Texas Winter 2017-2018

[ThunderSleetDreams]

I am all with the euro right now and a blend of cmc

Euro is out to lunch. It makes absolutely no sense in its operational run given that it’s showing a negative EPO and a MJO move into 7/8.

With that said, the Euro does move the cold air to us sometime on the 24th, about 36-48 hours after GFS. I think the CMC is doing okay.

[ThunderSleetDreams]

Wouldn’t call it warm for Houston, but an arctic front isn’t going to stall for 3 days. A Canadian front in October/November? Sure.

Not one in late December with this pattern.

[gboudx]

Update from jeff:

A weak cold front will cross the region this evening with rain chances increasing Saturday and Saturday night.

Low confidence forecast next week and beyond

A weak cold front will move across the region today and tonight with high clouds streaming across the area. Rain and thunderstorms will develop offshore on Friday and some of this activity may graze the coastal locations, but the bulk of the activity will remain offshore. Appears the surface front will remain over the area going into Saturday as a strong upper level storm system approaches from northern Mexico. Lift will spread across the region on Saturday along with rapid moisture advection. Expect rain chances to increase from SW to NE across the area on Saturday afternoon into the overnight hours. A few strong or even severe thunderstorms may form off the coast south of a warm front Saturday night with most of the area seeing widespread showers and isolated thunderstorms inland. Rainfall totals up to an inch will be possible especially near the coast with lesser amounts inland. Storm system will be fast moving and exit the area early Sunday with rain ending. No real air mass change behind this departing storm on Sunday and temperatures will begin to warm next week as southerly flow returns to the region.

May see some rain chances again toward the middle of next week as another front moves toward the area, but moisture return and quality may be in question.

Warm temperatures will remain in the forecast for much of next week with highs in the 70’s most days.

Extended:

As is common with model guidance the GFS has backed away with the intensity of the cold air mass around Christmas and beyond more in favor of the ECMWF solution. GFS still has a strong cold front arrives around the 24th across the area, but is not as cold as previous runs. Models tend to underestimate the intensities of these cold arctic air masses that can surge down the plains and extended range guidance usually struggle greatly with such events. There is really no confidence at this time as to what may transpire around Christmas or the week after with respect to the incoming cold air mass and how cold it may be and what if any precipitation may fall in that air mass. Use caution when viewing the extended range guidance and making an assumptions. This portion of the forecast will continue to be of interest over the next several days.

[Ralph's Weather]

Latest model runs would indicate another warm Christmas in the cards for SE Texas and South LA. Let's hope this changes after two years in a row in the 80's on Christmas day

The chance for a warm Christmas for SE TX and SW LA are near zero. Now SE LA could be closer to average but likely still chilly.

[orangeblood]

CHART IS FOR ENTERTAINMENT PURPOSES ONLY....although given the anomalies now showing up in the forecasted Upper Level charts, some of these GFS Ensemble Members show the extreme that this pattern could go to (check out Member #14 ). With Arctic air pouring into the pattern and the Southeast Ridge holding strong, there could be one heck of a battleground setting up across the south late next week.

[stormlover2013]

we are over a week out, just like hurricanes I don't trust any model this far out!!

[Cpv17]

Wouldn’t call it warm for Houston, but an arctic front isn’t going to stall for 3 days. A Canadian front in October/November? Sure.

Not one in late December with this pattern.

I agree. That cold air has to go somewhere. It’s not just going to stop and stall out over the Rockies and TX panhandle like the 6z GFS is showing. It doesn’t make any sense. A huge artic front like that with a huge artic high coming down isn’t just going to stall out like that.

[ThunderSleetDreams]

CHART IS FOR ENTERTAINMENT PURPOSES ONLY....although given the anomalies now showing up in the forecasted Upper Level charts, some of these GFS Ensemble Members show the extreme that this pattern could go to (check out Member #14 ). With Arctic air pouring into the pattern and the Southeast Ridge holding strong, there could be one heck of a battleground setting up across the south late next week.

http://models.weatherbell.com/gefs/2017 ... ow_384.png

That would be something. Wow

[wxman22]

Yep I agree, the GFS is notorious for not handling shallow arctic air very good. if we get a front as strong as the model is showing there is no way it's going to stall along the coast and then come back up as a warm front, instead, it would move straight into the Gulf, don't buy into the temperatures that it's outputting across the southern half of the state I've seen this time and time again...

[wxman57]

CHART IS FOR ENTERTAINMENT PURPOSES ONLY....although given the anomalies now showing up in the forecasted Upper Level charts, some of these GFS Ensemble Members show the extreme that this pattern could go to (check out Member #14 ). With Arctic air pouring into the pattern and the Southeast Ridge holding strong, there could be one heck of a battleground setting up across the south late next week.

http://models.weatherbell.com/gefs/2017 ... ow_384.png

I'm fairly certain that the graphic is not properly interpreting the model data. The GFS is indicating a VERY shallow Arctic airmass with rather warm air above 2000 ft or so. What I think may be happening is that whoever made that graphic is assuming that sub-freezing surface temperatures automatically mean that the precip is snow. However, very shallow Arctic air would mean freezing rain, not snow, which would be far worse, of course.

[TeamPlayersBlue]

Christmas is still 11 days out, still 3 days too early for even GUESSING Christmas weather. The pattern looks good for us. Lets be happy about that.

Maybe some of the pros on here can help us identify particular things to watch NOW, which will lead to this massive -EPO.

This run, the block turned even bigger at the end of the run.

[Portastorm]

Yep I agree, the GFS is notorious for not handling shallow arctic air very good. if we get a front as strong as the model is showing there is no way it's going to stall along the coast and then come back up as a warm front, instead, it would move straight into the Gulf, don't buy into the temperatures that it's outputting across the southern half of the state I've seen this time and time again...

I think what the model is showing more than anything else ... and wxman57 mentions this ... is that the Arctic airmass may be shallow and there may be some strong overrunning developing and inflow from the Gulf. I've seen this before where the GFS showed a front backing up like this and it was more a reflection on the upper level flow.

[Tireman4]

Yep I agree, the GFS is notorious for not handling shallow arctic air very good. if we get a front as strong as the model is showing there is no way it's going to stall along the coast and then come back up as a warm front, instead, it would move straight into the Gulf, don't buy into the temperatures that it's outputting across the southern half of the state I've seen this time and time again...

I think what the model is showing more than anything else ... and wxman57 mentions this ... is that the Arctic airmass may be shallow and there may be some strong overrunning developing and inflow from the Gulf. I've seen this before where the GFS showed a front backing up like this and it was more a reflection on the upper level flow.

Yes. Yes. Yes and wait, yes!! We are still over 10 days out. Anything and everything will change. Run to run might be vastly different. Stay tuned young Jedi!!

[orangeblood]

CHART IS FOR ENTERTAINMENT PURPOSES ONLY....although given the anomalies now showing up in the forecasted Upper Level charts, some of these GFS Ensemble Members show the extreme that this pattern could go to (check out Member #14 ). With Arctic air pouring into the pattern and the Southeast Ridge holding strong, there could be one heck of a battleground setting up across the south late next week.

http://models.weatherbell.com/gefs/2017 ... ow_384.png

I'm fairly certain that the graphic is not properly interpreting the model data. The GFS is indicating a VERY shallow Arctic airmass with rather warm air above 2000 ft or so. What I think may be happening is that whoever made that graphic is assuming that sub-freezing surface temperatures automatically mean that the precip is snow. However, very shallow Arctic air would mean freezing rain, not snow, which would be far worse, of course.

Yes, I agree...this was more to illustrate the type of battleground potential this pattern could set up (Some of the members are forecasting 3.5-4.5 inches of liquid in sub-freezing surface temps). Some of these same Ensembles showed the Harvey Rain potential this far out as well but forecasting frozen precip is a different animal

[weatherdude1108]

I know we've already alluded to this here many times. I just noticed the EWX had a blurb of the long range models showing signals for a pattern change next weekend and the following week, and to "use long range models with extreme caution."

It should be noted that long range models are continuing to show
signals for a pattern which could be rather active synoptically for
the next weekend and following week. This pattern of 2-3 cold front
passages per week will likely continue, some more significant than
others, but details beyond large scale pattern changes cannot be
determined at this stage with any reasonable confidence. Especially
if those details (prospects for winter weather) hinge on a
temperature forecast of 32 vs 33+ degrees, as is often the case for
this part of the country. So use long range models with extreme
caution. More details will be discussed as our confidence increases.

http://forecast.weather.gov/product.php ... glossary=0

[Tireman4]

HGX agrees with EWX


000
FXUS64 KHGX 140936
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
336 AM CST Thu Dec 14 2017



It is still too early to correctly predict what kind of weather the
area will see over the Christmas holiday weekend. 42

[aggiecutter]

"Yes, I agree...this was more to illustrate the type of battleground potential this pattern could set up (Some of the members are forecasting 3.5-4.5 inches of liquid in sub-freezing surface temps). Some of these same Ensembles showed the Harvey Rain potential this far out as well but forecasting frozen precip is a different animal"


Texarkana received 3.5" of rain over 36 hours falling into mid-20 degree air Christmas of 2000. The results were catastrophic.

[CaptinCrunch]

NWS FTW Long Range...... These guys must be watching our Winter Thread......

Some larger changes are possible in the day 8-10 time period when
models have persistently shown deep troughing engulfing much of
the Central US. This pattern would be favorable for delivering
multiple shots of arctic air to the Central US and Southern
Plains, the first of which could arrive in Texas at the end of
next week. By now, we`ve all seen far too many model graphics
irresponsibly floating on social media depicting winter weather
potential due to this pattern shift. While it`s important we
acknowledge some winter weather is a possibility in the Dec 22-27
time frame, it`s much too early to suggest this is a guarantee. It
is something we`ll certainly be monitoring in the next several
days and will introduce if/when appropriate.

[CaptinCrunch]

A storm system will approach the region on Saturday, which will begin to draw Gulf moisture back northward. By Saturday evening and overnight, rain chances (perhaps with a few thunderstorms as well) will overspread all of North and Central Texas. Not everyone will get rain from this system, however. The highest rain chances will be along and east of I-35.

[orangeblood]

"Yes, I agree...this was more to illustrate the type of battleground potential this pattern could set up (Some of the members are forecasting 3.5-4.5 inches of liquid in sub-freezing surface temps). Some of these same Ensembles showed the Harvey Rain potential this far out as well but forecasting frozen precip is a different animal"


Texarkana received 3.5" of rain over 36 hours falling into mid-20 degree air Christmas of 2000. The results were catastrophic.

Yep, different synoptic pattern than 2000 but the potential is there this time of year....when you start seeing anomalies around Hawaii of 7-8 Standard Deviations below normal, it should get every pro mets attention in this part of the world because those type anomalies typically have significant downstream implications (Sometimes Very Extreme)