DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 010053
SWODY1
SPC AC 010051

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0751 PM CDT SAT APR 30 2011

VALID 010100Z - 011200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID-SOUTH TO THE SRN
PLAINS...

...MID-SOUTH...
COMBINATION OF WEAK ASCENT IN ENTRANCE REGION OF AN EJECTING
JET-STREAK...DEEPENING MOIST BOUNDARY LAYER AND MODEST HEATING HAVE
CONTRIBUTED TO TSTM DEVELOPMENT LATE AFTN OVER CNTRL/NERN AR. 00Z
LZK SOUNDING EXHIBITED MLCAPE AROUND 2000 J/KG AND EFFECTIVE SHEAR
50+ KTS...MORE THAN SUFFICIENT FOR ORGANIZED STORMS INCLUDING BRIEF
SUPERCELLS AND CLUSTERS/BANDS. NRN STORMS WILL DEVELOP ENE INTO THE
LOWER OH VLY AND PROBABLY WEAKEN WITH EWD EXTENT GIVEN SLIGHTLY MORE
STABLE ENVIRONMENT. FARTHER S...COMPARATIVELY MORE ROBUST
INSTABILITY AND AMPLE 0-1KM SHEAR OF 30+ KTS WILL YIELD A FEW
STRONG-SEVERE STORMS CAPABLE OF LARGE HAIL...DMGG WIND GUSTS...AND
PERHAPS A COUPLE OF TORNADOES.

...NRN TX...
SCATTERED DISCRETE STORM DEVELOPMENT...INCLUDING
SUPERCELLS...OCCURRED ALONG A COLD FRONT LATE THIS AFTERNOON OVER
NCNTRL TX AMID STRONG BOUNDARY LAYER HEATING AND STEEP MID-LEVEL
LAPSE RATES. SOUNDING AND VWP DATA INDICATE A WEAK LOW-LEVEL WIND
FIELD...BUT MAGNITUDE OF MID-TROP LAPSE RATES AND 40-50 KTS OF
EFFECTIVE SHEAR ARE COMPENSATING TO SUPPORT ROTATING STORMS. AS
STORMS CONTINUE ENE OFF THE FRONT AND INTO AN ENVIRONMENT
CHARACTERIZED BY A COMPARATIVELY RICHER MOISTURE AND STRONGER
LOW-LEVEL SHEAR OVER NE TX...THREATS FOR VERY LARGE HAIL AND A
COUPLE OF TORNADOES WILL EXIST THROUGH MID-EVENING.

SOME OF THESE STORMS WILL EVOLVE ENE INTO THE MID-SOUTH OVERNIGHT
WITH A CONTINUED THREAT FOR AT LEAST HAIL AND HIGH WINDS.
BUT...EXPECT ACTIVITY ALONG SRN END OF THE SLIGHT RISK AREA TO
DIMINISH AND/OR EVOLVE FARTHER N OF THE COLD FRONT AS ELEVATED BANDS
OF STORMS ALONG THE RED RIVER OVERNIGHT. A FEW OF THESE STORMS MAY
CONTAIN LARGE HAIL.

..RACY.. 05/01/2011

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