November Weather Discussion. Rollercoaster Pattern.

[Paul]

Nice down pour here in Pearland....gusty winds also....since this am I got about .50 inches so far.....

did someone mention pattern change? is TS season over? I missed it...

[TexasMetBlake]

Regarding the first potential arctic front of the year...

Norman, OK:

MODELS INDICATE A VERY COLD AIR MASS BUILDING IN
THE FAVORABLE FETCH REGION OF ALASKA AND WESTERN CANADA. THERE IS NO
INDICATION THAT THE COLD AIR WILL BREAK LOOSE IN A RAPID
FASHION...BUT INCREASINGLY COOLER AIR MAY SLIP INTO THE SOUTHERN
PLAINS BEHIND THE INITIAL FRONT ON WEDNESDAY.

[srainhoutx]

SPC:

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1110 AM CST THU NOV 11 2010

VALID 121200Z - 131200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
POSITIVE-TILT MID-LEVEL IMPULSE OVER THE SRN ROCKIES WILL SWING EWD
ACROSS THE SRN PLAINS ON FRIDAY...THEN BECOME ABSORBED INTO THE NRN
STREAM UPPER LOW OVER THE UPPER MS VALLEY BY FRIDAY NIGHT.
CONTINENTAL POLAR AIR MASS BUILDING OVER THE HIGH PLAINS TODAY WILL
SLOWLY MOVE SEWD INTO THE MID-MS VALLEY AND THE GREAT PLAINS BEHIND
A WEAK SFC LOW MIGRATING NEWD ALONG THE FRONT ON DAY 2. PORTIONS OF
THIS FRONT WILL BE THE FOCUS FOR CONVECTION FRIDAY AND FRIDAY NIGHT.


...SRN PLAINS...
TONGUE OF PRECIPITABLE WATERS AVERAGING 1 TO 1.25 INCHES GATHERING
IN E TX WILL SURGE NWD TODAY AHEAD OF THE PREVIOUSLY MENTIONED
MID-LEVEL WAVE. POSITIVE-TILT NATURE TO THE IMPULSE WILL ONLY
RESULT IN A MODEST INCREASE IN MID-LEVEL LAPSE RATES AND FRIDAY
AFTERNOON THERMAL BUOYANCY WILL BE LIMITED. HOWEVER...INCREASING
LARGE SCALE ASCENT AND IMPROVING DEEP-LAYER SHEAR PROFILES WILL
RESULT IN A MARGINALLY-SUPPORTIVE SEVERE THUNDERSTORM ENVIRONMENT
AMIDST MLCAPES 200-500 J/KG. THIS WILL ESPECIALLY BE THE CASE IF
SURFACE-BASED THUNDERSTORMS CAN FORM WITHIN THE WARM SECTOR FROM
NCNTRL TX INTO CNTRL/ERN OK FRIDAY AFTERNOON/EVENING BEFORE BECOMING
UNDERCUT BY THE SURGING COLD FRONT.

PRIMARY THREATS WILL BE GUSTY WINDS/HAIL APPROACHING SEVERE
CRITERIA. WIDESPREAD SEVERE THUNDERSTORMS ARE NOT LIKELY AND THE
SEVERE THREAT SHOULD DIMINISH RAPIDLY DURING THE EVENING.

[helloitsb]

If cold air isn't immediately overridden by low level warm moist air to produce at least freezing drizzle, better yet a nice disturbance over that with mixed snow and sleet with thunder, like T-Day 1993 in Bedford, or, failing that, a potent upper disturbance with enough dynamic cooling to support snow, it is uncomfortable, causes painful static shocks, dry skin, and threatens my citrus.

Just say no to dry Arctic outbreaks!

Is there any chance that the stated will happen?

[Andrew]

If cold air isn't immediately overridden by low level warm moist air to produce at least freezing drizzle, better yet a nice disturbance over that with mixed snow and sleet with thunder, like T-Day 1993 in Bedford, or, failing that, a potent upper disturbance with enough dynamic cooling to support snow, it is uncomfortable, causes painful static shocks, dry skin, and threatens my citrus.

Just say no to dry Arctic outbreaks!

Is there any chance that the stated will happen?

Doubtful... In a regular year it is hard enough to get snow in November or even at all for Houston. Along with that we are in a La Nina pattern which supports a milder winter. While we will see a couple of big blasts of cold air this year, it is hard this early in the year to get that type of set up down here. First off you have to get the cold air down here. Then you need a semi-deep layer of it if you want snow otherwise you will get sleet/freezing rain. Then after that you actually have to have moisture around after the front goes through. So as you can see it can be pretty hard to get snow down here but I would of never guessed we would of gotten snow as early as we did last year. Many of the models do show a giant ridge building over the central U.S., but with it being so far out it is really questionable to how strong it will be. This will continue until late next week. I am just as hopeful as anyone else that we get another miracle this year especially this early but as of now it looks doubtful. The promising thing is that the more fronts that we get, the more snow there will be to the north allowing for the colder air to come down stronger each time. It will take time for this process but I have a feeling that in January we may get lucky.


Once we get closer to Thanksgiving if it looks like we will see freezing temps here with some moisture look at some of the upper level plots to see if it supports snow. I am sure Wxman along with some others will post those if needed.

[helloitsb]

If cold air isn't immediately overridden by low level warm moist air to produce at least freezing drizzle, better yet a nice disturbance over that with mixed snow and sleet with thunder, like T-Day 1993 in Bedford, or, failing that, a potent upper disturbance with enough dynamic cooling to support snow, it is uncomfortable, causes painful static shocks, dry skin, and threatens my citrus.

Just say no to dry Arctic outbreaks!

Is there any chance that the stated will happen?

Doubtful... In a regular year it is hard enough to get snow in November or even at all for Houston. Along with that we are in a La Nina pattern which supports a milder winter. While we will see a couple of big blasts of cold air this year, it is hard this early in the year to get that type of set up down here. First off you have to get the cold air down here. Then you need a semi-deep layer of it if you want snow otherwise you will get sleet/freezing rain. Then after that you actually have to have moisture around after the front goes through. So as you can see it can be pretty hard to get snow down here but I would of never guessed we would of gotten snow as early as we did last year. Many of the models do show a giant ridge building over the central U.S., but with it being so far out it is really questionable to how strong it will be. This will continue until late next week. I am just as hopeful as anyone else that we get another miracle this year especially this early but as of now it looks doubtful. The promising thing is that the more fronts that we get, the more snow there will be to the north allowing for the colder air to come down stronger each time. It will take time for this process but I have a feeling that in January we may get lucky.


Once we get closer to Thanksgiving if it looks like we will see freezing temps here with some moisture look at some of the upper level plots to see if it supports snow. I am sure Wxman along with some others will post those if needed.

Thanks that was a great explanation. Thanks!

[TexasMetBlake]

You know, there is no such thing as conformity in weather. Last year was a El Nino year that didn't act like one. There have been La Nina winters when snow and ice have happend here. There have been El Nino years that produced nothing. I think the fact that a 1060 mb high is being depicted by the Euro and mid 1050s by Canadian and GFS is promising....although it certainly is no precurser to the rest of the winter. From what I have seen today, the NAO is turning neg. again. Let's hope it continues!

[srainhoutx]

Keep an eye on the NW Pacific Ocean and the ITCZ...

[Ptarmigan]

Here is what Thanksgiving Day forecast, 2 weeks away.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _324.shtml

[srainhoutx]

It's snowing in Amarillo this morning...



Dumas, TX


DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0629 AM CST FRI NOV 12 2010

VALID 121300Z - 131200Z

...NO SVR TSTM AREAS FORECAST...

...SRN PLAINS...

MIDLEVEL VORTICITY MAXIMUM AND ASSOCIATED 50-70 KT JET STREAK OVER
THE SRN HIGH PLAINS THIS MORNING WILL TRANSLATE NEWD INTO THE
MIDWEST BY THE END OF THE DAY ONE PERIOD RESULTING IN A CORRIDOR OF
50-100 M/12-HR HEIGHT FALLS SPREADING THROUGH OK/KS INTO THE
MID/LOWER MO VALLEY. HOWEVER...BASED ON CURRENT RADAR AND SURFACE
OBSERVATIONAL DATA...THESE HEIGHT FALLS/STRONGER DYNAMIC FORCING FOR
ASCENT WILL REMAIN ON COOL SIDE OF SURFACE BAROCLINIC ZONE....
EXTENDING FROM E-CNTRL KS SEWD THROUGH N-CNTRL OK INTO WRN TX AS OF
12Z. SURFACE LOW CURRENTLY CONSOLIDATING NE OF MAF IS FORECAST TO
RAPIDLY DEVELOP NEWD ALONG THE SURFACE FRONT THROUGH CNTRL OK INTO
W-CNTRL MO BY EVENING BEFORE UNDERGOING OCCLUSION OVER NRN MO INTO
IA TONIGHT. AS THIS OCCURS...TRAILING COLD FRONT WILL ACCELERATE
SEWD THROUGH THE REMAINDER OF THE SRN PLAINS BY SATURDAY MORNING.

A 40+ KT SSWLY LLJ OBSERVED FROM CNTRL TX INTO THE LOWER MO VALLEY
WILL BE MAINTAINED THROUGH THE DAY IN ADVANCE OF EJECTING MIDLEVEL
TROUGH. THIS WILL SUPPORT THE NWD FLUX OF A PARTIALLY MODIFIED AIR
MASS CHARACTERIZED BY DEW POINTS IN THE LOW/MID 60S AND PW VALUES OF
1.00-1.25 INCHES. HOWEVER... ANTECEDENT CLOUDS/PRECIPITATION AND
POOR LAPSE RATES WILL LIMIT DIURNAL STABILIZATION WITHIN PRE-FRONTAL
WARM SECTOR WITH MLCAPE VALUES REMAINING GENERALLY BELOW 1000 J/KG.

EXPECT TSTMS TO CONTINUE TODAY BEHIND/ALONG/AHEAD OF COLD FRONT AS
LARGE-SCALE FORCING FOR ASCENT IS ENHANCED AHEAD OF MIDLEVEL
VORTICITY MAXIMUM. CURRENT VWP/PROFILER OBSERVATIONS AND FORECAST
SOUNDINGS INDICATE VERTICALLY-VEERING WIND PROFILES AHEAD OF THE
FRONT WITH SUFFICIENT /35-45 KT/ EFFECTIVE BULK SHEAR TO SUPPORT
ORGANIZED STORM MODES. WHILE ISOLATED OCCURRENCES OF SEVERE WEATHER
WILL BE POSSIBLE INTO THIS EVENING...THE MARGINAL INSTABILITY AND
ANAFRONTAL AIRFLOW REGIME ASSOCIATED WITH THE COLD FRONT WILL TEND
TO LIMIT THE POTENTIAL FOR A MORE ORGANIZED THREAT.

..MEAD/GARNER.. 11/12/2010

[srainhoutx]

A lot of discussion from the HPC regarding the pattern change this morning. While Operational Guidance is struggling with the pattern of ridges in the Pacific and a deep trough in the Central CONUS, the Euro ensembles was the choice today...

[srainhoutx]

While most of the energy is to our N, radar does suggests some strong storms are building. We'll see how close they get to our area as the day wears on...

[Ptarmigan]

Looks to be a stormy night and rainy Sunday. NWS Houston says that Sunday could see heavy rain.

[srainhoutx]

Cold front is making progress this evening. I see the it's passed San Antonio, sweeping SE into Austin.

[Ptarmigan]

I wonder if any severe weather watches could be issued tonight.

[Mrs.Frosty]

Does the approaching line of showers have thunder and lightning in it or just rain ?

[srainhoutx]

Good morning. After a couple of days of model flip flopping, the Arctic Cold Front is back in the picture for Thanksgiving week.

[srainhoutx]

Some TX AFD's concerning the Thanksgiving Week Arctic Front...

San Angelo...

JUST BEYOND THE FORECAST
PACKAGE...MODELS ARE HINTING AT A MUCH STRONGER COLD FRONT MOVING
INTO THE REGION...AT THE BEGINNING OF THE WEEK OF THANKSGIVING.



Dallas/Ft Worth...

BOTH THE ECMWF AND THE GFS ARE INDICATING A POSSIBLE PATTERN
SHIFT DURING THE FIRST PART OF THE WEEK OF THANKSGIVING WITH A
HIGH AMPLITUDE RIDGE BUILDING OFF THE WEST COAST. THIS PATTERN IS
USUALLY ASSOCIATED WITH AN INTRUSION OF VERY COLD AIR ACROSS THE
PLAINS. OF COURSE...THIS IS A FEW DAYS BEYOND THIS FORECAST CYCLE...
BUT A PATTERN SUCH AS THIS USUALLY BRINGS A WIDE SPREAD FREEZE TO
THE REGION. THEREFORE...WILL BE KEEPING A CLOSE EYE ON THE LARGE
SCALE PATTERN IN THE COMING DAYS.

[srainhoutx]

The 12Z GFS continues the trend of the overnight 00Z run. While there are some minor differences on how that model wants to handle all the 'cold air', it is becoming a bit clear that an early season Arctic High Pressure will spill S into the Plains bringing some chilly temps and even possible cold rain chances to TX for Thanksgiving. Areas to our N may even see some precip of the frozen variety.

[srainhoutx]

Interesting snip from Brownville this afternoon. Ah, the good ole days of great disco's out of KBRO...

AN ARCTIC AIR MASS INITIALLY OVER THE BERING SEA BUT CENTERED OVER
ALASKA ON TUESDAY WILL UNLEASH ITS FURY BY MID WEEK. HIGH PRESSURE
WILL RUSH SOUTH THROUGH CANADA AND THE DESOLATE PLAINS WHERE THERE
IS LITTLE MORE THAN BARBED WIRE FENCES TO IMPEDE ITS STAMPEDE. A
1030 MB HIGH WILL BE OVER NORTH TEXAS WEDNESDAY NIGHT WITH A FRONT
KNOCKING ON DEEP SOUTH TEXAS` DOOR EARLY THURSDAY MORNING. HIGH
PRESSURE AND BREEZY NORTH WINDS WILL SPREAD OVER THE CWA THURSDAY
AND FRIDAY...BUT LITTLE RAIN IS EXPECTED WITH THE DRY AIR. TEMPS
WILL DROP SEVERAL DEGREES TO NEAR OR SLIGHTLY BELOW NORMAL IN THIS
EARLY TASTE OF NORTHERN AIR.