DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 081923
SWODY1
SPC AC 081921

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0221 PM CDT MON OCT 08 2012

VALID 082000Z - 091200Z

...NO SVR TSTM AREAS FORECAST...

ASIDE FROM A MINOR EWD ADJUSTMENT TO THE BACK EDGE OF LOWER THUNDER
PROBABILITY LINE...EARLIER THOUGHTS REGARDING THE LIKELIHOOD FOR
LIGHTNING WITHIN DEEPER CONVECTION REMAIN. TSTM THREAT SHOULD
GRADUALLY SPREAD FROM W-E ACROSS THE REGION AS SUBSIDENCE DEEPENS IN
THE WAKE OF PROGRESSIVE SFC BOUNDARY.

..DARROW.. 10/08/2012

.PREV DISCUSSION... /ISSUED 1128 AM CDT MON OCT 08 2012/

...SYNOPSIS...
A LARGE-SCALE UPPER TROUGH WILL CONTINUE TO INFLUENCE THE MAJORITY
OF THE CONUS E OF THE ROCKIES...WHILE A SLOW-MOVING CLOSED LOW WILL
DRIFT EWD TOWARD NRN CA. A SERIES OF EMBEDDED SHORTWAVE TROUGHS
WILL PROGRESS THROUGH THE CYCLONIC FLOW REGIME E OF THE
ROCKIES...WITH ONE TROUGH MOVING FROM THE TN VALLEY TO THE MID
ATLANTIC REGION...AS AN UPSTREAM WAVE AMPLIFIES OVER THE NRN PLAINS.
THE SURFACE WARM SECTOR WILL REMAIN CONFINED TO THE FL PENINSULA
AND THE IMMEDIATE SE ATLANTIC COASTAL WATERS...AS WEAK CYCLOGENESIS
IS EXPECTED JUST OFF THE NC COAST BY EARLY TONIGHT IN ASSOCIATION
WITH THE EJECTING MIDLEVEL TROUGH TO THE MID ATLANTIC.

A SWATH OF ELEVATED CONVECTION WILL OCCUR IN THE ZONE OF WEAK
WAA/FRONTOGENESIS ABOVE THE SHALLOW COOL AIR MASS ACROSS THE
CAROLINAS...WHERE REGIONAL 12Z SOUNDINGS REVEALED MUCAPE GENERALLY
IN THE 500-1000 J/KG RANGE. THOUGH EFFECTIVE BULK SHEAR WILL BE IN
THE RANGE FAVORABLE FOR ELEVATED SUPERCELLS...RATHER POOR LAPSE
RATES AND LITTLE INCREASE IN BUOYANCY SUGGEST THAT THE RISK FOR
LARGE HAIL WILL BE MARGINAL AT BEST.

FARTHER S INTO N FL...THE SURFACE WARM SECTOR /WITH BOUNDARY LAYER
DEWPOINTS IN THE LOW 70S/ WILL CONTRIBUTE TO MODERATE INSTABILITY
THIS AFTERNOON /MLCAPE NEAR 2000 J PER KG/. THOUGH MODEST VERTICAL
SHEAR WILL BE PRESENT ALOFT...MIDLEVEL LAPSE RATES ARE UNLIKELY TO
INCREASE FROM NEAR 6 C/KM OBSERVED THIS MORNING AS MIDLEVEL
MOISTENING OCCURS...AND LOW-LEVEL FLOW WILL REMAIN WEAK. THESE
FACTORS...IN COMBINATION WITH HIGH CLOUDS INTERFERING WITH SURFACE
HEATING...SUGGEST THAT ANY DAMAGING WIND/HAIL RISK WILL BE TOO
MARGINAL TO WARRANT INTRODUCTION OF SEVERE PROBABILITIES.

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