SPC AC 121629
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT WED MAY 12 2010
VALID 121630Z - 131200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM NW TX INTO THE MID MS AND
LOWER OH VALLEYS...TO THE MID ATLANTIC COAST...
...CENTRAL/SOUTHERN PLAINS...
A LARGE UPPER TROUGH REMAINS OVER THE WESTERN STATES TODAY...WITH
BAND OF 70-90 KNOT MID LEVEL WINDS EXTENDING FROM AZ/NM INTO THE
CENTRAL PLAINS. THE MAIN SURFACE BAROCLINIC ZONE LIES FROM CENTRAL
MO INTO SOUTH CENTRAL KS WHERE A WEAK SURFACE LOW IS EVIDENT. THIS
BOUNDARY WILL PROVIDE THE PRIMARY FOCUS FOR STRONG/SEVERE
THUNDERSTORM DEVELOPMENT LATER TODAY AND TONIGHT. 12Z RAOBS IN THE
WARM SECTOR SUGGEST THAT THE STRONG CAP WILL INHIBIT DEEP CONVECTION
AWAY FROM THE BOUNDARY THROUGH MOST OF THE DAY.
HOWEVER...INCREASING LOW LEVEL WARM ADVECTION AND LIFT ASSOCIATED
WITH WEAK SHORTWAVE TROUGH OVER EASTERN NM/WEST TX MAY EVENTUALLY
ERODE THE CAP OVER NORTHERN OK/SOUTHERN KS. THIS WILL LEAD TO
SCATTERED SEVERE STORMS ALONG THE FRONT...AND THE POTENTIAL FOR AT
LEAST ISOLATED CELLS FORMING DISCRETELY IN THE WARM SECTOR.
THERMODYNAMIC PROFILES IN THIS AREA WILL BE VERY UNSTABLE WITH
DEWPOINTS NEAR 70F AND MLCAPE VALUES OF 3000-4000 J/KG. FORECAST
SOUNDINGS SUGGEST STRONG EFFECTIVE SHEAR /OVER 50 KNOTS/ WILL
SUPPORT SUPERCELL STORMS CAPABLE OF VERY LARGE HAIL AND DAMAGING
WINDS. ANY DISCRETE STORM THAT FORMS OFF THE FRONT WILL ALSO HAVE
SUFFICIENT LOW LEVEL VERTICAL SHEAR /ESPECIALLY AFTER 00Z/ FOR THE
THREAT OF A FEW TORNADOES. ACTIVITY SHOULD TRACK/DEVELOP
NORTHEASTWARD ACROSS SOUTH CENTRAL KS AND INTO WESTERN MO THROUGH
THE EVENING WITH THE RISK OF RATHER WIDESPREAD HAIL.
FARTHER SOUTHWEST...IT APPEARS LIKELY AT LEAST ISOLATED
THUNDERSTORMS WILL DEVELOP ALONG THE SURFACE DRYLINE OVER WESTERN OK
AND WESTERN NORTH TX. THESE STORMS WILL TRACK EAST-NORTHEASTWARD
THIS EVENING AND WILL ALSO POSE A RISK OF LARGE HAIL AND DAMAGING
WINDS.
...KY/WV INTO VA...
A LARGE MCS IS ONGOING THIS MORNING OVER PARTS OF KY/WV. GIVEN THE
MESOSCALE ORGANIZATION OF THIS SYSTEM...IT APPEARS LIKELY TO
MAINTAIN ITS INTENSITY THROUGH THE DAY AS IT CROSSES THE
APPALACHIANS INTO VA. SUNNY SKIES AHEAD OF THE STORMS...COMBINED
WITH DEWPOINTS CLIMBING THROUGH THE 60S WILL PROVIDE SUFFICIENT
DESTABILIZATION FOR THE RISK OF SEVERE STORMS. DAMAGING WINDS
APPEAR TO BE THE MAIN THREAT.
..HART/SMITH.. 05/12/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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