SPC AC 021657
DAY 1 CONVECTIVE OUTLOOK CORR 2
NWS STORM PREDICTION CENTER NORMAN OK
1157 AM CDT SAT AUG 02 2008
VALID 021630Z - 031200Z
...THERE IS A SLGT RISK OF SVR TSTMS ALONG THE EASTERN SEABOARD AND
CNTRL/SRN APPALACHIANS...
...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE NRN
PLAINS FROM NERN MT TO ND...
CORRECTED FOR FORECASTER NAMES
...NORTHEAST...
INTENSIFYING LARGE SCALE ASCENT WITHIN DEEPENING CYCLONE ACROSS ERN
GREAT LAKES/NEW ENGLAND AREAS WILL CONTINUE TO ACT UPON VERY MOIST
AIR MASS AND RESULT IN WIDESPREAD THUNDERSTORM ACTIVITY THROUGH THE
AFTERNOON. MOST ORGANIZED CONVECTION SO FAR WAS BOWING COMPLEX OF
STORMS MOVING ACROSS SRN CT. WIND DAMAGE MAY ACCOMPANY THIS ACTIVITY
EWD ACROSS SERN NEW ENGLAND NEXT 1-3 HOURS. A LOW PROBABILITY
TORNADO THREAT MAY ALSO EVOLVE WITHIN BOWHEAD OF THIS MCS.
SOUTHWEST OF THE NY/CT CONVECTION...CLUSTER OF STORMS MOVING ACROSS
SERN PA AND NJ WILL ALSO POSE SOME THREAT FOR DAMAGING WINDS THIS
AFTERNOON. THIS ACTIVITY WILL MOVE INTO AN INCREASINGLY UNSTABLE AIR
MASS ACROSS NJ/NRN DELMARVA REGION NEXT FEW HOURS AS DEEP-LAYER WLY
WIND FIELDS INTENSIFY WITHIN THE BASE OF THE DEEPENING LARGE SCALE
CYCLONE.
...VA/CAROLINAS...
YET ANOTHER CLUSTER OF SLIGHTLY LESS ORGANIZED STORMS WAS DEVELOPING
SEWD ACROSS THE CNTRL APPALACHIANS OF SWRN VA AND NWRN NC. VERY
STRONG DESTABILIZATION AHEAD OF THIS CONVECTION SHOULD RESULT IN A
GRADUAL INTENSIFICATION OF THIS ACTIVITY AS IT SPREADS SEWD ACROSS
THE NC FOOTHILLS AND PIEDMONT AREAS THROUGH THE AFTERNOON. SLIGHTLY
WEAKER EFFECTIVE SHEAR THESE AREAS SHOULD BE OVERCOME BY STEEPENING
BOUNDARY LAYER LAPSE RATES AND GRADUAL INCREASE IN LARGE SCALE
ASCENT AHEAD OF THE TROUGH/FRONT SETTLING INTO THE AREA THROUGH THIS
EVENING. IF MULTICELLULAR STORMS CAN GENERATE A STRONG/DEEP ENOUGH
COLD POOL PREFERENTIALLY ALIGNED WITH WNWLY DEEP-LAYER FLOW...AN
INCREASING THREAT OF DAMAGING WINDS MAY ENSUE FROM THE PIEDMONT
ESEWD ACROSS THE SANDHILLS OF NC AND INTO UPSTATE SC THROUGH LATER
TODAY.
...NRN PLAINS...
SCATTERED STRONG TO SEVERE STORMS HAVE BEEN ONGOING MUCH OF THE
MORNING OVER NRN ND WITHIN VERY PERSISTENT WARM AIR ADVECTION REGIME
BENEATH AND WEST OF APEX OF UPPER RIDGE AXIS. THESE STORMS ARE BEING
FUELED BY PLUME OF HIGH INSTABILITY AIR WITH ORIGINS IN HOT CAPPED
AIR MASS FARTHER SOUTH. SHORT WAVE TROUGH SPREADING ACROSS THE
REGION WAS FURTHER ENHANCING ASCENT.
DESPITE STRONG CAPPING ACROSS MUCH OF THE REGION...WATER VAPOR
IMAGERY REVEALS A NUMBER OF LOW AMPLITUDE SHORT WAVES EMBEDDED
WITHIN THE FAST FLOW REGIME UPSTREAM ACROSS MT/WY. IT APPEARS LIKELY
THAT THESE FEATURES MAY LEAD TO ADDITIONAL CONVECTIVE DEVELOPMENT
THROUGH THE PERIOD...FIRST ACROSS THE HIGH TERRAIN OF MT/WY LATER
TODAY AND EVENTUALLY ALONG THE EDGE OF THE CAP...FROM NERN MT INTO
ND...PROBABLY LATE TONIGHT.
MAGNITUDE OF INSTABILITY/LAPSE RATES AND EFFECTIVE SHEAR WITHIN THE
AREA LIKELY TO EXPERIENCE SOME DEVELOPMENT THROUGH EARLY SUNDAY
MORNING SUGGESTS THE INTRODUCTION OF A SLGT RISK AREA SEEMS PRUDENT
AT THIS TIME.
FARTHER SOUTH AND EAST...WHILE SIGNALS EXIST AMONGST THE VARIOUS
FORMS OF GUIDANCE THAT POTENTIAL FOR TSTM DEVELOPMENT MAY INCREASE
ACROSS PARTS OF SD...EAST TO MN/IA LATE...STRONG CAP AND SLIGHTLY
WEAKER FORCING FOR ASCENT ACROSS MUCH OF THESE AREAS RESULTS IN
LOWER SEVERE WEATHER PROBABILITIES AT THIS TIME.
THE CHANCE FOR A FEW BETTER-ORGANIZED TSTMS MAY EVOLVE THIS
AFTERNOON INTO EARLY EVENING ACROSS PARTS OF SERN AZ. HEATING WILL
SUPPORT DEEP WELL-MIXED BOUNDARY LAYER OVER THE DESERTS AS
CONVECTIVE POTENTIAL INCREASES THROUGH THE PERIOD WITH THE APPROACH
OF ELY WAVE MOVING ACROSS NRN MEXICO/SRN NM ATTM. A FEW STORMS COULD
PRODUCE STRONG TO SEVERE WIND GUSTS AND PERHAPS MARGINALLY SEVERE
HAIL DURING THE LATER AFTERNOON AND INTO THE EVENING.
..CARBIN/HURLBUT.. 08/02/2008
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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