Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
SPC AC 311629
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT THU MAR 31 2016
VALID 311630Z - 011200Z
...THERE IS AN ENH RISK OF SVR TSTMS THIS AFTERNOON/EVENING FOR NE
LA...SE AR...WRN TN...WRN KY...NRN MS...AND NW AL...
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE LOWER MS VALLEY TO THE
OH VALLEY...
...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLGT
RISK...FROM THE N CENTRAL GULF COAST TO LOWER MI...
...SUMMARY...
SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS A LARGE AREA EXTENDING FROM
THE CENTRAL GULF COAST STATES NORTHWARD ACROSS THE OHIO VALLEY TO
SOUTHERN MICHIGAN. THE GREATEST THREAT FOR TORNADOES AND VERY LARGE
HAIL WILL BE CENTERED OVER NORTHERN MISSISSIPPI AND ALABAMA THIS
AFTERNOON AND EVENING.
...MID SOUTH REGION THIS AFTERNOON/EVENING...
ONGOING CONVECTION HAS REINFORCED AN OUTFLOW BOUNDARY ACROSS NW AL
AND NRN MS...WHILE CLOUD STREETS ARE ALREADY DEVELOPING IN THE
UNSTABLE WARM SECTOR TO SW ACROSS NRN LA. THE PRE-FRONTAL
CONFLUENCE ACROSS NRN LA /ALSO REFLECTED IN 12Z 850 MB ANALYSES/
SHOULD SERVE AS THE INITIATION ZONE FOR SEVERE STORMS BY EARLY
AFTERNOON...WITH STORMS SPREADING ENEWD THROUGH THE
AFTERNOON/EVENING. THE WARM SECTOR ENVIRONMENT WILL FAVOR
SUPERCELLS CAPABLE OF VERY LARGE HAIL AND DAMAGING WINDS...GIVEN
MLCAPE NEAR 2000 J/KG AND EFFECTIVE BULK SHEAR NEAR 50 KT. THOUGH
LOW-LEVEL FLOW/SHEAR WILL TEND TO WEAKEN ACROSS THE MID SOUTH AS THE
SYNOPTIC WAVE MOVES NEWD OVER THE GREAT LAKES REGION...LOCALLY
BACKED WINDS ALONG THE REMNANT OUTFLOW BOUNDARY WILL HELP FOCUS THE
TORNADO THREAT FROM NRN MS INTO NW AL THIS AFTERNOON. A STRONG
TORNADO OR TWO WILL BE POSSIBLE AS SUPERCELLS INTERACT WITH THE
REMNANT OUTFLOW BOUNDARY WHERE LOW-LEVEL SHEAR WILL BE ENHANCED.
...NE AR/WRN TN/WRN KY THIS AFTERNOON...
CONVECTION IS ONGOING ACROSS E CENTRAL/NE AR JUST AHEAD OF THE
SURFACE COLD FRONT. SOME DESTABILIZATION IS OCCURRING INTO WRN
TN/KY TO THE N OF THE OUTFLOW BOUNDARY IN NRN MS...AND IT APPEARS
THAT THIS CONVECTION WILL POSE A SEVERE RISK INTO THIS AFTERNOON.
PRIMARILY STRAIGHT HODOGRAPHS SUGGEST THAT LARGE HAIL AND DAMAGING
WINDS WILL BE THE MAIN THREATS...THOUGH AN ISOLATED TORNADO CANNOT
BE RULED OUT. THE TIMING OF STORM DEVELOPMENT LATE THIS MORNING
CASTS DOUBT ON WHETHER OR NOT THE BOUNDARY LAYER CAN RECOVER THIS
AFTERNOON...WHICH MAY LIMIT THE POTENTIAL FOR ADDITIONAL SEVERE
STORMS ALONG THE COLD FRONT TOWARD THE CONFLUENCE OF THE MS/OH
RIVERS.
...SRN AL THIS AFTERNOON...
A SMALL SUPERCELL CLUSTER IS ONGOING IN SW AL...ON THE N EDGE OF THE
RICHEST RETURNING MOISTURE AND IN ASSOCIATION WITH THE SRN LOBE OF A
LEAD SHORTWAVE TROUGH NEAR THE MS/AL BORDER. VERTICAL SHEAR AND
BUOYANCY SHOULD REMAIN SUFFICIENT TO MAINTAIN THE RISK FOR LARGE
HAIL...DAMAGING WINDS...AND A TORNADO OR TWO WITH THE CLUSTER AS IT
DEVELOPS EWD ALONG A DIFFERENTIAL HEATING ZONE ACROSS SRN AL.
...IL/INDIANA THIS AFTERNOON...
STORMS HAVE ALREADY DEVELOPED NEAR THE SURFACE CYCLONE AND NW EDGE
OF THE WEAKLY UNSTABLE WARM SECTOR INTO NW IL. THIS CONVECTION WILL
MOVE QUICKLY EWD ACROSS NRN IL BY EARLY AFTERNOON...WITH SOME
ADDITIONAL SWD DEVELOPMENT POSSIBLE ALONG THE SURFACE COLD FRONT
INTO E CENTRAL IL AND INDIANA. A FEW DAMAGING GUSTS AND LARGE HAIL
WILL BE THE MAIN THREATS.
..THOMPSON/GLEASON.. 03/31/2016
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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