SPC AC 121227
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0727 AM CDT TUE JUN 12 2007
VALID 121300Z - 131200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE NORTHERN AND
CENTRAL HIGH PLAINS...
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF
SC...GA...AL...AND FL...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF NY AND PA...
...SOUTHEAST STATES...
UPPER RIDGE REMAINS IN PLACE OVER THE CENTRAL UNITED STATES THIS
MORNING...WITH UPPER TROUGHS AFFECTING THE MOUNTAINOUS WEST AND THE
EASTERN STATES. WATER VAPOR IMAGERY CLEARLY SHOWS A SHORTWAVE
TROUGH OVER NORTHERN AL/GA ROTATING SOUTHEASTWARD TOWARD FL. A
CLUSTER OF STRONG THUNDERSTORMS HAS BEEN ONGOING AHEAD OF THIS
FEATURE ACROSS SOUTHERN GA. THESE STORMS WILL LIKELY INTENSIFY BY
MID MORNING AS DAYTIME HEATING COMMENCES OVER NORTHERN FL. ACTIVITY
MAY THEN PERSIST THROUGH THE AFTERNOON...TRACKING SOUTHEASTWARD DOWN
THE FL PENINSULA. FAVORABLE VERTICAL SHEAR PROFILES WILL PROMOTE
ORGANIZED MULTICELL OR ISOLATED SUPERCELL STORMS CAPABLE OF DAMAGING
WINDS AND HAIL.
FARTHER NORTH...EXTENT OF DESTABILIZATION IN WAKE OF GA CONVECTION
IS UNCERTAIN. HOWEVER...IT APPEARS POSSIBLE THAT SCATTERED
THUNDERSTORMS WILL RE-DEVELOP OVER THE MOUNTAINS OF UPSTATE SC AND
NORTHERN GA THIS AFTERNOON AND TRACK SOUTHWARD. THESE STORMS COULD
POSE A THREAT OF LOCALLY DAMAGING WINDS AND HAIL THROUGH SUNSET.
...NORTHERN/CENTRAL PLAINS...
WEAK UPPER LOW IS CURRENTLY OVER NORTHWEST NM...WHILE STRONG UPPER
TROUGH ROTATES EASTWARD ACROSS ID/MT/WY. APPROACHING LARGE SCALE
FORCING WILL HELP MAINTAIN A LEE SURFACE TROUGH OVER THE NORTHERN
AND CENTRAL HIGH PLAINS. POCKETS OF STRONG HEATING AND CONVERGENCE
ALONG THIS AXIS WILL AID INITIATION OF SCATTERED THUNDERSTORMS BY
EARLY AFTERNOON OVER THE WESTERN DAKOTAS...THEN BUILDING SOUTHWARD
INTO PARTS OF NEB...EASTERN CO...AND WESTERN NEB BY LATE AFTERNOON.
FORECAST SOUNDINGS ACROSS THIS AREA SHOW RELATIVELY STEEP MID LEVEL
LAPSE RATES AND FAVORABLE VERTICAL SHEAR FOR SUPERCELL STORMS.
LARGE HAIL AND DAMAGING WINDS WILL BE POSSIBLE WITH STRONGER CELLS.
ACTIVITY MAY PERSIST WELL AFTER DARK AS NOCTURNAL LOW LEVEL JET
STRENGTHENS AND ENHANCES VERTICAL SHEAR/CONVERGENCE.
...NORTHEAST STATES...
LARGE UPPER LOW IS OFF THE COAST OF ME...AND IS DRIFTING SLOWLY
SOUTHWESTWARD. FULL SUNSHINE WILL RESULT IN STEEP LOW LEVEL LAPSE
RATES AND AFTERNOON MLCAPE VALUES OVER 1000 J/KG. SCATTERED
THUNDERSTORMS ARE FORECAST TO DEVELOP BY EARLY AFTERNOON ALONG AND
WEST OF THE HUDSON VALLEY AND SPREAD SOUTH-SOUTHWESTWARD.
SUFFICIENT VERTICAL SHEAR AND CAPE SUGGEST A RISK OF DAMAGING WINDS
AND HAIL WITH THESE STORMS. ACTIVITY SHOULD DIMINISH RAPIDLY AFTER
SUNSET.
..HART/GUYER.. 06/12/2007
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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