SPC AC 021247
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0747 AM CDT SAT APR 02 2011
VALID 021300Z - 031200Z
...NO SVR TSTM AREAS FORECAST...
...MID ATLANTIC STATES...
MORNING WATER VAPOR IMAGERY SHOWS A MIDLEVEL VORTICITY MAXIMUM
TRANSLATING RAPIDLY ESEWD THROUGH THE REGION WITH AN UPSTREAM
IMPULSE AMPLIFYING OVER IL/IND WHICH WILL ARRIVE LATER TODAY. THE
AMBIENT AIR MASS WILL REMAIN RELATIVELY DRY WITH BOUNDARY LAYER DEW
POINTS IN THE 30S. BUT...PROVIDED BREAKS IN CLOUD SHIELD CURRENTLY
CRESTING THE BLUE RIDGE...THE DEVELOPMENT OF STEEP LOW TO MIDLEVEL
LAPSE RATES WILL YIELD SBCAPE VALUES APPROACHING 300-500 J/KG BY
AFTERNOON.
FORCING FOR ASCENT IN EXIT REGION OF UPPER-LEVEL JET STREAK
ATTENDING UPSTREAM VORTICITY MAXIMUM AND CONVERGENCE ALONG SURFACE
TROUGH/WEAK COLD FRONT ARE EXPECTED TO FOSTER SCATTERED...LOW-TOPPED
TSTMS THIS AFTERNOON. THE MOST INTENSE STORMS WILL BE CAPABLE OF
ISOLATED OCCURRENCES OF HAIL AND/OR GUSTY WINDS GIVEN THE STEEP
LAPSE RATES AND RELATIVELY STRONG WNWLY TROPOSPHERIC WIND FIELD.
...GREAT BASIN INTO SNAKE RIVER VALLEY...
POTENT SHORTWAVE TROUGH NOW MOVING THROUGH WRN PARTS OF WA/ORE IS
FORECAST TO UNDERGO FURTHER INTENSIFICATION WHILE TRANSLATING ESEWD
THROUGH THE NRN INTERMOUNTAIN REGION AND GREAT BASIN. ASSOCIATED
PACIFIC FRONT WILL CONCURRENTLY ADVANCE EWD...AND WILL LIKELY EXTEND
FROM DEEPENING LEE CYCLONE OVER SERN MT SWWD THROUGH SERN ID...NRN
UT AND CNTRL NV BY 03/00Z. PRE-FRONTAL ENVIRONMENT WILL REMAIN
RATHER DRY WITH PW VALUES LESS THAN 0.5 INCH. HOWEVER...WEAK
DESTABILIZATION IS FORECAST LATER TODAY AS DAYTIME HEATING AND
MIDLEVEL COOLING/HEIGHT FALLS CONTRIBUTE TO STEEPENING OF LOW TO
MIDLEVEL LAPSE RATES.
FRONTAL UPLIFT...OROGRAPHIC FORCING AND INCREASING INFLUENCE OF
MIDLEVEL TROUGH WILL CONTRIBUTE TO THE DEVELOPMENT OF ISOLATED TO
WIDELY SCATTERED TSTMS LATE THIS AFTERNOON INTO EVENING.
DEEP...WELL-MIXED SUB-CLOUD CONDITIONS WILL ENHANCE DOWNDRAFT
POTENTIAL WITH LOCALLY STRONG WIND GUSTS POSSIBLE.
..MEAD/SMITH.. 04/02/2011
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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