SWODY2
SPC AC 020559
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT SAT AUG 02 2008
VALID 031200Z - 041200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER MS
VALLEY REGION...
...THERE IS A SLGT RISK OF SVR TSTMS OVER PORTIONS OF THE NRN HIGH
PLAINS...
...SYNOPSIS...
UPPER RIDGE -- CENTERED OVER THE PLAINS -- IS FORECAST TO PERSIST
OVER THE SRN HALF TO 2/3 OF THE CONUS...WITH A BELT OF FASTER
WLY/WSWLY FLOW CONFINED TO THE N CENTRAL U.S. S OF A LARGE CENTRAL
CANADA VORTEX. ELSEWHERE...TROUGHS ARE FORECAST TO PREVAIL OVER THE
PAC NW AND THE ERN U.S. THROUGH THE PERIOD.
AT THE SURFACE...A LOW IS FORECAST TO LINGER INVOF NEW
ENGLAND...WITH A TRAILING COLD FRONT EXTENDING SSWWD ACROSS THE
CAROLINAS INTO THE SOUTHEAST/GULF COAST STATES. MEANWHILE...HIGH
PRESSURE IS FORECAST TO SETTLE INTO THE MIDWEST/OH VALLEY IN THE
WAKE OF THIS FRONT.
AROUND THE BACK SIDE OF THIS HIGH...A SSE-NNW BOUNDARY IS FORECAST
ACROSS ROUGHLY THE LOWER AND MID MO VALLEY...WHERE ELY FLOW
EMANATING FROM THE HIGH WILL CONVERGE WITH SLY/SSWLY FLOW ACROSS THE
PLAINS. THIS BOUNDARY SHOULD TRAIL NNWWD INTO NEB...TO A WEAK
SURFACE WAVE ALONG A SECOND COLD FRONT EXTENDING SSWWD FROM THE
CANADIAN PRAIRIE. AREAS BOTH TO THE NE AND NW OF THIS FRONTAL WAVE
-- A ZONE OF LOW-LEVEL WARM ADVECTION AND A ZONE OF UPSLOPE FLOW
RESPECTIVELY -- WILL LIKELY BE THE REGIONS WHERE THE GREATEST SEVERE
POTENTIAL WILL EXIST THIS PERIOD.
...UPPER MS VALLEY REGION...
SHOWERS AND THUNDERSTORMS SHOULD BE ONGOING ACROSS PARTS OF THE
SLIGHT RISK AREA AT THE START OF THE PERIOD...NEAR THE NOSE OF A
STRONG SWLY LOW-LEVEL JET. STORMS MAY CONTINUE/SHIFT EWD AWAY FROM
THE WARM FRONT THROUGH THE DAY...AS WARM ADVECTION PERSISTS.
REDEVELOPMENT OF STORMS JUST TO THE COOL SIDE OF THE BOUNDARY WILL
LIKELY BECOME MORE PRONOUNCED THROUGH THE AFTERNOON AS THE AIRMASS
DESTABILIZES...AND INTO THE EVENING AS THE LOW-LEVEL JET DIURNALLY
INTENSIFIES.
WITH FAVORABLY VEERING FLOW WITH HEIGHT ON THE COOL SIDE OF THE
FRONT INCREASING TO 30 TO 40 KT FROM THE W AT MID LEVELS...SHEAR
WILL SUPPORT SUPERCELLS. THUS...POTENTIAL FOR LOCALLY-DAMAGING
WINDS AND LARGE HAIL IS EXPECTED WITH STRONGER STORMS -- BOTH WITH
STORMS ONGOING AT THE START OF THE PERIOD AS WELL AS WITH NEW
CONVECTION INITIATING DURING THE AFTERNOON AND EVENING. THE THREAT
WILL LIKELY PERSIST THROUGH THE END OF THE PERIOD...SHIFTING
EWD/ESEWD TOWARD LK MI BY 04/12Z.
...NRN HIGH PLAINS...
CONVECTION MAY BE ONGOING AT THE START OF THE PERIOD ACROSS PORTIONS
OF THE HIGH PLAINS...THOUGH STORMS SHOULD SHIFT EWD AND DIMINISH
THROUGH THE DAY. AS AIRMASS DESTABILIZES THROUGH THE
AFTERNOON...ISOLATED TO SCATTERED STORM DEVELOPMENT SHOULD ONCE
AGAIN OCCUR...AIDED BY SELY UPSLOPE FLOW.
WITH LOW-LEVEL SELYS VEERING/INCREASING WITH HEIGHT TO WLY AT 40 TO
50 KT...SHEAR WILL FAVOR SUPERCELLS -- AND ASSOCIATED THREAT FOR
LARGE HAIL AND LOCALLY-DAMAGING WINDS. OVERNIGHT...STORMS SHOULD
SPREAD EWD OFF THE HIGHER TERRAIN INTO WRN SD AND VICINITY...AS SELY
LOW-LEVEL JET AND ASSOCIATED WARM ADVECTION ZONE DEVELOPS.
...THE SOUTHEAST...
LINGERING FRONT ACROSS THE SOUTHEAST SHOULD REMAIN A FOCUS FOR
WIDESPREAD SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD. FLOW ALOFT
MAY BE SUFFICIENT FOR A FEW SEMI-ORGANIZED STORM CLUSTERS TO
EVOLVE...WHICH WOULD SUPPORT A LOCALLY-ENHANCED THREAT FOR DAMAGING
WINDS AND/OR HAIL. ELSEWHERE...MAINLY MARGINAL/BRIEF THREAT IS
EXPECTED WITH PULSE-TYPE STORMS.
..GOSS.. 08/02/2008
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