DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 181728
SWODY2
SPC AC 181726

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1226 PM CDT FRI MAY 18 2012

VALID 191200Z - 201200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM SERN NEB SSWWD INTO WRN OK
AND VICINITY...

...SYNOPSIS...
A WRN U.S. UPPER TROUGH IS FORECAST TO CONTINUE MOVING INTO THE
CENTRAL U.S. THIS PERIOD...WEAKENING WITH TIME AS ENCOUNTERS
LONGER-WAVELENGTH ERN U.S. RIDGING. MEANWHILE WITHIN THE ERN U.S.
RIDGE...A WEAK UPPER LOW CENTERED INVOF THE COASTAL CAROLINAS IS
FORECAST TO LINGER THROUGH THE PERIOD.

AT THE SURFACE...A COLD FRONT IS FORECAST TO SHIFT ACROSS THE NRN
AND CENTRAL PLAINS...IN CONJUNCTION WITH THE PROGRESSING UPPER
TROUGH. THIS FRONT WILL SERVE AS A FOCUS FOR THE MOST ACTIVE
CONVECTIVE THREAT THIS PERIOD.

...KS/OK AND VICINITY...
AS THE COLD FRONT CROSSES THE PLAINS THROUGH THE AFTERNOON...A
MODESTLY MOIST/HEATING BOUNDARY LAYER SHOULD RESULT IN WARM SECTOR
MIXED-LAYER CAPE RANGING FROM ROUGHLY 1000 TO 2000 J/KG. THOUGH
CAPPING SHOULD HINDER DEVELOPMENT ACROSS THE SLIGHT RISK AREA
THROUGH EARLY TO MID AFTERNOON...LATER AFTERNOON DEVELOPMENT OF
ISOLATED TO SCATTERED STORMS IS EXPECTED -- INITIALLY FARTHER NORTH
ACROSS THE LOWER PROBABILITY RISK AREA OF MN/ERN SD AND THEN SWD
WITH TIME ACROSS ERN NEB/CENTRAL KS/WRN OK. WITH 40-PLUS KT
MID-LEVEL SWLYS SPREADING ACROSS THE SERN NEB/KS/OK WARM SECTOR IN
CONJUNCTION WITH THE EJECTING SHORT-WAVE TROUGH ASSUMING AN
INCREASINGLY NEGATIVE TILT...SHEAR PROFILES WILL BE FAVORABLE FOR
ROTATING UPDRAFTS. THUS...A FEW SUPERCELLS CAPABLE OF PRODUCING
LARGE HAIL AND DAMAGING WINDS ARE EXPECTED. A TORNADO OR TWO WILL
ALSO BE POSSIBLE...THOUGH THIS THREAT SHOULD BE SOMEWHAT MITIGATED
BY THE RELATIVELY DRY/WELL-MIXED BOUNDARY LAYER EXPECTED TO EXIST.

THOUGH A FAIRLY STRONG LOW-LEVEL JET MAY ALLOW STORMS TO CONTINUE
OVERNIGHT ACROSS PARTS OF THE PLAINS REGION...SEVERE THREAT SHOULD
DIMINISH AFTER DARK AS THE BOUNDARY LAYER COOLS AND STORMS BECOME
MORE ELEVATED WITH TIME.

..GOSS.. 05/18/2012

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