILL BOTTOM OUT IN THE 20S JUST ABOUT AREA WIDE. THE MID-
HIGH CLOUDS WILL BECOME DENSE BY SUNDAY AFTERNOON WHICH WILL
LIMIT THE WARM UP DESPITE INCREASING SOUTH WINDS.

THE UPPER LEVEL LOW WILL BECOME GENERALLY STATIONARY OVER THE
DESERT SOUTHWEST SUNDAY...BUT A SHORTWAVE WILL ROTATE AROUND IT
AND COME ACROSS NORTH TEXAS ON MONDAY. IN ADVANCE OF THE IMPULSE
ISENTROPIC LIFT WILL INTENSIFY SUNDAY EVENING WITH RAIN BREAKING
OUT ACROSS THE NORTHWEST HALF OF THE AREA. INITIALLY THIS RAIN
WILL FALL AS VIRGA SUNDAY AFTERNOON...BUT THE LOW LEVELS WILL BE A
BIT TOO DRY FOR ANYTHING MORE THAN SPRINKLES UNTIL AFTER SUNSET.
RAIN WILL CONTINUE TO INCREASE IN COVERAGE AND INTENSITY GOING
INTO MONDAY MORNING WITH A LARGE SHIELD OVERSPREADING THE REGION
FROM WEST TO EAST DURING THE DAY. RAINFALL AMOUNTS SHOULD RANGE
FROM 0.75 INCH IN THE NORTH TO 0.25 INCH IN THE SOUTH BEFORE THE
ACTIVITY COMES TO AN END LATE MONDAY AFTERNOON IN THE WEST AND
EARLY MONDAY EVENING IN THE EAST. DUE TO THE STRONG WARM ADVECTION
ATOP THE VERY MOIST/COOL SURFACE AIRMASS...IT LOOKS LIKE FOG WILL
BECOME WIDESPREAD AND AFFECT THE REGION DURING THE DAY MONDAY. AS
THE SHORTWAVE PASSES THE AREA...IT WILL ALLOW A COLD FRONT TO MOVE
THROUGH MONDAY NIGHT. DRY/COLD ADVECTION SHOULD DISPERSE THE FOG
AND TEMPERATURES WILL COOL INTO TUESDAY MORNING AS THE COLD
AIRMASS RESIDING OVER THE PLAINS SLOSHES BACK TO THE SOUTH.

12Z GUIDANCE HAS CHANGED REGARDING ITS HANDLING OF A PIECE OF
ENERGY THAT ROTATES THROUGH WESTERN CANADA AND INTO THE STATES BY
MIDWEEK. TODAY THE GUIDANCE HAS EITHER SLOWED THE TIMING OF THAT
ENERGY DOWN OR HAS FORECAST IT TO DROP INTO THE STATES MUCH
FARTHER WEST THAN YESTERDAY. THE CHANGE RESULTS IN LESS NORTHERLY
WINDS AT 850MB WHICH WOULD HAVE SERVED TO DRY THE REGION OUT AND
LIMIT PRECIP POTENTIAL WED-THURS AS ANOTHER SHORTWAVE ROTATES IN
FROM THE SOUTHWEST AROUND THE AFOREMENTIONED UPPER LOW. PRECIP HAD
BEEN FORECAST BY THE CANADIAN AND ECMWF...AND NOW THAT THE GFS IS
ON BOARD...WILL GO AHEAD AND BRING POPS INTO THE FORECAST
WEDNESDAY IN THE SOUTH AND FOR MOST OF THE AREA WEDNESDAY NIGHT.

ALTHOUGH WE HAVE SEEN SOME SUBTLE FEATURES CHANGE IN THE LATEST
MODEL GUIDANCE...THERE IS HIGH CONFIDENCE ON THE FORECAST UPPER
LEVEL SYNOPTIC PATTERN. THIS PATTERN WILL FEATURE A RIDGE OVER THE
PACIFIC NORTHWEST...WITH TELECONNECTIONS FAVORING A BROAD POSITIVE
TILT TROUGH AXIS FROM HUDSON BAY TO THE FOUR CORNERS. THIS IS A
SYNOPTIC PATTERN THAT ALWAYS SEEMS TO END UP BEING COLDER THAN
FORECAST BY THE MODELS. I AM AT A LOSS FOR THE TECHNICAL REASON
BEHIND THE MODEL BIAS...BUT THE UPPER PATTERN DOES ALLOW FOR A
PROLONGED FETCH OF NORTHERLY WINDS AT THE SURFACE TO TRANSPORT
COLD AIR SOUTHWARD OVER THE COURSE OF 2+ DAYS. SEEING THIS PATTERN
RAISES CONCERNS FOR SURFACE TEMPS COLDER THAN CURRENTLY FORECAST
AND SUBSEQUENTLY WINTER WEATHER WHEN THAT SHORTWAVE MOVES ACROSS
FROM THE SOUTHWEST WEDNESDAY NIGHT. THE ECMWF AND CANADIAN SHOW A
POTENTIAL FOR SNOW ACROSS CENTRAL TEXAS AND THAT FORECAST SEEMS
REASONABLE. ELSEWHERE ACROSS NORTH TEXAS...THE COLD AIR MAY NOT BE
DEEP ENOUGH FOR SNOW...AND SOME TYPE OF WINTER MIX WOULD BE THE
RESULT. IT IS TOO EARLY FOR PRECIP TYPE FORECASTING BUT CONFIDENCE
IS HIGH ENOUGH TO INSERT A LOW CHANCE OF RAIN/SNOW MIX ACROSS THE
WESTERN/SOUTHWESTERN ZONES WEDNESDAY NIGHT. HAVE KEPT PRECIP
LIQUID OVER THE REMAINING AREAS...BUT AS CONFIDENCE THAT THE
MODELS HAVE SETTLED DOWN ON ONE SOLUTION INCREASES THIS MAY BE
EXPANDED. EITHER WAY...EXPECT GENERALLY CLOUDY AND CHILLY WEATHER
MID-LATE WEEK. HAVE GONE QUITE A BIT COOLER THAN GUIDANCE FOR HIGH
TEMPS THROUGH FRIDAY. THE UPPER TROUGH AXIS WILL FINALLY MOVE EAST
BY SATURDAY WITH CLEARING SKIES AND WARMING TEMPERATURES.

[iorange55]

I'm telling you, all it takes is for me to start being negative about the potential event and things turn back in our favor. You should all thank me.

[Portastorm]

I'm telling you, all it takes is for me to start being negative about the potential event and things turn back in our favor. You should all thank me.

Sssshhh! The anti-jinx only works if you don't acknowledge that it is just that, the anti-jinx! Now, continue your pessimism, iorange55!

[GaryHughes]

NWS FW:

12Z GUIDANCE HAS CHANGED REGARDING ITS HANDLING OF A PIECE OF ENERGY THAT ROTATES THROUGH WESTERN CANADA AND INTO THE STATES BY MIDWEEK. TODAY THE GUIDANCE HAS EITHER SLOWED THE TIMING OF THAT ENERGY DOWN OR HAS FORECAST IT TO DROP INTO THE STATES MUCH FARTHER WEST THAN YESTERDAY. THE CHANGE RESULTS IN LESS NORTHERLY WINDS AT 850MB WHICH WOULD HAVE SERVED TO DRY THE REGION OUT AND LIMIT PRECIP POTENTIAL WED-THURS AS ANOTHER SHORTWAVE ROTATES IN FROM THE SOUTHWEST AROUND THE AFOREMENTIONED UPPER LOW. PRECIP HAD BEEN FORECAST BY THE CANADIAN AND ECMWF...AND NOW THAT THE GFS IS ON BOARD...WILL GO AHEAD AND BRING POPS INTO THE FORECAST WEDNESDAY IN THE SOUTH AND FOR MOST OF THE AREA WEDNESDAY NIGHT.

ALTHOUGH WE HAVE SEEN SOME SUBTLE FEATURES CHANGE IN THE LATEST MODEL GUIDANCE...THERE IS HIGH CONFIDENCE ON THE FORECAST UPPER LEVEL SYNOPTIC PATTERN. THIS PATTERN WILL FEATURE A RIDGE OVER THE PACIFIC NORTHWEST...WITH TELECONNECTIONS FAVORING A BROAD POSITIVE TILT TROUGH AXIS FROM HUDSON BAY TO THE FOUR CORNERS. THIS IS A SYNOPTIC PATTERN THAT ALWAYS SEEMS TO END UP BEING COLDER THAN FORECAST BY THE MODELS. I AM AT A LOSS FOR THE TECHNICAL REASON BEHIND THE MODEL BIAS...BUT THE UPPER PATTERN DOES ALLOW FOR A PROLONGED FETCH OF NORTHERLY WINDS AT THE SURFACE TO TRANSPORT COLD AIR SOUTHWARD OVER THE COURSE OF 2+ DAYS. SEEING THIS PATTERN RAISES CONCERNS FOR SURFACE TEMPS COLDER THAN CURRENTLY FORECAST AND SUBSEQUENTLY WINTER WEATHER WHEN THAT SHORTWAVE MOVES ACROSS FROM THE SOUTHWEST WEDNESDAY NIGHT. THE ECMWF AND CANADIAN SHOW A POTENTIAL FOR SNOW ACROSS CENTRAL TEXAS AND THAT FORECAST SEEMS REASONABLE. ELSEWHERE ACROSS NORTH TEXAS...THE COLD AIR MAY NOT BE DEEP ENOUGH FOR SNOW...AND SOME TYPE OF WINTER MIX WOULD BE THE RESULT. IT IS TOO EARLY FOR PRECIP TYPE FORECASTING BUT CONFIDENCE IS HIGH ENOUGH TO INSERT A LOW CHANCE OF RAIN/SNOW MIX ACROSS THE WESTERN/SOUTHWESTERN ZONES WEDNESDAY NIGHT. HAVE KEPT PRECIP LIQUID OVER THE REMAINING AREAS...BUT AS CONFIDENCE THAT THE MODELS HAVE SETTLED DOWN ON ONE SOLUTION INCREASES THIS MAY BE EXPANDED. EITHER WAY...EXPECT GENERALLY CLOUDY AND CHILLY WEATHER MID-LATE WEEK. HAVE GONE QUITE A BIT COOLER THAN GUIDANCE FOR HIGH TEMPS THROUGH FRIDAY. THE UPPER TROUGH AXIS WILL FINALLY MOVE EAST

[Ntxw]

*Pessimistic post* You know it feels like February with all these threats. I hope it doesn't take away that month when it actually comes!

[Portastorm]

Gary, your colleagues who work at duty stations further south in the state may be busy next week!

[GaryHughes]

:uarrow:

Gary, your colleagues who work at duty stations further south in the state may be busy next week!

I'm afraid you right, looks like a pretty large area may be effected.

[gpsnowman]

CBS 11 in Dallas just in the past hour or so has changed the 7 day oulook. They are calling for a 30% chance of a winter mix Thursday. Let the slow temp drop trend begin.

[Ntxw]

FIM's water equivalent for the period in question of snow. 0.5-1+ inches!

[LaBreeze]

[quote="wxman57"]12Z Euro has more snow across TX than the 00Z.

So, this is primarily a TX snow event, right? No chance of this moving east? Just wondering.

[ndale]

Given what the last few Euro op runs have shown, what the CMC has shown, what the ensembles are now suggesting ... and the trend today of the GFS coming towards the Euro solution, I am completely baffled and scratching my head by the area forecast discussion (below) issued this afternoon by the forecasters at EWX. Why do they refuse to acknowledge the possibility of frozen precip or freezing rain next week? No, I'm asking for snow or freezing rain to be included in the forecast ... but if you're going to reference the Euro in your AFD, at least you might mention the possibility. It's not like only one model run showed winter weather happening. And, you really got to wonder when the neighboring NWSFOs reference it (Fort Worth and Houston/Galveston).

----.

Do you think because predicting snow in central Tx is so difficult and they have been burned on forecasts so many times, they want to wait to the last minute to even mention it.