December: Warm Days & Cool-Foggy Nights To End 2011

[txflagwaver]

Looks like a real live thunderstorm headed our way...hopefully nothing severe. Glad for the rain though

[srainhoutx]

It looks like guidance did fairly well after all the hand wringing by a few and showers/storms are heading toward the coast this morning. The good news is nothing severe occurred. The next chance of beneficial rains starts Wednesday night into Thursday. Some rather interesting developments over night via guidance as well. The Euro now shows a much stronger cut off low over Mexico near Monterrey and the GFS has flipped drier. Most guidance suggests much chillier air settling across the Lone Star State with a modified Arctic/Canadian front. Over running precip is possible during the Christmas Holiday Weekend with cold air at the surface. Once again caution is advised with the models flip flopping from run to run as an active pattern continues with multiple short wave impulses riding along the various jet stream flow.

Dallas/Ft Worth for Friday:

ANOTHER STRONG POTENTIAL VORTICITY ANOMALY THAT ANCHORS THE BASE
OF THE TROUGH WILL MOVE THROUGH FRIDAY. MODELS AGREE ON THE
POSITION AND STRENGTH OF THIS SYSTEM...BUT DIVERGE REGARDING THE
AMOUNT OF MOISTURE AVAILABLE. ISENTROPIC LIFT SHOULD BE STRONG
ENOUGH IN THE MID LEVELS...THAT IF MOISTURE IS AVAILABLE...THERE
WOULD BE PRECIPITATION FRIDAY. RIGHT NOW THE NAM...GFS AND GEM ARE
INDICATING MEASURABLE PRECIP IN THE WESTERN CWA...WITH ALL THE
SREF MEMBERS AND THE ECMWF DRY. THERMAL PROFILES SHOULD BE COLD
ENOUGH FOR SNOW...PARTICULARLY IN THE NW ZONES. WE THINK THAT
PARTS OF THE AREA WILL CONTEND WITH SPRINKLES OR SNOW FLURRIES ON
FRIDAY...BUT ARE NOT QUITE READY TO MENTION ANY MEASURABLE PRECIP.
SINCE THE EVENT LOOKS PRETTY MINOR AS FAR AS IMPACTS GO...WOULD
PREFER TO LEAVE THE MENTION OF SPRINKLES/FLURRIES OUT OF THE
OFFICIAL FORECAST FOR AT LEAST ANOTHER MODEL CYCLE OR TWO TO SEE
WHAT DIRECTION THE CONSENSUS TRENDS TOWARD.

REGARDLESS OF PRECIP POTENTIAL FRIDAY...THE UPPER PATTERN IS
FAVORABLE FOR TRANSPORTING COLD AIR INTO THE REGION. TEMPS WILL
LIKELY BE 5 TO 10 DEGREES BELOW NORMAL THROUGH THE HOLIDAY
WEEKEND. MEX MOS LOOKS ABSURDLY WARM AND WILL CONTINUE WITH THE
FORECAST OF HIGHS IN THE 40S AND LOWS IN THE 20S. MODEL GUIDANCE
DIVERGES SUNDAY...AS THEY DO NOT KNOW HOW TO RESOLVE THE FINAL
VORT LOBE ROTATING DOWN THE BACKSIDE OF THE TROUGH. SOME SOLUTIONS
KEEP AN UPPER LOW CUT OFF OVER NORTHERN MEXICO AND OTHERS CLEAR
THE ENTIRE TROUGH OFF TO THE EAST. WILL KEEP SOME CLOUDS IN THE
FORECAST SUNDAY AND NOT BITE ON THE TOTAL CLEARING ADVERTISED BY
THE GFS.



San Angelo:

THE MOST RECENT MODEL RUNS ARE IN GOOD AGREEMENT WITH THE SYNOPTIC
PATTERN DURING THIS PERIOD AND HAVE MOISTENED THE LOW/MID LEVELS
SUFFICIENTLY TO CONCERN ME WITH THE POTENTIAL FOR LIGHT WINTER
PRECIP. THE ECMWF REMAINS THE DRIER OUTLIER AT THIS POINT BUT THERE
IS ENOUGH OF A SIGNAL THERE FOR ME TO ADD MENTIONABLE POPS TO THE
BIG COUNTRY THURSDAY NIGHT AND FRIDAY AHEAD OF THE NEXT UPPER TROF
WHICH WILL DIVE QUICKLY SOUTH SOUTHEAST ALONG THE SPINE OF THE
ROCKIES AND TURNING THE CORNER TO THE EAST OVER NEW MEXICO. MODEST
FRONTOGENESIS IN THE H85-H7 LAYER WILL ENHANCE VERTICAL MOTION
THROUGH WHAT IS DEPICTED AS A SATURATED DENDRITIC GROWTH ZONE.
BUFR SOUNDINGS INDICATE PRECIP TYPE AS SNOW FOR ALL AREAS WITH NO
WARM LAYER PRESENT IN THE MODELS. AT THIS TIME...PRECIP IS
EXPECTED TO REMAIN LIGHT /LESS THAN 1 INCH/. THERE IS PLENTY OF
OPPORTUNITY TO INCREASE SNOW AMOUNTS OR EVEN REMOVE THEM IF
CONDITIONS CHANGE.



Midland/Odessa:

MODELS HAVE BEEN HAVING DIFFICULTY THIS WINTER SEASON WITH THE
STRENGTH AND MOVEMENT OF UPPER LOWS THIS YEAR AND AGAIN THERE IS
MODEL DISAGREEMENT WITH THIS LOW. THE CANADIAN IS SLOWEST AND
STRONGEST AND THE ECMWF IS THE WEAKEST AND FASTEST...AND GIVEN THE
AMPLIFYING UPSTREAM RIDGE OVER THE WEST COAST IT SEEMS SLOWER AND
DEEPER IS THE BETTER SOLUTION AT THIS POINT. A STRONGER LOW WILL
BE ABLE TO PROVIDE THE MOISTURE AND LIFT NEEDED FOR PRECIPITATION
FORMATION. HAVE UPPED POPS THURSDAY NIGHT INTO FRIDAY FOR THE
NORTHERN HALF OF THE CWA WITH LOW TO MID CHANCE POPS. THE BEST
CHANCE FOR SNOW WILL BE WEST OF THE PECOS RIVER IN EDDY COUNTY
WHERE DYNAMICS...OROGRAPHICS...AND ISENTROPIC LIFT ARE ALL
MAXIMIZED. THE PRECIP SPREADS EAST ON FRIDAY AND TEMPERATURES
SHOULD BE COLD ENOUGH FOR THERE TO BE ALL SNOW. THE CANADIAN MODEL
SPREADS PRECIP FURTHER SOUTH GIVEN ITS DEEPER SOLUTION AND THIS
MAY WELL PROVE CORRECT SO AREAS SOUTH OF I-20 MAY NEED INCREASED
POPS DURING FUTURE SHIFTS. THE WEEKEND WILL BE COLD THOUGH THE
UPPER RIDGE WILL BREAK DOWN BY MONDAY WITH MORE ZONAL CONDITIONS
EXPECTED EARLY NEXT WEEK.

[srainhoutx]

LCH issues Flash Flood Warning for our neighbors in far SE TX/SW LA. I guess djmike won't be singing the bust tune after all...

[djmike]

LCH issues Flash Flood Warning for our neighbors in far SE TX/SW LA. I guess djmike won't be singing the bust tune after all...

Ok...ok...lol..My bust was BUSTED! MAJOR line of thunderstorms moving through Beaumont now! I'll admit, I jumped the gun on calling this a bust. BUT, for many areas it was! I do understand weather is VERY unpredictable! Just hopeing Wed/Thurs storms will be generous for all. ....closing in fast to the 1" mark now...I'm a happy camper!

[Rich]

Definitely nice to get the rain...Crazy how it always seems to occur around morning commute time though

[srainhoutx]

LCH issues Flash Flood Warning for our neighbors in far SE TX/SW LA. I guess djmike won't be singing the bust tune after all...

Ok...ok...lol..My bust was BUSTED! MAJOR line of thunderstorms moving through Beaumont now! I'll admit, I jumped the gun on calling this a bust. BUT, for many areas it was! I do understand weather is VERY unpredictable! Just hopeing Wed/Thurs storms will be generous for all. ....closing in fast to the 1" mark now...I'm a happy camper!

Good to hear, djmike. I had just under an inch in NW Harris County. The pattern remains a bit chaotic and expect changes throughout the next several days. Guidance is struggling so much with the short waves and various vorts embedded in the flow both in the northern and southern streams that changes from run to run, and model to model that little confidence in any one solution is just not prudent. For the weather lover, this active pattern has certainly been interesting to watch unfold since Thanksgiving. It looks to continue into the weekend and perhaps next week as well to end 2011. It's hard to believe another year is coming to an end, isn't it?

HPC Morning Update:

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
851 AM EST TUE DEC 20 2011

VALID 12Z SAT DEC 24 2011 - 12Z TUE DEC 27 2011

MEDIUM RANGE GUIDANCE AGREES THAT THE MEAN PATTERN SHOULD TREND
TOWARD A MORE ZONAL CONFIGURATION BY NEXT MON-TUE AS FAST PACIFIC
FLOW STREAMS INTO THE CONUS. THIS REGIME IS FCST TO REPLACE A
MORE AMPLIFIED PATTERN EARLY-MID PERIOD... CONSISTING OF A RIDGE
BUILDING FROM THE ERN PAC INTO WRN NOAM AND A POSITIVELY TILTED
MEAN TROF FROM ERN CANADA INTO THE SRN ROCKIES/NRN MEXICO. MOST
IF NOT ALL MULTI-DAY MEANS BY D+8 SHOW A PREVAILING CORE OF
NEGATIVE HGT ANOMALIES ASSOC WITH A CLOSED LOW OVER ALASKA... WITH
TELECONNECTIONS RELATIVE TO THIS FEATURE SUPPORTING LOW AMPLITUDE
AND VERY BROADLY CYCLONIC FLOW. THE 06Z GFS AND TO A LESSER
EXTENT 00Z GFS ARE ON THE FAST SIDE OF THE SPREAD INCLUDING THE
00Z GEFS/ECMWF ENSEMBLE MEANS WITH THE ARRIVAL OF SHRTWV ENERGY...
WITH THE 06Z GFS SCENARIO LEADING TO FASTER THAN CONSENSUS
DOWNSTREAM PROGRESSION AS WELL. THE AMPLIFIED PATTERN IN PLACE
THRU MID-PERIOD SHOULD SUPPORT SLOWER PROGRESSION THAN INDICATED
BY THE 00Z/06Z GFS. MEANWHILE AROUND SUN-MON THE 00Z GFS MAY BE
OVERDONE WITH ITS SEWD EXTENT OF ITS TROF GIVEN THE PERSISTENCE OF
THE MEAN RIDGE OVER/NEAR THE BAHAMAS. THE 00Z ECMWF CONFORMS
BETTER TO ENSEMBLE GUIDANCE INTO DAY 6 MON. 00Z ECMWF AMPLITUDE
WITH FEATURES BY DAY 7 IS STILL POSSIBLE BUT THE TREND TOWARD
FLATTER FLOW IN THE MEAN FAVORS LEANING AWAY FROM ITS SPECIFICS
UNTIL BETTER CLUSTERING DEVELOPS.

BEFORE THE AFOREMENTIONED PATTERN CHANGE OCCURS... EXPECT ENERGY
REACHING THE PAC NW/BC AS OF EARLY DAY 3 FRI TO RELOAD THE E-CNTRL
CANADA TO SRN ROCKIES/NRN MEXICO MEAN TROF BY THE CHRISTMAS
WEEKEND. UNCERTAINTIES IN DETAILS OF THE INITIALLY SPLIT FLOW
OVER THE CONUS AND RELOADING OF THE MEAN TROF CONTINUE TO IMPACT
THE FCST OF LOW PRESSURE THAT MAY AFFECT SOME AREAS ALONG THE EAST
COAST DURING A PORTION OF THE SAT-MON PERIOD. ENSEMBLE MEMBERS
ARE STILL NOT PARTICULARLY WELL CLUSTERED BUT THEIR CORRESPONDING
MEANS ARE SIMILAR IN DEPICTING A WAVE REACHING NEAR NOVA SCOTIA BY
EARLY DAY 6 MON... WHICH IS CLOSEST TO THE TRACK/TIMING OF THE 00Z
ECMWF. THIS REPRESENTS A SLOWER TREND OVER THE PAST 12-24 HRS.
OTHER OPERATIONAL SOLNS VARY FROM THIS GROUP WITH THE 00Z
GFS/UKMET MUCH FASTER... THE 06Z GFS QUITE FAR OFFSHORE... AND THE
00Z CANADIAN SLOW AND MODERATELY OFFSHORE. SHARP/SLOW DEPICTION
OF 06Z GFS ENERGY ENTERING THE WRN CONUS AT THE START OF THE FCST
AND ITS FAST TIMING OF UPSTREAM FLOW LEAD TO DISCOUNTING THE 06Z
GFS OVERALL. SLOWER/MORE AMPLIFIED THAN CONSENSUS NRN STREAM
SHRTWV CROSSING THE NORTHEAST IN THE 00Z ECMWF AND FAST EJECTION
OF THE SRN SHRTWV IN THE 00Z GFS ON SAT LOWERS CONFIDENCE IN THEIR
SOLNS... BUT AT LEAST THE AGREEABLE ENSEMBLE MEANS YIELD MORE
CONFIDENCE IN SOME VARIATION OF THE 00Z ECMWF THAN ANOTHER
OPERATIONAL FCST AT THIS TIME. PRIOR CONTINUITY THAT WAS FASTER
WOULD SUPPORT A FASTER COMPROMISE FROM THIS SOLN IF SUPPORTED BY
12Z GUIDANCE.

BASED ON THE ABOVE CONSIDERATIONS THE DAYS 3-6 FRI-MON FCST STARTS
WITH THE MOST AGREEABLE SOLN CLUSTER CONSISTING OF A NEARLY EVEN
WEIGHTING OF THE 00Z ECMWF/00Z GEFS MEAN/00Z ECMWF ENSEMBLE MEAN.
THE 00Z ECMWF WAS REMOVED AND ENSEMBLE MEANS WEIGHTED EQUALLY FOR
DAY 7 TUE DUE TO LACK OF CONFIDENCE IN ECMWF SPECIFICS LATE IN THE
FCST.

[srainhoutx]

I wish the warmer colors were a little closer to my backyard, but really, if the NAM verifies, I can't complain.

SPC Day 2 Update:

...SERN TX THROUGH LA...

THUNDERSTORMS ARE EXPECTED TO INCREASE FROM PORTIONS OF SERN TX INTO
THE LOWER MS VALLEY LATE WEDNESDAY NIGHT IN ASSOCIATION WITH
STRENGTHENING LLJ AND FORCING ATTENDING THE NEXT IN A SERIES OF
SHORTWAVE TROUGHS. MOST OF THIS ACTIVITY WILL DEVELOP WITHIN ZONE OF
ISENTROPIC ASCENT NORTH OF THE QUASI-STATIONARY FRONT WHERE MARGINAL
INSTABILITY WILL EXIST AND CONVECTION WILL LIKELY BE ELEVATED.
HOWEVER...THERE IS SOME CHANCE THAT STORMS DEVELOPING NEAR THE
STATIONARY FRONT FROM THE TX COASTAL AREA INTO SRN LA COULD BECOME
SURFACE BASED GIVEN INFLUX OF RICHER GULF MOISTURE. EFFECTIVE
VERTICAL SHEAR WILL BE SUFFICIENT FOR UPDRAFT ROTATION WITH ANY
SURFACE BASED ACTIVITY...BUT CONFIDENCE IN A MORE ROBUST SEVERE
THREAT IS NOT SUFFICIENT TO WARRANT MORE THAN 5% SEVERE
PROBABILITIES AT THIS TIME.

[srainhoutx]

Morning e-mail from Jeff:

Decent coverage of rainfall this morning over mainly the northern and central parts of SE TX and most recently right along the coast from Freeport to Galveston.

Cold front currently along US 59 will push toward the coast over the next few hours with rains ending from north to south. In the last 24 hours rainfall amounts have averaged .5 to .75 of an inch across the region with the most rainfall in two corridors: 1. From northern Waller County across NW Montgomery County into Walker County with 1-2 inches and the other from Downtown Houston to Kingwood into Liberty County with 1-2 inches. A third region is still getting heavy rainfall from SE Matagorda County to the west side of Galveston Island.

Cold front will progress off the coast by noon with drier and cooler air mass moving into the area and skies clearing from the WNW to ESE. Satellite already shows high level moisture ahead of the next digging trough moving in W and C TX this morning. Next potent trough is digging southward off the Baja coast this morning with a good sub-tropical tap noted over Mexico aimed at Texas. Given the look of the features on the water vapor and first few visible frames this morning…clearing this afternoon may be short lived.

Next SW US system will eject eastward across N MX Wednesday and into TX Thursday. Downstream forcing will foster NW Gulf of Mexico coastal surface low formation on the frontal boundary moving through today by Wednesday afternoon. Strong isentropic upglide will begin in earnest by Wednesday afternoon with cloud layer rapidly thickening and lowering as Gulf moisture is advected over the top of the cold dome at the surface. Combination of the developing surface trough/low over the Gulf waters and incoming strong sub-tropical jet core will result in widespread lift across the region Wed PM into Thurs AM with widespread rains likely. Models have come into good agreement and increased QPF for this period and HPC progs are showing upwards of a 1-2 inch widespread rain across SE TX during this period. Will taper back these amounts into the .5 to 1.0 inch range as previous overrunning events have not pan out as expected, but with that said this does look like another decent and widespread soaking for the area to help put more dents in the still exceptional drought. Both the NAM and GFS show highs in the lower 60’s on Wed, but potential for rapid increase in clouds could result in highs only in the mid 50’s.

Storm system moves on eastward on Thursday by midday with clearing skies by afternoon. How quickly skies clear will likely determine how much of a warm up will be in store for Thursday afternoon. Guidance is showing the mid 60’s, but is clouds linger longer than expected, highs will be held once again in the 50’s.

Models are still not in overall very good agreement for the holiday weekend. One aspect does appear certain, that colder conditions will be felt across the state as Canadian air mass is transported southward. This air mass may end up being slightly colder than what would normally be expected for a fairly mild western Canada source region due in large part to the recent/ongoing blizzard over the western high plains and TX/OK panhandles which will help slow the air mass modification on its trip southward. Bigger question remains how much energy drops into the semi-permanent large scale trough over the SW US and does another upper level storm close off and where. GFS is the most progressive and driest of the models while the CMC is the strongest and deepest. The ECMWF is even stronger than the CMC, but keeps the upper storm buried deep in central MX too far S and W to impact the weather over the holiday weekend which seems a little on the extreme side. Will take a blend of the GFS and CMC with clouds increasing late Friday into Saturday and possibly light rain developing Saturday afternoon mainly near the coast and offshore as western energy forms another coastal trough. Models continue to have a hard time forecasting in this highly progressive spilt flow jet stream pattern, but we should begin to see some better consensus in the next few days for this weekend. For now will go with cool and cloudy conditions with a slight chance of rain.

[MontgomeryCoWx]

I got 1.5 inches of rain at the house in Conroe.

Now, if we could only have that same amount of moisture come in snow.

[jasons2k]

I had .69" at the house. Not too bad, but was hoping for more.

[srainhoutx]

The 12Z GFS suggests, like the NAM, a wet Wednesday night into Thursday is ahead for Coastal Texas...

[srainhoutx]

Well look what the 12Z Canadian just spit out... ...

[srainhoutx]

SRAIN ,EXPLAIN WHAT THOSE CANADIAN MAPS SHOW? I DONT UNDERSTAND THOSE GRAPHICS

No need to look, AZ. You're not a model hugger. Remember?...
Actually the Canadian is suggesting a solution somewhat similar to what the over night Euro was suggesting. There is yet another Winter Storm developing across New Mexico for Friday. An upper level disturbance drops into Old Mexico and slowly strengthens. Meanwhile a coastal trough develops on Friday setting the stage for over running moisture to spread N. Surface temps look chilly as the snow cover from the Winter Storm yesterday will mean a bit less air mass modification. Right now, it's just something to monitor. It is clear that we will get some more beneficial rains late Wednesday into Thursday. That much looks likely at this point.

[srainhoutx]

The 12Z Euro is coming in more in line with what the Canadian suggested. Wintry mischief for Christmas Eve may increase just a bit for areas N and W of SE TX...

[biggerbyte]

LOL

Don't you guys think that it is enough with the sarcasm about the models? I was not going to say anything, but this "gloating" over them is not deserving. This last event was not entirely with guidance, though closer than ANY of us expected at one point during the evening. For some people, it WAS a bust. 80% chance of rain is pretty convincing. It nearly did not happen at all. Also, I'd like to point out that we have had MANY more let downs and inaccurate forecasts following these models than we've had them verify. So we get something remotely close last night and suddenly all of us "disbelievers" are to be damned. Folks like Arizona, and many others, are simply looking for anyone, and anything to give a glimmer of hope for some winter weather around here. Enough already..

No disrespect to anyone, but it needed to be said.

Now back to our regularly scheduled programming.

[MontgomeryCoWx]

I'll be in Weimar Christmas Eve Night and Christmas Morning, then to CS then to Longview on Christmas... Hoping NE TX can get that freeze line to inch farther east.

They should be fine at the surface.

[wxman57]

The Euro is the coldest of the 3 main models (Euro, Canadian, GFS). I wouldn't count on any snow in central or SE TX this weekend, and probably not in northeast Texas either.

[srainhoutx]

HPC suggesting a bit too much uncertainty to make any changes at this time regarding the Friday-Monday period. They are mentioning temps running 10-20 degrees below average for the Southern Rockies/Central & Southern Plains. They are leaning toward the Euro as it has done rather well in the shorter range of the medium guidance. The HPC QPF update is suggesting 1/2 to 1 inch totals for Wednesday night into Thursday with heavier amounts N and E of the Houston Metro Area.

[djmike]

....another round of showers for Beaumont and the Golden Triangle!! Yayy....

[MontgomeryCoWx]

Christmas Eve.....