January: Calmer Pattern To End The Month

[srainhoutx]

Right now harpman this looks more like a Central and Coastal Texas/SW Louisiana event regarding any wintry precip. SE Louisiana looks to be much closer to the base of the mean trough with a dry northerly flow.

[harpman]

Thank you for the response. Not giving up hope here yet.

[srainhoutx]

12Z MEX/MOS text data suggests about 12 hours or so of mixed frozen precip for IAH beginning Thursday evening until Friday morning to noon time.

[srainhoutx]

Updated 3 Day QPF valid 00Z Wednesday to 00Z Saturday:

[srainhoutx]

Updated freezing rain probabilities from the WPC/Winter Weather Forecast Desk:

The attachment 01212014 Ice 1930Z 06Z Friday prb_24hicez_ge_01_2014012200f054.gif is no longer available

[cperk]

The maps above indicate that I could possibly see a little wintry action in my area.

[cristina6871]

srainhoutx - what do the colors mean and is it showing all the way to Houston metro?

[srainhoutx]

Updated snow probabilities from the WPC/Winter Weather Desk:

[srainhoutx]

srainhoutx - what do the colors mean and is it showing all the way to Houston metro?

Those are percentages of chances of seeing the various amounts suggested by the freezing rain and snow probabilities as seen on the left side of each graphic. These are just forecasting tools/graphics issued as a guide by the Weather Prediction Center and are used to assist the local forecasters and are not an actual forecast issued by the various NWS offices, cristina.

[srainhoutx]

Updated QPF Discussion from the WPC:

QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
308 PM EST TUE JAN 21 2014


PRELIM DAY 1...DAY 2 AND DAY 3 QPF DISCUSSION
VALID JAN 22/0000 UTC THRU JAN 25/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR


DAYS 2 AND 3...

...CENTRAL ROCKIES TO TEXAS...

A SHORTWAVE TROUGH IS FORECAST TO DROP INTO THE CENTRAL GREAT
BASIN WED NIGHT BEFORE SHIFTING TO THE SOUTHEAST AS IT BECOMES
INCORPORATED INTO THE BROADER SCALE TROUGH CENTERED OVER THE
MIDWEST. EXPECT MAILY LIGHT AMOUNTS TO SPREAD SOUTH FROM THE
CENTRAL INTO THE SOUTHERN ROCKIES ON THU. MEANWHILE...INCREASING
ISENTROPIC LIFT AND LOW LEVEL CONVERGENCE ALONG A PASSING ARCTIC
FRONT WILL ENCOURAGE MAINLY LIGHT AMOUNTS ACROSS CENTRAL INTO
SOUTH TX. THE FRONT IS FORECAST TO PLUNGE WELL SOUTH OF THE STATE
ON FRI...HOWEVER A DEVELOPING COASTAL TROUGH WILL HELP TO FOCUS
SHOWERS ALONG THE TX COAST AND THE LOWER RIO GRANDE LATE INTO THE
PERIOD. WPC AMOUNTS REFLECT A BLEND OF THE GFS/ECMWF THROUGH THE
PERIOD.

[srainhoutx]

Afternoon Update from the WPC Winter Weather Desk:

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
328 PM EST TUE JAN 21 2014

VALID 00Z WED JAN 22 2014 - 00Z SAT JAN 25 2014


...ROCKIES INTO TX...

A SHORTWAVE TROUGH ARRIVING INTO WRN CANADA WILL DIG SOUTHEASTWARD
TOWARD THE GREAT BASIN/CENTRAL ROCKIES ON THURS BEFORE SHEARING
OUT DOWNSTREAM THROUGH THE SRN PLAINS ON FRI. MOISTURE AVAILABLE
WITH THIS SYSTEM WILL NOT BE IN ABUNDANCE...BUT SUFFICIENT FORCING
AND UPSLOPE FLOW WILL SUPPORT LOCALLY HEAVY SNOWFALL ACROSS CO
INTO ERN NM. FARTHER SOUTH INTO TX... A HUGE AND COLD SURFACE
ANTICYCLONE WILL CONSUME THE PLAINS ...EAST TO SOUTHEASTERLY FLOW
OFF THE GULF OF MEXICO WILL ATTEMPT TO BRING MOISTURE INLAND
ACROSS TEXAS. THIS MOISTURE OVERRUNNING INTO THE ANOMALOUS COLD
AIR MASS COULD SET THE STAGE FOR SNOW AND LIGHT ICING . THE THREAT
FOR THURS APPEARS MAINLY ACROSS WEST TX INTO THE HILL COUNTRY BUT
BECOMES MUCH MORE WIDESPREAD ON FRI FROM THE HILL COUNTRY TO
SRN/SERN TX. THOUGH THE AMOUNTS WILL NOT BE SIGNIFICANT...
HAZARDOUS DRIVING CONDITIONS WILL BE LIKELY FOR AN AREA OF THE
COUNTRY NOT VERY USED TO FROZEN PRECIP. WPC STAYED VERY CLOSE TO
THE MORE CONSERVATIVE OPERATIONAL GFS/ECMWF OVER THE MUCH MORE
BOLD NAM.

THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT FOR
ALL 3 DAYS.

MUSHER

[Portastorm]

NWSFO Austin/San Antonio (EWX) just issued their afternoon AFD. Sounds like they're "all in" with regards to wintry precip chances for the Austin area ... albeit light amounts.

Here's the latest take from EWX on wintry weather possibilities for south central Texas:

.LONG TERM (THURSDAY THROUGH TUESDAY)...
THE ARCTIC FRONT WILL RACE TOWARD THE COAST THURSDAY MORNING WITH
COLD AIR ADVECTION BEHIND THE FRONT DURING THE DAY THURSDAY. THE
MID LEVEL FLOW WILL BECOME MORE WESTERLY THURSDAY/THURSDAY NIGHT
WITH MINOR DISTURBANCES MOVING ACROSS S CENTRAL TX...BRINGING
INCREASING PRECIPITATION CHANCES. WINDY AND MUCH COLDER THURSDAY
INTO THURSDAY NIGHT. TEMPERATURES FALLING TO BELOW FREEZING ALL
AREAS THURSDAY NIGHT WITH 20S TO NEAR 20 DEGREES ALL AREAS BY
SUNRISE FRIDAY. IN ADDITION A WIND ADVISORY MAY BE REQUIRED FOR
THURSDAY AFTERNOON/ EVENING...ESPECIALLY ALONG THE I35 CORRIDOR
WHERE WINDS TEND TO BE CLOSER TO THE SUSTAINED 25 MPH THRESHOLD.
INCREASING CHANCES FOR PRECIPITATION/MIX OF WINTER PRECIPITATION
THURSDAY AFTERNOON/NIGHT INTO FRIDAY MORNING AS A 24-36 HOUR
PERIOD OF ISENTROPIC LIFT OCCURS ABOVE THE COLD AIRMASS. WILL SEE
LIGHT RAIN OR SPRINKLES DEVELOPING THURSDAY MORNING...WITH A MIX
OF WINTER PRECIPITATION(LIGHT RAIN/LIGHT SLEET/SNOW) BEGINNING AS
EARLY THURSDAY AFTERNOON IN THE NORTHERN HILL COUNTRY/EDWARDS
PLATEAU. THEN A MORE WIDESPREAD MIX OF WINTER PRECIPITATION
CHANGING OVER FROM LIGHT RAIN TO A MIX OF LIGHT SLEET AND SNOW
OVER MOST ALL OF THE CWA BY FRIDAY MORNING. MODEL SOUNDINGS WERE
SHOWING A DEEP LAYER OF SUB FREEZING TEMPERATURES AT THE LOW
LEVELS WHICH INDICATES SLEET/SNOW RATHER THAN THE PREVIOUSLY
INDICATED FREEZING RAIN. MODELS STILL SHOW LIGHT QPF AMOUNTS WITH
THE NAM SHOWING HIGHER POCKETS OF ONE TENTH INCH. HAVE INCLUDED
SOME LIGHT SNOW ACCUMULATIONS THURSDAY NIGHT ACROSS THE HILL
COUNTRY AND NORTHERN SECTIONS OF SOUTH CENTRAL TEXAS OF ONE TENTH
TO NEAR ONE QUARTER INCH. THESE AMOUNTS WILL LIKELY NEED TO BE
ADJUSTED OVER THE NEXT SEVERAL FORECAST PACKAGES. OTHERWISE THE
WINTER PRECIPITATION TAPERS OFF FROM THE WEST FRIDAY MORNING AS A
SHORT WAVE PASSES AND THE DRY NWLY FLOW RESUMES ACROSS TX LATE
FRIDAY.

[TexasBreeze]

Our HGX seems in on it too. Could get interesting...

[cristina6871]

trying not to get too excited as I know what will happen.....it will go another direction or pull and stall some where.

[tireman4]

From HGX AFD Today...


000
FXUS64 KHGX 212144
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
344 PM CST TUE JAN 21 2014

.DISCUSSION...
A NORTHWESTERLY FLOW CONTINUE OVER SE TX THIS AFTERNOON. THIS WAS
DUE TO THE UPPER LEVEL RIDGE OVER THE PACIFIC COAST AND THE UPPER
LEVEL TROUGH EAST OF THE MISSISSIPPI RIVER. THE AMPLIFIED FLOW
WILL PUSH THE CURRENT COLD AIRMASS OUT OF THE AREA AND BRING FAIR
SKIES AND SLIGHTLY ABOVE NORMAL TEMPERATURES ON WEDNESDAY. ANOTHER
ARCTIC AIRMASS WILL ARRIVE INTO SE TX BEGINNING LATE THURSDAY.
THE MAIN WEATHER IMPACTS OF NOTE WILL BE CHANCES FOR WINTRY
PRECIPITATION LATE THURSDAY NIGHT INTO FRIDAY AND COLD
TEMPERATURES FRIDAY AND FRIDAY NIGHT.

MODELS ARE HAVING A TOUGH TIME WITH THE PRECIPITATION EVENT FOR
THURSDAY AND FRIDAY. THE AIRMASS WILL BE START OUT DRY BUT WILL
MOISTEN UP OVER THE UPPER AND MID LEVELS DURING THE DAY THURSDAY
AS THE SHORTWAVE TROUGH TAPS INTO PACIFIC MOISTURE. THE NAM12
HOLDS OFF ON RAINFALL DEVELOPMENT UNTIL LATE IN THE DAY WHILE THE
GFS AND ECMWF DEVELOP RAINFALL THURSDAY MORNING. THURSDAY NIGHT
AND FRIDAY WILL BE TRICKY AS THE 12Z NAM12 MOISTENS UP THE LOW-
LEVELS...DEVELOPS GOOD ISENTROPIC LIFT IN THE MOIST AIRMASS WITH A
SURFACE TROUGH OFF THE COAST...AND KEEPS SE TX UNDER THE RIGHT
REAR QUAD OF THE UPPER JET. THE GFS AND ECMWF END THE
PRECIPITATION FRIDAY MORNING WHILE THE NAM12 ENDS IT FRIDAY
EVENING.

GIVEN ALL THE UNCERTAINTY...WENT WITH A CONSENSUS OF THE GFS AND
ECMWF ON THURSDAY...AND A CONSENSUS OF ALL THREE MODELS THURSDAY
NIGHT AND FRIDAY. WITH TEMPERATURES FALLING BELOW FREEZING AFTER
MIDNIGHT THURSDAY NIGHT...THIS WILL MEAN THAT THERE IS A CHANCE
THAT LIGHT RAIN WILL MIX WITH OR CHANGING TO FREEZING RAIN AND
SLEET IF THE PRECIPITATION CONTINUES INTO FRIDAY MORNING. FROM
LATE THURSDAY NIGHT TO MID MORNING FRIDAY WENT WITH A CHANCE OF
SLEET AND SNOW MIXED WHERE THE COLDEST PART OF THE AIRMASS WILL
BE LOCATED...MAINLY ALONG AND NORTH OF A LINE FROM CALDWELL TO
TRINITY.

TEMPERATURES THURSDAY NIGHT AND FRIDAY MORNING ARE EXPECTED TO
DROP INTO THE MID 20S MAINLY ALONG AND NORTH OF THE INTERSTATE 10
CORRIDOR. WITH CLOUDY CONDITIONS ON FRIDAY...THE TEMPERATURES MAY
HAVE A DIFFICULT TIME WARMING THROUGH THE 30S. TRENDING DOWN THE
HIGHS FOR FRIDAY CLOSER TO THE ECMWF OUTPUT. AFTER ANOTHER COLD
NIGHT FRIDAY NIGHT...EXPECT WARMING TREND OVER THE WEEKEND.

[tireman4]

Not trying to sound like Wxman 57, but I would say that the models will continue to flip flop until Thursday. I am going ( me personally) going to wait until the 12z Thursday models before I buy into it. Right now though, there are eyebrows being raise. I will assure you of that.

[TexasBreeze]

Flipping around 18z GFS few degrees warmer and drier. ( DW Hooks) Interesting but not quite feeling it with this event considering the flipping and ecmwf.

[stormlover]

Ignore 18 runs they have been bad the last 3 days!!!

[Paul Robison]

Two questions:

1. How much icing does it take to break tree limbs and power lines?

2. Will the area get a sufficient coating for these things to happen?

3. Will ERCOT have to initiate rolling outages again?

[wxman57]

Two questions:

1. How much icing does it take to break tree limbs and power lines?

2. Will the area get a sufficient coating for these things to happen?

3. Will ERCOT have to initiate rolling outages again?

I count three questions. It would take probably over 1/2" of ice accumulation to cause significant issues with trees/power lines. It is quite unlikely that the greater Houston area will see such accumulations. We're looking at light rain, a little freezing rain (probably under 1/8" accumulations) and a little sleet mixed in. This will probably not be significant enough for any power issues anywhere near Houston.

Latest GFS run has no post-frontal precip across Houston, by the way. It's all to our west on that run. Too soon to be sure about post-frontal precip, but if we get any it should be light.