Texas winter wx thread (2009-2010)

[srainhoutx]

One more post regarding the New Year system suggested via guidance. Here is the Prelim Extended Disco from the HPC this morning. There are some "hints" regarding an active STJ again, but their may focus is dealing with all the mess this week with the busy Christmas Storm...

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
859 AM EST TUE DEC 22 2009

VALID 12Z SAT DEC 26 2009 - 12Z TUE DEC 29 2009


UPDATED PRELIM PROGS SUBSTITUTED THE NEW 00Z/22 ECMWF ENSEMBLE
MEAN FOR THE CORRESPONDING 12Z MEAN USED IN THE EARLIER PRELIM.
CONCERNING RECENT CONTINUITY...A BLOCKING RIDGE OVER NERN CANADA
EARLIER IN THE MEDIUM RANGE PERIOD NO LONGER YIELDS TO/PHASES WITH
HEIGHT FALLS FROM THE ARCTIC FOR SUN-TUE DAYS 6-7. THE UPSHOT OF
THIS CHANGE IS THAT THE GFS/ECMWF/UKMET DETERMINISTIC MODELS ARE
NOW TRENDING TOWARDS THE GREAT LAKES VORTEX DRIFTING ESE ACROSS
NEW ENG TOWARDS THE END OF THIS MEDIUM RANGE PERIOD. YESTERDAYS
GFS RUNS HAD HINTED AT THAT SCENARIO AND TODAYS 06Z GFS IS HOLDING
A STRONGER RIDGE OVER THE DAVIS STRAIT AND NE CANADA THAN
YESTERDAYS GFS RUNS. THE EFFECT THE THIS BLOCKING PATTERN WILL BE
TO HOLD TEMPS BELOW AVERAGE OVER THE SE QUARTER OF THE CONUS
DURING THE LATTER PORTION OF THE MEDIUM RANGE.
PERHAPS MORE SIGNIFICANTLY...THE BLOCK OVER THE DAVIS STRAIT AND
ERN CANADA WILL SLOW DOWN THE PROGRESSION OF AN OCCLUDED FRONTAL
PASSAGE ACROSS NEW ENGLAND DUMPING PROLIFIC SNOWFALL ACROSS MUCH
OF INTERIOR MAINE.

THE ENSEMBLE SPAGHETTI PLOTS SHOW GOOD CONSENSUS AMONG ECMWF FOR
THE BLOCKING PATTERN EARLY NEXT WEEK....IN CONTRAST TO GEFS
MEMBERS WHICH SHOWED LESS. GIVEN THE PERSISTENCE OF RECENT
BLOCKING IN OUR WEATHER HISTORY...THINK THAT WE SHOULD CONTINUE TO
FAVOR A THE BLOCKING SOLUTION IN THIS FORECAST.

FOR THE END OF THE PERIOD...WE WILL BE CAREFULLY WATCHING A SRN
STREAM PACIFIC SYS WORKING ACROSS THE SW BORDER STATES. MORE ON
THIS FEATURE LATER WITH NEW MODEL GUIDANCE.

FLOOD

[msstateguy83]

i dont have time this am to look into all the details so if someone else does good, but past this system
looking ahead, there seems to be something bigger lurking for poss early next wk per the oun
forecast discussion this am. i will check the models out when i have time, post some thoughts

[gofrogs]

I actually like what the gfs has . . . say about 180 hours out for the dallas fort worth area, granted it s only the 6z so well have to see what the 12z run shows for texas.

[CaptinCrunch]

It's all a bunch of BS, when you look out side and the weather rock is white you know it snowed....lmao

[Portastorm]

It's all a bunch of BS, when you look out side and the weather rock is white you know it snowed....lmao

Yes Captin ... my money is on the weather rock!

Meanwhile, the 12z GFS is running. It's a tease. After about 100 hours on the run, you'll see moisture creep up from the Valley into south and central Texas. Surface temps over the weekend are going to be colder than what is currently forecast ... I really believe that considering how the GFS underestimates cold and the snow cover that will be laid down and enhanced by this coming storm over the Plains. Will be curious to see if future runs of the GFS and Euro pick up on this. Could make the weekend interesting after all.

[Ntxw]

So far on the 12z gfs, that's quite a prolonged period of chill after this week's storm.

[msstateguy83]

i looked over it not in detail but you take it with lastnights runs, then the 12z just MAYBE we are seeing something in the making that will be big, actually pan out! we are serriously getting about that time anyways where we should see stuff pick up.

[Ntxw]

I was just going over some stuff JB said (though he does at times hype things a bit, however he backs his stuff on data whether it be models or climatological information) that storms should be picking up further south through California. This should wake things up from areas I-20 north, possibly further south too. And the newest runs seems to suggest this possibility.

[gofrogs]

Heck yes did oyu guys see the lastest run of the gfs i liked it alot for my neck of the woods in fort worth it will be intresting to see how the fort worth office words their afd coming up one even is exactly a week away, and after that the new year storm will alsobring in the chance for some wintry precip, and with alll this talk of the storms in california taking a deeper route south iam starting to like this.

[wxman22]

The 12z GFS certainly is interesting

[srainhoutx]

Look for some 'changes' for the Christmas Storm track via the 12Z ECMWF...

[cheezyWXguy]

Look for some 'changes' for the Christmas Storm track via the 12Z ECMWF...

cant read EC, could you explain it?

[srainhoutx]

I'll repost the noon hour e-mail from Jeff in the TX Topic since everyone is watching closely...

Air mass continues to modify this morning under strong southerly winds.



Warm air advection regime in full swing with south winds of 15-25mph and greater across the region brining upper 50 to low 60 degree dewpoints northward. GPS sounder and morning radio soundings indicate the air mass over the Gulf of Mexico is modified continental air with the rich tropical air mass confined to the Caribbean Sea. Upper level trough will deepen and move into the central US Wed with continued flow of warm and increasing moist air northward. Scattered showers this afternoon will build into more numerous showers and thunderstorms tonight and Wednesday as the air mass becomes increasingly unstable. Capping inversion will spread ENE from the higher terrain of NE Mexico Wed with deeper surface based convection limited to areas mainly along and E of I-45. SPC has most of the area within the Day 2 slight risk…but feel the severe threat is fairly marginal at this time.



Upper level storm system really cranks up Wed PM into Thurs with a large winter storm/blizzard developing over the central US. Cold polar air mass will drop southward down the backside of this feature and into Texas late Christmas Eve. Will trend colder than guidance and show lows near freezing Christmas morning and highs only in the 40’s during the day. Models remain unsettled into the weekend with the CMC showing precip. developing within the cold air mass while the GFS and ECMWF are dry. Will go ahead and trend toward the colder solutions…as feel the GFS is too warm anyhow. For now will increase clouds, but not any rain chances Sat-Sun. If the GFS starts to show a deeper S/W and coastal trough and sling the moisture northward precipitation chances may be needed this weekend and some of what falls could be freezing/frozen…but for now will keep it dry.


Stormy and cold pattern looks to continue for the last week of the decade!

[wxman22]

The European model is also on board...

[cctxhurricanewatcher]

This afternoon's AFD's should be very interesting...........

[Portastorm]

Have to admit that the 12z runs of both the GFS and Euro are encouraging for early next week. The 12z Canadian kinda shears out the low in the Desert SW as compared to the Euro solution.

[TexasStorm]

Look for some 'changes' for the Christmas Storm track via the 12Z ECMWF...

Looks like it is tracking further north correct? Appears that it will barely even get down to Oklahoma City.

[srainhoutx]

Look for some 'changes' for the Christmas Storm track via the 12Z ECMWF...

cant read EC, could you explain it?

The ECMWF suggest a track near/along the Red River into N LA. At that point the guidance suggests the track will go due N into AR and MO. There have been some "hints" that the track would be further E than what guidance has been suggesting over the past several days. The is a lot of High Pressure to the N. Guidance suggests that the storm would bust through the High and stall as well as wash out or open up. There are also suggestions that another low will develop along the N GOM. As has already been posted, the pattern into next week looks rather interesting for those looking for any wintry precip in TX. We will see.

[HockeyTx82]

Perhaps more snowpack to our north? Look at warnings and watches map.

http://www.weather.gov/

This would mean that temps could be colder, yes?

[srainhoutx]

Perhaps more snowpack to our north? Look at warnings and watches map.

http://www.weather.gov/

This would mean that temps could be colder, yes?

Yes. This is what has been missing since Mid December. Also of note is the consistant 'hints' via guidance that an Omega Block (discussed today in the Alaskan Final Extended) will establish over the N Pole. What does that suggest? Cold air locked in from Coast to Coast. Now add to the mix a noisy STJ...you get the picture...

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
229 PM EST TUE DEC 22 2009

VALID 12Z FRI DEC 25 2009 - 12Z TUE DEC 29 2009


UPDATED PRELIM PROGS SUBSTITUTED THE NEW 00Z/22 ECMWF ENSEMBLE
MEAN FOR THE CORRESPONDING 12Z MEAN USED IN THE EARLIER PRELIM.
THERE WAS AN IMPORTANT A CONTINUITY CHANGE IN LATEST MODEL RUNS
FROM YESTERDAYS ECMWF...AND TO A LESSER EXTENT...YESTERDAYS GFS
RUNS. CONSENSUS OF DETERMINISTIC MODELS DELAYS THE PHASING OF
HEIGHT FALLS FROM CANADA WITH A GREAT LAKES VORTEX FOR SUN-TUE
DAYS 6-7. THE UPSHOT OF THIS CHANGE IS THAT 00Z AND 12ZZ/22
GFS/ECMWF/UKMET DETERMINISTIC MODEL RUNS ARE TRENDING TOWARDS A
GREAT LAKES VORTEX DRIFTING E ACROSS NEW ENG/THE ST LAWRENCE
SEAWAY TOWARDS THE END OF THIS MEDIUM RANGE PERIOD. YESTERDAYS GFS
RUNS HAD HINTED AT THAT SCENARIO. THE EFFECT OF THE VORTEX
DRIFTING EWD ACROSS NEW ENG WILL BE TO HOLD TEMPS BELOW AVERAGE
OVER THE SE QUARTER OF THE CONUS DURING THE FIRST PART OF NEXT
WEEK.

MORE SIGNIFICANTLY...THE LINGERING BLOCK OVER THE DAVIS STRAIT
THAT FORCES THE GRT LAKES VORTEX TO DRIFT EWD ACROSS NEW ENG AND
ERN CANADA WILL SLOW DOWN THE PROGRESSION OF AN OCCLUDED FRONTAL
PASSAGE ACROSS NEW ENGLAND...POSSIBLY DUMPING PROLIFIC SNOWFALL
ACROSS MUCH OF INTERIOR MAINE SAT NIGHT INTO EARLY MON. THE
ENSEMBLE SPAGHETTI PLOTS SHOW GOOD CONSENSUS AMONG ECMWF FOR THE
BLOCKING PATTERN EARLY NEXT WEEK....IN CONTRAST TO GEFS MEMBERS
WHICH SHOWED LESS. GIVEN THE PERSISTENCE OF RECENT BLOCKING IN OUR
WEATHER HISTORY...WE PREFER A BLOCKING SOLUTION IN THIS FORECAST.
IN LINE WITH THAT THINKING...
THE 12Z/22 GFS HAS TRENDED TOWARD THE ECMWF IN KEEPING THE GREAT
LAKES VORTEX WELL SEPARATE FROM AN ARCTIC VORTEX WELL FARTHER N
RATHER THAN PHASING THEM...AS DID THE 00Z GFS RUN. THE NEW 12Z/22
UKMET/CANADIAN ARE ALSO ON BOARD WITH THIS TREND. HOWEVER...THE
CANADIAN BECOMES A ERN OUTLIER SAT-MON ON THE POSITION OF THIS
GREAT LAKES LOW.

CONCERNING SENSIBLE WEATHER...WE AR LOOKING AT ANOTHER MAJOR SYS
TO AFFECT CHRISTMAS EVE/DAY FROM THE PLAINS TO THE E COAST. MODELS
SHOW A STRONG SRN STREAM SHORTWAVE/CLOSED LOW MOVING ACROSS THE
SWRN CONUS IN THE SHORT RANGE...GOING NEGATIVE TILT FRI DAY 3 AS A
FRESH SURGE OF ENERGY FROM CANADA RE-ENFORCES THE ENTIRE SYS. NOT
JUST AN ORDINARY WHITE CHRISTMAS...BUT VERY HEAVY SNOWFALL AND
HIGH WINDS ARE POSSIBLE FRI DAY 3 OVER MUCH OF
NEBRASKA/DAKOTAS/MINNESOTA.

FARTHER E... A WAVE WILL FORM ON THE TRIPLE POINT OF AN
OCCLUSION/COLD FRONT FRI DAY 3 AND MOVE SLOWLY NEWD INTO A FAIRLY
STRONG SURFACE HIGH PRES RIDGE EXTENDING SW INTO NEW ENG. THE
RELATIVELY SLOW NWD MOVEMENT OF THIS WAVE AND THE CHANNEL OF MOIST
WARM SE FLOW AHEAD OF IT THREATENS HEAVY RAINFALL IN THE MID
ATLANTIC OVER REGIONS THAT SAW RECORD HEAVY SNOWFALL LAST WEEKEND.
SOME RUNOFF PROBLEMS POSSIBLE IN THIS AREA FRI NIGHT INTO SAT. THE
SYS WILL BE PREDOMINATELY RA EXCEPT FOR INTERIOR NEW ENG WHERE A
MIX OF SN AND FREEZING RAIN/ICE PELLETS MAY OCCUR SAT/SUN...EXCEPT
FOR MOSTLY SN IN MAINE.

WILL THERE BE ANOTHER IMPORTANT SRN STREAM SYS TO END THE ACTIVE
YEAR OF 2009? 12Z/22 DETERMINISTIC MODEL CONSENSUS SEEMS TO POINT
IN THAT DIRECTION. THE NEW DETERMINISTIC GFS/UKMET/CANADIAN
CLUSTER RATHER WELL IN MOVING A POTENT SRN STREAM SYS INTO THE NRN
BAJA/SRN CA/SW AZ REGION BY MON DAY 6. THIS IS ALSO IN AGREEMENT
WITH THE ENSEMBLE SPAGHETTI PLOTS ...ALTHOUGH THE ENSEMBLE PLOTS
DID SHOW A GOOD BIT OF SPREAD ON THAT SHORTWAVE FEATURE. CONSENSUS
OF MODELS AND ENSEMBLE MEANS INDICATES A POSSIBLE RESPONSE TO THIS
FEATURE OF AN INVERTED TROF IN THE WRN GULF OF MEXICO BY TUE DAY
7.


FLOOD