Texas winter wx thread#4 - big changes on the way eventually

[Extremeweatherguy]

Continue the TX winter discussion here..

Last thread: http://www.storm2k.org/phpbb2/viewtopic.php?t=91652

[aggiecutter]

If that EURO run were to verify, there wouldn't be a widespread winter storm in Texas. The main low would be too far off shore. However, when the upper level feature ejects out there could be a pretty decent accumulating snow a long and just north of its path, which looks to be from Austin to NW Louisiana, SW Arkansas, and extreme NE Texas. Since this is big change from yesterday's EURO runs, I would disregard for it now. Let's see if it verifies in later runs. I do feel very confident that something significant is going to happen late this weekend, early next week, though. The question still remains where will the players eventually end up.

[aggiecutter]

I just checked the morning Ensembles, and for the 3 day in a row, it shows a low forming in the NW gulf and tracking NE through SE Louisiana into Alabama and Mississippi. Until I see something different with consistency, that is where I am hedging my bets right now. The operational model should have a good handle on this by Thursday or Friday.

The morning Ensembles:
http://wwwt.emc.ncep.noaa.gov/gmb/ens/t ... 21900.html

On a sidenote: If you continue to look at the Graph " mslp HRC:" 192hrs-384, you will see repetitive shots of cold air into Texas.

[Yankeegirl]

this is Jeffs e mail from this morning, and yes, the comment about north of I 10 did catch my attention... though i am only 7 miles north of 10.... but I am still north!!!

Highly active weather pattern to evolve over TX over the next week.

Short Term:

Air mass is moist and becoming unstable this morning with approach of short wave and incoming cold front over N TX. Expect numerous showers and thunderstorms to begin developing late this afternoon and continue through the night as coastal trough offshore moves inland and 1.5 inch PW air surges northward. Low level backing favors turning updrafts and a few tornadoes will be possible along the coastal and first inland tier counties. Cold front moves through sometimes Thursday, however best moisture departs late Wednesday so rain chances on Thursday may be a little lower than currently suggested.

Weekend into Christmas:

Forecasting nightmare continues for this period as one must attempt to balance model flip flopping and true meteorological reasoning and the wishes from many for snow around Christmas. After an exhaustive look at the nighttime model guidance and GFS forecast soundings for this weekend into Christmas one must continue to at least entertain the idea of frozen precip. across TX from the 24th to the 26th.

Latest GFS and EURO model runs suggest an even deeper and further south track of a very strong upper level trough this weekend. GFS fires off an intense surface low near Brownsville and crashes pressures into the low 1000's off the upper TX coast by late on the 24th. Cold polar boundary moves southward ahead of the upper low over Mexico and pushes across the state late on the 23rd. Cold low level air mass will be in place before the upper level storm moves across...however forecast soundings and surface temps. show a large above freezing layer from the surface to around 700mb at KCRP and below 850mb at KFWD on the 24th. Deep upper trough with associated strong cold pool begins to move late on the 24th crossing the Rio Grande and heading toward EC TX. 120hr forecasting sounding for KDRT shows the profile frozen from about 925mb on up and saturated from the surface to 400mb suggesting a changeover to sleet and snow. 850mb, 700mb, and 500mb RH was examined from the period late on the 23rd to the 26th. Moisture appears marginal in the 850mb layer (50-70%)and the 700mb layer (70-90%) on the 25th and even at 500mb (60-80%) by the 26th.

Main difference today is the slower nature of the entire event and the one very important detail of a secondary vort max rounding the western side of the closing off upper low over LA late on the 25th. Moisture profiles gradually decrease across SE TX after the intense surface low passage late on the 24th...really before the air column will be cold enough to support anything than rain. However by late on the 25th a SSE moving 500mb vort max is progged to dig into NC and then SE TX allowing some moisture recovery in the low to mid levels and mid level lift. By this time the temp. profiles look much more conducive for frozen precip especially along and north of I-10 where wrap around precip. may be ongoing. Both the GFS and EURO have 850mb temps between -2C and -4C and although surface temps are being forecast above freezing...strong cold air advection behind the departing intense surface low may very well drive the surface temps. down into the mid 30's.

As has been noted each day since Sunday, the exact track of the upper air features combined with the temps profiles and moisture levels will determine where and what kind of precip. falls. Feel there is a shot of sleet and snow from deep SW TX (Laredo) to near San Antonio to Austin and then ENE toward Shreveport. Secondary vorticity maximum and/or wrap around moisture may bring frozen precip. further southward Christmas afternoon and evening (along and north of a line from Columbus to Conroe to Lufkin).

Persons planning travels to central or N TX for the holiday weekend should be alert to the potential for Winter Storm conditions and hazardous driving.

JL

[double D]

Maybe it's our turn in central Texas to have some of the white stuff this year. I will really be looking forward to what Jeff has to say as the event gets closer.

I bet the NWS offices around the state are working overtime to determine where that upper low is going to track and "IF" any watches will be warranted in the future.

[Lowpressure]

I just checked the morning Ensembles, and for the 3 day in a row, it shows a low forming in the NW gulf and tracking NE through SE Louisiana into Alabama and Mississippi. Until I see something different with consistency, that is where I am hedging my bets right now. The operational model should have a good handle on this by Thursday or Friday.

The morning Ensembles:
http://wwwt.emc.ncep.noaa.gov/gmb/ens/t ... 21900.html

On a sidenote: If you continue to look at the Graph " mslp HRC:" 192hrs-384, you will see repetitive shots of cold air into Texas.

Look at the size of the storm in the Pacific moving into Western Canada!!

[weatherrabbit_tx]

this is Jeffs e mail from this morning, and yes, the comment about north of I 10 did catch my attention... though i am only 7 miles north of 10.... but I am still north!!!

Highly active weather pattern to evolve over TX over the next week.

Short Term:

Air mass is moist and becoming unstable this morning with approach of short wave and incoming cold front over N TX. Expect numerous showers and thunderstorms to begin developing late this afternoon and continue through the night as coastal trough offshore moves inland and 1.5 inch PW air surges northward. Low level backing favors turning updrafts and a few tornadoes will be possible along the coastal and first inland tier counties. Cold front moves through sometimes Thursday, however best moisture departs late Wednesday so rain chances on Thursday may be a little lower than currently suggested.

Weekend into Christmas:

Forecasting nightmare continues for this period as one must attempt to balance model flip flopping and true meteorological reasoning and the wishes from many for snow around Christmas. After an exhaustive look at the nighttime model guidance and GFS forecast soundings for this weekend into Christmas one must continue to at least entertain the idea of frozen precip. across TX from the 24th to the 26th.

Latest GFS and EURO model runs suggest an even deeper and further south track of a very strong upper level trough this weekend. GFS fires off an intense surface low near Brownsville and crashes pressures into the low 1000's off the upper TX coast by late on the 24th. Cold polar boundary moves southward ahead of the upper low over Mexico and pushes across the state late on the 23rd. Cold low level air mass will be in place before the upper level storm moves across...however forecast soundings and surface temps. show a large above freezing layer from the surface to around 700mb at KCRP and below 850mb at KFWD on the 24th. Deep upper trough with associated strong cold pool begins to move late on the 24th crossing the Rio Grande and heading toward EC TX. 120hr forecasting sounding for KDRT shows the profile frozen from about 925mb on up and saturated from the surface to 400mb suggesting a changeover to sleet and snow. 850mb, 700mb, and 500mb RH was examined from the period late on the 23rd to the 26th. Moisture appears marginal in the 850mb layer (50-70%)and the 700mb layer (70-90%) on the 25th and even at 500mb (60-80%) by the 26th.

Main difference today is the slower nature of the entire event and the one very important detail of a secondary vort max rounding the western side of the closing off upper low over LA late on the 25th. Moisture profiles gradually decrease across SE TX after the intense surface low passage late on the 24th...really before the air column will be cold enough to support anything than rain. However by late on the 25th a SSE moving 500mb vort max is progged to dig into NC and then SE TX allowing some moisture recovery in the low to mid levels and mid level lift. By this time the temp. profiles look much more conducive for frozen precip especially along and north of I-10 where wrap around precip. may be ongoing. Both the GFS and EURO have 850mb temps between -2C and -4C and although surface temps are being forecast above freezing...strong cold air advection behind the departing intense surface low may very well drive the surface temps. down into the mid 30's.

As has been noted each day since Sunday, the exact track of the upper air features combined with the temps profiles and moisture levels will determine where and what kind of precip. falls. Feel there is a shot of sleet and snow from deep SW TX (Laredo) to near San Antonio to Austin and then ENE toward Shreveport. Secondary vorticity maximum and/or wrap around moisture may bring frozen precip. further southward Christmas afternoon and evening (along and north of a line from Columbus to Conroe to Lufkin).

Persons planning travels to central or N TX for the holiday weekend should be alert to the potential for Winter Storm conditions and hazardous driving.

JL

things maybe getting very interesting before all said and done

[Yankeegirl]

Please.. I dont care if it snows or not...just get rid of this hot yucky sticky weather we have down here now!!! its nasty!!!

[Opal storm]

Please.. I dont care if it snows or not...just get rid of this hot yucky sticky weather we have down here now!!! its nasty!!!

I am not even in Texas yet I know what your talking about! Our forecasted high today was 76...right now it's 78 and feels even warmer under the sun,definitely not the kind of weather to get you into the holiday mood.Unfortunately we won't see any major cool down like you folks in TX will,just a warm and rainy Christmas for us.

[Portastorm]

Well, Jeff just gave me permission to post his forecast note he sent out ... but I see that it has already been posted.

Yankeegirl, I hope you got his permission beforehand ... just think its a courtesy and that's why I didn't post until I asked his permission.

[Extremeweatherguy]

latest AFDs and forecasts should be coming out shortly. It should be interesting to see the NWS's viewpoint as of this afternoon.

[gboudx]

latest AFDs and forecasts should be coming out shortly. It should be interesting to see the NWS's viewpoint as of this afternoon.

Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
232 PM CST TUE DEC 19 2006

.DISCUSSION...
...

BENIGN WEATHER EXPECTED TONIGHT THROUGH AT LEAST FRI IN WAKE OF
UPPER LOW MOVING INTO GREAT LAKES AREA. LATEST MODEL RUNS HAVE THE NEXT
SYSTEM DIGGING INTO AZ ON FRI AND TAKING A MORE SOUTHERN ROUTE
ACROSS S TX... WHICH WOULD LEAVE MOST OF THE PRECIP SW-S-SE OF THE
CWA. MODELS HAVE DONE THEIR SHARE OF FLIP-FLOPPING WITH THIS
ONE... SO NEXT SET OF RUNS COULD FLOP THE TRACK BACK TO THE N
AGAIN. WILL CONTINUE LOW POPS MAINLY S SAT THROUGH SUN... BUT
BETWEEN THE CURRENT SOUTHERN TRACK AND THE QUESTION OF WHETHER OR
NOT IT WILL BE COLD ENOUGH FOR SNOW... THE CHANCES OF MEASURABLE
SNOW BEFORE CHRISTMAS APPEAR TO BE DWINDLING FOR MOST OF OUR CWA.

[JenBayles]

Ah, you're just whining cuz she beat you to the punch, Portastorm! j/k

This situation looks to be a fun one to keep us busy over Christmas. I just hope the OCMs and radio jockeys get the word out for messy travel weather soon enough for people to pay attention to it. It's all fun and games when we're snug in our homes, but so many people will be on the roads, and even a big rainstorm can spell trouble. Add anything frozen to it here in Texas and you've got a fair disaster in the making.

[Extremeweatherguy]

latest AFDs and forecasts should be coming out shortly. It should be interesting to see the NWS's viewpoint as of this afternoon.

Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
232 PM CST TUE DEC 19 2006

.DISCUSSION...
...

BENIGN WEATHER EXPECTED TONIGHT THROUGH AT LEAST FRI IN WAKE OF
UPPER LOW MOVING INTO GREAT LAKES AREA. LATEST MODEL RUNS HAVE THE NEXT
SYSTEM DIGGING INTO AZ ON FRI AND TAKING A MORE SOUTHERN ROUTE
ACROSS S TX... WHICH WOULD LEAVE MOST OF THE PRECIP SW-S-SE OF THE
CWA. MODELS HAVE DONE THEIR SHARE OF FLIP-FLOPPING WITH THIS
ONE... SO NEXT SET OF RUNS COULD FLOP THE TRACK BACK TO THE N
AGAIN. WILL CONTINUE LOW POPS MAINLY S SAT THROUGH SUN... BUT
BETWEEN THE CURRENT SOUTHERN TRACK AND THE QUESTION OF WHETHER OR
NOT IT WILL BE COLD ENOUGH FOR SNOW... THE CHANCES OF MEASURABLE
SNOW BEFORE CHRISTMAS APPEAR TO BE DWINDLING FOR MOST OF OUR CWA.

as they dwindle for OK, they increase for TX. It is looking better and better for TX it seems.

[gboudx]

as they dwindle for OK, they increase for TX. It is looking better and better for TX it seems.

Don't put that cart before the horse just yet. I've seen it happen too many times where the low is forecasted to dig south, but as the event got closer, it actually went further north. I'm not buying anything until about Friday.

[cctxhurricanewatcher]

Looking at some of the these AFD's and JB's comments.

Is history going to repeat itself again this Christmas for one particular part of the state???????????

[Yankeegirl]

No, I know Jeff, and i have posted his e mails several times... He doesnt mind,.. and I always let everyone know that it is from him... Sometimes people dont get his e mails, he is cool about posting here... Its all good...

[gboudx]

DFW AFD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
256 PM CST TUE DEC 19 2006

.DISCUSSION...
...
IN THE EXTENDED...WEEKEND UPPER LOW POSITION STILL NOT WELL
RESOLVED...BUT MODEL CONSENSUS SEEMS TO BE PUSHING UPPER LOW MORE
TOWARDS SOUTH TEXAS. THIS WOULD MAKE US COLD BUT DRY. DUE TO
UNCERTAIN UPPER LOW LOCATION/TIMING HAVE KEPT THE LOW POPS IN FOR
THE WEEKEND IN SOUTHEAST HALF OF NORTH TX BUT STILL SEE NO NEED TO
MENTION WINTER IN THE ZONES. WILL REEVALUATE TOMORROW. HOPING FOR
BETTER CONTINUITY BY THEN AMONGST THE MODELS AND THE GFS
ENSEMBLE...WHICH CURRENTLY (12Z RUN) SEEMS TO BE CONSISTENT
THROUGH FRIDAY BUT BREAKS DOWN SATURDAY ONWARD.

[Portastorm]

Looking at some of the these AFD's and JB's comments.

Is history going to repeat itself again this Christmas for one particular part of the state???????????

Am I going to have to drive to Corpus to see snow?!?!?!

[jasons2k]

as they dwindle for OK, they increase for TX. It is looking better and better for TX it seems.

Maybe precip. chances but not necessarily snow. Did you read the discussion from Corpus? This isn't exactly the coldest system in the world. I wouldn't give the impression that b/c the low is tracking south that automatically means the chances for snow is looking "better and better" for us. It's irresponsible IMO.

As AFM has needed to state a few too many times now, you have to look at other parameters.