Texas winter wx thread (2009-2010)

[wxman22]

Look what the CMC shows:







But of course its the CMC...

[Ntxw]

So far from the PSU ewall the EC has again shifted back west from what I can see. Same goes for the storm.

Edit: Also a bit colder than the previous run with a more north to south trajectory. Sigh, it's messing with our heads.

[gofrogs]

Iam confused s o does it look like we might be back on vfor snow in north texas.

[iorange55]

Iam confused s o does it look like we might be back on vfor snow in north texas.

Yes, no, maybe, YES! NO! I dunno, it's possible, it could happen, no chance, real good chance, who knows.

[gofrogs]

haha exactly you could not have said it better.

[srainhoutx]

The ECMWF suggests the Cold Air will head straight S into TX. The Baja disturbance is still on the table as well as some strung out Upper Air distburances across the Plains behind the front. We shall see.

[cycloneye]

12z ECMWF

[srainhoutx]

HPC Final Extended Disco...

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
154 PM EST SUN JAN 03 2010

VALID 12Z WED JAN 06 2010 - 12Z SUN JAN 10 2010

MEDIUM RANGE GUIDANCE CONTINUES TO DEPICT AN AMPLIFIED WRN NOAM
RIDGE/ERN NOAM TROF MEAN PATTERN FOR MOST OF THE FCST PERIOD.
SOME WEAK SRN STREAM PAC ENERGY IS GENERALLY EXPECTED TO FLOW
ALONG/S OF 30-35N LATITUDE BY NEXT WEEKEND. THE MOST SIGNIFICANT
UNCERTAINTIES DURING THE 3-7 DAY PERIOD REMAIN THE SAME AS YDAY...
NAMELY DETERMINING THE EVOLUTION OF ERN PAC ENERGY THAT MAY TRY TO
TRAVEL THRU OR AROUND THE WRN NOAM MEAN RIDGE BY THE LATTER HALF
OF THE PERIOD... AND THE HANDLING OF A VIGOROUS TROF FCST TO
AMPLIFY INTO THE PLAINS ON WED AND THEN CONTINUE EWD THEREAFTER.

THE 00Z ECMWF IS FASTER THAN OTHER OPERATIONAL MODELS WITH A
SHRTWV REACHING WRN NOAM ON SAT... AND IS PROBABLY NOT IDEAL IN
LIGHT OF MOST MODEL/ENSEMBLE TRENDS TOWARD SLOWER PROGRESSION OF
ENERGY INTO OR OVER THE WRN RIDGE COMPARED TO 24 HRS AGO. THESE
TRENDS ALSO SEEM TO FAVOR A MORE PERSISTENT RIDGE AS FCST BY THE
00Z GEFS MEAN VERSUS THE 12Z ECMWF/CANADIAN ENSEMBLES WHICH TO
VARYING DEGREES ARE MORE AGGRESSIVE WITH BRINGING ENERGY THRU THE
WRN CONUS. FARTHER EWD... THERE IS A FAIR CONSENSUS REGARDING THE
VIGOROUS MID LVL TROF FCST TO CROSS THE CNTRL-ERN STATES WED-FRI
AND SUPPORT WRN ATLC SFC DEVELOPMENT BY FRI. DAY TO DAY SHUFFLING
OF MODEL/ENSEMBLE GUIDANCE FAVORS AN AVERAGE SOLN AS THE TROF
CROSSES THE CNTRL-ERN CONUS. THEN STRONG DYNAMICS ALOFT AND
EXPECTED FAVORABLE ENVIRONMENT OVER THE WRN ATLC SEEM TO SUPPORT A
TRACK WITHIN THE WRN HALF OF THE SOLN SPREAD OFF THE EAST COAST.
HOWEVER THE 00Z GFS IS SOMEWHAT EXTREME WITH ITS DEPTH ALOFT...
AND ONLY A VERY SMALL NUMBER OF GEFS MEMBERS ARE AS DEEP/WWD AS
THE GFS. THE 12Z ECMWF ENSEMBLE MEAN LEANS FASTER THAN BEST
CLUSTERING OF LATEST GUIDANCE.

A 50/30/20 BLEND OF THE 00Z ECMWF/GFS/GEFS MEAN WAS USED DAYS 3-6
WED-SAT TO ARRIVE AT THE PREFERRED FCST FOR THE SYSTEM PROGRESSING
FROM THE PLAINS THRU THE WRN ATLC... WITH MINOR ADJUSTMENTS MADE
TO ACCOUNT FOR MINIMIZING ECMWF WEIGHTING FOR THE SHRTWV REACHING
WRN NOAM BY SAT. DAY 7 SUN USES AN EVEN WEIGHTING OF THE 00Z
ECMWF/GEFS MEAN AS THE GFS MAY BECOME TOO AGGRESSIVE WITH A SYSTEM
TRACKING SEWD FROM CNTRL CANADA... AND ENSEMBLES OFFER SOME DEGREE
OF SUPPORT FOR SFC TROFFING FROM CNTRL CANADA INTO THE HIGH PLAINS
BY THAT TIME.

UPDATED MORNING PRELIMS AND AFTN FINALS FOLLOW THE SAME BLEND USED
EARLIER WITH A MINOR EWD ADJUSTMENT OF THE LOW PRESSURE OFF THE NC
COAST DAY 5 CLOSER TO THE CLUSTERING OF ENS MEMBERS OF BOTH GFS
AND ECMWF.

OTHERWISE THE SAME OVERALL PATTERN PERSISTS FOR THE FORSEEABLE
FUTURE OF A STRONG NEG AO/NAO WITH A POSITIVE MID LEVEL HT ANOMALY
IN THE N ATLC AND ANOTHER STRONG POSITIVE HT ANOMALY ASSOCIATED
NEAR 55N 115W WITH THE PNA PATTERN OVER NOAM.

MAJOR MODEL DIFFERENCES OCCUR BETWEEN 12Z GFS AND ECMWF AS GFS
FOLLOWS THE MEAN PATTERNS
AND TELECONNECTIONS BASED ON THE AO/NAO/PNA RELATIONSHIP. ECMWF
HAS A MUCH MORE POSITIVELY TILTED SHEARED TROF COMING ACROSS THE
PLAINS TO THE EAST COAST LIMITING ANY W ATLC CYCLOGENESIS AND
HAVING A MORE WRLY MID LEVEL COMPONENT WITH MUCH LESS COLD AIR
DELIVERY INTO THE EAST NEXT WEEKEND. PREFERENCE IS TOWARDS GFS
BASED IDEAS WITH NO CHANGES TO PROGS OR THINKING AT THIS TIME.

A MASSIVE DOME OF COLD HIGH PRESSURE WILL PUSH SWD OUT OF WRN AND
CENTRAL CANADA EARLY THIS PERIOD SPILLING OVER THE DIVIDE AND
PUSHING SWD THRU THE PLAINS BRINGING AN OFFSHORE EVENT TO THE WEST
COAST AND A REINFORCING SURGE OF VERY COLD TEMPS DEEP INTO THE
PLAINS AND GULFMEX. TEMPS IN THE PLAINS MID WEEK RUNNING 20-30
DEGREES BELOW NORMAL WHILE WESTWARD TEMPS WILL AVERAGE ABOVE
NORMAL ALONG THE WEST COAST UNDER MID LEVEL RIDGING.

BREEZY WINDY COLD CONDITIONS CONTINUE OVER ERN CONUS INTO MID
WEEK. ALL GUIDANCE NOW INDICATES THE DEVELOPMENT OF A NRN GLFMEX
SFC WAVE WHICH WILL SPREAD A COLD RAIN INTO THE LOWER
SOUTHEAST...NRN FL/GA/SC COAST WITH A FAIRLY WIDESPREAD LT SNOW
FROM THE INTERIOR GULF COAST STATES NEWD THRU THE SOUTHEAST AND
MID ATLC REGIONS. AS THE SFC WAVES MOVES OFF AND ALONG THE NC
COAST RAPID INTENSIFICATION SHOULD OCCUR AS THE CURRENT AND
CONTINUING STRONG COLD ADVECTION OVER WARMER COASTAL WATERS
CREATES AN UNSTABLE AND FAVORABLE ENVIRONMENT FOR RAPID DEEPENING.
GFS RUNS/ECMWF DO THIS AS DOES GEFSP BUT UKMET AND LATEST CMC DO
NOT. PREFER THE DEEPER STRONGER MODEL SOLUTIONS.

EXPECT A SWATH OF LIGHT SNOW UP THE COAST FROM SE VA TO NEW ENG
WITH THE SFC LOW AND INLAND WITH THE MID LEVELS COVERING MUCH OF
THE CENTRAL AND NRN PLAINS MID WEKK EASTWARD TO THE COAST BY FRI
AND SAT. ONCE THE LOW STRONGLY DEEPENS ON ITS WAY TO NOVA SCOTIA
ERN CONUS AGAIN EXPECT A REPEAT OF THE CURRENT VERY WINDY COLD
CONDITIONS NEXT WEEKEND. THICKNESS AND H850 TEMPS ARE COLDER FOR
DAYS 6 AND 7 SAT/SUN OVER ERN THIRD OF CONUS THAN CURRENTLY AND
HPC TEMPS WILL BE LOWERED ACCORDINGLY. TEMP DEPARTURES OF GREATER
THAN 25 BELOW NORMAL WILL BE COMMON.

BELOW FREEZING TEMPS WILL OCCUR THRU MID WEEK AT LEAST AS FAR
SOUTH AS CENTRAL FL. NEXT SURGE OF COLD AIR LATE WEEK/WEEKEND
EQUALLY AS COLD AS THE CURRENT COLD OUTBREAK OVER FLORIDA.
RAUSCH/ROSENSTEIN

[southerngale]

BLECH!!! That is what I have to say about this 12z GFS run.

Dry Arctic cold through Saturday. No signs of upper-level energy out west. Booo!

Who needs it?! This run is like serving a basket of freshly made tortilla chips with no salsa or queso.

I hear ya!

I see that some are mentioning this model and that model showing some post frontal precip, and while I hope that happens, I'm not holding my breath. We're 4 days away from Thursday and 5 away from Friday. I could be wrong, but I'm pretty sure at this point before the snow event on December 4th, wxman57 was already on board with the snow, and he's usually our buzzkiller when we start dreaming. lol When he said it was going to snow, I believed it.

And I know the GFS was on board at this point in early December. I hope this situation is different and the GGEM and the CMC (is that the other one showing post frontal precip?) are right, and the GFS and Euro start to fall in line with them. Unfortunately, I doubt it.

I'm crossing my fingers and singing some Bing Crosby nonetheless.

[wxman22]

BLECH!!! That is what I have to say about this 12z GFS run.

Dry Arctic cold through Saturday. No signs of upper-level energy out west. Booo!

Who needs it?! This run is like serving a basket of freshly made tortilla chips with no salsa or queso.

I hear ya!

I see that some are mentioning this model and that model showing some post frontal precip, and while I hope that happens, I'm not holding my breath. We're 4 days away from Thursday and 5 away from Friday. I could be wrong, but I'm pretty sure at this point before the snow event on December 4th, wxman57 was already on board with the snow, and he's usually our buzzkiller when we start dreaming. lol When he said it was going to snow, I believed it.

And I know the GFS was on board at this point in early December. I hope this situation is different and the GGEM and the CMC (is that the other one showing post frontal precip?) are right, and the GFS and Euro start to fall in line with them. Unfortunately, I doubt it.

I'm crossing my fingers and singing some Bing Crosby nonetheless.

The GGEM and the CMC are the same model just different names.

[wxman57]

Thought y'all might want to see a graphic my coworker made off the 12Z GFS. It's a graphic of temps/dewpoints and 3hr precip for IAH (north Houston). Check out the dry air over Houston on Friday and Saturday. Precip ends with frontal passage as the temps plunge down.

[southerngale]

The GGEM and the CMC are the same model just different names.

Oh.
For years, we've talked about the CMC. I haven't really heard anyone use the term GGEM until recently. I wondered where it came from. heh

[Big Easy]

After much consideration, I think this cold weather is alot of hype. It really is cold, but not nearly of record cold. We have seen colder. It does look as if the major part of the cold is going to be more centered towards Mississippi/Alabama, then say Texas/Louisiana. It also appears where Alabama, Georgia and even aprst of Florida, may see a significant winter precipitation event. Just saying.

[Portastorm]

Wxman 57's helpful post and chart reminds me that the NWSFO in Fort Worth also mentions the CMC run in their afternoon AFD but they added that with dewpoints in the single digits, moisture on Friday will be hard to come by.

For the moment, I don't have much confidence in today's Canadian runs.

As for where the brunt of the coldest air is going ... we've seen both the GFS and Euro flip-flop today. To be determined.

[Ntxw]

Wxman 57's helpful post and chart reminds me that the NWSFO in Fort Worth also mentions the CMC run in their afternoon AFD but they added that with dewpoints in the single digits, moisture on Friday will be hard to come by.

For the moment, I don't have much confidence in today's Canadian runs.

As for where the brunt of the coldest air is going ... we've seen both the GFS and Euro flip-flop today. To be determined.

I agree, they haven't given us any notion of why they wouldn't flip.

[Portastorm]

I gotta give props to my homeboys in New Braunfels.

Good afternoon AFD out of NWSFO Austin/San Antonio. Good for them for not just following the GFS MOS grid numbers by rote and considering other angles!

Here's a portion of the AFD dealing with the big front:

AN ARCTIC FRONT WILL PLUNGE DOWN THE PLAINS REACHING THE HILL COUNTRY
OVERNIGHT HOURS WEDNESDAY NIGHT AND REMAINDER OF SOUTH CENTRAL TEXAS
EARLY THURSDAY MORNING. HIGHS WILL LIKELY BE REACHED EARLY IN THE DAY.
HAVE LOWERED POPS DUE TO DECREASING MOISTURE AND STRONG COLD ADVECTION
IN THE WAKE OF THE FRONT, HOWEVER THERE IS A BRIEF WINDOW FOR SOME SLEET TO
MIX IN AND HAVE KEPT MENTION.

THURSDAY WILL BE WINDY WITH WIND ADVISORIES POSSIBLE. COLD HIGH PRESSURE
WILL REMAIN OVER THE AREA GOING INTO NEXT WEEKEND. HAVE FAVORED THE ECMWF
AS GFS APPEARS TO MODIFY AIRMASS TOO FAST WHICH SEEMS UNREASONABLE DUE TO ARCTIC
NATURE OF THE AIRMASS. HARD FREEZES WITH LOWS IN THE UPPER TEENS
TO MID 20S CAN BE EXPECTED THURSDAY NIGHT AND FRIDAY NIGHT AND
TEMPERATURES STRUGGLING TO RISE INTO THE 30S AND 40S FRIDAY AND
SATURDAY. HAVE GONE WELL BELOW GUIDANCE TEMPERATURES FOR THE POST-
FRONTAL AIRMASS. OF INTEREST, THE CANADIAN HANGS BACK A TROUGH
LEADING TO POSSIBLE SNOW EVENT ON FRIDAY, HOWEVER FOR NOW WILL
DISREGARD THIS AS IT IS ONLY MODEL TO SHOW THIS.

[txagwxman]

GEM is an complete outlier, however, it is fun to watch...2.5" in Houston if that verified.

[gofrogs]

of liquid or snow and no comments about the 18z gfs.

[southerngale]

of liquid or snow and no comments about the 18z gfs.

I'm watching the Cowboys annihilate the Eagles and loving every second of it!!


I did see where the 18z came in much colder and with a little more moisture I believe, but it's the 18z.

[Big O]

With the front plunging way south, is there any chance of post-frontal freezing precipitation across Deep South Texas (i.e., Brownsville, McAllen)?

Are there any indications that their will be moisture in North Texas (i.e., Dallas) with the secondary surge of arctic air over the weekend? Anywhere else over Texas?