Cold Turkey Day for Texas?

[Portastorm]

The 12z GFS run continues to show some real cold air headed for Texas by Thanksgiving. It appears to be less bullish on overrunning precip though. Here's a snippet for you:

Does the blue line indicate below freezing?

Thanks.

Generally speaking Irak, the answer is yes. However, there are always atmospheric components that may mean that areas slightly in front of that line are below freezing or that ardas behind that line are actually slightly above freezing. The pro mets on here can explain much better than I ... but the "blue line" is one of those general markers that suggests it's the freezing line.

[Ed Mahmoud]

The 12z GFS run continues to show some real cold air headed for Texas by Thanksgiving. It appears to be less bullish on overrunning precip though. Here's a snippet for you:

Does the blue line indicate below freezing?

Thanks.

Generally speaking Irak, the answer is yes. However, there are always atmospheric components that may mean that areas slightly in front of that line are below freezing or that ardas behind that line are actually slightly above freezing. The pro mets on here can explain much better than I ... but the "blue line" is one of those general markers that suggests it's the freezing line.

For freezing rain or sleet, I look for the 850 mb line to be South of the 700 mb 284 line to be South of the 540 dm 1000-500 mb thickness line. You can do that with almost any freely available inter-web weather model page.

My pay-per-view AccuWx page also has p-type forecasts, and 2 meter temp forecasts, and the such.


But when I see cold air at relatively low levels (the 850 mb line) well South of the 540 dm line, in Texas, I figure one of those shallow cool airmasses is coming in that can be over-run.

[Ed Mahmoud]

Noticing new WRF has a nice little rainfall bomb over SE Texas Sunday. After a very wet first 9 months of 2007, it hasn't rained hardly at all in weeks.

[Portastorm]

On interest from JB's videos today:

* Texas will have "a horrible Thanksgiving weekend."

* He referenced the Easter snow in Waco and said it could end up being perfect symmetry this year with a POSSIBLE shot at snow/ice well into Texas on Thanksgiving weekend.

* Says we probably have one more cold blast coming early in December and then he feels the "blow torch" will be on for most of the nation for the remainder of winter.

* He also said to expect the GFS to waffle back and forth until close to the event as there "is too much on the plate for the model to handle."

[Ed Mahmoud]

On interest from JB's videos today:

* Texas will have "a horrible Thanksgiving weekend."

* He referenced the Easter snow in Waco and said it could end up being perfect symmetry this year with a POSSIBLE shot at snow/ice well into Texas on Thanksgiving weekend.

* Says we probably have one more cold blast coming early in December and then he feels the "blow torch" will be on for most of the nation for the remainder of winter.

* He also said to expect the GFS to waffle back and forth until close to the event as there "is too much on the plate for the model to handle."

That wasn't in the Big Dog. Was it the 'Long Ranger'?

[Portastorm]

Yessir!

[gboudx]

Horrible Thanksgiving weekend huh? Guess I better plan to put up the Christmas light this weekend and Wednesday.

[Johnny]

I like what JB has to say, exept the part about it being pretty darn warm for the rest of the winter season after this cold shot. I hope we have at least some seasonal weather around Christmas. A warm Christmas is worse than a warm Thanksgiving to me.

gboudx, I just got inside after hanging some lights. I always put up lights little by little this time of year so I can turn them on come Thanksgiving night.

[gboudx]

gboudx, I just got inside after hanging some lights. I always put up lights little by little this time of year so I can turn them on come Thanksgiving night.

Black Friday is my day, but we've increased our lights display enough over the years that now it takes me so long that it goes right into the LSU/Arkansas game. So I stop at that point to go watch my Tigers play. I'm planning to start this weekend, but not bust my butt trying to get it all done. I'm taking Wednesday off, so I have some hours on that day too. But if the weather's gonna be wet on Friday, I will want to be done before then.

[Extremeweatherguy]

I like what JB has to say, exept the part about it being pretty darn warm for the rest of the winter season after this cold shot. I hope we have at least some seasonal weather around Christmas. A warm Christmas is worse than a warm Thanksgiving to me.

gboudx, I just got inside after hanging some lights. I always put up lights little by little this time of year so I can turn them on come Thanksgiving night.

This isn't the final cold shot according to him. He also expects another significant one in early December before we start to warm up.

[double D]

IN THE EXTENDED...GFS AND ECMWF HAVE SLOWED THE ARCTIC
OUTBREAK...AND IT MAY NOT PENETRATE AS FAR SOUTH AS THE OLD RUNS
SUGGESTED. AS FAR AS WINTER WEATHER IN NORTH TEXAS...GFS PUSHES
FRONT FARTHER SOUTH AND DRIES OUT THE AREA. ECMWF HAS LESS FRONTAL
PUSH AND KEEPS MOISTURE AVAILABLE THROUGH THURSDAY. THIS SOLUTION
WOULD BRING COLD RAIN TO MOST OF THE AREA...WITH THE SLIGHT
POSSIBILITY OF SOME WET SNOW OR MELTING SLEET IN THE NORTHWEST. I
INCLUDED LOW POPS IN THE DAY 6 AND 7 BECAUSE THE FRONT WILL BE
SOMEWHERE NEAR NORTH TEXAS...BUT I DID NOT PUT ANY WINTER WEATHER
INTO THE DAY 7 GRIDS...AGAIN BECAUSE OF LACK OF CONTINUITY. 84

I'm a little confused by this statement. Besides the 06z, the GFS actually has been more bullish on the cold air coming into Texas than the past couple of days. Maybe I'm missing something

[Extremeweatherguy]

Here is a look at the first official high temperature forecasts from the NWS for Thanksgiving day...

Dallas - 41˚
Lufkin - 61˚
Houston - 61˚
Austin - 61˚
Beaumont - 64˚

These numbers (except for may be Dallas) are likely still too warm...but for being 7 days out, I think these are pretty good looking predictions from the NWS. There is always time to adjust downward in the future (which they probably will have to do).

[Extremeweatherguy]

IN THE EXTENDED...GFS AND ECMWF HAVE SLOWED THE ARCTIC
OUTBREAK...AND IT MAY NOT PENETRATE AS FAR SOUTH AS THE OLD RUNS
SUGGESTED. AS FAR AS WINTER WEATHER IN NORTH TEXAS...GFS PUSHES
FRONT FARTHER SOUTH AND DRIES OUT THE AREA. ECMWF HAS LESS FRONTAL
PUSH AND KEEPS MOISTURE AVAILABLE THROUGH THURSDAY. THIS SOLUTION
WOULD BRING COLD RAIN TO MOST OF THE AREA...WITH THE SLIGHT
POSSIBILITY OF SOME WET SNOW OR MELTING SLEET IN THE NORTHWEST. I
INCLUDED LOW POPS IN THE DAY 6 AND 7 BECAUSE THE FRONT WILL BE
SOMEWHERE NEAR NORTH TEXAS...BUT I DID NOT PUT ANY WINTER WEATHER
INTO THE DAY 7 GRIDS...AGAIN BECAUSE OF LACK OF CONTINUITY. 84

I'm a little confused by this statement. Besides the 06z, the GFS actually has been more bullish on the cold air coming into Texas than the past couple of days. Maybe I'm missing something

yeah, I don't understand it either. The ensembles all show the air sinking south at a good clip, and so does the GFS. The EURO is pretty much the only really slow model. I guess the Dallas office is just being careful. Strangely though, even with this slightly "bearish" AFD, the Dallas NWS is still predicting a quicker moving front and a cold Thanksgiving. Their current Turkey Day forecast is calling for a high of only 41-degrees!

[cctxhurricanewatcher]

IN THE EXTENDED...GFS AND ECMWF HAVE SLOWED THE ARCTIC
OUTBREAK...AND IT MAY NOT PENETRATE AS FAR SOUTH AS THE OLD RUNS
SUGGESTED. AS FAR AS WINTER WEATHER IN NORTH TEXAS...GFS PUSHES
FRONT FARTHER SOUTH AND DRIES OUT THE AREA. ECMWF HAS LESS FRONTAL
PUSH AND KEEPS MOISTURE AVAILABLE THROUGH THURSDAY. THIS SOLUTION
WOULD BRING COLD RAIN TO MOST OF THE AREA...WITH THE SLIGHT
POSSIBILITY OF SOME WET SNOW OR MELTING SLEET IN THE NORTHWEST. I
INCLUDED LOW POPS IN THE DAY 6 AND 7 BECAUSE THE FRONT WILL BE
SOMEWHERE NEAR NORTH TEXAS...BUT I DID NOT PUT ANY WINTER WEATHER
INTO THE DAY 7 GRIDS...AGAIN BECAUSE OF LACK OF CONTINUITY. 84

I'm a little confused by this statement. Besides the 06z, the GFS actually has been more bullish on the cold air coming into Texas than the past couple of days. Maybe I'm missing something

yeah, I don't understand it either. The ensembles all show the air sinking south at a good clip, and so does the GFS. The EURO is pretty much the only really slow model. I guess the Dallas office is just being careful. Strangely though, even with this slightly "bearish" AFD, the Dallas NWS is still predicting a quicker moving front and a cold Thanksgiving. Their current Turkey Day forecast is calling for a high of only 41-degrees!

Meanwhile NWS Corpus is very bullish (mind you they have been pretty spot on the last few winters) I think NWS Fort Worth is afraid to pull the trigger for some reason.

DESPITE A PREVAILING SOUTHWEST FLOW
ALOFT WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT...BELIEVE THE
DENSITY OF THE AIRMASS UPSTREAM WILL FORCE A STRONG COLD FRONT
THROUGH THE REGION WEDNESDAY NIGHT(ENSEMBLES ADD CREDENCE TO THIS AS
WELL). MOISTURE/INSTABILITY/FORCING WILL BE GREATEST OVER THE EAST.
WILL SHOW SLIGHT CHANCE/MARGINAL LOW-END CHANCE POPS WEDNESDAY
AFTERNOON ACROSS THE NORTHERN COUNTIES THEN GRADE POPS FROM SLIGHT
CHANCE WEST TO MID-GRADE CHANCE EAST WEDNESDAY NIGHT. ISENTROPIC
UPGLIDE WILL SUSTAIN CLOUDINESS(BUT NOT PRECIPITATION) THURSDAY THEN
CLOUDS WILL DIMINISH SOME THURSDAY NIGHT AS A SURFACE ANTICYCLONE
ENCROACHES. TEMPERATURES WILL AVERAGE WELL ABOVE NORMAL PRIOR TO THE
FRONTAL PASSAGE THEN DROP WELL BELOW NORMAL IN THE POST-FRONTAL
AIRMASS. SCEC/LOW-END SCA SOUTHERLIES PRECEDING THE FRONT WILL
BECOME STRONG SCA NORTHERLIES BEHIND THE FRONT.

[Extremeweatherguy]

Well so much for that 41˚ Thanksgiving high temperature forecast for Dallas. To better match surrounding offices, they have decided to raise the forecast up to 57˚. Over the next few days though, I expect the Dallas forecast and other forecasts to be adjusted downward. In the end, the original forecast for Dallas (low 40s) may actually end up being closer to what actually happens than what their new updated forecast (mid/upper 50s) shows.

We shall see...

[double D]

I think that's the right move considering that we are still 7 days away. I wonder if that forecaster was "told" to raise the high temp. for Thanksgiving?

[Extremeweatherguy]

Surprise, surprise! The 00z GFS has sped up the front a bit. It now shows it reaching us by Wednesday afternoon instead of Thursday morning...

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/00/images/gfs_ten_138l.gif

...The Corpus Christi afternoon AFD may have been onto something.

[Extremeweatherguy]

It is worth noting that the 00z ECMWF significantly sped up the front. Instead of a weekend crossing, it now shows a Thanksgiving day frontal passage. This is still 24 hours slower than the GFS, but it is much faster than previous runs of the ECMWF.

[Portastorm]

I was also going to add that -- in general terms -- today's 0z GFS run looks a lot more like yesterday's 12z GFS run and a lot less like yesterday's 0z GFS run. All of this to say that the more dramatic cold appears less likely but it definitely will be a good 10 to 15 degrees below normal for several days around Thanksgiving!

[Johnny]

As has been pointed out by pro mets many times over, from now till the actually arrival of the front, their will be alot of flip flopping with the models. JB pointed out that their is just too much on the plate for the models to handle. I would not rule out dramatic temperatures just yet. More flip flops on the way!!