SPC AC 070509
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1209 AM CDT FRI MAY 07 2010
VALID 081200Z - 091200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN VA SWWD INTO THE ERN
CAROLINAS...
...SYNOPSIS...
FAST ZONAL FLOW WILL CONTINUE ACROSS THE COUNTRY INTO THE WEEKEND.
AN EMBEDDED MID-LVL SHORTWAVE TROUGH CURRENTLY MOVING INTO THE
NRN/CNTRL PLAINS IS FCST TO AMPLIFY ACROSS THE NERN STATES ON
SATURDAY. MEANWHILE...THE NEXT DISTURBANCE...LOCATED NEAR
40N/142W...WILL ADVANCE TO THE PAC NW COAST BY THE END OF THE
PERIOD.
IN THE LWR-LVLS...A LOW WILL TRAVEL FROM THE LWR GRTLKS REGION INTO
THE ST. LAWRENCE VLY BY SATURDAY NIGHT. A TRAILING CDFNT WILL SWEEP
SEWD OFF THE ATLC SEABOARD AND SWD INTO NRN FL BY EVENING. WRN-MOST
PORTIONS OF THE FRONT WILL BEGIN TO REDEVELOP NWD ACROSS THE SRN
PLAINS SATURDAY NIGHT.
...ERN VA TO NRN FL...
THE AIR MASS AHEAD OF THE APPROACHING CDFNT WILL BE CHARACTERIZED BY
MID-60S SFC DEW POINTS...VERY WARM BOUNDARY LAYER TEMPERATURES AND
MID-LVL LAPSE RATES OF 6.5-7 DEG C PER KM. THIS WILL CONTRIBUTE TO
MLCAPES APPROACHING 2500 J/KG. AS SRN FRINGES OF THE UPR TROUGH
GRAZES THE REGION...WDLY SCTD TSTMS ARE EXPECTED TO FORM ACROSS THE
COASTAL PLAINS OF SERN VA SWD INTO NRN FL BY MID-AFTN. STRONGER
DEEP LAYER SHEAR WILL EXIST ACROSS SERN VA INTO THE CAROLINAS WHERE
SUPERCELLS WILL BE POSSIBLE WITH PRIMARILY LARGE HAIL AND DMGG WIND
GUSTS. FARTHER SW ACROSS SRN GA/NRN FL...THE DEEP LAYER SHEAR WILL
BE COMPARATIVELY WEAKER...BUT STILL SUFFICIENT FOR AT LEAST ISOLD
SVR STORMS WITH MAINLY LARGE HAIL. TSTMS WILL DIMINISH AND/OR MOVE
OFF THE COAST BY LATE EVENING.
...MID-ATLC TO NEW ENGLAND...
A 40-50 KT SSWLY LLJ AHEAD OF THE APPROACHING UPR TROUGH WILL
PROBABLY BE DRIVING TSTM CLUSTERS OVER PARTS OF NY AND SRN NEW
ENGLAND EARLY SATURDAY.
IF MORNING ACTIVITY WEAKENS AND SUFFICIENT HEATING CAN MATERIALIZE
ACROSS PARTS OF THE MID-ATLC REGION NWD INTO SRN NEW
ENGLAND...POTENTIAL WILL EXIST FOR A SHORT TEMPORAL THREAT FOR ISOLD
SVR TSTMS LATE SATURDAY MORNING THROUGH MID-AFTN. DEEP LAYER SHEAR
WILL BE ON THE ORDER OF 50-55 KTS WITH PRIMARY SVR THREATS BEING
DMGG WIND GUSTS...THOUGH A BRIEF TORNADO CANNOT BE RULED OUT
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