ZCZC SPCSWOMCD ALL
ACUS11 KWNS 271808 
SPC MCD 271808 
LAZ000-TXZ000-271945-

MESOSCALE DISCUSSION 0482
NWS STORM PREDICTION CENTER NORMAN OK
0108 PM CDT MON APR 27 2015

AREAS AFFECTED...SE TX...LA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 271808Z - 271945Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...ISOLATED LARGE HAIL THREAT LIKELY TO DEVELOP ACROSS LA
EARLY THIS AFTERNOON AND MAY EXTEND BACK INTO SE TX LATER THIS
AFTERNOON. WW ISSUANCE MAY BE NEEDED ACROSS THE REGION THIS
AFTERNOON.

DISCUSSION...A CLUSTER OF ELEVATED THUNDERSTORMS IS DEVELOPING
ACROSS SW AND CNTRL LA TO THE NORTH OF AN OUTFLOW BOUNDARY SAGGING
SWD ACROSS THE NRN GULF OF MEXICO PER VISIBLE SATELLITE IMAGERY.
MUCAPE IS ESTIMATED TO BE NEAR 500 J/KG TO THE NORTH OF THE BOUNDARY
WITH 850 TO 500 MB LAPSE RATES NEAR 7.5 C/KM. IN ADDITION...THE POE
WSR-88D VWP SHOWS 50 TO 55 KT OF FLOW AT 5 KM THAT IS CONTRIBUTING
TO SUFFICIENT EFFECTIVE SHEAR FOR STORM ORGANIZATION. THE STEEP
MID-LEVEL LAPSE RATES AND SHEAR SHOULD SUPPORT ISOLATED LARGE HAIL
WITH CELLS THAT CAN ROTATE. SHORT-TERM MODEL FORECASTS INCLUDING THE
HRRR MOVE THIS CONVECTION NEWD ACROSS CNTRL LA OVER THE NEXT FEW
HOURS. A POTENTIAL FOR HAIL COULD CONTINUE WITH CELLS THAT MOVE INTO
SW MS. FURTHER SOUTHWEST...MODEL SOLUTIONS SUGGEST THAT CELLS WILL
PROBABLY INITIATE IN THE HOUSTON AREA ON THE ERN EDGE OF AN AXIS OF
INSTABILITY WHERE MLCAPE IS ESTIMATED TO BE IN THE 1000 TO 1200 J/KG
RANGE. THIS CONVECTION COULD BE CLOSER TO BEING SFC-BASED AND A
POTENTIAL FOR ROTATING STORMS WITH ISOLATED LARGE HAIL MAY ALSO
DEVELOP THERE LATE THIS AFTERNOON.

..BROYLES/MEAD.. 04/27/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...JAN...LIX...LCH...SHV...HGX...

LAT...LON   30069262 29479430 29469494 29799531 30369559 30869550
            31119516 31369467 31929263 31479177 30709167 30069262 

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