Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 4

[somethingfunny]

I love Dennis Cavanaugh so much.

AREA FORECAST DISCUSSION...UPDATED

NATIONAL WEATHER SERVICE FORT WORTH TX

1224 PM CDT SAT NOV 3 2012

.AVIATION...

CONCERNS...AFTERNOON AND EVENING CONVECTION...AND MVFR CIGS AT KACT.

A COLD FRONT IS PUSHING SOUTHEAST THROUGH HE METROPLEX AIRPORT AT

THIS HOURS. THE FRONT SHOULD SLOW THIS AFTERNOON AND EVENING THEN

MOVE THROUGH KACT LATE TONIGHT 9-10Z. SCATTERED SHRA HAVE

DEVELOPED FROM KT35/KHBN SOUTHWARD TO THE GULF COAST. AIR MASS

WILL BE UNSTABLE ALONG AND AHEAD OF THE FRONT THIS AFTERNOON

THROUGH EARLY EVENING AND COULD AFFECT KACT. STRONG THUNDERSTORMS

ARE POSSIBLE AND IF THEY DEVELOP...SMALL HAIL AND GUSTY WINDS WILL

BE THE MAIN HAZARD. SOME ACTIVITY IS ALSO POSSIBLE ACROSS THE

METROPLEX...AND HAVE VCSH TO COVER THIS POTENTIAL THROUGH 19-03Z.

EXPECT CIGS TO FORM AROUND 5000 THIS EVENING ACROSS THE METROPLEX

AND LAST INTO SUNDAY MORNING. KACT WILL HAVE ANOTHER POTENTIAL FOR

MVFR CIGS SUNDAY MORNING 12-15Z AND HAVE A TEMPO GROUP TO COVER

THE EVENT SINCE CONFIDENCE IS NOT VERY HIGH.

SUNDAY AFTERNOON WILL BE VFR ACROSS THE METROPLEX WITH NORTH WINDS 5-9KTS.

75

&&

.UPDATE...

AREAS OF FOG DEVELOPED THIS MORNING FROM THE FORT HOOD AREA TO

SOUTHEASTERN DALLAS COUNTY EASTWARD. THERE WAS WIDESPREAD 1 TO 3

MILE VISIBILITIES WITH SOME 1/2 MILE OR LESS VISIBILITIES NOTED

FROM KILLEEN TO CORSICANA TO ATHENS AREA EASTWARD INTO EAST

TEXAS. VISIBILITIES ARE IMPROVING AS OF 1530Z...AND ALMOST ALL OF

THE FOG SHOULD BE DISPERSED BY 17Z. A WEAK FRONTAL BOUNDARY HAS

BEEN MOVING A LITTLE FASTER TO THE SOUTHEAST THAN HAD EARLIER

EXPECTED. THIS BOUNDARY EXTENDED SOUTHEAST OF A BONHAM...TO

DECATUR...TO ABILENE LINE AS OF 15Z. WITH 1.5 TO 3 MB 3-HOUR

PRESSURE RISES BEHIND THIS BOUNDARY IT SHOULD MOVE THROUGH DFW

17-18Z BUT SHOULD SLOW ITS FORWARD PROGRESS LATER THIS AFTERNOON

BEFORE PICKING UP SOME SPEED THIS EVENING. HAVE ADJUSTED THE

HOURLY TEMPERATURE/DEWPOINT/WIND GRIDS FOR CURRENT TIMING. 58

&&

.PREV DISCUSSION... /ISSUED 231 AM CDT SAT NOV 3 2012/

EARLY MORNING SURFACE OBSERVATIONS AND REGIONAL RADARS DEPICTED A

COLD FRONT MOVING SOUTHEAST TOWARDS THE RED RIVER. INFRARED

SATELLITE IMAGERY INDICATED NO CLOUD COVER ASSOCIATED WITH THE

FRONT AS OF 06Z WHICH IS LIKELY DUE TO THE RELATIVELY DRY LOW

LEVEL AIR MASS SOUTH OF THE FRONT EARLY THIS MORNING. THE 00Z FWD

RAOB OBSERVED A PRECIPITABLE WATER OF UNDER ONE HALF INCH. HOWEVER

EARLY MORNING SURFACE OBSERVATIONS DID INDICATE THAT AT LEAST

SHALLOW MOISTURE WAS BEGINNING TO WORK ITS WAY NORTH INTO NORTH TX

WITH LOWER 60S DEW POINTS OBSERVED AS FAR NORTH AS WACO AT THE

TIME OF THIS DISCUSSION. EARLY MORNING WATER VAPOR IMAGERY

INDICATED BROAD ANTICYCLONIC FLOW OVER THE SOUTH PLAINS WITH A

SHORTWAVE TROUGH LOCATED OVER SOUTHERN NEW MEXICO.

TODAY THROUGH SUNDAY...LATEST FORECAST GUIDANCE CONSENSUS

INDICATES THAT THE COLD FRONT WILL SLOW DOWN BUT CONTINUE

SOUTHEAST THROUGH NORTH TEXAS THROUGH THE DAY TODAY. GUIDANCE ALSO

INDICATES THAT THE NEW MEXICO SHORTWAVE TROUGH WILL MOVE EAST

SPREADING WEAK BUT PERSISTENT LARGE SCALE FORCING FOR ASCENT OVER

MUCH OF NORTH TX OUT AHEAD OF THE COLD FRONT. WITH LOW LEVEL

MOISTURE CONTINUING TO WORK NORTH THIS MORNING...THINK THAT WEAK

FORCING FOR ASCENT WILL AID IN DEEPENING THE MOIST LAYER SOUTH OF

THE COLD FRONT BY THIS AFTERNOON.

ASSUMING THIS PANS OUT...THE STRONGER FORCING FOR ASCENT ALONG THE

COLD FRONT WILL LIKELY RESULT IN ISOLATED TO SCATTERED CONVECTION

INITIATION DURING THE PEAK HEATING HOURS OF THE DAY...WHICH IS

AROUND 21Z THIS TIME OF YEAR. AT THAT TIME THE COLD FRONT IS

EXPECTED TO BE LOCATED ROUGHLY ALONG A LINE FROM COMANCHE TO DFW

AIRPORT TO PARIS...SO WENT AHEAD AND MOVED THE AREAL COVERAGE OF

30 POPS ALONG AND SOUTHEAST OF THIS LINE FOR THIS AFTERNOON.

CANNOT RULE OUT ISOLATED STORMS DEVELOPING BEFORE 21Z WHEN THE

FRONT IS FURTHER NORTHWEST...OR WELL SOUTHEAST OF THE FRONT IN THE

WEAK WARM AIR ADVECTION REGIME. AS A RESULT MAINTAINED 20 POPS FOR

THESE AREAS AWAY FROM THE FRONT THIS AFTERNOON. IN GENERAL

CONTINUED TO PLACE BEST POPS ALONG AND SOUTHEAST OF THE COLD FRONT

AS IT CONTINUES SOUTHEAST THROUGH NORTH TX TONIGHT.

THUNDERSTORM HAZARDS...AT THIS TIME ORGANIZED SEVERE THUNDERSTORM

ACTIVITY IS NOT EXPECTED ACROSS NORTH TX TODAY THROUGH SUNDAY.

OVERALL LACK OF OBSERVED DEEP MOISTURE IN PLACE EARLY THIS MORNING

COMBINED WITH FORECAST MEAGER MID-LEVEL LAPSE RATES AND WEAK DEEP

LAYER SHEAR SEEM TO FAVOR AN UNORGANIZED SINGLE CELL STORM MODE.

SINGLE CELL STORMS CAN STILL PRODUCE SMALL HAIL...GUSTY

WINDS...AND CLOUD TO GROUND LIGHTNING...SO THAT IS THE GENERAL

EXPECTATION OF THUNDERSTORM HAZARDS ACROSS NORTH TX THIS AFTERNOON

AND EVENING.

/THIS BLOCK OF DISCUSSION WILL DESCRIBE THE VERY TINY CHANCES FOR

LANDSPOUT TORNADOES TODAY NEAR THE FRONT AT 21Z. TO RETURN TO THE

REMAINDER OF THE FORECAST DISCUSSION...PLEASE SKIP BELOW A FEW

PARAGRAPHS./

WHILE THE CHANCES ARE VERY SMALL (LESS THAN 1 PERCENT)...IT IS

WORTH MENTIONING THAT THE ENVIRONMENT IN THE IMMEDIATE VICINITY OF

THE FRONT MAY BRIEFLY BECOME FAVORABLE FOR LANDSPOUT TORNADOES

DURING THE PEAK HEATING HOURS OF THE DAY TODAY. THE KEY

INGREDIENTS FOR LANDSPOUT TORNADOES IN GENERAL ARE A GOOD SOURCE

OF VERTICAL VORTICITY...STEEP LOW-LEVEL LAPSE RATES AND A VERY

SLOW MOVING OR STATIONARY BOUNDARY/WIND SHIFT LINE. THESE

CONDITIONS ARE NOT INDEPENDENT OF ONE ANOTHER...THE BOUNDARY

ITSELF IS THE BIG SOURCE OF VERTICAL VORTICITY...SO THE PRIMARY

FACTOR TO LOOK FOR THIS AFTERNOON WILL BE THE MOVEMENT OF THE COLD

FRONT THROUGH NORTH TX.

THE 03/00Z NAM INDICATES THE WORST-CASE SCENARIO IN THESE REGARDS

BECAUSE THE NAM ESSENTIALLY STALLS THE FRONT IN THE MIDDLE OF THE

CWA AT 21Z THIS AFTERNOON BEFORE MOVING THE FRONT MORE QUICKLY TO

THE SOUTHEAST THIS EVENING. IF THE FRONT DOES STOP...OR SLOWS DOWN

TO A VERY SLOW SPEED...IT WILL BE WORTH WATCHING FOR ISOLATED

CELLS THAT TRY TO DEVELOP RIGHT ON TOP OF THE BOUNDARY. IF AN

UPDRAFT BEGINS VERY NEAR THE BOUNDARY IT CAN STRETCH VERTICAL

VORTICITY CAUSING A RAPID INCREASE IN ROTATIONAL VELOCITY WHILE

REMAINING ATTACHED TO THE CLOUD BASE OF THE DEVELOPING STORM. IF

THIS HAPPENS IT WOULD RESULT IN A LANDSPOUT TORNADO. IF THE STORM

MOVES AWAY FROM THE BOUNDARY OR IF THE BOUNDARY KEEPS

MOVING...THIS PROCESS IS INTERRUPTED RESULTING IN A BENIGN RAIN

SHOWER OR VERY ISOLATED THUNDERSTORM. ALSO...IF CLOUDS HAPPEN TO

DEVELOP OVER THE BOUNDARY...LOW LEVEL LAPSE RATES WILL BE DAMPENED

ONCE AGAIN INTERRUPTING THE LANDSPOUT CREATION PROCESS.

AT THIS TIME...MOST MODEL GUIDANCE INDICATES THAT THE FRONT WILL

KEEP MOVING SOUTHEAST FAST ENOUGH TO PREVENT ANY LANDSPOUT

ACTIVITY. HOWEVER EVEN IF THE FRONT STALLS...THE OPPORTUNITY FOR

A LANDSPOUT IS EXTREMELY LIMITED BECAUSE EVEN THE NAM FORECASTS

STEEP LAPSE RATES IN THE VICINITY OF THE BOUNDARY FOR ONLY A FEW

HOURS THIS AFTERNOON. AS A RESULT PROBABILITIES FOR LANDSPOUTS

REMAIN TOO LOW TO MENTION IN ANYTHING BUT THE AFD HERE. IT IS

MENTIONED HERE FOR GENERAL INTEREST AND JUST AS A HEADS UP FOR

SOMETHING TO WATCH FOR THIS AFTERNOON WITH A SIGNIFICANT AMOUNT OF

PEOPLE LIKELY TO BE OUTDOORS ENJOYING THE WEEKEND.

/END OF LANDSPOUT DISCUSSION/

FOR SUNDAY...KEPT A MENTION OF THUNDERSTORMS IN THE FORECAST FOR

LOCATIONS GENERALLY SOUTHEAST OF WACO AS THE COLD FRONT IS

EXPECTED TO STALL OUT SOMEWHERE NORTHWEST OF COLLEGE STATION

SUNDAY MORNING. NO SEVERE WEATHER IS EXPECTED ON SUNDAY...AND

OWING TO THE LIKELIHOOD OF MID AND UPPER LEVEL CLOUDS IN

PLACE...MOST PRECIPITATION MAY END UP BEING RAIN SHOWERS DUE TO A

LACK OF INSTABILITY SUNDAY AFTERNOON. TEMPERATURES WILL BE COOLER

BEHIND THE FRONT SUNDAY ACROSS THE ENTIRE CWA WITH HIGHS HOLDING

CLOSER TO SEASONAL NORMALS.

NEXT WEEK...THE ECMWF AND THE GFS INDICATE THAT A POWERFUL

NORTHERN STREAM SHORTWAVE TROUGH WILL MOVE SOUTHEAST THROUGH THE

CENTRAL PLAINS ON MONDAY. AT THIS TIME THE STRONG FORCING FOR

ASCENT ASSOCIATED WITH THIS SYSTEM IS EXPECTED TO REMAIN NORTH OF

THE FORECAST AREA. IT IS EXPECTED TO SEND A REINFORCING SHOT OF

COOL AND DRY AIR INTO THE REGION...BUT SHOULD NOT RESULT IN ANY

PRECIPITATION DUE TO THIS WEEKENDS FRONT MOVING SOUTHEAST OF THE

CWA. AFTER THIS TROUGH MOVES EAST...UPPER LEVEL RIDGING IS

EXPECTED TO BUILD OVER THE SOUTH PLAINS RESULTING IN MOSTLY CLEAR

SKIES AND A GRADUAL WARM UP FOR THE REMAINDER OF THE WEEK. THE GFS

AND ECMWF BOTH INDICATE A POWERFUL UPPER LEVEL STORM SYSTEM WILL

BUILD OVER THE WESTERN CONUS TOWARDS THE END OF THE WEEK INTO NEXT

WEEKEND. IF THIS SYSTEM IMPACTS NORTH TX IT WILL LIKELY OCCUR

AFTER SUNDAY NEXT WEEKEND WHICH IS BEYOND THE SCOPE OF THE CURRENT

FORECAST PACKAGE. REGARDLESS...THERE ARE SIGNIFICANT DIFFERENCES

IN THE EVOLUTION OF THIS SYSTEM HEADED INTO NEXT WEEK. AT THIS

TIME THIS SYSTEM IS JUST SOMETHING TO KEEP AN EYE ON MOVING

FORWARD BECAUSE THERE IS TOO MUCH UNCERTAINTY TO KNOW IF IT WILL

IMPACT NORTH TX OR NOT THIS FAR OUT. CAVANAUGH

[Srain]

DAY 2 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1134 PM CDT SAT NOV 03 2012

VALID 051200Z - 061200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

A LARGE UPPER TROUGH WILL EXIST OVER THE ERN HALF OF THE CONUS WITH

AN UPPER RIDGE CENTERED OVER CA. OF INTEREST THIS PERIOD WILL BE A

STRONG SHORTWAVE EMBEDDED IN THE TROUGH WHICH WILL MOVE RAPIDLY FROM

THE CNTRL PLAINS MON MORNING TO THE CNTRL GULF COAST BY 12Z TUE.

LIFT WITH THIS FEATURE WILL COMBINE WITH WEAK INSTABILITY FROM TX

INTO THE LOWER MS VALLEY TO PRODUCE SCATTERED THUNDERSTORMS.

...CNTRL AND SERN TX INTO LA AND SRN MS...

A COLD FRONT WILL BE SITUATED FROM NWRN TX INTO MO MON

MORNING....AND WILL PUSH SEWD TO A LITTLE ROCK TO SAN ANTONIO LINE

BY 00Z. AHEAD OF THE UPPER SHORTWAVE...WEAK LOW PRESSURE MAY FORM

ACROSS LA...WITH SFC TROUGH EXTENDING SWWD INTO SRN TX. MOISTURE

WILL BE LIMITED WITH DEWPOINTS MAINLY IN THE UPPER 50S TO NEAR 60 F.

HOWEVER...STRONG HEATING AND COOL TEMPERATURES ALOFT WILL CREATE

FAVORABLE PROFILES FOR STRONG UPDRAFTS...AND DEEP LAYER SHEAR WILL

STRENGTHEN FROM ERN TX INTO THE LOWER MS VALLEY WITH THE APPROACH OF

THE TROUGH.

FORCING WILL BE RELATIVELY WEAK ALONG THE TX PORTION OF THE COLD

FRONT...BUT WILL INCREASE ACROSS THE LOWER MS VALLEY LATE WHERE

INSTABILITY WILL BE WEAKER. THUS...ISOLATED STORMS WITH HAIL WILL BE

POSSIBLE OVER MUCH OF TX...WITH A HAIL AND WIND THREAT FARTHER E

INTO LA AND SRN MS DURING THE EVENING.

..JEWELL.. 11/04/2012

[DoctorMu]

Saw a modest Wall Cloud N of Bryan around noon yesterday with just the beginning of some rotation/mini-funnel, but it died quickly...

Stormy afternoon across Central/SE TX...

SPECIAL WEATHER STATEMENT

NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX

151 PM CDT SAT NOV 3 2012

TXZ163-164-176>179-195>200-210>214-226-227-235>238-032130-

HOUSTON-TRINITY-MADISON-WALKER-SAN JACINTO-POLK-BURLESON-BRAZOS-

WASHINGTON-GRIMES-MONTGOMERY-LIBERTY-COLORADO-AUSTIN-WALLER-

HARRIS-CHAMBERS-WHARTON-FORT BEND-JACKSON-MATAGORDA-BRAZORIA-

GALVESTON-

INCLUDING THE CITIES OF...CROCKETT...TRINITY...GROVETON...

MADISONVILLE...HUNTSVILLE...SHEPHERD...COLDSPRING...LIVINGSTON...

CORRIGAN...ONALASKA...CALDWELL...LAKE SOMERVILLE...

COLLEGE STATION...BRYAN...BRENHAM...NAVASOTA...THE WOODLANDS...

CONROE...WILLIS...LIBERTY...CLEVELAND...DAYTON...COLUMBUS...

EAGLE LAKE...WEIMAR...SEALY...BELLVILLE...HEMPSTEAD...

PRAIRIE VIEW...BROOKSHIRE...HOUSTON...PASADENA...KATY...TOMBALL...

HUMBLE...WINNIE...MONT BELVIEU...ANAHUAC...EL CAMPO...WHARTON...

PIERCE...SUGAR LAND...MISSOURI CITY...RICHMOND...ROSENBERG...

EDNA...BAY CITY...PALACIOS...PEARLAND...LAKE JACKSON...ALVIN...

ANGLETON...FREEPORT...LEAGUE CITY...TEXAS CITY...FRIENDSWOOD...

GALVESTON

151 PM CDT SAT NOV 3 2012

...FUNNEL CLOUDS POSSIBLE THIS AFTERNOON...

A WARM BUOYANT ATMOSPHERE AND NUMEROUS INTERSECTING BOUNDARIES

WILL SET THE STAGE FOR FUNNEL CLOUDS THIS AFTERNOON. THESE FUNNEL

CLOUDS WILL BE SHORT LIVED AND DIFFICULT TO DETECT WITH RADAR.

THESE FUNNEL CLOUDS OCCASIONALLY STRETCH TO THE GROUND AND BECOME

WEAK SHORT LIVED TORNADOES. BE PREPARED TO SEEK SHELTER IF YOU

OBSERVE A FUNNEL CLOUD. THE THREAT FOR THE FUNNEL CLOUDS SHOULD

END AROUND SUNSET.

[Srain]

SPC has a Slight Risk for portions of SE TX/SW LA for tomorrow. Not too surprised with the upgrade.

[Srain]

Update from SPC:

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0944 AM CST MON NOV 05 2012

VALID 051630Z - 061200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER SOUTHEAST TX AND SRN LA...

...TX/LA...

MORNING WATER VAPOR LOOPS SHOW A VIGOROUS SHORTWAVE TROUGH DIGGING

SOUTH-SOUTHEASTWARD INTO THE WESTERN GULF COAST REGION.

MEANWHILE...A SURFACE COLD FRONT LIES ACROSS EASTERN OK INTO

NORTHEAST TX...AND IS EXPECTED TO SAG SOUTHWARD ACROSS TX/AR/LA.

STRONG HEIGHT FALLS AND INCREASING LARGE SCALE FORCING FOR ASCENT

WILL HELP TO INITIATE SCATTERED THUNDERSTORMS ALONG THE FRONT FROM

EAST-CENTRAL TX INTO SOUTHERN LA LATER THIS AFTERNOON AND EVENING.

LOW LEVEL WINDS ARE NOT PARTICULARLY STRONG...WHICH WILL LIMIT LOW

LEVEL SHEAR/CONVERGENCE AND OVERALL ORGANIZATION OF THE STORMS.

HOWEVER...STRENGTHENING WINDS AND COOL TEMPERATURES ALOFT WILL

PROVIDE SUPPORT FOR A FEW INTENSE STORMS. FORECAST SOUNDINGS

INDICATE SUFFICIENT EFFECTIVE SHEAR AND STEEP MID LEVEL LAPSE RATES

FOR A FEW ROTATING STORMS CAPABLE OF HAIL AND DAMAGING WINDS. THE

THREAT SHOULD DIMINISH BY MID-EVENING AS THE STORMS MOVE OFFSHORE

AND DIURNAL COOLING OCCURS.

..HART/MOSIER.. 11/05/2012

[Srain]

MESOSCALE DISCUSSION 2101

NWS STORM PREDICTION CENTER NORMAN OK

0119 PM CST MON NOV 05 2012

AREAS AFFECTED...CENTRAL AND ERN TX INTO SRN LA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 051919Z - 052045Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...SEVERE POTENTIAL IS FORECAST TO INCREASE OVER THE NEXT 1-2

HOURS ACROSS THE DISCUSSION AREA...WITH THREAT PERHAPS BECOMING

SUFFICIENT TO WARRANT WW ISSUANCE.

DISCUSSION...LATEST VISIBLE SATELLITE IMAGERY SHOWS INCREASING

VERTICAL DEVELOPMENT WITHIN THE EVOLVING CU FIELD ACROSS PARTS OF

CENTRAL AND ERN TX AND ADJACENT SWRN LA...AS A WEAK TROUGH/COOL

FRONT SHIFTS SEWD ACROSS E TX. AS HEATING/DESTABILIZATION CONTINUES

ACROSS THIS REGION...EXPECT INITIATION OF AT LEAST ISOLATED STORMS

WITHIN THE NEXT 1-2 HOURS.

THE FLOW FIELD ALOFT REMAINS RELATIVELY WEAK ACROSS MOST OF THE

REGION ATTM...THOUGH AN INCREASE IN MID-LEVEL FLOW IS FORECAST AS A

MID-LEVEL JET CONTINUES SPREADING ACROSS THIS AREA. WHILE LOW-LEVEL

FLOW REMAINS GENERALLY VEERED/WLY WHICH WILL MITIGATE APPRECIABLE

TORNADO POTENTIAL...THE INCREASING MID-LEVEL FLOW MAY SUPPORT

UPDRAFT ORGANIZATION -- AND ASSOCIATED/ISOLATED HAIL AND/OR WIND

THREAT WITH A FEW STRONGER CELLS.

..GOSS/HART.. 11/05/2012

ATTN...WFO...JAN...LIX...LCH...SHV...HGX...FWD...CRP...EWX...

[Srain]

E-mail from Jeff:

SPC has issued a Severe thunderstorm Watch for all of SE TX until 900pm.

Early this afternoon visible images show an increasingly agitated cumulus field across SE and C TX as a strong shortwave approaches from the north. Radar in the last 30 minutes has shown the formation of echoes in west-east bands from near Austin to Hempstead. With continue heating and incoming southward moving frontal boundary reaching our northern counties, expect rapid development of strong to severe thunderstorms over the next 1-2 hours. Storms are moving toward the SSE to SE at 10-15mph.

Main threats will be strong gusty winds possibly to 60mph and isolated large hail. While storms will remain scattered in nature, those that do develop will have a decent shot at becoming severe. Broken line of storms should move off the TX coast between 600-800pm evening any severe weather threat.

Severe Thunderstorm Watch Outline and Radar overlay:

[Srain]

Morning e-mail from Jeff:

Little variation in our local weather for the next 2-3 days as weak onshore winds return this afternoon. Moisture will be slow to return until the weekend, then a fairly steep increase in moisture is expected as the next storm system approaches from the west. Upper level pattern over the US will undergo a transition over the next 5 days from a trough in the eastern part of the country to a trough in the western part of the country. As this western US trough develops, an increasing WSW to SW flow aloft over TX will result is small disturbances riding into the region and interacting with increasing Gulf of Mexico moisture to produce a few streamer showers by Saturday.

Main upper trough and strong cold front will move into and through TX by Sunday. Deeper Gulf moisture will surge into the region and expected a few scattered showers and thunderstorms Sunday afternoon mainly north of I-10 closer to the stronger jet stream dynamics. Front slices into the warm and humid air mass on Sunday night/early Monday morning and forecast models are suggesting a squall line of thunderstorms will affect at least the northern ½ of SE TX in the overnight period. I am not all that impressed with the instability nor the jet dynamics aloft and think any strong/severe threat will be north and east of our local area.

Models are in decent timing on the front pushing off the coast and with rapid drying behind the boundary along with decent cold air advection. Lows will fall into the 30’s/40’s by Tuesday morning with highs in the 60’s and 70’s under mainly clear skies. Will continue to monitor the Sunday PM-Monday AM time period for any changes to the forecast.

NE US Nor’easter:

Strong nor’easter moving up the US east coast this morning with strong winds, damaging waves, and rain/snow. Surface low continues to intensify off the DELMARVA this morning with gusty winds of 20-30mph affecting the New Jersey and NE US coasts. Rain shield has moved into the coastal areas hit hard by Sandy just over a week ago. Given the further offshore track of this system compared to the right angle strike of Sandy, the worst of the weather will remain offshore however destruction of large dunes and massive beach erosion from Sandy will result in only minor coastal flooding and wave action causing problems.

Current forecast suggest winds of 40-50mph with gust to 60mph which may bring down additional trees and result in more power outages on top of the 1 million still without power. Storm surge values of 1-4 feet are expected along the coast with total water level rise at high tide (surge plus tide) of 4-7 feet. With coastal protection already destroyed, overwash and flooding of coastal barrier islands and low lying areas is likely and evacuation orders are once again in effect for portions of the New Jersey and New York City area. Large waves of 4-9 feet on top of the coastal water level rise will result in additional heavy erosion and potential failure of damaged coastal structures.

Unlike Sandy, more cold air is wrapped into this system and snow will fall on the north and western edge of the precipitation shield. Snow amounts will average 1-4 inches with isolated totals up to 12 inches mainly away from the immediate coast and likely just NW of NYC.

Additional damage is likely on several fronts from this storm system and ongoing recovery efforts will be hampered however damages will be nowhere close to that of Sandy.

[Srain]

The overnight guidance continues to advertise a strong front arriving late Sunday/early Monday. The main interest regarding this front will be the rain potential and if we remained capped preventing severe storms from developing. It does appear that a line of showers/storms will accompany the frontal passage, but we will likely clear out fairly quickly with brisk NW gusty winds and falling temps during the day on Monday. Tuesday morning may see temps drop into the mid to upper 30’s across our northern regions and folks in Central Texas may see some frost and perhaps their first freeze of the year. We’ll monitor those temps in the days ahead to see if they extend further S. The Colorado Rockies may well see a rather significant snow event this weekend that extends into the Plains with this front along with a severe episode prior to the front sweeping S as moisture from the Gulf spreads N. Locally we can expect warmer nights and temps in the 80’s with gusty winds out of the SE ahead of the front Friday and Saturday as this potent storm system ejects into the Plains.

[Ed Lizard]

SWODY3 misses my yard, but gets Northern part of the HGX CWA.

[Srain]

SPC has placed the Slight Risk a bit closer to the Houston Metro, but still to our N. We may see that Slight Risk moved a tad further S today in future updates but that remains to be seen. It appears a quall line with the Polar cold front will be our best chance of rain and storms later this evening. Tomorrow will feel much different than day with blustery NW winds and temps falling into the 50's/upper 60's. Tomorrow night and early Wednesday may see areas flirt with some near freezing temps N of the area and in Central Texas.

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0657 AM CST SUN NOV 11 2012

VALID 111300Z - 121200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM E TX AND THE ARKLATEX INTO

PARTS OF THE OZARKS AND LWR MS VLY...

...SYNOPSIS...

DEEP RCKYS TROUGH WILL CONTINUE E INTO THE PLNS TODAY AND INTO THE

MID/UPR MS VLY EARLY MON. IN ITS WAKE...ZONAL FLOW WILL OVERSPREAD

THE WEST. SHORTWAVE IMPULSE NOW IN THE BASE OF THE TROUGH OVER NM

SHOULD TURN NEWD THIS AFTN...REACHING ERN KS BY THIS EVE AND WI

EARLY MON.

SFC LOW ASSOCIATED WITH THE UPR TROUGH WILL CONTINUE TO MOVE NNE

INTO WRN ONT TODAY AS TRAILING POLAR COLD FRONT CONTINUES ESE ACROSS

THE MID MS VLY...OZARKS...AND ERN PARTS OF THE SRN PLNS. THE SRN

PART OF THE FRONT WILL OVERTAKE REMAINING PORTION OF PACIFIC FRONT

OVER ERN OK AND CNTRL TX LATER TODAY. THE PACIFIC FRONT LIKELY WILL

SERVE AS THE MAIN FOCUS FOR STRONG TO SVR TSTMS THIS PERIOD.

....E TX/ARKLATEX/SRN OZARKS TODAY/TNGT...

MODERATE SFC-BASED INSTABILITY SHOULD DEVELOP ALONG/AHEAD OF PACIFIC

COLD FRONT TODAY...WITH SBCAPE EXPECTED TO BE AOA 1000 J/KG FROM ERN

OK/WRN AR S AND SW INTO E TX/WRN LA BY EARLY AFTN. COUPLED WITH

GLANCING INFLUENCE OF NM UPR IMPULSE...AND ARRIVAL OF SOMEWHAT MORE

MOISTURE-RICH RETURN FLOW /SFC DEWPOINTS IN THE LOW TO MID 60S

F/...THE DESTABILIZATION SHOULD FOSTER INTENSIFICATION OF STORMS

ALONG THE FRONT...AND/OR DEVELOPMENT OF NEW STORMS JUST AHEAD OF IT.

50-60 KT DEEP SWLY SHEAR WILL PERSIST OVER REGION...SUPPORTING THE

POTENTIAL FOR SUSTAINED STORMS/SUPERCELLS. WITH A MAJORITY OF THE

ACTIVITY EXPECTED TO FOCUS ALONG THE FRONT...THE PREDOMINANT

CONVECTIVE MODE SHOULD BE QUASI-LINEAR. HOWEVER...SOMEWHAT CONFLUENT

LOW-LVL...PRE-FRONTAL FLOW BENEATH APPRECIABLE UPR DIVERGENCE

SUGGESTS THAT POTENTIAL ALSO WILL EXIST FOR A FEW DISCRETE OR

SEMI-DISCRETE SUPERCELLS IF CAP IS BREACHED AHEAD OF THE LINE. THESE

COULD POSE AN ISOLD TORNADO RISK GIVEN CURVED LOW-LVL HODOGRAPHS

WITH SUBSTANTIAL SPEED SHEAR...ESPECIALLY FROM E TX/NW LA INTO CNTRL

AR. HOWEVER...PRE-FRONTAL STORM COVERAGE SHOULD BE WDLY SCTD AT

BEST...AND FCST WIND PROFILES SHOW LOW TO MID-LVL BACK-VEER PATTERNS

THAT ARE NOT FAVORABLE FOR TORNADOES. THUS...THE MAIN SVR THREAT

SHOULD BE WIND DAMAGE ASSOCIATED WITH SMALL-SCALE BOWS LIKELY TO

EVOLVE ALONG THE FRONTAL SQUALL-LINE. SOME HAIL ALSO MAY

OCCUR...MAINLY IN TX.

THE SEVERE THREAT SHOULD BE GREATEST THIS AFTN INTO EARLY TNGT AND

SHOULD DIMINISH LATER TNGT AS THE NM IMPULSE CONTINUES NEWD AWAY

FROM AREA OF GREATEST MOISTURE RETURN...AND SQUALL LINE MOVES E

BEYOND RELATIVELY NARROW AXIS OF RETURN FLOW.

..CORFIDI/SMITH.. 11/11/2012

[Srain]

MESOSCALE DISCUSSION 2117

NWS STORM PREDICTION CENTER NORMAN OK

1012 AM CST SUN NOV 11 2012

AREAS AFFECTED...NERN TX...SWRN AR...FAR SERN OK

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 111612Z - 111815Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...N/S-ORIENTED BAND OF PRE-FRONTAL TSTMS MAY ACQUIRE

TRANSIENT SUPERCELL STRUCTURES BY MIDDAY. ALTHOUGH BUOYANCY IS

WEAK...STRONG LOW-LEVEL SHEAR SHOULD PROMOTE A LOW-END RISK FOR

TORNADOES AND DAMAGING WINDS.

DISCUSSION...N/S-ORIENTED BAND OF TSTMS...ROUGHLY FROM 25 SW PRX TO

50 S CRS AT 16Z...HAS INITIATED IN THE PAST HALF HOUR. INTERPOLATED

PROFILER/VWP DATA INDICATE FAVORABLE 0-1 KM SHEAR FOR LOW-LEVEL

ROTATION. HOWEVER...WEAKNESS IN THE HODOGRAPH AROUND 2-3 KM AGL

/ESPECIALLY WITH SRN EXTENT/ SHOULD LIMIT SUSTAINABILITY OF

SUPERCELL UPDRAFTS WITHIN A WEAKLY UNSTABLE AIR MASS. ALTHOUGH

SURFACE HEATING IS BEING RETARDED BY WIDESPREAD CLOUD COVER...THERE

IS CONCERN FOR A LOW-END TORNADO/DAMAGING WIND RISK THAT MAY BE

SUFFICIENT FOR A WW ISSUANCE BY MIDDAY.

..GRAMS/WEISS.. 11/11/2012

ATTN...WFO...LZK...SHV...TSA...HGX...FWD...

[Srain]

Morning e-mail from Jeff:

Strong cold front has moved into the Gulf of Mexico overnight with much colder conditions and gusty winds now in place across the area.

Morning temperatures are starting out in the upper 40’s to mid 50’s across the region under clearing skies and gusty NW winds. Upstream temperatures have fallen to near freezing over the Dallas area and this second push of colder air will arrive during the day today. Expect highs only in the mid 60’s even with full sun as cold air advection offsets solar heating. Little change is expected through much of the week as high pressure controls from the north with a cool and dry air mass in place through the end of the week. Lows both Tuesday and Wednesday mornings could get close to the freezing mark over our northern counties.

Winds will attempt to swing around to the SE by this weekend, but moisture return will be slow with several days of offshore flow this week and do not expect much in the way of rain chances until maybe early next week. It is starting to get dry as most of the October rainfall was well below normal. Hopefully we can get into a pattern shift and more active storm track by the middle to end of this month.

[DoctorMu]

wow, didn't see this upper trough coming. I expected verga with DPs in the 20s...but lo and behold a thunderstorm with a decent soaking as the system meanders east.

[msp]

wow, didn't see this upper trough coming. I expected verga with DPs in the 20s...but lo and behold a thunderstorm with a decent soaking as the system meanders east.

quite a bit of lightning walking around campus this evening. i was totally caught off guard.

[Srain]

A zonal flow pattern is in the works for the remainder of the week. Seasonal temps with dry weather should continue into the weekend before a return flow becomes established and moisture slowly builds ahead of another Western trough. The GFS ensembles are in agreement that the best chance for rain will occur next Tuesday into Wednesday as an upper level disturbance traverses across the Lone Star State/Southern Plains. At this time it appears the rain chances will decrease just in time for Thanksgiving as another East Coast storm threatens the Mid Atlantic.

SPC:

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0348 AM CST WED NOV 14 2012

VALID 171200Z - 221200Z

...DISCUSSION...

DAY 4-5...SEVERE POTENTIAL SHOULD REMAIN LOW THROUGH AT LEAST DAY 5

WITH A CUTOFF UPPER LOW MOVING SLOWLY THROUGH THE SERN U.S. AND

OFFSHORE FLOW OVER MOST OF THE GULF WITH THE EXCEPTION OF THE WRN

GULF DAY 5.

DAY 6-7...THREAT FOR SEVERE STORMS COULD INCREASE DAY 6-7 OVER TX.

MODELS CONTINUE TO ADVERTISE A SRN STREAM SHORTWAVE TROUGH THAT WILL

MOVE THROUGH TX AND THE LOWER MS VALLEY DURING THIS TIME.

HOWEVER...AMPLITUDE AND TIMING DIFFERENCES PERSIST AMONG

DETERMINISTIC RUNS AND ENSEMBLE MEMBERS. PRIMARY CONCERN IS DEGREE

OF MOISTURE RETURN IN ADVANCE OF THIS FEATURE. ECMWF IS SLOWER

MOVING THE ERN U.S. TROUGH OFF THE ATLANTIC SEABOARD...RESULTING IN

LESS TIME FOR GULF MODIFICATION AND A MORE LIMITED RETURN OF LOW

LEVEL MOISTURE THAN THE GFS. GIVEN PERSISTENT MODEL DIFFERENCES AND

POTENTIAL FOR LIMITED MOISTURE RETURN...WILL MAINTAIN LOW

PREDICTABILITY THIS FORECAST.

..DIAL.. 11/14/2012

[Srain]

The pattern heading into Thanksgiving week suggests some embedded upper air disturbances will sweep across Texas via the noisy sub tropical jet. A return flow from the Gulf should allow for modest moisture to flow inland ahead of these disturbances as a zonal flow continues throughout the week. Light precip is possible Tuesday and again on Thursday/Friday, but rainfall amounts will be light at best. I hope everyone has a great Thanksgiving Holiday!

[Srain]

Heh...

[Srain]

18Z GFS Ensembles:

[Srain]

Some mighty chilly air is poised to spill S from Canada. It appears the first true Blue Norther of the season may well be in the works to end the month...

[Srain]

Fairly impressive signal for a Winter Storm potential somewhere in the Southern/Central Rockies/Southern Plains Region via the 12Z GFS...

[Ed Lizard]

Some mighty chilly air is poised to spill S from Canada. It appears the first true Blue Norther of the season may well be in the works to end the month...

Euro is prettier. Cold with a chance of precip beats cold and dry every time. At least the 500 mb flow isn't a complete bummer on the Euro.

Joys of early sunsets, 1 hour to new Euro...

[Srain]

12Z Euro:

[DoctorMu]

Some Panhandle Pummeling potential. Love to see some wintery action sneak past Waco and even Hearne (where Aggiedome blockage usually sets up against wintry stuff)

The GFS is modifying after 240 hrs out...we'll see.

[somethingfunny]

Ho, this is a surprise!

[wxmx]

I know that for most of the region it has been mostly dry, but for me this is the 8th consecutive day with no sun and at least 50% of the time has been drizzling. It also looks like this will continue for the rest of the week.

[Srain]

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

[wxmx]

Still stuck in the wet pattern for NE MX, might even get the rare cold season TS today afternoon.

[bubba hotep]

Still stuck in the wet pattern for NE MX, might even get the rare cold season TS today afternoon.

I'm glad y'all are picking up some rain but I am ready for this pattern to break, esp. across N. Texas.

[Srain]

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

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