November Weather Discussion. Rollercoaster Pattern.

[wxman57]

Canadian looks way off - holds front back until Friday. Not likely with dense, cold air.

[srainhoutx]

Canadian looks way off - holds front back until Friday. Not likely with dense, cold air.

Yep, and keeps shifting the storm further W as well in the Great Lakes Region.

[ticka1]

Just a side note - there are going to be alot of cold folks out at the stores on Black Friday at 3:00 to 5:00 a.m. when they open. I will be snuggled in my warm bed sleeping all warm and comfy! Brrr for the forecast but it will at least feel like Thanksgiving this year!

[sambucol]

Just a side note - there are going to be alot of cold folks out at the stores on Black Friday at 3:00 to 5:00 a.m. when they open. I will be snuggled in my warm bed sleeping all warm and comfy! Brrr for the forecast but it will at least feel like Thanksgiving this year!

Me, too. My shopping will be online from the comfort of my home in front of the fire.

[Andrew]

Good sat. to look at with this event:

http://aviationweather.gov/adds/satelli ... g&itype=ir

[srainhoutx]

The 12Z Euro is still a bit slower than the GFS regarding the Arctic front. It appears to be 6-12 hours slower as that model keeps energy back across the Great Basin similar to what the Canadian was showing. Also of note is the repeat via the 00Z run of a strong shot of cold air and a big storm wrapping up in the Plains near the end of the month of November for the Euro...

[srainhoutx]

Afternoon HPC Final Update Discussion covers the slowing down of the front...

12Z DETERMINISTIC MODELS: THE GFS HAS EXCELLENT CONTINUITY OVER
THE CONUS DAYS 3-5 BUT BECOMES A FAST OUTLIER THEREAFTER WITH THE
NEXT TROF OFF THE PACIFIC COAST. IT MARKEDLY FLATTENS THE
DOWNSTREAM PATTERN OVER THE CONUS FROM CONTINUITY FOR NEXT
FRI/SAT. THESE CONTINUITY CHANGES APPEAR EXCESSIVE.
MEANWHILE THE UKMET/CANADIAN PLAY UP A SRN SPOKE OF ENERGY WELL
BEHIND THE MAIN THANKSGIVING GREAT LAKES LOW...WITH THE
CANADIAN/UKMET HAVING DECENT CONTINUITY FOR THIS SRN STREAM
FEATURE. BOTH THE UKMET AND ESPECIALLY THE CANADIAN ARE SLOWER TO
BRING THE MAIN RIDGE INTO THE ROCKIES EARLY NEXT WEEKEND. THE NEW
12Z ECMWF ...LIKE THE CANADIAN AND UKMET...IS PLAYING UP A STRONG
LOBE OF VORTICITY SWINGING THRU THE SWRN STATES ON THANKSGIVING
DAY. IF CORRECT...THE ECMWF SOLUTION OPENS THE DOOR FOR THE FRONT
TO RETARD ACROSS THE GULF COAST REGION THU/FRI...ACCOMPANIED BY A
BAND OF OVERRUNNING PCPN N OF THE FRONT.

ONE MAIN WEATHER FEATURE DURING THE MEDIUM RANGE PERIOD WILL BE
THE AMPLIFIED TROF/SURFACE SYS CROSSING THE NE CORNER OF THE
CONUS DURING DAY 5...THANKSGIVING. THIS PARTICULAR SYSTEM WILL
BRING DECENT COOLING WELL DOWN INTO THE GULF STATES IN ITS WAKE. N
OF THE MAIN SURFACE LOW TRACK...A GOOD SWATH OF SYNOPTIC SNOWFALL
WED WILL BE FOLLOWED BY LAKE EFFECT SNOW AND BLUSTERY WINDS THU
INTO MUCH OF FRI. UPPER RIDGING IS THEN EXPECTED NEXT WEEKEND OVER
THE ROCKIES AND PLAINS AHEAD OF THE NEXT LARGE SCALE PACIFIC TROF.
A COMPLICATION IN THE FORECAST IS THAT BEHIND THE ABOVE MENTIONED
SYS... THE NEW UKMET/CANADIAN/ECMWF LEAVE ENOUGH ENERGY BEHIND
OVER THE SRN PLAINS FRI DAY 6 TO SUPPORT A FLAT WAVE WITH
OVERRUNNING PCPN ALONG THE W GULF COAST. WHILE EARLIER DOWNPLAYING
THIS WAVE DEVELOPMENT....IT APPEARS MORE LIKELY....NOW THAT THE
12Z/20 ECMWF HAS A WAVY SCENARIO ACROSS THE GULF STATES FRI-SAT. I
WOULD OFFER MODERATE CONFIDENCE THAT SOME KIND OF WAVE WITH
OVERRUNNING PCPN WILL OCCUR BETWEEN THU AND SAT ALONG THE GULF
COAST.



Also of note were the signals of waning -NAO (heading toward a +NAO) and that signal has collasped with the 12Z Euro...

11202010 12Z Euro NAO 12zecmwfnao.gif

[srainhoutx]

The afternoon discussions are a bit late due to the 12Z model output and coordination between various WFO's regarding how they want to handle the differences...

Houston/Galveston...

THE GREATEST FORECAST CHALLENGE REMAINS IN THE TIMING OF A COLD
FRONT WHICH WILL PASS THROUGH OUR REGION LATE IN THE WEEK. THE GFS HAS
BEEN CONSISTENT IN BRINGING THIS FRONT THROUGH THE REGION LATE
WEDNESDAY AND OFF THE COAST EARLY THURSDAY. THE ECMWF...WHICH HAD BEEN
TRENDING SLIGHTLY SLOWER...IS NOW A FULL 24 HRS LATER WITH THE
FRONTAL PASSAGE IN THE LATEST MODEL RUNS. FOR NOW...WILL TREND THE
FORECAST TOWARDS THE MORE CONSISTENT GFS TIMING...ALTHOUGH THIS
MAY CHANGE OVER THE NEXT FEW DAYS DEPENDING UPON RUN TO RUN
CONSISTENCY AND ALSO THE INPUT OF SHORTER RANGE FORECAST MODELS.

REGARDLESS OF WHICH SOLUTION IS CORRECT...MUCH COOLER AND WETTER
CONDITIONS ARE EXPECTED BY LATE IN THE WEEK FOR ALL OF SOUTHEAST
TEXAS.

Dallas/Ft Worth...

STRONG MIDWEEK COLD FRONT REMAINS THE PRIMARY FORECAST CHALLENGE.
ARCTIC AIR IS POOLING IN WESTERN CANADA AS A BROAD LONGWAVE TROUGH
DEVELOPS ACROSS THE ROCKIES. THE ARCTIC AIR WILL REMAIN BOTTLED UP
ACROSS THE NW CONUS UNTIL A STRONG VORT LOBE SWINGS INTO THE
NORTHERN PLAINS ON WEDNESDAY. ONCE THIS OCCURS THE COLD AIR WILL
SURGE DOWN THE PLAINS INTO THE REGION. MODELS WERE IN A LITTLE
BETTER AGREEMENT ON THE EVOLUTION/TIMING OF THE PRIMARY 500 MB
FEATURES YESTERDAY...AND NOW SOME DIFFERENCES ARE APPEARING. THE
GFS IS THE FAST OUTLIER WITH THE EJECTION OF THE NORTHERN PLAINS
TROUGH AND THUS HAS THE FRONT INTO NORTH TEXAS AROUND NOON
WEDNESDAY...BUT THIS IS 12-24 HOURS FASTER THAN THE OTHER MODELS.
ALTHOUGH I BELIEVE THE 500 MB HEIGHT FORECAST FROM THE GFS IS IN
ERROR...ARCTIC AIR HAS A TENDENCY TO ARRIVE EARLY...SO AM STILL
LEANING TOWARD THE FASTER TIMING OF THE FRONT. HAVE RAISED HIGHS
WEDNESDAY INTO THE 70S SINCE THERE IS REASONABLE CONFIDENCE THE
FRONT WILL NOT ARRIVE UNTIL AFTER PEAK HEATING. BUT DUE TO LOW
CONFIDENCE WILL STAY CLOSE TO MEX MOS FOR WED NIGHT LOWS...BUT IF
THE GEM/ECMWF/NOGAPS ARE INDEED CORRECT WITH THE SLOWER FRONTAL
TIMING...THESE VALUES MAY BE TOO COOL. EITHER WAY...FRONT SHOULD
BE THROUGH BY THANKSGIVING DAY...AND TEMPS LOOK LIKE THEY WILL
STAY IN THE 40S WITH COLD ADVECTION CONTINUING THROUGH THE DAY.

THERE WERE HINTS IN THE MODELS YESTERDAY THAT THE MAIN UPPER
TROUGH AXIS WOULD HANG BACK AND NOT CLEAR THE AREA UNTIL THURSDAY
EVENING. ALL OF THE GUIDANCE CONTINUES TO SEEMINGLY TREND IN THIS
DIRECTION TODAY...WITH THE UPPER TROUGH AXIS LOOKING SHARPER AND
MORE POTENT. SOME OF THE GEM AND GFS MODEL ENSEMBLES ACTUALLY
CLOSE OFF A LOW AT THE BASE OF THE TROUGH OVER THE DESERT SW. THE
INTENSIFICATION OF THE TROUGH AXIS APPEARS TO BE RELATED TO A
TROPOPAUSE FOLDING EVENT AS A STRONG RIDGE OVER THE WESTERN
PACIFIC PUSHES ONSHORE. STRATOSPHERIC AIR IS HIGH IN POTENTIAL
VORTICITY...AND DETERMINING JUST HOW MUCH OF THIS AIR DESCENDS IS
IMPOSSIBLE AT THIS POINT. HOWEVER THE POSSIBILITY EXISTS THAT THE
LAGGING DISTURBANCE WILL INDUCE ENOUGH OF A DYNAMIC RESPONSE TO
RESULT IN ISENTROPIC LIFT OVER THE AREA THURSDAY. THE LOW LEVEL
AIR MASS WILL BE FAIRLY DRY...BUT SATURATION ALOFT AND SOME
ELEVATED INSTABILITY ARE INDICATED IN THE VARIOUS SOLUTIONS. WILL
SHOW A LOW CHANCE OF A VERY COLD RAIN THURSDAY OVER THE CENTRAL
AND SOUTHEAST HALF OF THE AREA.


Norman, OK...


UPPER TROUGH LIFTS OUT FROM THE INTERMOUNTAIN W INTO THE N PLAINS
SUN-MON... JUST ENOUGH TO NUDGE THE SFC FRONT S FROM KS INTO AT
LEAST N OK MON NIGHT INTO TUE. WE HAVE DRAWN A FAIRLY SIGNIFICANT
N-TO-S GRADIENT IN THE HIGHS TUESDAY... AS FAR N OK MAY STRUGGLE
TO REACH THE 50S WHILE THE S CWA WARMS INTO THE 70S. THIS IS A
CONTINENTAL/CANADIAN AIR MASS N OF THE FRONT... AND SO THE USUAL
CONCERNS WILL APPLY IN TERMS OF HOW FAR S THE COLD AIR WILL GET
AND HOW LONG IT WILL LINGER. IN GENERAL COLDER IS USUALLY BETTER
IN THESE CASES... AND SOMETIMES NONE OF THE MODELS GIVE THE COLD
AIR ENOUGH RESPECT. WHICH LEADS US INTO WEDNESDAY - THE TOUGHEST
PART OF THE FORECAST.

IT IS CERTAIN THAT THE AREA WILL BE PLUNGED INTO THE GRIPS OF THE
COLDEST AIR SO FAR THIS SEASON BY WED NIGHT AND THANKSGIVING DAY...
BUT THE MODELS ARE AT ODDS ON HOW FAST IT WILL GET HERE. AGAIN...
THE MORE AGGRESSIVE AND FASTER SOLUTIONS USUALLY WORK OUT BETTER IN
THESE CASES... BUT NONE OF THE MED-RANGE MODELS OR ENSEMBLES HAVE
EXACTLY BEEN POSTER CHILDREN FOR CONSISTENCY LATELY. OPERATIONAL GFS
REMAINS ON THE MORE AGGRESSIVE END OF THE SPECTRUM... BRINGING IN
THE COLD AIR HARD AND FAST WEDNESDAY MORNING... BUT ENSEMBLE MEMBERS
REPRESENT THE ENTIRE SPECTRUM OF SOLUTIONS. THESE INCLUDE THE MUCH
WARMER ECMWF. WE ARE VERY LEARY OF THE ECMWF IN THIS SITUATION...
ONE OF THE FEW SCENARIOS WHERE TRUST ISSUES ARISE WITH THE ECMWF.
THAT AND THE HIGHLY-VARIABLE AND INCONSISTENT SOLUTIONS THE ECMWF
HAS OFFERED IN GENERAL OVER THE PAST 3-4 DAYS LEADS US TO LEAN MORE
TOWARD THE GFS AND A NASTIER DAY WEDNESDAY IN TERMS OF WIND AND
COLD. WE WOULD LIKELY GO EVEN COLDER THAN OUR CURRENT MAX-T GRIDS
WEDNESDAY... BUT FOR THE REASONING OFFERED BY NEIGHBORING OFFICES IN
FAVOR OF THE WARMER ECMWF. IN ANY EVENT... COLD AIR WILL COME IN ON
STRONG WINDS BY WED NIGHT AND TEMPERATURES WILL REACH THEIR LOWEST
LEVELS SO FAR BY THANKSGIVING MORNING IN MOST AREAS. WIND CHILLS LIKELY
TO BE IN THE SINGLE DIGITS AND TEENS OVER MOST OF THE AREA...
POSSIBLY NEAR ZERO IN NW OK.



San Angelo...

UPPER LEVEL WEST-SOUTHWEST FLOW WILL BRING DRY WEATHER AND ABOVE
NORMAL TEMPERATURES EARLY NEXT WEEK. HIGHS WILL BE IN THE 70S...WITH
LOWS IN THE 40S AND 50S. LOOKS LIKE A MAJOR CHANGE IS IN STORE
MIDDLE TO LATE NEXT WEEK AS FIRST ARCTIC AIRMASS OF THE SEASON
ARRIVES. CURRENT NORTHERN HEMISPHERE SURFACE MAP INDICATES AN
ARCTIC AIRMASS MOVING SOUTH ACROSS THE NORTHWEST TERR WITH
TEMPERATURES OF -15 TO -25. THIS VERY COLD AIR WILL MOVE SOUTH
INTO THE NORTHERN ROCKIES AND NORTHERN PLAINS EARLY THIS
WEEK...AND THEN BLAST SOUTH ACROSS THE PLAINS TUESDAY AND
WEDNESDAY WITH THE HELP OF A STRONG UPPER SHORT WAVE TROF MOVING
ACROSS THE NORTH CENTRAL US. THE ARCTIC FRONT WILL ARRIVE IN THE
TEXAS PANHANDLE WEDNESDAY MORNING...AND BE LOCATED JUST NORTH OF
BROWNSVILLE BY THURSDAY MORNING. EXPECT GUSTY NORTH WINDS BEHIND
THE FRONT WEDNESDAY NIGHT AND THURSDAY. NO DOUBT THIS AIRMASS WILL
BE MODIFIED SOME...HOWEVER MUCH COLDER TEMPERATURES ARE
EXPECTED...WITH HIGHS THANKSGIVING DAY IN THE 40S...POSSIBLY EVEN
COLDER. THE COLDEST NIGHT WILL BE THURSDAY...WITH LOWS FRIDAY
MORNING IN THE UPPER TEENS TO LOWER 20S. GOING WITH A LOW OF 20 AT
SAN ANGELO ON FRIDAY MORNING(11/26). THE KSJT RECORD LOW FOR THIS
DATE IS 19 SET IN 1993. TEMPERATURES WILL REMAIN BELOW NORMAL
FRIDAY AND SATURDAY...BUT SLOWLY MODIFY. ALSO...WILL REMAIN DRY
FOR THE NEXT 7 DAYS.



Austin/San Antonio...

THE GFS SHOWS A COLD FRONT ENTERING THE CWA AROUND 0Z ON THURSDAY
WHILE THE ECMWF BRINGS IT THROUGH AROUND 18Z ON THURSDAY. STAYED
CLOSER TO THE GFS WITH A FROPA BETWEEN 0Z AND 6Z ON THURSDAY AS
BOTH MODELS ARE STARTING TO CONVERGE ON TIMING.

OVERRUNNING BEHIND THE FRONT WILL CAUSE CLOUDY SKIES AND LIGHT RAIN
FOR THURSDAY BEFORE A SHORTWAVE TROUGH MOVES THROUGH TO BRING CLEARER
SKIES. THE TROUGH WILL PROVIDE A REINFORCING SHOT OF COLD AIR
INTO THE AREA HELPING OVERNIGHT LOW TEMPERATURES DROP TO NEAR
FREEZING ALONG THE ESCARPMENT AND BELOW FREEZING IN THE HILL
COUNTRY FOR FRIDAY MORNING. TOWARDS THE WEEKEND...WEAK RIDGING
WILL ALLOW TEMPERATURES TO REBOUND SLIGHTLY AS RETURN FLOW SETS UP.



Lubbock...

AS FOR THE SURGE OF COLD AIR MIDWEEK...GFS REMAINS CONSISTENT
WHILE ECMWF HAS BACKED OFF ABOUT 12 HOURS. HOWEVER...HISTORY
SUGGESTS A MORE AGGRESSIVE TIMING ESPECIALLY CONSIDERING LACK OF
STRONG CLOSED LOW TO THE WEST WHOSE LOW LEVEL WARM ADVECTION MIGHT
COUNTERACT COLD AIR. IN THIS CASE THERE DOES NOT APPEAR MUCH TO
KEEP THE DENSITY CURRENT FROM RACING SWD AND WILL MAINTAIN TIMING
FROM PREVIOUS FCST. COOL SFC HIGH TO SETTLE OVER THE AREA LATE
WEDNESDAY NIGHT AND THURSDAY WITH EASILY THE COLDEST TEMPS OF THE
SEASON.

[srainhoutx]

Big picture tonight. Our Upper Air feature in dropping out of the NW Territories tonight that will bring the front through. The first in a series of storms or waves as the HPC mentions is along the W Coast tonight producing feet of snow in the Sierras...

[sleetstorm]

How warm are the tempreatures going to be in the mid/upper layers of the troposhere during next Thursday?

[wxman57]

How warm are the tempreatures going to be in the mid/upper layers of the troposhere during next Thursday?

Mid 60s at 850mb (5000 ft up) and freezing level at 600mb (12-14,000 ft up). Precip is long gone before the temps aloft cool significantly. You can forget any chance of anything but rain.

[Mr. T]

Should see the first freeze of the season for many saturday morning...

[Mr. T]

A headliner for an uncertain forecast... That's new

NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
407 AM CST SUN NOV 21 2010

...UNCERTAIN FORECAST FOR THANKSGIVING HOLIDAY...

.DISCUSSION...
YESTERDAY MORNING IT WAS NOTED THAT THE ECMWF AND CANADIAN MODELS
WERE SLOWER WITH MOVING AN UPPER LEVEL LOW ACROSS THE N PLAINS MID
WEEK WHICH CAUSED THEM TO HAVE A LATER COLD FRONTAL PASSAGE FOR
SE TX. THE GFS HAS COME MORE IN SYNC WITH THE ECMWF/CANADIAN
SOLUTIONS SO THERE WERE MAJOR CHANGES TO THE FORECAST FOR THE
THANKSGIVING HOLIDAY. MORE ON THIS LATER...

INCREASING GULF MOISTURE WILL CONTINUE TO SUPPORT LOW CLOUDS AND
PATCHY FOG ACROSS SE TX THIS MORNING. THIS HAS LED TO MILD
MORNING LOW TEMPS IN THE 60S. CLOUDS SHOULD SCATTER OUT ENOUGH
FOR DAY TIME HEATING TO INCREASE TEMPS INTO THE UPPER 70S TO NEAR
80 FOR MAX TEMPS. THESE CONDITIONS ARE LIKELY TO CONTINUE THROUGH
THE MIDDLE OF THE WEEK.

UPPER LEVEL PATTERN HAS BECOME A BIT MORE AMPLIFIED WITH UPPER AIR
ANALYSIS SHOWING A DEEPENING LOW OVER N CALIFORNIA THIS MORNING.
THIS LOW SHOULD MOVE OUT INTO THE PLAINS MONDAY WITH ANOTHER DEEP
LOW MOVING SOUTH INTO THE INTER-MOUNTAIN WEST BY MON NIGHT. THIS
WILL KEEP A MEAN LONG WAVE TROUGH IN PLACE OVER THE WESTERN HALF
OF THE U.S. THROUGH WED. WED THROUGH THUR THIS SECOND UPPER LOW
WILL MOVE ACROSS THE N PLAINS WHICH WILL SUPPORT A SIGNIFICANT
COLD FRONT WITH A DRY/COLD CANADIAN AIRMASS BEHIND IT. IT IS THIS
FRONT THAT HAS BEEN TROUBLESOME TO FORECAST DUE TO THE LACK OF
UPPER LEVEL SUPPORT. LATEST GFS/ECMWF SEEM TO SHOW A MORE
FAVORABLE PATTERN FOR A COLD FRONT PUSH LATE THUR INTO FRI AS THE
TROUGH AXIS PUSH ACROSS THE PLAINS. THIS MEANS THE FRONT SHOULD
ENTER SE TX THU AFTERNOON QUITE POSSIBLY WITH A LINE OF
SHOWERS/THUNDERSTORMS ALONG IT. INSTABILITY APPEARS TO BE LIMITED
AT THIS TIME AND NOT SUPPORT AN ORGANIZED SEVERE THREAT. WHILE I
HAVE LITTLE CONFIDENCE IN WHEN THE FRONT WILL ACTUALLY PUSH
THROUGH SE TX...I AM CONFIDENT THAT SHOWERS/THUNDERSTORMS WILL
ACCOMPANY THE FRONT SO I INCREASED POPS BASED ON THE CONSENSUS OF
GFS/ECMWF FRONTAL TIMING. POPS WERE BUMPED UP TO 50 PERCENT AND
WILL NOT GO HIGHER UNTIL FRONTAL TIMING IS NAILED DOWN WITH LATER
MODEL RUNS. THE COLD FRONT WILL BE STRONG ENOUGH SO THAT TEMPS
WILL DROP BEHIND THE FRONT DURING THE AFTERNOON TIME FRAME AND
OVERNIGHT. COLDER AIRMASS SHOULD BE IN PLACE ON FRI WITH MAYBE
SOME LINGERING POCKETS OF RAIN. CLEARING SHOULD OCCUR DURING THE
DAY FRI WITH MOST OF SE TX HAVING MIN TEMPS IN THE 30S FOR SAT
MORNING. SFC RIDGE WILL BE IN CONTROL FOR MUCH OF NEXT WEEKEND AND
ALLOW FOR A DRY FORECAST.

IN SUMMARY...THE FORECAST IS ONE OF EXTREMES WITH ABOVE NORMAL
TEMPS TO START AND BELOW NORMAL TEMPS IN THE EXTENDED RANGE.
FRONTAL TIMING WILL CONTINUE TO BE A FORECAST CHALLENGE FOR
THURSDAY SO PEOPLE TRAVELING FOR THE THANKSGIVING HOLIDAY NEED
TO KEEP INFORMED ABOUT THE LATEST FORECAST CHANGES.

39

[wxman57]

If the front doesn't arrive until mid afternoon Thursday, then that sure changes things. Latest model runs keep our temps in the mid 40s from shortly after frontal passage through the day on Friday. Black Friday may be "very cold Friday". Line of showers/storms ahead of the front around noon-ish Thursday then turning sharply colder. Not much precip post-frontal. Here are the latest 2 meter temps from the overnight GFS:

[srainhoutx]

Good morning. Well the overnight guidance threw another wrinkle in the forecast for Thanksgiving Day due to the slow ejection of our Upper Air feature from the Intermountain West portrayed by guidance. I do suspect that the models are under estimating the strength of the dense cold air and may be as much as 24 hour off on their timing of frontal passage in our area, if not a bit more. The other concern is the severe weather that may well be associated with the Arctic Boundary. Severe weather parameters look to be shaping up for parts of TX and will need to be monitored the next couple of days. I wouldn't be surprised to see some major forecasting busts as well and in reading some of the discussions this morning one can almost sense some frustration from forecasters. Past experience tells me that the front will be sharp and faster than progged by models. Interesting days ahead.

[wxman57]

Good morning. Well the overnight guidance threw another wrinkle in the forecast for Thanksgiving Day due to the slow ejection of our Upper Air feature from the Intermountain West portrayed by guidance. I do suspect that the models are under estimating the strength of the dense cold air and may be as much as 24 hour off on their timing of frontal passage in our area, if not a bit more. The other concern is the severe weather that may well be associated with the Arctic Boundary. Severe weather parameters look to be shaping up for parts of TX and will need to be monitored the next couple of days. I wouldn't be surprised to see some major forecasting busts as well and in reading some of the discussions this morning one can almost sense some frustration from forecasters. Past experience tells me that the front will be sharp and faster than progged by models. Interesting days ahead.

Good chance the front will arrive earlier. Won't be certain until we see how it's progressing south through KS/OK the day before it reaches Texas. Probably late Tuesday or on Wednesday morning before the timing is pinned down to within a few hours. Regardless of timing, it doesn't appear as though daytime temps will get out of the 40s behind the front. I don't buy the NWS forecast of upper 50s Friday if the front comes through Thursday. I just don't understand why they're reluctant to forecast highs below the upper 50s.

[srainhoutx]

Along with a very -NAO as posted earlier, the AO index is tanking as well...



Last winter we had a lot of discussions regarding these parameters, along with +PNA and what they mean regarding cold air intrusions and storminess across the CONUS. Amazingly, we are again seeing some signals that are not associated with La Nina patterns, but more of a stout El Nino signal. I'll continue to monitor and update in the days ahead as this has some significance in what our sensible weather will be as we near the winter season. With that said, expect some volatility in the models and we may well be seeing that now with the pattern ahead. More later.

[wxman57]

Euro really doesn't bring that much cold air south this week. 850mb temps only around 50 degrees. Could be worse, I guess.

I better get out on my bike before the cold hits later this week. Good day for a ride today - 80-81 degrees. Was kind of cool yesterday when it got cloudy.

[srainhoutx]

The 12Z GFS suggests a Thanksgiving evening frontal passage with some storms along the the boundary. Black Friday looks cold and no post frontal precip this time around. Saturday morning looks down right chilly with a possible widespread freeze across much of SE TX.

[Ptarmigan]

The 12Z GFS suggests a Thanksgiving evening frontal passage with some storms along the the boundary. Black Friday looks cold and no post frontal precip this time around. Saturday morning looks down right chilly with a possible widespread freeze across much of SE TX.

If we have a freeze on Saturday, it would be earlier than average. The average freeze date is December 2, which is at KIAH from 1969 to 2009. I have looked at old records and sometimes Houston does not see its first freeze until February! It happened in 1922.