SWODY2
SPC AC 101723
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1223 PM CDT WED JUN 10 2009
VALID 111200Z - 121200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF SRN KS/OK/ERN TX
ENEWD INTO THE MID-ATLANTIC REGION...
...THERE IS A SLGT RISK OF SVR TSTMS OVER THE CENTRAL HIGH PLAINS...
...SYNOPSIS...
A RELATIVELY PRONOUNCED SHORT-WAVE TROUGH IS PROGGED TO PROGRESS
ENEWD ACROSS THE OH/TN VALLEY REGION THIS PERIOD. THIS TROUGH IS
EMBEDDED WITHIN A BELT OF ENHANCED MID-LEVEL FLOW PROGGED TO EXTEND
FROM THE SRN ROCKIES ENEWD INTO THE NORTHEAST...IN CONJUNCTION WITH
A MID-LEVEL HEIGHT GRADIENT BETWEEN A CENTRAL/ERN CANADA TROUGH AND
NRN MEXICO/WRN AND CENTRAL GULF OF MEXICO RIDGE. ELSEWHERE...A
TROUGH WILL LINGER ALONG THE W COAST IN THE SRN STREAM OF A SPLIT
FLOW REGIME PREVAILING OVER WRN NOAM.
AT THE SURFACE...A FRONT EXTENDING FROM THE GREAT LAKES/OH VALLEY
REGION INTO THE OK VICINITY SHOULD MOVE SLOWLY SEWD ALONG ITS ERN
EXTENT...WHILE MAKING LITTLE SWD PROGRESS ACROSS OK THROUGH THE
PERIOD. ELY UPSLOPE FLOW JUST TO THE COOL SIDE OF THIS FRONT IS
FORECAST TO INCREASE ACROSS SERN WY/NERN CO THROUGH THE PERIOD.
...OH/TN VALLEYS...
A BELT OF RELATIVELY-STRONG DEEP-LAYER FLOW IS FORECAST TO SPREAD
ENEWD ACROSS THE OH/TN VALLEY REGION THIS PERIOD...IN CONJUNCTION
WITH THE SHORT-WAVE TROUGH SHIFTING ACROSS THIS REGION. STORMS --
AND ASSOCIATED SEVERE THREAT -- SHOULD BE ONGOING INVOF THE MID
MS/LOWER OH VALLEYS AT THE START OF THE PERIOD...AND THEN SHOULD
SPREAD EWD AND INCREASE THROUGH THE DAY ACROSS THE OH/TN VALLEY
REGION INVOF THE SLOWLY SEWD-SAGGING FRONTAL ZONE.
WHILE DESTABILIZATION DOWNSTREAM OF ONGOING STORMS MAY BE HINDERED
BY CLOUDS/PRECIPITATION...AMPLE INSTABILITY SHOULD EXIST SUCH THAT
-- COMBINED WITH THE STRENGTH OF THE DEEP-LAYER WIND FIELD -- AN
ENHANCED POTENTIAL FOR DAMAGING WINDS APPEARS TO EXIST ACROSS THIS
REGION. STORMS/SEVERE POTENTIAL SHOULD CONTINUE ACROSS THIS REGION
THROUGH THE EVENING...BEFORE DIMINISHING SOMEWHAT OVERNIGHT.
...OK/NERN QUARTER OF TX AND VICINITY...
VERY MOIST BOUNDARY LAYER AND STEEP LAPSE RATES ALOFT WILL COMBINE
WITH DIURNAL HEATING TO YIELD MODERATE DESTABILIZATION ACROSS
PORTIONS OF OK/NERN TX/AR NEAR AND SOUTH OF THE SURFACE FRONT
LINGERING ACROSS THIS AREA. STORMS SHOULD DEVELOP INVOF THE FRONT
AND OTHER LINGERING/CONVECTIVE BOUNDARIES DURING THE AFTERNOON...AND
WHILE SUBTLE SHORT-WAVE RIDGING/WEAK HEIGHT RISES ANTICIPATED MAY
LIMIT OVERALL STORM COVERAGE...30 TO 40 KT DEEP-LAYER SHEAR COMBINED
WITH THE DEGREE OF INSTABILITY SUGGESTS THAT ISOLATED/ROTATING
STORMS WILL LIKELY EVOLVE. LIMITED LOW-LEVEL SHEAR IS EXPECTED --
WHICH SUGGESTS THAT PRIMARY SEVERE THREATS WILL BE VERY LARGE HAIL
AND LOCALLY-DAMAGING DOWNBURSTS.
...VA/NC AND SURROUNDING AREAS...
MODEST/VEERING FLOW WITH HEIGHT COMBINED WITH MODERATE AFTERNOON
DESTABILIZATION WILL SUPPORT STORM DEVELOPMENT IN LEE OF THE
APPALACHIANS -- PARTICULARLY ACROSS MD/VA/NC -- AS THE OH VALLEY
SHORT-WAVE TROUGH BRUSHES THIS REGION. DEGREE OF SHEAR ANTICIPATED
SHOULD SUPPORT SEMI-ORGANIZED/MULTICELL STORMS...AND ASSOCIATED
THREAT FOR HAIL AND LOCALLY-DAMAGING WINDS. THREAT WILL BE CONFINED
PRIMARILY TO THE AFTERNOON...WITH DIURNAL WEAKENING AFTER SUNSET.
...CENTRAL HIGH PLAINS...
SELY UPSLOPE FLOW IS FORECAST TO DEVELOP ACROSS THE CENTRAL HIGH
PLAINS REGION THROUGH THE DAY...WHICH WILL HELP TO MAINTAIN MODEST
/LOW 50S/ DEWPOINTS BENEATH FAIRLY-STEEP MID-LEVEL LAPSE RATES.
RESULTING MARGINAL DESTABILIZATION WITHIN THE UPSLOPE FLOW REGIME
WILL SUPPORT STORM DEVELOPMENT -- PARTICULARLY OVER THE HIGHER
TERRAIN OF NRN CO/SERN WY. VEERING WIND PROFILE WITH HEIGHT SHOULD
SUPPORT ISOLATED/ORGANIZED CELLS -- CAPABLE OF PRODUCING
LOCALLY-DAMAGING WINDS AND MARGINAL HAIL. WITH TIME...STORMS SHOULD
SPREAD EWD/SEWD ACROSS PARTS OF WRN NEB/WRN KS -- THOUGH OVERALL
SEVERE POTENTIAL SHOULD DIMINISH OVERNIGHT.
..GOSS.. 06/10/2009
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