SPC AC 031629
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1129 AM CDT TUE AUG 03 2010
VALID 031630Z - 041200Z
...THERE IS A SLGT RISK OF SVR TSTMS THROUGH THIS EVENING FOR PARTS
OF THE NRN HIGH PLAINS...
...NRN HIGH PLAINS THROUGH THIS EVENING...
THUNDERSTORMS ARE ONGOING FROM NE WY INTO SE MT IN ADVANCE OF AN
EJECTING MIDLEVEL TROUGH OVER ID/WRN WY. SOME SURFACE HEATING WILL
OCCUR IN CLOUDS BREAKS FROM NW NEB INTO WRN SD...WHERE WEAK
LOW-LEVEL UPSLOPE FLOW WILL BE MAINTAINED THIS AFTERNOON. THE
COMBINATION OF MLCAPE OF 500-1500 J/KG...EFFECTIVE BULK SHEAR OF
30-40 KT...AND CLOCKWISE CURVED HODOGRAPHS WILL SUPPORT ORGANIZED
CLUSTERS AND SUPERCELLS CAPABLE OF PRODUCING A TORNADO OR TWO...A
FEW DAMAGING GUSTS...AND ISOLATED LARGE HAIL THROUGH THIS EVENING.
...CENTRAL PLAINS TO THE OH VALLEY THROUGH TONIGHT...
THE REMNANTS OF OVERNIGHT MCS/S CONTINUE TO WEAKEN OVER ERN
INDIANA/WRN OH AND OVER CENTRAL NEB. OUTFLOW WITH THE NEB MCS HAS
DISPLACED THE BAROCLINIC ZONE SWD INTO SW/CENTRAL KS...WHILE THE
FRONT EXTENDS EWD ACROSS SRN IA FROM A WEAK SURFACE CYCLONE IN
EXTREME SE NEB. FARTHER E...OUTFLOW WITH THE WEAKENING ERN MCS WILL
CONTINUE TO MOVE SEWD ACROSS ERN/SRN INDIANA INTO WRN OH BEFORE
BECOMING DIFFUSE THIS AFTERNOON...AND THE WRN EXTENT OF THE OUTFLOW
APPEARS TO HAVE STALLED ALONG A NW-SE AXIS ACROSS CENTRAL IL.
LOW-LEVEL DRYING AND A WARM EML HAVE OVERSPREAD ERN KS/WRN MO...WITH
THE RICHER MOISTURE/INSTABILITY CONFINED TO THE COOL SIDE OF THE
BOUNDARY IN KS/NEB. THE COVERAGE OF DIURNAL CONVECTION SHOULD
REMAIN SPARSE ALONG THE KS TO SRN IA SEGMENT OF THE BOUNDARY...WITH
MORE ROBUST STORM INITIATION LIKELY DELAYED UNTIL TONIGHT WHEN
LOW-LEVEL WAA INCREASES N OF THE BOUNDARY IN CONJUNCTION WITH THE
25-30 KT NOCTURNAL LLJ OVER KS. FARTHER E ACROSS SE IA/NE
MO/IL...STRONG SURFACE HEATING AND BOUNDARY LAYER DEWPOINTS IN THE
MID-UPPER 70S WILL CONTRIBUTE TO STRONG INSTABILITY ALONG THE
STALLED BOUNDARY. HOWEVER...CONVECTIVE INHIBITION WILL LIKELY
LINGER THROUGH THE AFTERNOON ALONG THE NOSE OF THE WARM EML
PLUME...MAKING ADDITIONAL THUNDERSTORM DEVELOPMENT UNCERTAIN THIS
AFTERNOON. MEANWHILE...A FEW STORMS COULD FORM THIS AFTERNOON
ACROSS SRN OH/NRN KY/WV ON THE REMNANT OUTFLOW AS LOW-LEVEL
WARMING/MOISTENING OCCURS FROM THE SW...BUT THE DAMAGING WIND THREAT
APPEARS TO BE MARGINAL IN THIS AREA. OVERALL...THE DAMAGING
WIND/HAIL THREAT APPEARS MARGINAL ACROSS THIS ENTIRE REGION GIVEN
CAP CONCERNS AND ONLY A NARROW CORRIDOR WHERE MODEST DEEP-LAYER
VERTICAL SHEAR COINCIDES WITH MODERATE-STRONG INSTABILITY.
...SRN MS/AL AREA THIS AFTERNOON...
STRONG SURFACE HEATING IS UNDERWAY N OF THE ONGOING CONVECTION NEAR
THE COAST. MODIFIED REGIONAL 12Z SOUNDINGS SUGGEST AFTERNOON MLCAPE
VALUES COULD EXCEED 4000 J/KG WITH PW VALUES IN EXCESS OF 2.25
INCHES...WITH SOME DRYING ABOVE 500 MB. THUS...A FEW STORMS WILL BE
CAPABLE OF PRODUCING WET MICROBURSTS WITH ISOLATED DAMAGING WINDS
THIS AFTERNOON.
...UPSTATE NY/NRN VT THIS AFTERNOON...
A SERIES OF EMBEDDED SPEED MAXIMA WILL TRANSLATE EWD FROM
ONTARIO/SRN QUEBEC TO UPSTATE NY AND NRN NEW ENGLAND THROUGH
TONIGHT. IN THE LOW LEVELS...A DIFFUSE WARM FRONT IS MOVING SLOWLY
NEWD NEAR THE ERN NY BORDER...WITH SOME CLOUD BREAKS AND MID-UPPER
60S DEWPOINTS W OF THE BOUNDARY ACROSS NY. A COMPARISON OF 12Z
SOUNDINGS REVEALS SUBSTANTIAL WARMING AND MOISTENING ALOFT FROM
YESTERDAY MORNING TO THIS MORNING AT ALB AND WMW IN SRN
QUEBEC...WITH TEMPERATURE PROFILES/LAPSE RATES THAT ARE NOT
FAVORABLE FOR LARGE HAIL PRODUCTION. DEEP-LAYER VERTICAL SHEAR WILL
BE SUFFICIENT FOR ORGANIZED STORMS IN THE WEAKLY UNSTABLE
ENVIRONMENT...AND ISOLATED STRONG WIND GUSTS STILL APPEAR TO BE A
POSSIBILITY THIS AFTERNOON.
..THOMPSON/GRAMS.. 08/03/2010
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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