November: Warm and Dry To End The Month

[Ptarmigan]

Hopefully this is short term and we see rain returning.

[skidog40]

remember this is fall, winter doesn't start for another month.
i dont remember where i saw that jan. could bring something here that we have never seen before.

[srainhoutx]

Happy Thanksgiving KHOU Weather Forum Family. We are blessed with a great group of folks and I wish everyone all the best during the Holiday Season.

[txflagwaver]

I hope everyone had a great Thanksgiving....I am thankful we are getting a little shower here today

[wxman57]

Half inch of rain in Westbury yesterday. 1.3" for the month so far.

[srainhoutx]

It appears that a rather progressive pattern is ahead once we get past Thanksgiving with an active NW flow that will bring cold fronts and even some rain chances as we end November and begin December. A cold front will pass through the area early Friday knocking temps back down to the 60’s for highs and upper 30’s/low 40’s Saturday night. A brief warm up is ahead as we enter a roller coaster pattern of active fronts and embedded short wave disturbances traversing the Lone Star State next week. A second strong push of cold air should arrive next Tuesday with another shot of cold air and even better rain chances next Thursday as an upper air feature swings past with yet a third cold front to end November.

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0359 AM CST WED NOV 21 2012

VALID 241200Z - 291200Z

...DISCUSSION...
PROGRESSIVE AND GENERALLY HIGH-AMPLITUDE PATTERN ALOFT IS FCST
THROUGH PERIOD. ORGANIZED SVR POTENTIAL WILL DEPEND ON SUBSTANTIAL
MOISTURE RETURN FROM WRN/CENTRAL GULF...WHICH IS NOT PROBABLE UNTIL
AT LEAST LATE DAY-5/25TH-26TH...AND MORE LIKELY DAY-6/26TH-27TH. BY
LATE DAY-5 AND EARLY DAY-6...OPEN-WAVE REMNANTS OF GULF OF AK
CYCLONE SHOULD BE MOVING SEWD OVER NRN/CENTRAL ROCKIES. MAIN
CONCERN NOW APPEARS TO BE MID-LATE DAY-6 OVER PORTIONS E TX AND
ARKLATEX REGION...PERHAPS MANIFEST AS
WELL-ORGANIZED...LOW-CAPE/STG-SHEAR NOCTURNAL EVENT.

SLGT DISAGREEMENT IS EVIDENT ON TIMING/AMPLITUDE OF DAY-6 UPPER WAVE
AND RELATED SFC FRONTAL ZONE AMONG ECMWF/SPECTRAL AND MOST MREF
MEMBERS. HOWEVER...PROGS GENERALLY CONCUR WITH JUXTAPOSITION OF
100+ KT 250-MB JET MAX...FAVORABLY STG DEEP SHEAR...HEIGHT FALLS
ALOFT...INCREASINGLY MOIST WARM SECTOR INTRUDED BY STG COLD
FRONT...AND PREFRONTAL DEW POINTS REACHING 60S F. SUCH SCENARIOS
TYPICALLY YIELD AOA 30% COOL-SEASON/TOTAL-SVR RESULTS. SIMILAR
POTENTIAL MAY CARRY OVER INTO DAY-7/27TH-28TH OVER PORTIONS
MID-SOUTH...TN VALLEY AND/OR CENTRAL GULF COAST STATES.
HOWEVER...PHASE UNCERTAINTIES IN KEY FEATURES -- BOTH SFC AND UPPER
AIR -- ARE LARGE ENOUGH TO PRECLUDE UNCONDITIONAL 30% AREA THEN.

..EDWARDS.. 11/21/2012

Although the SPC backed away from the above mentioned area for a couple of days (too much model mayhem), it is being mentioned again this morning and should we see a quick return flow off the Gulf as expected tomorrow there may well be a Slight Risk issued for Monday night/early Tuesday with the next upper air disturbance and attending cold front.

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CST SAT NOV 24 2012

VALID 261200Z - 271200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
LARGE SCALE PATTERN AMPLIFICATION WILL CONTINUE TO OCCUR INTO
MONDAY...HIGHLIGHTED BY GRADUAL LONGWAVE TROUGH DEVELOPMENT EAST OF
THE ROCKIES. A COLD FRONT WILL STEADILY ADVANCE SOUTHEASTWARD ACROSS
THE SOUTHERN PLAINS/ARKLATEX/LOWER MS VALLEY WITH INCREASING
CONVECTIVE POTENTIAL NEAR THE FRONT BY MONDAY AFTERNOON/NIGHT.

...EAST TX/SOUTHEAST OK/ARKLATEX TO LOWER MS VALLEY...
GIVEN THE AFOREMENTIONED LARGE SCALE SCENARIO AND ANTICIPATED
GRADUAL AIRMASS MODIFICATION INTO MONDAY...THE ADVANCING COLD FRONT
WILL INTERCEPT AN INCREASINGLY MOIST LOW-LEVEL AIRMASS ACROSS THE
REGION...WITH LOWER 60S F SURFACE DEWPOINTS EXPECTED IN THE WARM
SECTOR BY PEAK HEATING. THIS MOISTURE MAY CONTRIBUTE TO AS MUCH AS
1000-2000 J/KG OF MLCAPE MONDAY AFTERNOON/EVENING.

WHILE SOME TIMING/AMPLITUDE SPREAD EXISTS AMONGST AVAILABLE
GUIDANCE...CURRENT THINKING IS THAT TSTMS WILL INCREASE THROUGH THE
AFTERNOON AND...MORE SO...EVENING NEAR THE ADVANCING FRONT ACROSS
AREAS POTENTIALLY INCLUDING EAST TX/FAR SOUTHEAST OK AND THE
ARKLATEX. BASED ON FORECAST SOUNDINGS...VERTICAL SHEAR WILL BE AT
LEAST MARGINALLY SUPPORTIVE /30-40 KT EFFECTIVE SHEAR/ OF ORGANIZED
STORM STRUCTURES INCLUDING SOME POSSIBLE SUPERCELLS/BOWS. THE REGION
WILL BE REEVALUATED IN SUBSEQUENT OUTLOOKS FOR A POSSIBLE
CATEGORICAL SLIGHT RISK.

..GUYER.. 11/24/2012

CLICK TO GET WUUS03 PTSDY3 PRODUCT

[srainhoutx]

Dropped to a chilly 35 degrees here in NW Harris County this morning. Winds have already turned back to the ESE and modest moisture should return later today as winds swing off the Gulf. The SPC has outline a Slight Risk for severe storms for late tomorrow for areas mainly N and E of Metro Houston as a upper air disturbance near the Baja Region rapidly moves E and yet another cold front drops SE over night Monday/early Tuesday...





DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1256 AM CST SUN NOV 25 2012

VALID 261200Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS EAST TX/ARKLATEX...

...SYNOPSIS...
LARGE SCALE PATTERN AMPLIFICATION WILL CONTINUE TO OCCUR INTO
MONDAY...HIGHLIGHTED BY GRADUAL LONGWAVE TROUGH DEVELOPMENT EAST OF
THE ROCKIES. A COLD FRONT WILL STEADILY ADVANCE SOUTHEASTWARD ACROSS
THE SOUTHERN PLAINS/ARKLATEX/LOWER MS VALLEY WITH INCREASING
CONVECTIVE POTENTIAL NEAR THIS FRONT BY MONDAY LATE AFTERNOON/NIGHT.

...EAST TX/FAR SOUTHEAST OK/ARKLATEX TO LOWER MS VALLEY...
GRADUAL AIRMASS MODIFICATION WILL OCCUR INTO MONDAY AS THE REGION
INCREASINGLY COMES UNDER THE INFLUENCE OF BROAD/MODERATELY STRONG
CYCLONIC FLOW ALOFT. A SOUTHEASTWARD-ADVANCING COLD FRONT WILL
INTERCEPT AN INCREASINGLY MOIST LOW-LEVEL AIRMASS ACROSS THE
REGION...WITH LOWER 60S F SURFACE DEWPOINTS EXPECTED IN THE WARM
SECTOR BY MONDAY AFTERNOON. THIS MOISTURE COULD CONTRIBUTE TO AS
MUCH AS 1000-2000 J/KG OF MLCAPE ACROSS EAST/SOUTHEAST TX AND
ADJACENT WESTERN LA/FAR SOUTHWEST AR MONDAY AFTERNOON/EVENING.

SOME TIMING/SPATIAL VARIABILITY STILL EXISTS IN THE SHORT-TERM
AMONGST AVAILABLE NUMERICAL GUIDANCE...BUT SCENARIO APPEARS TO
WARRANT AT LEAST A MARGINAL CATEGORICAL SLIGHT RISK. CURRENT
THINKING IS THAT SURFACE BASED TSTMS WILL INCREASE NEAR THE
ADVANCING COLD FRONT/POSSIBLE WEAK SURFACE WAVE THROUGH LATE
AFTERNOON AND ESPECIALLY MONDAY NIGHT. SUCH INITIAL DEVELOPMENT MAY
OCCUR ACROSS EAST TX...EXTREME SOUTHEAST OK...SOUTHERN AR...AND
WESTERN/NORTHERN LA. GIVEN THE ANTICIPATED WEAK TO MODERATE
BUOYANCY...VERTICAL SHEAR WILL BE AT LEAST MARGINALLY SUPPORTIVE
/30-40 KT EFFECTIVE SHEAR/ OF ORGANIZED STORM STRUCTURES INCLUDING
SOME POSSIBLE SUPERCELLS/BOWS. SEVERE HAIL WILL BE POSSIBLE WITHIN
THE FIRST FEW HOURS OF DEEP CONVECTIVE DEVELOPMENT...WITH DAMAGING
WINDS AND PERHAPS A TORNADO OTHERWISE POSSIBLE THROUGH THE
EVENING...PRIOR TO A PROBABLE DIMINISHING CONVECTIVE INTENSITY BY
LATE EVENING/OVERNIGHT.

..GUYER.. 11/25/2012

CLICK TO GET WUUS02 PTSDY2 PRODUCT

[srainhoutx]

The 12Z NAM (WRF/NMM) as well as the GFS are a tad more bullish that a line of showers/storms develop just ahead of the short wave crossing the area tomorrow and attending cold frontal passage. We will see.

[wxman666]

SPC stretches Slight risk area further west, now encompasses portions of Harris county as of the 11 AM update.

http://www.spc.noaa.gov/products/outloo ... k_1730.gif

...E TX INTO LA...SRN AR...WRN MS...
AREAS OF RAIN AND ELEVATED THUNDERSTORMS ARE EXPECTED TO INCREASE BY
MID MORNING FROM SRN AR INTO MS...BUT THESE SHOULD NOT BE SEVERE.
DAYTIME HEATING AND COOLING PROFILES ALOFT WILL LEAD TO MUCAPE ON
THE ORDER OF 1500-2000 J/KG FROM E CNTRL TX INTO NRN LA. WITH FULL
HEATING AND SWLY WINDS OVER CNTRL TX...THIS IS WHERE THE LOW LEVEL
LAPSE RATE PLUME WILL BE POINTED. THUS...INITIAL DEVELOPMENT IS
EXPECTED THERE...POSSIBLY HIGH BASED. FURTHER DEVELOPMENT WILL THEN
OCCUR NEWD ALONG THE ADVANCING COLD FRONT.

DEEP LAYER SHEAR WILL BE MOST FAVORABLE FOR SUPERCELLS ACROSS ERN TX
AND INTO SRN AR AND LA...WHERE MIDLEVEL WINDS WILL BE DUE WLY.
HERE...SUPERCELLS CAPABLE OF LARGE HAIL WILL BE LIKELY. COMBINED
PARAMETERS IN PLACE WILL GENERALLY FAVOR MAXIMUM HAIL SIZES AROUND
GOLF BALL...PERHAPS AS HIGH AS 2.00". HOWEVER...A SUBTLE VEER-BACK
WIND PROFILE IN THE 700-500 MB LAYER MAY HAVE AN ADVERSE IMPACT ON
STORM STRUCTURE. REGARDLESS...SEVERE HAIL GREATER THAN 1.00" IS
LIKELY.

DAMAGING WINDS MAY ALSO OCCUR...ESPECIALLY WITH THE ACTIVITY THAT
FORMS OVER CNTRL TX IN THE HEAT. THESE STORMS WILL LIKELY PERSIST
AND PROPAGATE ESEWD...POSSIBLY AFFECTING THE HOUSTON AREA AFTER
MIDNIGHT.

OVERALL...LOW LEVEL SHEAR WILL BE MARGINAL FOR TORNADOES...WITH ONLY
A LOW THREAT WITH THE INITIAL DEVELOPMENT BEFORE IT MERGES INTO A
LINE.

..JEWELL.. 11/25/2012

CLICK TO GET

[Ptarmigan]

If the forecast is true, we could have potential night time storm in the Houston area. I remember some years had more night time storms than other years. I notice fall and spring have more night time storms than summer and winter, largely due to cold fronts. I remember night time storms in the summer (warm core low pressure systems, troughs, and sea breeze showers that form early morning) and winter (severe weather does occur in the winter).

[wxman666]

If the forecast is true, we could have potential night time storm in the Houston area. I remember some years had more night time storms than other years. I notice fall and spring have more night time storms than summer and winter, largely due to cold fronts. I remember night time storms in the summer (warm core low pressure systems, troughs, and sea breeze showers that form early morning) and winter (severe weather does occur in the winter).

My migraine headaches have already set in. I usually start feeling the pain in my head a day or so in advance, and then right before the storm hits. I'm not quite sure why I feel them so early but I find it interesting that either a cold front or severe weather is usually forecast the following day. Other days I'm just fine. I think there have been some studies done on this. Kind of off/on topic so my apologies if I strayed a bit. Regardless, it's worth seeing a little action for me, as long as no one ends up hurt.

[Ptarmigan]

My migraine headaches have already set in. I usually start feeling the pain in my head a day or so in advance, and then right before the storm hits. I'm not quite sure why I feel them so early but I find it interesting that either a cold front or severe weather is usually forecast the following day. Other days I'm just fine. I think there have been some studies done on this. Kind of off/on topic so my apologies if I strayed a bit. Regardless, it's worth seeing a little action for me, as long as no one ends up hurt.

If you have headaches, does it always rain and gets stormy? We could use more rain as we are dry.

[wxman666]

My migraine headaches have already set in. I usually start feeling the pain in my head a day or so in advance, and then right before the storm hits. I'm not quite sure why I feel them so early but I find it interesting that either a cold front or severe weather is usually forecast the following day. Other days I'm just fine. I think there have been some studies done on this. Kind of off/on topic so my apologies if I strayed a bit. Regardless, it's worth seeing a little action for me, as long as no one ends up hurt.

If you have headaches, does it always rain and gets stormy? We could use more rain as we are dry.

Lol not always. It usually has to do with falling barometric pressure. If only it were that simple.

[unome]

just noticed this - New, on SPC's site - pretty cool: http://www.spc.noaa.gov/exper/sseo/

"New: The SPC Storm-Scale Ensemble of Opportunity (SSEO) is produced by postprocessing seven (7) deterministic convection-allowing model runs. Special emphasis is placed on hourly maximum storm-attribute fields. (Updated: November 13 2012) "

http://www.spc.noaa.gov/exper/sseo/sseo ... d=6MN-PREC

I hope we get enough rain, really getting dry here

[unome]

SPC graphic moved east, but maybe we'll still get some beneficial rain http://www.spc.noaa.gov/products/outlook/day1otlk.html

[srainhoutx]

The SPC has reconfigured the Slight Risk further NE of the Houston Metro and removed Central Texas from the outlined area. The best moisture levels appear to be E of College Station on down to NE of Katy and well N of I-10.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0640 AM CST MON NOV 26 2012

VALID 261300Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM NORTHEAST TX INTO PORTIONS
OF AR/LA/MS...

...ARKLATEX REGION...
MORNING WATER VAPOR LOOPS SHOW A DEVELOPING LARGE SCALE UPPER TROUGH
OVER THE WESTERN AND CENTRAL UNITED STATES. A SOUTHERN STREAM
IMPULSE IS MOVING ACROSS THE BAJA PENINSULA AND WILL APPROACH THE
WESTERN GULF OF MEXICO BY EVENING. MEANWHILE AT THE SURFACE...A
COLD FRONT IS SAGGING SOUTHWARD ACROSS OK INTO THE ARKLATEX REGION.
CURRENT INDICATIONS ARE THAT THE APPROACHING UPPER TROUGH WILL
RESULT IN SCATTERED STRONG-SEVERE STORMS ALONG THE COLD FRONT LATER
THIS EVENING AND TONIGHT.

LOW LEVEL WINDS ARE NOT PARTICULARLY STRONG THIS MORNING...NOR WILL
THEY INCREASE SIGNIFICANTLY THROUGH THE PERIOD. HOWEVER...
INCREASING LOW LEVEL WARM ADVECTION/ASCENT AHEAD OF THE UPPER TROUGH
WILL RESULT IN GREATER COVERAGE OF SHOWERS AND THUNDERSTORMS THROUGH
THE DAY. THIS PROCESS HAS ALREADY COMMENCED ACROSS PARTS OF LA/MS.
WHILE AN ISOLATED STRONG STORM IS POSSIBLE FROM THIS MORNING/EARLY
AFTERNOON ACTIVITY...THE PRIMARY SEVERE THREAT IS EXPECTED AFTER
00Z.

MOST MODEL SOLUTIONS AGREE THAT MORE ORGANIZED THUNDERSTORM ACTIVITY
WILL DEVELOP ALONG THE APPROACHING COLD FRONT THIS EVENING FROM
NORTHEAST TX...ACROSS SOUTHERN AR...INTO NORTHERN MS. THE AIR MASS
IN THIS REGION WILL BECOME MODERATELY MOIST/UNSTABLE WITH
SUFFICIENTLY STEEP MID LEVEL LAPSE RATES TO YIELD MLCAPE VALUES OF
1500-2000 J/KG. LOW AND MID LEVEL FORECAST WIND FIELDS WILL PROMOTE
SUPERCELL STORM STRUCTURES CAPABLE OF LARGE HAIL AND DAMAGING WINDS.
VEERED LOW LEVEL WINDS ARE LIKELY TO MITIGATE THE RISK OF LOW LEVEL
MESOCYCLONES...BUT AN ISOLATED TORNADO CANNOT BE RULED OUT. THE
ACTIVITY WILL SPREAD SOUTHEASTWARD ACROSS NORTHERN LA AND
NORTHERN/CENTRAL MS BY LATE EVENING AND EVENTUALLY WEAKEN DUE TO
DECREASING INSTABILITY.

..HART/DISPIGNA.. 11/26/2012

[unome]

still a decent chance



455 AM EST MON NOV 26 2012

...LWR MS VLY...

MODEL GUIDANCE STILL SHOWS AN INCREASE IN MOISTURE AVAILABILITY
EARLY ON...BUT NOT QUITE AS RAPID IN THE EARLY PERIODS AS WAS
SHOWN IN THE PREVIOUS MODEL RUNS. SOUTHERLY FLOW OFF THE GULF
WILL BE INCREASING LATER IN THE DAY AS A SHORTWAVE TROF APPROACHES
FROM THE NORTHWEST. MODEL QPFS ARE IN BROAD GNRL AGREEMENT
CONCERNING PLACEMENT BUT DIVERGE ON MAXIMA PLACEMENT WITHIN THE
AREA. THE 25/12Z ECMWF LOOKED LIKE IT SUFFERED FROM SOME
CONVECTIVE FEEDBACK...LEAVING THE BEST AGREEMENT BETWEEN THE GFS
AND THE 25/12Z UKMET.

SPC graphic moved east, but maybe we'll still get some beneficial rain http://www.spc.noaa.gov/products/outlook/day1otlk.html

[srainhoutx]

Morning e-mail from Jeff:

Good chance for thunderstorms tonight ahead of the next cold front.

First item this morning is the dense fog over parts of the area, mainly WSW and SW of metro Houston and into the coastal bend and central TX. Should see this fog blanket erode by mid morning, but between now and then visibilities will be on the low side running in the .25 of a mile to 1 mile range in the advisory area.

Also seeing a few showers on the radar…a rare sight…mainly along the coast and then inland over far SE Galveston County and Chambers County. These showers are along the leading edge of a deeper push of moisture off the western Gulf where dewpoints are running in the upper 60’s. Fairly impressive moisture return has taken place in the last 24 hours with morning lows today running some 30 degrees warmer over Sunday morning. Fast moving upper level storm is noted over Baja this morning tracking eastward while the next cold front is advancing down the plains into north TX. Combination of the approaching disturbance from the SW and front from the north along with decent moisture profile should support the best chance of rainfall this area has seen in a while tonight.

Moisture will continue to increase off the Gulf today as lower pressure over NW TX favor onshore winds. Will likely continue to see a few scattered showers move inland off the Gulf in the warm air advection pattern, but the main event will come after dark as large scale forcing moves into the area from the SW near/ahead of the approaching cold front. Front should reach our northern counties in the 10pm-midnight time period and push off the coast by 300-600am Tuesday. Shorter term meso models are not overly impressive with rain chances along the boundary with most of the “action” focused east of the area in Louisiana where SPC slight risk area currently is in place. While parameters looks overall favorable for some severe weather this evening/overnight, think the risk is on the lower end of the spectrum. While models fully erode a weak cap over the region by late this afternoon, they may be a little fast in reducing this feature and the larger values of CAPE (instability) suggested also seems overdone given winds turning more SSW prior to the front and boundary layer cooling during the evening hours. Still expect to see widespread thunderstorms develop with favorable moisture influx and good lift from multiple sources, but think the severe threat will be limited to areas east of I-45 and even in this area the threat appears isolated. With that said, there could be some enhancement of low level shear in the corridor from roughly Coldspring to Liberty to Galveston overnight which could slightly favor a very small increase in the threat for tornado production is this area. Interestingly enough the regional WRF models suggest the bulk of the activity will affect areas west and southwest of Houston this evening/overnight or the counties of Jackson, Wharton, Matagorda, Brazoria, and Fort Bend…this could be a function of this area seeing the greatest amounts of sun today and instability last longer into the evening hours when the best forcing will arrive.

Overall most of the area should see at least some rainfall, although I would like to see more coverage and organization of convection on the meso models to be more confident that the W and NW areas will in fact see some activity. Best coverage will be over the central and eastern counties and then east into Louisiana. A general .50 of an inch to possibly an inch is expected which will help ease some of the developing dryness. Areas that do not see much rainfall tonight could see an elevated fire risk on Tuesday as a dry air mass and gusty NW winds move into the region behind the overnight storm system. Main concern would be north of I-10 where fine fuels are cured and dry and over Brazoria County where KBDI values are highest.

Fast progressive pattern will keep the bulk of the cold air bottled in Canada with only quick shots every 2-3 days as storm systems race across the US. Next system will cross TX Thursday/Friday. While such patterns usually favor overall dry conditions over the state, the next system does also show some potential for rains especially along the coast where coastal troughing over the western Gulf may spread moisture northward into the coastal bend and SE TX starting Thursday. Given the dry pattern of late, would like to see more model support for this event before suggesting better rain chances in the Thurs/Fri period, but it does look promising this morning. After the front tonight, there appears to be little cold air to drop southward as the persistent vortex over the Gulf of Alaska keeps the flow west to east over the US and cold air trapped from flowing southward. Even into the first week of December the temperatures look balmy with lows in the 50’s/60’s and highs in the 70’s/near 80.

[srainhoutx]

12Z NAM (WRF/NMM) a bit more suggestive of storm chances over SE TX. We will see.

[srainhoutx]

MESOSCALE DISCUSSION 2123
NWS STORM PREDICTION CENTER NORMAN OK
0334 PM CST MON NOV 26 2012

AREAS AFFECTED...NERN TX...NRN LA...EXTREME SRN AR

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 262134Z - 262300Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...THUNDERSTORMS ARE FORECAST TO DEVELOP ACROSS NERN TX...NRN
LA AND EXTREME SRN AR LATE THIS AFTERNOON AND EVENING. ACTIVITY WILL
EVENTUALLY EVOLVE INTO A LINE AS A COLD FRONT ADVANCES EWD ACROSS
THE AREA. STORMS WILL PRIMARILY POSE A DAMAGING WIND AND LARGE HAIL
THREAT. A WW MAY NEED TO BE ISSUED DURING THE NEXT COUPLE OF HOURS.

DISCUSSION...MESOANALYSIS AT 21Z PLACES A SURFACE LOW IN FAR NERN
TX...WITH A WARM FRONT SLOWLY RETREATING EWD INTO CNTRL PORTIONS OF
LA...AND A COLD FRONT ADVANCING E-SEWD ACROSS CNTRL TX. AMPLE
SUNSHINE HAS AIDED IN WARM SECTOR TEMPERATURES WARMING INTO THE 70S
TO LOW 80S...WHILE AN AXIS OF LOW TO MID 60S DEWPOINTS EXTENDS
N-NEWD FROM THE TX GULF COAST INTO WRN LA. THE WARM/MOIST BOUNDARY
LAYER COMBINED WITH 700-500 MB LAPSE RATES NEAR 7 C/KM IS YIELDING
MLCAPE VALUES ESTIMATED TO BE AROUND 1000-2000 J/KG AHEAD OF THE
COLD FRONT.

VISIBLE SATELLITE IMAGERY AS OF 2115Z SHOWS THE WARM SECTOR IS
CAPPED...WHICH IS ALSO SUPPORTED BY 18Z SHV RAOB.
HOWEVER...LARGE-SCALE ASCENT ASSOCIATED WITH A SERIES OF SRN STREAM
DISTURBANCES EMANATING OUT OF NRN MEXICO...COMBINED WITH FRONTAL
CONVERGENCE/ASCENT ARE FORECAST TO ERODE THE CAPPING INVERSION
DURING THE 22-00Z TIME PERIOD. THIS WILL FAVOR THUNDERSTORM
DEVELOPMENT ALONG THE COLD FRONT AND PERHAPS EWD INVOF THE SURFACE
LOW AND WARM FRONT. DEEP-LAYER SHEAR ON THE ORDER OF 30-40 KT WILL
SUPPORT MULTICELL CLUSTERS AND PERHAPS A FEW SUPERCELLS POSING A
THREAT FOR LARGE HAIL AND DAMAGING WIND GUSTS. LOW-LEVEL SHEAR
PROFILES WILL NOT BE PARTICULARLY STRONG...THUS ANY TORNADO THREAT
IS EXPECTED TO BE BRIEF AND FOCUSED NEAR THE LOW WHERE BACKED
SURFACE WINDS WILL BE MOST PROBABLE.

BY NIGHT...STORMS ARE FORECAST TO ORGANIZE INTO A LINE AS THE COLD
FRONT ADVANCES EWD...WITH THE THREAT FOR HAIL AND STRONG/SVR WIND
GUSTS CONTINUING.

..GARNER/EDWARDS.. 11/26/2012


ATTN...WFO...JAN...LCH...SHV...HGX...FWD...