DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 201729
SWODY2
SPC AC 201728

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT SUN MAY 20 2012

VALID 211200Z - 221200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
AS A SHORT-WAVE TROUGH CROSSING THE GREAT LAKES REGION EARLY IN THE
PERIOD BECOMES ENMESHED WITHIN LARGER CYCLONIC FLOW FIELD AROUND THE
WEAK LOW WHICH HAS LINGERED OFF THE CAROLINA COAST...THE RESULT WILL
BE MAINTENANCE OF A WEAK LONG-WAVE TROUGH OVER THE ERN CONUS.

FARTHER W...RIDGING WILL PREVAIL OVER THE INTERMOUNTAIN
REGION...DOWNSTREAM OF A NERN PACIFIC UPPER LOW/TROUGH WHICH IS
FORECAST TO BEGIN MOVING ONSHORE IN PIECEMEAL FASHION --
PARTICULARLY THROUGH THE LATTER HALF OF THE PERIOD.

AT THE SURFACE...A COLD FRONT WILL ADVANCE ACROSS THE NWRN U.S. AS
PIECES OF THE UPPER TROUGH MOVE ONSHORE...WHILE IN THE CENTRAL AND
ERN U.S. A FRONT EXTENDING FROM THE OH VALLEY WSWWD INTO THE SRN
PLAINS IS EXPECTED TO WEAKEN THROUGH THE PERIOD.

...CENTRAL/SRN HIGH PLAINS REGION...
DESPITE WEAK SHORT-WAVE RIDGING...A FEW AFTERNOON STORMS SHOULD
INITIATE INVOF THE HIGHER TERRAIN -- AND THEN DRIFT SEWD GIVEN NWLY
FLOW ALOFT ATOP LOW-LEVEL SLYS/SELYS. WHILE MODEST CAPE AND LACK OF
STRONG UVV SHOULD LIMIT STORM COVERAGE...FAIRLY DEEP/DRY BOUNDARY
LAYER COULD SUPPORT A STRONGER GUST OR TWO -- AND THUS WILL
INTRODUCE LOW-PROBABILITY THREAT AREA FOR ISOLATED AFTERNOON/EARLY
EVENING STORMS.

...NRN INTERMOUNTAIN REGION...
A WEAK LEAD IMPULSE AHEAD OF THE LARGER/OFFSHORE TROUGH WHICH IS
PROGGED TO SHIFT ACROSS ID/WRN MT DURING THE AFTERNOON SHOULD ALLOW
SCATTERED CONVECTIVE INITIATION ACROSS THIS AREA...WHERE
MODEST/HIGH-BASED INSTABILITY SHOULD EXIST.

WITH THE FAIRLY DEEP/DRY MIXED LAYER EXPECTED /SURFACE DEWPOINT
DEPRESSIONS OF 30 TO 40 F BENEATH THE MODEST CAPE LAYER/...AND AMPLE
SHEAR FOR SUSTAINED/ORGANIZED UPDRAFTS...POTENTIAL FOR
ISOLATED/EVAPORATIVELY ENHANCED WIND GUSTS WILL BE POSSIBLE --
JUSTIFYING ADDITION OF LOW PROBABILITY SEVERE THREAT AREA FOR LATE
AFTERNOON/EARLY EVENING STORMS.

..GOSS.. 05/20/2012

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