MCS Potential Houston and Gulf Coast Thursday

[srainhoutx]

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

[BlueJay]

So far I can report 0.02 inches of rain in my backyard.

[jeff]

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.