MCS Potential Houston and Gulf Coast Thursday

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srainhoutx
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The area highlighted in Larry's topic for the SE Texas and Coastal areas along and S of I-10 in Louisiana continues to have some attention by the Storm Prediction Center in their Day 2 Outlook...

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 AM CDT WED MAR 26 2014

VALID 271200Z - 281200Z

...WESTERN AND CENTRAL GULF COAST REGION...
CONFIDENCE REMAINS LOWER THAN AREAS TO THE NORTH...BUT MODELS
CONTINUE TO SUGGEST AT LEAST SOME POTENTIAL FOR ORGANIZED CONVECTIVE
DEVELOPMENT ACROSS PARTS OF SOUTHEAST TEXAS INTO UPPER TEXAS AND
LOUISIANA COASTAL AREAS THURSDAY...ALONG OR JUST NORTH OF THE
SUBTROPICAL JET AXIS.
GIVEN ACCESS TO BETTER MOISTURE RETURN OFF
THE GULF...AND GREATER POTENTIAL INSTABILITY...IT IS POSSIBLE THAT
DEEP LAYER SHEAR COULD BE SUFFICIENT FOR ISOLATED SUPERCELLS...BOTH
DURING INITIAL DEVELOPMENT...AND PERHAPS ALONG OR JUST AHEAD OF ANY
DEVELOPING STORM CLUSTER.


..KERR.. 03/26/2014
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wxman57
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There is some sort of atmospheric sciences program at UH. U of H started releasing balloons a year or two ago. The program is sponsored by CenterPoint. They generally work with us to determine optimal times for sending up a balloon.
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wxman57 wrote:There is some sort of atmospheric sciences program at UH. U of H started releasing balloons a year or two ago. The program is sponsored by CenterPoint. They generally work with us to determine optimal times for sending up a balloon.

Yea the program at U.H got started a couple of years ago I believe. One thing that is useful for launches at KCLL is the fact that it gives a good representation of upstream conditions. That reason alone is why we do a lot of our launches.
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OK time to un-hijack the thread.

With all the talk of severe weather (or not) we've lost the original discussion. Are we still looking for an MCS to develop? We need the rain. Don't really care if it hails or not.
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srainhoutx
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Rain is definitely welcomed up here in NW Harris County. We had missed all the rain the folks S of I-10 received last Sunday. The pollen is finally getting washed away.

SHORT TERM FORECAST
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
226 PM CDT WED MAR 26 2014

TXZ193-194-207>209-221>225-262130-
BASTROP-LEE-GUADALUPE-CALDWELL-FAYETTE-WILSON-KARNES-GONZALES-
DE WITT-LAVACA-
INCLUDING THE CITIES OF...BASTROP...GIDDINGS...SEGUIN...
LOCKHART...LA GRANGE...FLORESVILLE...KARNES CITY...GONZALES...
CUERO...HALLETTSVILLE
226 PM CDT WED MAR 26 2014

.NOW...
SHOWER ACTIVITY HAS BECOME BETTER ORGANIZED ACROSS THE SOUTHEAST
COUNTIES THIS AFTERNOON. MODERATE TO ISOLATED HEAVY SHOWERS AND
ISOLATED THUNDERSTORMS WILL CONTINUE TO AFFECT MAINLY PARTS OF
GUADALUPE...GONZALES...CALDWELL...FAYETTE AND LAVACA COUNTIES FOR
THE NEXT SEVERAL HOURS. RADAR TRENDS SUGGEST A MID LOW LEVEL
PRESSURE SYSTEM FORMING AS THE CONVECTION PUSHES TO THE NORTHEAST.
RAINFALL ACCUMULATIONS WILL GENERALLY BE AROUND ONE TENTH TO ONE
QUARTER INCH WITH ISOLATED STORMS PRODUCING UP TO ONE HALF INCH.
EXPECT BREEZY CONDITIONS WITH GUSTS OF 30 TO 45 MPH AS STORMS MOVE ACROSS
YOUR AREA. WEATHER CONDITIONS ARE EXPECTED TO IMPROVE LATER THIS
AFTERNOON AND EARLY EVENING.



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Currently we are getting barely enough drops of rain to allow for the yellow pollen to become a paste...
Patience is a virtue.
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HGX thoughts concerning how Thursday may develop...

MODELS APPEAR TO BE ON THE SAME PAGE FOR THURSDAY WITH REGARD TO
RAIN CHANCES. SE TX WILL ONCE AGAIN LIE IN A LEFT FRONT QUAD WITH
THE NAM AND ECMWF INDICATING A SPLIT IN THE JET STRUCTURE. THE
850-700MB LAYER IS NEARLY SATURATED AS WELL. FCST SOUNDINGS SHOW
A CAP IN PLACE DURING THE MORNING THAT WILL ERODE IN THE AFTN.
NOW...WE`VE BEEN BURNED IN THE PAST WITH FCSTING THE CAP TO ERODE
SO AM A LITTLE GUN SHY...BUT THE UPPER LEVEL JET DYNAMICS LOOK
STRONGER WITH THIS SYSTEM SO WILL BUY INTO RAPID CONVECTIVE
DEVELOPMENT RIGHT OVER THE CWA WITH BEST RAIN CHANCES OVER THE
EASTERN HALF OF THE CWA.
THE PRECIP WILL MOVE EAST QUICKLY AND
EXIT THE CWA BY 00Z. INSTABILITY PARAMETERS DON`T LOOK TOO
IMPRESSIVE BUT THE WET BULB ZERO IS AROUND 9000 FEET SO SOME OF
THE STRONGER STORMS COULD PRODUCE SOME HAIL.
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Mesoscale Convective System (MCS) or Mesoscale Convective Complex (MCC) can bring either severe weather and/or heavy rain. Some big flood events were from MCS.
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srainhoutx
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The dry line is progressing E toward the I-35 Corridor as it nears the Hill Country. While capping issues appear to be the main limiting factor particularly SW of Metro Houston, there is a chance the cap can erode near College Station and basically N of HWY 105 on to the E later today. Water Vapor imagery show a short wave crossing Mexico and if we are going to have a 'trigger' across portions of SE Texas for surface based storms firing, that S/W will be the disturbance to watch as the afternoon continues.
03272014 17Z TX VIS latest.jpg
03272014 17Z_metars_abi.gif
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03272014 mcd0210.gif
MESOSCALE DISCUSSION 0210
NWS STORM PREDICTION CENTER NORMAN OK
0201 PM CDT THU MAR 27 2014

AREAS AFFECTED...ERN TX...WRN LA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 271901Z - 272100Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A CLUSTER OF STORMS ROOTED JUST ABOVE THE SURFACE SHOULD
FORM BY LATE AFTERNOON WITHIN A PERSISTENT LOW-LEVEL WAA REGIME AS
INHIBITION WANES. ISOLATED SEVERE HAIL SHOULD BE THE PRIMARY
THREAT...BUT LOCALLY DAMAGING WINDS AND A BRIEF TORNADO ARE POSSIBLE
WITH POTENTIAL FOR EMBEDDED SUPERCELL STRUCTURES.

DISCUSSION...MOST CONVECTION-ALLOWING AND CONVECTION-PARAMETRIZED
GUIDANCE HAS BEEN TOO QUICK TO DEVELOP SIMULATED STORMS ACROSS
E-CNTRL/SERN TX. THIS IS LIKELY DUE TO A STRONG CAPPING INVERSION
NOTED IN 12Z CRP RAOBS AND A SPECIAL 15Z RAOB NEAR IAH ALONG WITH
LATE MORNING AMDAR DATA. MOST RECENT AMDAR DATA SUGGEST THE
INVERSION IS WEAKENING AND A SPECIAL 17Z RAOB NEAR CLL INDICATES
LITTLE INHIBITION WITH RICH LOW-LEVEL SATURATION.

CONTINUED LOW-LEVEL WAA AND DEEPENING CLOUDS ATOP THE LOW-LEVEL
STRATUS DECK SUGGEST THAT STORMS ROOTED ABOVE THE SURFACE WILL
INCREASE IN COVERAGE THOUGH LATE AFTERNOON. STEEP MID-LEVEL LAPSE
RATES AND MODERATE BUOYANCY WOULD SUPPORT A RISK FOR SEVERE HAIL
WITH SUFFICIENT DEEP-LAYER SHEAR FOR ORGANIZED UPDRAFTS.
HOWEVER...THE LIKELIHOOD OF A CLUSTER CONVECTIVE MODE WITHIN AN
ILL-DEFINED SURFACE PATTERN SHOULD TEMPER LONGEVITY OF INDIVIDUAL
UPDRAFTS AND HAIL SIZE. EVEN WITH CONVECTION LIKELY INITIATING ABOVE
THE SURFACE...SATURATED LOW-LEVEL THERMODYNAMIC PROFILES WITH
NEAR-NEUTRAL LAPSE RATES COULD YIELD LOCALLY DAMAGING WINDS AND A
BRIEF TORNADO.

..GRAMS/THOMPSON.. 03/27/2014


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


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srainhoutx
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The Storm Prediction Center issues Slight Risk for severe storms across SE Texas and Western Louisiana for today.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
ISSUED BY 15TH OWS SCOTT AIR FORCE BASE IL
0243 PM CDT THU MAR 27 2014

VALID 272000Z - 281200Z

...THERE IS A SLGT RISK OF SVR TSTMS ERN PARTS OF KS AND OK INTO MID
MS VALLEY AND OZARK PLATEAU...

...THERE IS A SLGT RISK OF SVR TSTMS ERN TX INTO THE LOWER MS
VALLEY...


...SYNOPSIS...

A PROGRESSIVE...LOW-AMPLITUDE PATTERN WILL EXIST OVER THE CONUS
THROUGH THE REMAINDER OF THE D1 PERIOD. WITHIN THIS REGIME...A
POLAR-BRANCH SHORT-WAVE TROUGH AND ASSOCIATED 70-80 KT MIDLEVEL JET
STREAK WILL TRANSLATE FROM THE CNTRL/SRN PLAINS ENEWD INTO THE GREAT
LAKES AND OH VALLEY BY 28/12Z. THIS SYSTEM WILL BE ATTENDED BY A
BROAD 50-60+ KT SWLY LLJ WHICH WILL CORRESPONDINGLY MIGRATE FROM
LOWER ELEVATIONS OF THE GREAT PLAINS AND OZARKS TO UPPER OH VALLEY
AND NERN U.S. BY THE END OF THE PERIOD.

AT THE SURFACE...LOW PRESSURE OVER SWRN IA WILL UNDERGO GRADUAL
WEAKENING WHILE DEVELOPING NEWD TO ERN IA BY 28/00Z...PRIOR TO
REACHING NRN LOWER MI BY DAYBREAK FRIDAY. A DRYLINE EXTENDING SWD
FROM THIS LOW WILL MIX EWD INTO ERN PARTS OF KS/OK THIS AFTERNOON
WHILE BEING GRADUALLY OVERTAKEN FROM THE N BY A COLD FRONT ADVANCING
SEWD THROUGH THE CNTRL INTO SRN PLAINS. THE SRN EXTENSION OF THE
DRYLINE WILL LIKELY REACH THE I-35 CORRIDOR OF TX BEFORE STALLING IN
RESPONSE TO CYCLOGENESIS OVER N-CNTRL TX TONIGHT.

...ERN PARTS OF KS/OK INTO THE MID MS VALLEY AND OZARK PLATEAU THIS
AFTERNOON INTO TONIGHT...

THE POLEWARD FLUX OF HEAT AND MOISTURE WILL BE MAINTAINED TODAY
ALONG THE ABOVE-MENTIONED LLJ AXIS WITH WARM SECTOR DEWPOINTS RISING
INTO THE 50S OVER ERN KS/WRN MO...AND UPPER 50S TO LOWER 60S ACROSS
PARTS OF ERN OK AND AR. THIS MOISTURE INCREASE WILL BE SURMOUNTED BY
A WELL-DEFINED EML WITH AFTERNOON MLCAPE VALUES APPROACHING 500-1200
J/KG WITHIN THE NWD-EXPANDING WARM SECTOR.

CLEARING SKIES IN CENTRAL AND EASTERN KS ALLOWING FOR FURTHER
DESTABILIZATION IN LOW LEVEL...SURFACE-BASED STORM DEVELOPMENT HAS
BEGUN FROM THE VICINITY OF THE SURFACE LOW OVER SWRN IA SWWD ALONG
THE COLD FRONT-DRYLINE OCCLUSION INTO ERN KS. THIS COUPLED WITH
STRONG SHORTWAVE WILL ALLOW THE LINEAR NATURE OF LOW-LEVEL FORCING
MECHANISM AND ITS ALIGNMENT TO THE DEEP-LAYER SHEAR VECTOR WOULD
INDICATE THAT STORMS SHOULD EVOLVE INTO LINE SEGMENTS OR A
CONTINUOUS BAND WITH HAIL AND DAMAGING WINDS BEING THE PRIMARY
HAZARDS. AS THESE STORMS SPREAD EWD/SEWD INTO THE OZARK PLATEAU AND
MID MS VALLEY OVERNIGHT...EXPECT THE SEVERE WEATHER THREAT TO
GRADUALLY DIMINISH OWING TO THE COOLING AND RESULTANT STABILIZATION
OF THE BOUNDARY LAYER.

DIURNAL STORM DEVELOPMENT SWD ALONG THE DRYLINE INTO ERN OK/WRN AR
REMAINS MORE UNCERTAIN GIVEN THE TENDENCY FOR THE HEIGHT
FALLS/FORCING FOR ASCENT ASSOCIATED WITH THE MIDLEVEL TROUGH TO
SHIFT AWAY FROM THE REGION DURING THE TIME OF PEAK HEATING. AS
SUCH...INITIATION WILL BE HEAVILY RELIANT ON BOUNDARY LAYER HEATING
ALONG AND WEST OF THE DRYLINE. SHOULD SURFACE-BASED STORMS FORM AND
BECOME SUSTAINED...THE COMBINATION OF MODERATE INSTABILITY...50-60
KT OF DEEP-LAYER SHEAR ORIENTED NORMAL TO THE DRYLINE AND MODERATELY
STRONG LOW-LEVEL SHEAR WILL BE SUPPORTIVE OF SUPERCELLS CAPABLE OF
LARGE HAIL AND A FEW TORNADOES.

...ERN TX INTO THE LOWER MS VALLEY THIS AFTERNOON THROUGH
TONIGHT...

A CLUSTER OF STORMS HAS DEVELOPED THIS AFTERNOON JUST ABOVE THE
SURFACE IN A PERSISTENT LOW-LEVEL WAA REGIME. A SPECIAL 17Z RAOB
NEAR CLL SHOWED THAT A STRONG CAPPING INVERSION OVER THE AREA HAD
WEAKENED SIGNIFICANTLY LEAVING THE AREA WITH LITTLE INHIBITION AND
RICH LOW-LEVEL SATURATION. EXPECT STORMS TO CONTINUE TO DEVELOP AND
INCREASE IN COVERAGE ACROSS THE AREA THIS AFTERNOON. STEEP
MID-LEVEL LAPSE RATES AND MODERATE BUOYANCY SUPPORT A RISK FOR
SEVERE HAIL. HOWEVER, THE LIKELIHOOD OF A CLUSTER CONVECTIVE MODE
WITHIN AN ILL-DEFINED SURFACE PATTERN SHOULD TEMPER LONGEVITY OF
INDIVIDUAL UPDRAFTS AND HAIL SIZE. EVEN WITH CONVECTION LIKELY
INITIATING ABOVE THE SURFACE, SATURATED LOW-LEVEL THERMODYNAMIC
PROFILES WITH NEAR-NEUTRAL LAPSE RATES COULD YIELD LOCALLY DAMAGING
WINDS AND A BRIEF TORNADO.

..15_OWS.. 03/27/2014
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BlueJay
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So far I can report 0.02 inches of rain in my backyard.
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SPC has been a little aggressive in their slight risk for SE TX thus far this year...given the capping seen. Soundings launched by UH this morning clearly showed significant capping. Tomorrow may be a different story...but it does not look widespread...maybe a few severe storms in the heat of the afternoon, but we are going to have to burn off the low clouds and sea fog/mist and that may be hard to do given dewpoints in the upper 60's over shelf waters in the low 60's and weakening winds.
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