DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 291731
SWODY2
SPC AC 291728

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT SAT AUG 29 2009

VALID 301200Z - 311200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
HIGHLY-AMPLIFIED UPPER FLOW FIELD WILL PERSIST ACROSS THE U.S. DAY
2...WITH A LARGE TROUGH OVER THE EASTERN HALF OF THE COUNTRY AND A
LARGE RIDGE IN THE WEST. WITHIN THE WRN RIDGE...A CLOSED LOW IS
PROGGED TO DRIFT FROM THE PAC NW EWD INTO ID THROUGH THE END OF THE
PERIOD.

AT THE SURFACE...A COLD FRONT -- ASSOCIATED WITH THE LARGE ERN UPPER
TROUGH -- IS PROGGED TO MOVE EWD ACROSS THE APPALACHIANS...AND SEWD
ACROSS THE SOUTHEAST U.S./GULF COAST REGION...AS A LARGE SURFACE
HIGH SHIFTS SWD INTO THE CENTRAL CONUS. MEANWHILE...THE WRN FRINGE
OF THIS FRONT IS PROGGED BECOME STATIONARY ACROSS THE CENTRAL/SRN
HIGH PLAINS.

...CENTRAL HIGH PLAINS REGION...
SELY LOW-LEVEL FLOW AND THE PRESENCE OF THE FRONT SHOULD CONTRIBUTE
TO AFTERNOON CONVECTIVE DEVELOPMENT...AS AIRMASS
HEATING/DESTABILIZATION THROUGH THE DAY RESULTS IN 500 TO 1000 J/KG
MIXED-LAYER CAPE.

WHILE MID-LEVEL FLOW ACROSS BOTH THE SRN AND NRN HIGH PLAINS IS
PROGGED TO REMAIN GENERALLY WEAK...A BELT OF NWLY H5 FLOW NEAR 30 KT
ATOP THE LOW-LEVEL SELYS SHOULD YIELD A ZONE OF SHEAR SUPPORTIVE OF
ORGANIZED CONVECTION. WHILE THE LIMITED INSTABILITY SHOULD LIMIT
OVERALL CONVECTIVE INTENSITY...A FEW STRONGER CELLS APPEAR LIKELY --
THUS WARRANTING A CONTINUATION OF 5% HAIL/WIND THREAT ACROSS THIS
AREA.

...PARTS OF ERN ID/SWRN MT/NWRN WY...
DAYTIME HEATING BENEATH COOL MID-LEVEL TEMPERATURES /-12 TO -14 AT
H5/ ASSOCIATED WITH THE UPPER LOW SHOULD RESULT IN MODEST
DESTABILIZATION ACROSS PARTS OF ID AND ADJACENT WRN MT/NWRN WY.
THIS WILL SUPPORT FAIRLY WIDESPREAD AFTERNOON CONVECTIVE
DEVELOPMENT. WHILE STRONGER FLOW ALOFT SHOULD REMAIN SOUTH AND EAST
OF THE REGION LIKELY TO EXPERIENCE GREATER DESTABILIZATION...A FEW
STRONGER STORMS WILL BE POSSIBLE...ALONG WITH
ASSOCIATED/LOW-PROBABILITY THREAT FOR HAIL -- AND POSSIBLY A
STRONGER GUST OR TWO.

...COASTAL CAROLINAS WWD INTO THE LOWER MS VALLEY REGION...
MODEST DESTABILIZATION INVOF THE SEWD-MOVING COLD FRONT SHOULD
SUPPORT AN AFTERNOON CONVECTIVE INCREASE...FROM THE COASTAL
CAROLINAS WWD INTO E TX. THOUGH LIMITED BY THE GENERAL LACK OF
STRONGER INSTABILITY...BELT OF 30-PLUS KT MID-LEVEL SWLYS MAY
SUPPORT LOCAL STORM ORGANIZATION -- AND ASSOCIATED/LOW-END SEVERE
THREAT DURING THE AFTERNOON.

...SRN NEW ENGLAND TO THE MID-ATLANTIC COASTAL REGION...
WHILE THE SURFACE COLD FRONT WILL LIKELY REMAIN ONSHORE THROUGH THE
AFTERNOON ACROSS THIS REGION...INSTABILITY IS FORECAST TO REMAIN
MINIMAL. NONETHELESS...WILL MAINTAIN LOW-PROBABILITY SEVERE
POTENTIAL FOR THE AFTERNOON HOURS...AS STRONG DEEP-LAYER WIND FIELD
WOULD SUPPORT THE POTENTIAL FOR ORGANIZED CONVECTION IF ANY
SUSTAINED STORMS CAN OCCUR.

..GOSS.. 08/29/2009

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