January: Calmer Pattern To End The Month

[Andrew]

A couple of things to keep in mind when looking at the wintry precip. First off where the mid level disturbance/ surface low sets up will be key for determine the location of precipitation. Many times in the past some areas could see plenty of precip while some areas see hardly any at all. Activity could be very scattered in nature and closer to the coast will likely see a greater chance compared to places farther north. This is another issue as we have a pretty deep layer of cold air filtering south with some strong dry air advection taking place. It will be a battle between the dry air from the north and the moist air from the south and west. In many cases I have seen the drier air win the battle. It does look like this disturbance looks more promising but that is always a concern for this part of the state. Finally, temps will be hard to predict and timing is always crucial. As of now moisture looks to stream across the area from the west beginning Thursday night, but if things are delayed until the daytime Friday temps could be too warm for any different p-types. While the models do look promising and exciting don't get too excited just yet. Luckily most people here understand the predictability issues that we have down here. Once we get closer to the actual event hopefully models will come into better consensus on where moisture will stream and the temps to accompany it.

[cperk]

A couple of things to keep in mind when looking at the wintry precip. First off where the mid level disturbance/ surface low sets up will be key for determine the location of precipitation. Many times in the past some areas could see plenty of precip while some areas see hardly any at all. Activity could be very scattered in nature and closer to the coast will likely see a greater chance compared to places farther north. This is another issue as we have a pretty deep layer of cold air filtering south with some strong dry air advection taking place. It will be a battle between the dry air from the north and the moist air from the south and west. In many cases I have seen the drier air win the battle. It does look like this disturbance looks more promising but that is always a concern for this part of the state. Finally, temps will be hard to predict and timing is always crucial. As of now moisture looks to stream across the area from the west beginning Thursday night, but if things are delayed until the daytime Friday temps could be too warm for any different p-types. While the models do look promising and exciting don't get too excited just yet. Luckily most people here understand the predictability issues that we have down here. Once we get closer to the actual event hopefully models will come into better consensus on where moisture will stream and the temps to accompany it.

Why is the NWS putting it in their forecast so early.

[Andrew]

A couple of things to keep in mind when looking at the wintry precip. First off where the mid level disturbance/ surface low sets up will be key for determine the location of precipitation. Many times in the past some areas could see plenty of precip while some areas see hardly any at all. Activity could be very scattered in nature and closer to the coast will likely see a greater chance compared to places farther north. This is another issue as we have a pretty deep layer of cold air filtering south with some strong dry air advection taking place. It will be a battle between the dry air from the north and the moist air from the south and west. In many cases I have seen the drier air win the battle. It does look like this disturbance looks more promising but that is always a concern for this part of the state. Finally, temps will be hard to predict and timing is always crucial. As of now moisture looks to stream across the area from the west beginning Thursday night, but if things are delayed until the daytime Friday temps could be too warm for any different p-types. While the models do look promising and exciting don't get too excited just yet. Luckily most people here understand the predictability issues that we have down here. Once we get closer to the actual event hopefully models will come into better consensus on where moisture will stream and the temps to accompany it.

Why is the NWS putting it in their forecast so early.

Because models have been relatively consistent that there is a chance. Not saying it won't happen just saying there are a lot of factors to be watched. Keep an eye on the discussions that come out and an eye on the temps upstream.

[srainhoutx]

Challenging forecast to say the least. What would you do if you were in the ‘hot seat’ making decisions that may or may not have an impact for a lot of folks? The longer range NAM suggests a moist pattern with an Eastern Pacific connection. While the air mass may be border line, there is enough data and imagery to suggest it is worth monitoring. It's been a while since we had any 'night crew' activity...

[Ptarmigan]

Even if there is a small amount of frozen rain, it could be a problem. The February 2011 event was bad as there were fatalities from people driving on frozen road. I do not remember any power outages in the 2011 ice storm, unlike the January 1997 ice storm.

I have noticed forecasting winter events is really tricky. In many ways more so than tropical storms or hurricanes as freezes is not something Houston often sees as compared to tropical weather events.

[Texaspirate11]

YIKES - I'll be freezing in North Carolina and will miss this exciting event....

Stay warm, y'all.

I am so dreaming of flip flops.

[Andrew]

Very interesting to note on a lot of the vertical profiles coming from the models, they show a possible completely frozen profile. It is a close one (especially around 850mb) and would indicate that if wintry precip did transition to snow it would be a very wet snow with a ratio closer to 1:2 or 1:5. This would only occur if the models were completely correct which I don't completely believe with such a shallow front and south winds around 800mb. It does look like most of the atmosphere could be below freezing which would indicate more of a sleet threat looks likely. Still a ton of questions to be answered but it does look interesting to say the least. I just hope moisture levels are abundant enough for precip.

Edit to add this profile does remind me of a couple years ago where we expected a better chance of snow but ended up with sleet and freezing rain due to the models underestimating the warm nose present. Looks very similar to this where those south winds could really warm temps.

[Katdaddy]

Victoria, TX now has a Winter mix in the forecast. This morning's Corpus Christi AFD has added a Winter mix from Cotulla to Victoria and N of that line.

[srainhoutx]

The overnight guidance has come into better agreement, but significant forecast challenges remain for. The Thursday afternoon into mid day Friday time frame. While the odds have increased that areas from San Antonio, Austin and College Station have slightly increased for wintry mix of freezing rain, sleet and possibly some light snow with areas further S seeing a freezing rain and sleet mix as far S as our Coastal Counties early Friday. It is noteworthy that the 06Z NAM and GFS trended drier, but lack of run to run continuity raise an eyebrow and add the forecasting challenge. It is likely that we may not know with any certainty the amount, duration and type of frozen precip until Wednesday into Thursday morning as Winter Weather Events are rare and extremely difficult to forecast beyond 18-24 hour in Central/SE Texas. Stay Tuned to additional forecasts and further updates. Over night Thursday into mid day Friday could bring Significant travel troubles with icy conditions on over passes, fly overs and other elevated surfaces including bridges.

Additional Arctic intrusions appear to be growing again next week with additional precip chances that even extend into Early February. It is looking like we are entering a very active period with several chances of more wintry michief before the pattern breaks down and we transition to a more typical weather pattern later in February.

[Katdaddy]

Continued mostly sunny skies will continue today as the cold front is now off the coast. Temps in the mid to upper 50s with gusty N winds this morning. Highs should reach the low to mid 60s today and Wednesday and then a big change comes Thursday as another Arctic front moves across TX. Models continue to bounce around with possible freezing rain and sleet across SE TX. Friday morning. Remember Winter precip in SE TX is a very tough forecast. For now I will continue watch the models and look for consistency…..perhaps better details tomorrow evening and Thursday morning. The Houston-Galveston NWS say it perfectly in the last sentence of this morning's AFD: THIS REMAINS A TRICKY EVENT SO PLEASE STAY TUNED.

[Portastorm]

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.

[srainhoutx]

Morning Update from Jeff:

Red Flag Warning has been issued for today for the western 2/3rds of SE TX

Elevated to near critical fire weather conditions will be in place from early this morning to around mid afternoon. Overnight cold frontal passage has brought strong NW winds to the region this morning with gusts upwards of 35-45mph across the area. Favorable mixing of the low level wind field will be enhanced once the sun rises so expect strong winds to continue into the early afternoon hours. Dewpoints have already plunged into the mid 20’s and will likely fall into the 10’s this afternoon resulting in RH values between 10-20% across the region. Fine fuels are dried and killed from the recent hard freezes and overall top layer moisture is low as wetting rainfall has been lacking since late November and the recent air mass has been very dry. Any grass fire that may develop will likely burn quickly in the strong winds and dry fuels and extreme caution should be used with any outdoor flames today.

On to much bigger challenges….

Strong arctic cold front will barrel into the state late Wednesday and blast off the TX coast early Thursday with rapidly falling temperatures. Upstream air mass over Canada is pretty cold and suspect models may be a touch too warm with their expected temperatures Thursday and Friday at the moment…but do not expect a widespread hard freeze like we had early this month due to cloud cover.

Cold arctic air will be in place by late Thursday and a short wave trough will approach the area from the west Thursday night into Friday. This trough will induce moisture moving northward into the very cold air mass producing the potential for a mixture of winter precipitation. Expect surface temperatures to fall to near/below freezing over much of the area by late Thursday evening which is an important component when dealing with freezing/frozen precip in this area…typically this is the missing link. Given the intensity of this air mass do not think we will have much of a problem falling to and below freezing at the surface. Following that line of thinking one must then look at what the temperatures is doing above the surface throughout the entire air column to attempt to resolve P-type and amounts.

One thing that is striking to me this morning is the large amounts of dry air being shown on model guidance in the near surface to roughly 850mb level at the time when the model is showing precipitation falling…looks like a lot of mid and high level moisture will be present, but a very dry sub cloud layer which could evaporate much of the falling precipitation. Other interesting item is the cooling of the entire atmospheric profile at both College Station and IAH Friday morning possibly from the evaporation of the precipitation falling into the dry air helping to cool the air column…known as wet bulb cooling.

It is pretty pointless at this time frame to attempt to determine P-type across the region Thursday night into Friday morning. Cold see a mixture of all winter weather types from freezing rain to sleet and some snow (especially around College Station to Huntsville). Given the fairly strong 850mb flow out of the SSW I would not think this is a very favorable snow profile for the area. Sub freezing surface temperatures with a modest warm nose in the mid levels is more of a freezing rain and ice set up likely with sleet mixed in.

With all that said…the dry layer will have to be overcome and if it is not we will end up cloudy and very cold, but dry. Model generated QPF amounts are on the low side ranging from a trace to .20 of an inch of liquid precipitation which equates to varying amounts of frozen precipitation, but that in freezing rain would cause some major problems on overpasses and elevated surfaces.

[wxman57]

I can't see soundings yet, the usual free maps and AccuWx PPV precip totals, heights and temps, and the as it begins and ends, 12 hours apart, but not the middle.

Ed,

For soundings try the twister site:

http://www.twisterdata.com/

Click a model (perhaps GFS) then in the left frame you can select "Winter" and then "Snow Depth". You'll get that plot plus you can click anywhere on the map to generate a sounding. Then you can use the small map in the right frame to drag the sounding marker to a more precise location and generate a new sounding. You can select any time (6hr increments) for the sounding and advance from one time to the next while viewing the sounding.

Last night's GFS run indicates quite dry air behind the front here. Just a mid-level cloud deck when temps are below freezing.

[harpman]

Gentleman, I know you have followers all across the Gulf Coast, and I am one of them. I rarely post and mostly read. But I must ask if the current indications point to any indication of SE La. receiving any frozen precip. I thank you in advance for any response.

[wxman57]

Gentleman, I know you have followers all across the Gulf Coast, and I am one of them. I rarely post and mostly read. But I must ask if the current indications point to any indication of SE La. receiving any frozen precip. I thank you in advance for any response.

I don't see anything to indicate any precipitation in south Louisiana with this front. Just dry cold air.

[srainhoutx]

HPC/WPC Senior Forecaster Paul Kocin fresh back to work after a week of vacation in Breckenridge, CO offered this in his overnight Winter Weather Outlook...

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

VALID 12Z TUE JAN 21 2014 - 12Z FRI JAN 24 2014

DAY 3...

...TEXAS...

AS A HUGE AND COLD SURFACE ANTICYCLONE DROPS SOUTHWARD EAST OF THE
ROCKIES...EAST TO SOUTHEASTERLY FLOW WILL BRING MOISTURE INLAND
ACROSS TEXAS AS COLDER AIR MOVES SOUTHWARD ACROSS THE STATE. THE
POSSIBILITY OF LIGHT SNOWFALL OVER CENTRAL TEXAS COULD BE AN
UNUSUAL OCCURRENCE ON DAY 3...WHILE MIXED FROZEN PRECIPITATION
COULD FALL OVER MUCH OF SOUTH CENTRAL AND SOUTHERN TEXAS AS COLDER
AIR CONTINUES TO DRIFT SOUTHWARD INTO THE SOUTHERN PORTIONS OF THE
STATE. HAZARDOUS DRIVING CONDITIONS FOR RESIDENTS UNUSED TO
DEALING WITH SNOW/SLEET AND FREEZING RAIN/DRIZZLE APPEARS THE MOST
LIKELY PROBLEM AT THIS POINT.

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

KOCIN

[redneckweather]

Right on cue....the SNOW word has now entered the discussions. Hey, at least it has entered the discussions for once this winter.

[srainhoutx]

The 12Z NAM is considerably 'wetter' than the 06Z run. The 12Z NAM is also suggesting a bit stronger upper air disturbance and that old Coastal trough is back once again. The NAM also keep the precip going longer into Friday since it has slowed the progression of that upper air disturbance by about 6-12 hours. The Arctic front still arrives late Wednesday and makes it to the Coast By mid day Thursday and has a bit stronger 1044mb High pressure cell associated with the cold air.

[srainhoutx]

12Z Model Recap:

NAM = 'wetter' and slower with the precip ending. Upper air disturbance stronger and less strung out

GFS = precip for about 18 hours in Central TX/12-14 hours SE TX

Canadain = 'wetter' with a coastal low developing near Brownsville

UKMET = 'wetter' with a coastal trough

Euro = Colder and 'wetter' with a coastal trough

[harpman]

And Louisiana gets none of this?