Texas winter wx thread (2009-2010)

[gofrogs]

The worst run ever wow it completley flip flopped.

[Ntxw]

no fun

[iorange55]

The worst run ever wow it completley flip flopped.

I think you might be having trouble reading the model, it's still showing a strong strong strong front for Christmas with temps in the teens in North Texas. I think you're more concerned with the moisture aspect as am I, but I wouldn't focus on the moisture too much this far out it's too early to be guessing on that really, but my thinking is as long as the cold air is in place there is always a chance. And the GFS 00 definitely has the cold air here.

[AggieSpirit]

Im just curious -- was there anyone here or GFS runs that correctly predicted the heavy snowfall at Victoria and along the gulf coast a few years back?

I seem to remember expectations of a dusting to light accumulation - but not snow measured in some areas at greater than a foot.

[srainhoutx]

The worst run ever wow it completley flip flopped.

I think you might be having trouble reading the model, it's still showing a strong strong strong front for Christmas with temps in the teens in North Texas. I think you're more concerned with the moisture aspect as am I, but I wouldn't focus on the moisture too much this far out it's too early to be guessing on that really, but my thinking is as long as the cold air is in place there is always a chance. And the GFS 00 definitely has the cold air here.

Agreed. The trends are looking good. The 'finer' details(moisture/storm track/Upper AIr Disturabances) will not be fully known this far out. The constistancy is present with much colder air with temps very far S ranging from the 20's and 30's for highs and lows in the lower 20's and teens. The moisture and any STJ activity will show up later. All in all it looks very chilly and rather stormy for TX beginning around the 22nd through New Years Day.

[snow and ice]

Ho-Ho-Ho, the 0z Ensembles look mighty, mighty cold.
0z Ensembles Christmas Day:
http://www.meteo.psu.edu/~gadomski/ENSH ... /f192.html

[iorange55]

Quote from NWS offices this morning


Austin/San Antonio NWS

INCREASING CLOUDS
AND RAIN CHANCES BY MID WEEK AS GULF MOISTURE DEEPENS ACROSS SOUTH
TX AND A TROF APPROACHES FROM THE WEST. AN OUTBREAK OF VERY COLD
AIR STILL INDICATED BY LONG RANGE MODELS TOWARD LATE NEXT WEEK
AND INTO NEXT WEEKEND...WITH POSSIBLE MIX OF POST FRONTAL WINTER
PRECIPITATION BY THE WEEKEND...HOWEVER STILL MUCH UNCERTAINTY AND
FOR NOW HAVE JUST TRENDED TEMPERATURES DOWNWARD ON THE NEW DAY 7.

Oklahoma City NWS

THINGS BEGIN TO GET MORE COMPLICATED BY THE MIDDLE OF NEXT WEEK AS
THE MODELS BEGIN TO STRUGGLE WITH ALL THE ENERGY MOVING INTO THE
WEST. IT DOES APPEAR THAT TUE WILL SEE SOME WARMING AND IF THE ECMWF
IS CORRECT WARMER TEMPS CONT ON WEDNESDAY AHEAD OF STRONG CANADIAN
COLD FRONT. AT THIS POINT WILL GO WITH GFS... WHICH HAS SOME WAA
PRECIP DEVELOPING TUE AFTN IN THE FORM OF RAIN. THEN COLD FRONT
MOVES THROUGH TUE NIGHT... WHICH COULD ALLOW MORE OF A WINTRY MIX TO
DEVELOP...ESPECIALLY ACROSS THE NORTH. COLD AIR DEEPENS QUICKLY ON
WED... BUT ANY SIGNIFICANT PRECIP LOOKS TO BE ENDING AS UPPER WAVE
AND DEEPER MOISTURE WORK TO OUR EAST. WILL KEEP SOME LOW POPS FOR
WEDNESDAY... WITH MOST OF THE PRECIP... WHAT THERE IS OF IT...
TRANSITIONING TO SNOW.

DFW NWS

THERE REMAINS A LOT OF UNCERTAINTY CONCERNING THE FORECAST FROM MID
NEXT WEEK AND BEYOND. THE NEW EURO CAME IN A LITTLE COLDER THAN ITS
PREVIOUS RUNS...BUT IT IS NOT AS COLD AS THE LATEST SEVERAL GFS
RUNS. MODEL ENSEMBLE SOLUTIONS SEEM TO FAVOR SOME SORT OF
CONTINENTAL TROUGH DEVELOPING NEXT WEEK...BUT HOW LONG IT WILL
LAST AND HOW DEEP IT WILL BE REMAINS QUESTIONABLE. FOR NOW WILL
CONTINUE WITH OUR PREVIOUS THOUGHTS OF TEMPERATURES TURNING COLDER
WITH THE COLD FRONT EXPECTED WEDNESDAY AND REMAINING COLD THROUGH
INTO NEXT WEEKEND. THERE SHOULD BE SOME PRECIPITATION ACROSS THE
CWA TUESDAY THROUGH WEDNESDAY NIGHT...WITH SOME THUNDER DOWN SOUTH TUESDAY
NIGHT WHERE INSTABILITY IS BEST. AS COLD AIR ADVECTION INCREASES
ACROSS THE CWA WEDNESDAY NIGHT...LIFT FOR PRECIPITATION WILL
SHUTDOWN. WE WILL REVISIT AND REEVALUATE THIS AGAIN ON OUR NEXT
SHIFT. 75

So basically they have no idea what's going to happen, so they're being very cautious till the models start agreeing more.

[Portastorm]

Exactly iorange55! To show you how much volatility there is in the modeling right now, Lubbock's forecast discussion mentioned that the GFS ensembles have a high temp range for them next Wednesday between 37 and 64!! I would call that a rather significant spread.

Other than the likelihood of a major cold Polar dump of air by Christmas, everything else is up for debate.

[srainhoutx]

HPC thoughts this morning...

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
258 AM EST THU DEC 17 2009

VALID 12Z MON DEC 21 2009 - 12Z THU DEC 24 2009

A REX-BLOCK EXTENDING FROM GREENLAND TO ONTARIO/QUEBEC AND A LARGE
AMPLIFYING UPPER TROUGH OVER THE NORTHERN PACIFIC WILL SUPPORT AN
UNUSUALLY HIGH-AMPLITUDE SPLIT-FLOW REGIME OVER THE CONUS THROUGH
THE MEDIUM RANGE PERIOD. ONE SOURCE OF SHORTWAVE TROUGH
DEVELOPMENT WILL OCCUR WITHIN AND AROUND THE LOW SEGMENT OF THE
REX-BLOCK...WITH NORTHWESTERLY FLOW ALOFT LIKELY ALLOWING THESE
SYSTEMS TO PERPETUATE COLD AND SOMEWHAT UNSETTLED CONDITIONS
ACROSS THE DAKOTAS/GREAT LAKES/OHIO VALLEY/NORTHEAST.
MEANWHILE...AN UPPER LOW NEARING THE PACIFIC NORTHWEST DAY 3
SHOULD REMAIN CUT OFF FROM THE MAIN FLOW AS IT DRIFTS OVER THE
NORTHWEST BRINGING WET CONDITIONS TO THAT REGION DAYS 3-5 BEFORE
SHIFTING EASTWARD AHEAD OF THE APPROACHING PACIFIC UPPER TROUGH.
ALTHOUGH TIMING/PLACEMENT/INTENSITY DIFFERENCES ARE QUITE
LARGE...SEVERAL DETERMINISTIC SOLUTIONS ALONG WITH MANY GEFS
MEMBERS SHOW CYCLOGENESIS COMMENCING IN THE LEE OF THE SOUTHERN
ROCKIES DAYS 5/6...ESPECIALLY AS THE UPPER TROUGH NEARS THE GULF
COAST REGION BY DAY 7...WITH ALL MODELS HINTING TOWARD ANOTHER
SIGNIFICANT WINTER STORM DEVELOPING. GENERALLY PREFER THE DETAILS
OF THE ECMWF WITH THIS SYSTEM...ESPECIALLY EARLY IN THE PERIOD
ACROSS THE NORTHWEST WHERE THE GFS LIES NEAR THE FAST EDGE OF ALL
THE GUIDANCE. FINALLY...A CYCLONE NEAR THE MID-ATLANTIC/NORTHEAST
COAST AT THE START OF DAY 3 SHOULD ALREADY BE ACCELERATING
NORTHEASTWARD...BUT IS STILL EXPECTED TO POSE A SIGNIFICANT RISK
TO MARINERS. THE PRELIMINARY MEDIUM RANGE PRESSURES/FRONTS WILL
BEGIN WITH THE OPERATIONAL 00Z ECMWF DAYS 3-5 BEFORE SHIFTING TO A
50/50 BLEND OF THE OPERATIONAL ECMWF/ECMWF ENSEMBLE MEAN DAYS 6/7.
THE GEFS MEAN IS A REASONABLE SUBSTITUTE FOR THE ECMWF ENSEMBLE
MEAN LATE IN THE PERIOD...BUT APPEARS TOO QUICK WITH THE UPPER LOW
ACROSS THE NORTHWEST EARLIER IN THE PERIOD.

JAMES

[srainhoutx]

I'll repost the morning e-mail from Jeff in this Topic as it has some significance for folks further N of the SE TX Coastal Areas

Widespread light to moderate rainfall covers much of the area this morning.

While amounts will be on the low side, the coverage will be extensive through the morning hours as surface low pressure develops over the western Gulf and moves toward the central Gulf. Upper trough over Mexico will cross SC TX today with rainfall ending from west to east this afternoon. Back edge of rain currently is along a San Antonio to near Alice line and slowly moving eastward. Additional rainfall amounts of .25 to .50 an inch are likely through early afternoon. Skies should gradually clear tonight ahead of a cold front Friday. May see some ground fog early Friday with wet grounds and clear skies. Should see at least partly cloudy if not mostly sunny skies Friday-Sunday as the next surge of high pressure builds into the area. Will go with highs in the mid 60’s on Friday and then drop them into the mid –upper 50’s for the weekend with lows in the 30’s.

Early next week the active southern jet brings yet another storm system in our direction. Warm air advection regime will become established by early Monday. Potent upper trough moves into the SW US with surface low pressure forming over TX. This system looks to be fairly deep with the surface low possibly tracking north of our region instead of over the Gulf waters. Hence, it appears we will get warm sectored by Tuesday with a chance of strong to possibly severe thunderstorms along and ahead of the trough/cold front on Wednesday.

The cold front Wed. looks very cold according to the GFS as this system taps into very cold arctic air mass over NW Canada and the upper air pattern amplifies along the US western coast allowing a digging downstream central US trough. Given that this air mass looks true in arctic nature which suggests a shallow, dense air mass….I will go with the faster and colder solutions and that may even be too warm. Will show cold conditions Christmas Eve and beyond with the shallow air mass likely being overrun by the active southern branch jet. Will need to watch surface temperature forecast closely and low level profiles as the near surface could flirt with freezing frequently post 24 Dec. GFS brings another Gulf surface system into the picture on 26 Dec-27 Dec with a cold but what appears to be a shallow air mass cold air mass in place given sub-freezing 850mb line well south and further north colder thickness values. While the GFS is cranking out snow with this system…given the shallow nature of arctic air masses I am hard presses to buy into this solution and would opt more toward freezing rain…if in fact the advection of moisture northward into the cold air mass does occur. For now the period from the 24th-28th bears close watch

[gofrogs]

http://www.weather.com/outlook/recreati ... 0?dayNum=9

i geuess there on board.

[jasons2k]

In typical GFS fashion, lowest temp is now 29F at IAH on the 31st. The high temp for the 29th is now 71F. Looks like the new output is no different that the 'old days' of flip-flopping all over the place:

http://wxweb.meteostar.com/sample/sampl ... ?text=kiah.

[wxgirl69]

Am I understanding things correctly.. The cold air has been pushed back a few days. Instead of it coming down Monday with reinforcing shots following.. It will now come down Thursday with reinforcing cold shots following... And, I believe models are now coming into agreement that the air will shoot south instead of being pushed east.. at this time I do know any winter precip is still left to be answered... Just trying to get a grasp on where every thing stands...

Actually I really want it cold. .. Snow would be very nice.. I will just wait and see what mother nature has in store for us and keep reading everyones input.

[double D]

One thing I've noticed about the GFS is that it will show some historic winter event for us in Texas in the 8-10 day range only to show a more realistic solution in the 4-6 day solution. It always seems the GFS overdoes the moisture and cold in it's longer term outputs, which is good for some thoughtful discussion but also sets the stage for a lot of dissapointment when the cold/snow doesn't pan out.

Now I'm not saying that it wont be cold next week, but to some of our newbies out there be careful pinning all of your hopes on the long range GFS.

[srainhoutx]

One thing I've noticed about the GFS is that it will show some historic winter event for us in Texas in the 8-10 day range only to show a more realistic solution in the 4-6 day solution. It always seems the GFS overdoes the moisture and cold in it's longer term outputs, which is good for some thoughtful discussion but also sets the stage for a lot of dissapointment when the cold/snow doesn't pan out.

Now I'm not saying that it wont be cold next week, but to some of our newbies out there be careful pinning all of your hopes on the long range GFS.

Very good point. What concerns me is the fact that the Airmass may be shallow enough, setting up for freezing rain/sleet events. This would lead to a very dangerous situation for many folks. Ice on trees and powerlines are not a good thing. The images are fun to watch via guidance, but the actual outcome maybe far different than the guidance suggests. I do think there will be cold air involved though. The "bears watching" is warranted IMHO.

[severe]

Exactly what I was afraid would happen, srain. I read a few of wxman57's post yesterday hinting that these shots of cold air could be shallow in nature. Now this morning I read Jeff's email and he's hinting that this cold air may be shallow. Freezing rain is very nasty and something I'd rather not have around here.
Maybe just maybe the cold air will be deep enough to support sleet, which would be a lot better for power lines, trees, and whatever else that could get weighed down by freezing rain.

[Nederlander]

Due to all the talk I am planning a little trip to Alto on the 25th and 26th to ride four wheelers. My hope is that even if there is no snow here in extreme southeast texas, then maybe in Alto? Its between Lufkin and Tyler in East Texas. Ive always wanted to ride fourwheelers in snow but never had the oppurtunity obviously. Any chances on this verifying? Although the models have been consistent in the arctic front, it seems like the precip is tough to get a handle on..

[msstateguy83]

the gfs does go back and fourth alot and do as discribed HOWEVER
i think this is the real deal folks, i dont see the air moderating and i
would say cold compared to 83 and or 89 type weather for sure between
christmas and new years... the only ? there is moisture and how much snow
and or ice there will be... 12z coming out post thoughts on it shortly...

edit: even this far out when you would see that 'perfect' storm brewing
it would flip flop ALOT, the only flip flopping i have seen in the past say
36 hrs or so in runs on gfs was the overnight ones which we will see what
the 12z,18z put out today.. but bottom line yes we are still awaise out but
i think this has MUCH more promise then any setup we have seen remotely
this season for ok/tx.. one things for sure i would put highs in the 20s as
far south as central tx for christmas day now.. might see a light winter mix
in a broad region but i think the 'major storm' will be a day or so after christmas..
of course this could all change at anytime, just saying with my 2 cents i think this
is something not just the models pulling our leg.

[severe]

Just hope that major storm isn't a major freezing rain storm.
Snow, that would be great, but I'm reading these arctic air masses will be shallow in nature, at least for us here in southeast Texas.
Let's make them deeper and all will be fine.

[iorange55]

GFS 12 still plunging the cold air south just in time for Christmas, doesn't show a lot of moisture, but it's a long ways out. I'm still a little weary about even the outer details of this it seems like with these strong pushes of cold air the GFS always does it's typical things with them as it is now, and handles it very poorly till 3 or 4 days out. So all I'm confident with saying is more than likely it'll be a really chilly Christmas.