Texas Winter Weather Thread #3 - GFS showing cold christmas

[Extremeweatherguy]

18z GFS is coming in right now. It will be very interesting to see if it continues the trend. If it does, then this will be the fourth run in a row to show snow/ice around Christmas.

[gboudx]

DFW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
347 PM CST SUN DEC 17 2006

.DISCUSSION...
...

THE SECOND LOW APPEARS TO BE IN A SUFFICIENTLY COLD ENVIRONMENT
TO PRODUCE A CHANCE OF WINTRY PRECIPITATION ACROSS THE SOUTHERN
PLAINS...INCLUDING WEST AND SOUTHWEST TEXAS. THE MAIN TRACK OF
UPPER LOW #2 WILL HAVE IT DIG FAR TO THE SOUTH INTO NORTHERN
MEXICO...WEST OF THE RIO GRANDE. AT THIS TIME...THERE IS CONSIDERABLE
UNCERTAINTY ABOUT WINTRY PRECIPITATION NEXT WEEKEND.
HOWEVER...BOTH THE EUROPEAN AND THE GFS EXTENDED FORECASTS SHOW
THE MAIN THREAT OF WINTRY PRECIPITATION TO BE NEAR THE TRACK OF
THE LOW...FROM PORTIONS OF NORTHWEST AND WEST TEXAS INTO THE AREA
OF THE UPPER RIO GRANDE RIVER. WE WILL BE WATCHING THIS SYSTEM
CAREFULLY WITH TIME...AS SOME THREAT OF ICE AND SNOW MAY
EVENTUALLY DEVELOP ACROSS NORTH TEXAS.

TO REITERATE...THERE IS CONSIDERABLE UNCERTAINTY ABOUT NEXT
WEEKEND`S FORECAST. ADDITIONAL DATA IN THE NEXT 3-4 DAYS WILL HELP
IN FORECASTING THIS POTENTIAL WINTER STORM. ONLY MINOR CHANGES
HAVE BEEN MADE TO GFS GUIDANCE...BECAUSE OF THE MANY UNCERTAINTIES
AT THIS TIME. #26

We'll see how the week progresses, but it always seems like the forecast of these systems digging south, trend north as the actual forecast period nears. It figures something like this would happen, with Christmas travel planned.

[double D]

DFW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
347 PM CST SUN DEC 17 2006

.DISCUSSION...
...

THE SECOND LOW APPEARS TO BE IN A SUFFICIENTLY COLD ENVIRONMENT
TO PRODUCE A CHANCE OF WINTRY PRECIPITATION ACROSS THE SOUTHERN
PLAINS...INCLUDING WEST AND SOUTHWEST TEXAS. THE MAIN TRACK OF
UPPER LOW #2 WILL HAVE IT DIG FAR TO THE SOUTH INTO NORTHERN
MEXICO...WEST OF THE RIO GRANDE. AT THIS TIME...THERE IS CONSIDERABLE
UNCERTAINTY ABOUT WINTRY PRECIPITATION NEXT WEEKEND.
HOWEVER...BOTH THE EUROPEAN AND THE GFS EXTENDED FORECASTS SHOW
THE MAIN THREAT OF WINTRY PRECIPITATION TO BE NEAR THE TRACK OF
THE LOW...FROM PORTIONS OF NORTHWEST AND WEST TEXAS INTO THE AREA
OF THE UPPER RIO GRANDE RIVER. WE WILL BE WATCHING THIS SYSTEM
CAREFULLY WITH TIME...AS SOME THREAT OF ICE AND SNOW MAY
EVENTUALLY DEVELOP ACROSS NORTH TEXAS.

TO REITERATE...THERE IS CONSIDERABLE UNCERTAINTY ABOUT NEXT
WEEKEND`S FORECAST. ADDITIONAL DATA IN THE NEXT 3-4 DAYS WILL HELP
IN FORECASTING THIS POTENTIAL WINTER STORM. ONLY MINOR CHANGES
HAVE BEEN MADE TO GFS GUIDANCE...BECAUSE OF THE MANY UNCERTAINTIES
AT THIS TIME. #26

We'll see how the week progresses, but it always seems like the forecast of these systems digging south, trend north as the actual forecast period nears. It figures something like this would happen, with Christmas travel planned.

Just like the last system that was supposed to dig into northern Mexico, but instead it is expected to move well north of central and southern Texas. Let's see what the GFS shows on Wednesday and Thursday before we get to excited about snow/sleet.

[double D]

WOW! Austin/San Antonio NWS is calling for a 50% chance of rain on next Sunday, talk about being bold. I rarely see them so aggressive this far out.

[HarlequinBoy]

Will it only be cold enough for winter weather immediately along the track of the low?

Will areas to the north be too warm?

[Extremeweatherguy]

the 18z GFS continues the cold, wintry trend. This now officially makes 4 runs in a row with the GFS showing a winter storm for much of TX.

The more trusted 0z run should be more informative when it comes out late this evening though. I am looking foward to that!

BTW, here is a detailed look at the 18z run:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_174l.gif
^^Christmas Eve. Cold and wet in east TX, cold and icy/snowy in west and central TX.^^

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_192l.gif
^^Winter precip. spreads east Christmas day with rain turing to (or mixing with) sleet/snow in parts of the east TX and most of west and central TX will be looking at all snow.^^

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_204l.gif
^^Very early on the 26th. A few flurries remain north of I-10 but most of the precip. is on the way out.^^

So, if the 18z is correct, the best chance of winter weather in Houston is between Christmas afternoon and the morning of the 26th. Even so, it will be cold well before the winter precip. chances begin. Highs on Christmas eve will struggle to get out of the 40s and on Christmas day, they will struggle to get out of the 30s. Highs then look to stay below 50F on the 26th as well. Jackets will be required for sure (if the GFS is right)!

[Extremeweatherguy]

The 18z GFS then, like earlier runs, shows more cold air/winter precip. chances on the way after Christmas:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _264.shtml
^^Dec. 28^^

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _288.shtml
^^Dec. 29^^

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _300.shtml
^^Morning of Dec. 30^^

[Portastorm]

OK, I just took a gander at the new 12z Euro run. Looks fairly mild for central and souh Texas until next Sunday (Christmas eve) and then ... as John Madden might say: BOOM!

http://weather.cod.edu/forecast/ECMWF/e ... mp_168.gif

The low (and main energy) looks further north in this than what the GFS is suggesting ... but the trough still looks VERY deep. And, regardless with these 850 mb temps it would still mean wintry precip for some of us!!

[aggiecutter]

Based on how this situation is shaping up, I'd say anyone north of Austin to Lufkin line is going to have a very significant winter storm. With a low in the NW Gulf, there will be too much warm air pumped up over the immediate coastal areas in the mid-levels and inland for about a 80-100 miles for them to see significant winter weather. However, those areas could get a decent shot of sleet and snow as the low pulls away. This is just the way it looks now. I base that an past experience with this kind of weather situation. Of course, a lot of that depends on where the players actually end up on the field. But, I am feeling confident that something very significant is going to happen around Christmas time. The operational GFS should have a good handle on it by Thursday or Friday. Between now and then, expect variability in day to day runs. Now that we are in the 7 day window of the EURO, it will become a valuable tool in trying to pin point what is going to happen.

Before I forget, the most valuable tool will be JB sycophant portastorm. Tomorrow morning, he begins his trek up MT. Bastardi. On Wednesday, he will descend the mountain and enlighten us with his guru's every word.

[Janie2006]

As Martha Stewart might say: "Anytime you can work a John Madden reference into a wx discussion, its a good thing."

*ahem*

I like the way these models are trending. Bring on the cold air.

[tornadolvr]

This link below shows a couple of red blotches on the precip type right over DFW on Christmas Eve. Really hope we don't get any ice from this system!

http://www.rap.ucar.edu/weather/model/d ... typ&loop=1

[Portastorm]

Based on how this situation is shaping up, I'd say anyone north of Austin to Lufkin line is going to have a very significant winter storm. With a low in the NW Gulf, there will be too much warm air pumped up over the immediate coastal areas in the mid-levels and inland for about a 80-100 miles for them to see significant winter weather. However, those areas could get a decent shot of sleet and snow as the low pulls away. This is just the way it looks now. I base that an past experience with this kind of weather situation. Of course, a lot of that depends on where the players actually end up on the field. But, I am feeling confident that something very significant is going to happen around Christmas time. The operational GFS should have a good handle on it by Thursday or Friday. Between now and then, expect variability in day to day runs. Now that we are in the 7 day window of the EURO, it will become a valuable tool in trying to pin point what is going to happen.

Before I forget, the most valuable tool will be JB sycophant portastorm. Tomorrow morning, he begins his trek up MT. Bastardi. On Wednesday, he will descend the mountain and enlighten us with his guru's every word.

That's right, aggiecutter! And when I come back down, I better not find any of you folks worshipping the Golden GFS Calf or you're in for it!

[Johnny]

Reality check time....although these models are fun to look at, we will not be seeing any snow during this time period. Sure we will cool off once again but come on....snow again on Christmas in the deep south? Not gonna happen.

[wxman22]

Reality check time....although these models are fun to look at, we will not be seeing any snow during this time period. Sure we will cool off once again but come on....snow again on Christmas in the deep south? Not gonna happen.

Even though it would be very rare for us to see snow around Christmas again doesnt mean it wont happen Never Say Never

[Burn1]

Maybe some snow in North Texas, but I doubt highly the Gulf Coast will see any.... It is fun though to watch the people wishing so hard on this thread though...

[Extremeweatherguy]

Maybe some snow in North Texas, but I doubt highly the Gulf Coast will see any.... It is fun though to watch the people wishing so hard on this thread though...

Don't forget 2004 though. Many said it could never happen then and then it did. If it has happened once, it can happen again.

[cctxhurricanewatcher]

Maybe some snow in North Texas, but I doubt highly the Gulf Coast will see any.... It is fun though to watch the people wishing so hard on this thread though...

Don't forget 2004 though. Many said it could never happen then and then it did. If it has happened once, it can happen again.

Yep.

[Burn1]

Anything is possible, which is the beauty of life

[jeff]

See below for potential major winter storm event possible before and on Christmas Day.

Short Term:

Our new best friend "sea fog" continues to plague the area nightly and tonight will be no different. Visibilities have already tanked to 1/4th a mile at GLS and fog is marching inland.

Upper trough forecast to cross into the southern plains last Friday now looks to eject further northward from the 4 corners toward the Great Lakes. This is much further north than the models showed late last week and so less rain chances and only a modest cool down is expect toward Thursday. Still expect increasing moisture to bring rain into the area starting late Tuesday with Wed. being the wet day. Front passes through on Thursday with temps. falling back to seasonal normal and then as the saying goes "All hell brakes loose".

Next weekend into Christmas Day:

Understand we are talking about 7 days out and are at the mercy of computing power and forecasting variables that area far beyond any control. I am almost certain I will regret even brining this to print, however the models and more than one have had consistent runs for the past 3-4 model runs.

The potential exist for a significant winter storm event across TX Christmas Eve into Christmas Day including accumulating snowfall over a large portion of the state.

SW US trough reloads Thursday with potent short wave energy which digs SE toward N Mexico. At the surface polar/arctic boundary slides down the plains with 1035-1040mb high over the central Rockies. Expect strong polar front to blast through the state late on the 23rd and 24th with strong cold air advection. Mexican upper level trough deepens and tracks SE and then ESE toward SW TX with strong isentropic ascent starting on Christmas Eve morning across central TX and spreading east. Per GFS forecast soundings and ECMWF forecast trough position and movement a significant band of sleet and snow is possible from deep SW TX across much of the state Christmas Eve and Christmas Day. Impressive 700mb moisture advection ahead of the low may result in liquid for the start of the event along and east of I-35, however GFS profiles and critical thickness values tank by Christmas Eve evening along I-35 and push eastward suggesting a full change over from liquid to frozen. Given intensity of surface arctic boundary and models notoriously underforecasting of surface cold air advection and wet bulb cooling a period of freezing rain and icing may be possible ahead of the ejecting storm system before the air column cools and precip. changes to snow.

With all this said the track of the upper level trough and upper low will be the critical determining factor in this "potential" Christmas snow event for TX. GFS has done a poor job since last week of handling this weeks upper level features and is lifting the current SW US upper low out into the plains nearly 500 miles north of the position suggested at the middle of last week. The positives for those wanting any hope of a white Christmas is that other models are on board with a similar track and favor a significant winter storm episode across TX from the 24th to the 26th.

No need to speculate about potential totals or even P-type at this time as there is plenty of time to work out all the gritty details...and I fully expect the forecast models to reverse and show no winter storm at all by this time tomorrow.

We shall revisit the topic tomorrow

[Johnny]

Yep.

Nope. lol


Playing the devil's advocate here.