SPC AC 291222
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0722 AM CDT SAT MAY 29 2010
VALID 291300Z - 301200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE CENTRAL
HIGH PLAINS NORTHWARD INTO THE DAKOTAS...
A LARGE UPPER TROUGH REMAINS OVER THE WESTERN STATES THIS
MORNING...WITH SEVERAL SHORTWAVE TROUGHS ROTATING ACROSS THE
SOUTHWEST INTO THE CENTRAL/NORTHERN ROCKIES. ONE OF THESE SHORTWAVE
TROUGHS IS EVIDENT IN WATER VAPOR IMAGERY ROTATING ACROSS UT. AHEAD
OF THE TROUGH...INCREASING LARGE SCALE FORCING ALONG THE SURFACE
COLD FRONT WILL HELP TO WEAKEN THE CAPPING INVERSION AND LEAD TO
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS FROM NORTHEAST CO INTO
ND. VERTICAL SHEAR ALONG THIS CORRIDOR WEAKENS WITH SOUTHWARD
EXTENT...BUT STEEP LAPSE RATES AND A VERY UNSTABLE AIR MASS WILL
LIKELY BE SUFFICIENT FOR A FEW MULTICELL INTENSE/SEVERE STORMS
CAPABLE OF LARGE HAIL AND DAMAGING WINDS.
...SOUTHEAST...MID ATLANTIC...AND NEW ENGLAND STATES...
A LARGE AREA OF AT LEAST SCATTERED AFTERNOON THUNDERSTORMS IS
EXPECTED TO DEVELOP AGAIN THIS AFTERNOON FROM PORTIONS OF AL/GA
NORTHEASTWARD INTO THE MID ATLANTIC STATES AND SOUTHERN NEW ENGLAND.
VERTICAL SHEAR OVER THIS REGION WILL RANGE FROM 35 KNOTS IN THE
NORTH TO 15 KNOTS IN GA/AL. THUNDERSTORMS ARE LIKELY TO DEVELOP
FIRST OVER THE SOUTHERN APPALACHIAN MOUNTAINS NEAR POCKET OF COOL
MID LEVEL TEMPERATURES AND WEAK MID LEVEL LOW. THESE STORMS WILL
SPREAD/DEVELOP SLOWLY OUTWARD ACROSS THE REGION WITH DAMAGING WINDS
AND HAIL POSSIBLE. OTHER MORE ISOLATED THUNDERSTORMS ARE EXPECTED
TO DEVELOP ALONG THE SURFACE COLD FRONT OVER EASTERN NY/PA AND MOVE
EASTWARD INTO SOUTHERN NEW ENGLAND. DESPITE WEAK LAPSE RATES...A
FEW OF THE STRONGER CELLS COULD PRODUCE GUSTY WINDS AND HAIL.
OVERALL COVERAGE OF SEVERE REPORTS WILL LIKELY BE LESS TODAY THAN
YESTERDAY OVER THE SOUTHEAST STATES.
..HART/GRAMS.. 05/29/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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