DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 150559
SWODY2
SPC AC 150558

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT WED MAY 15 2013

VALID 161200Z - 171200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
THE UPPER PATTERN IS FORECAST TO UNDERGO SUBSTANTIAL AMPLIFICATION
THIS PERIOD...AS AN ERN PACIFIC TROUGH DIGS SEWD AND MOVES ONSHORE
OVER THE WEST. AS THIS OCCURS...A DOWNSTREAM RIDGE WILL STRENGTHEN
OVER THE CENTRAL U.S. -- THOUGH WEAK VORTICITY MAXIMA ARE FORECAST
TO SHIFT EWD ACROSS THE PLAINS WITHIN THE LARGER-SCALE/BACKGROUND
RIDGING. MEANWHILE...A LOW-AMPLITUDE/SRN STREAM TROUGH IS FORECAST
TO CROSS THE LOWER MS VALLEY AND MOVE INTO THE CENTRAL GULF COAST
REGION BY THE END OF THE PERIOD.

AT THE SURFACE...A LEE TROUGH OVER THE HIGH PLAINS IS PROGGED TO BE
THE MAIN CONVECTIVE FEATURE OF INTEREST THIS PERIOD -- ALONG WITH
THE WRN PORTION OF A WEAK W-E BAROCLINIC ZONE EXTENDING FROM THE
MID-ATLANTIC REGION WWD INTO THE CENTRAL PLAINS.

...CENTRAL HIGH PLAINS AND MUCH OF NEB AND VICINITY...
A WEAK VORT MAX CROSSING THE CENTRAL PLAINS REGION IS FORECAST TO
ASSIST IN AFTERNOON CONVECTIVE DEVELOPMENT -- BOTH ALONG A LEE
TROUGH AND EWD INVOF A VERY WEAK WARM FRONT PROGGED TO LIE ACROSS
THE KS/NEB VICINITY...AS DIURNAL HEATING SUPPORTS DEVELOPMENT OF
1000 TO 1500 J/KG MIXED-LAYER CAPE ACROSS THIS REGION.

THOUGH FLOW ALOFT IS FORECAST TO REMAIN MODEST...BOUNDARY-LAYER
SELYS VEERING TO WLY AT MID LEVELS WILL RESULT IN 0-6 KM SHEAR
SUFFICIENT FOR AT LEAST WEAKLY-ORGANIZED CONVECTION. WHILE SOME
MODEL DIFFERENCES WITH RESPECT TO TIMING AND LOCATION OF SUBTLE
FEATURES CROSSING THE PLAINS WITHIN THE LARGER-SCALE RIDGE DO
EXIST...WILL INTRODUCE LOW /5%/ PROBABILITY FOR HAIL/WIND ACROSS
PARTS OF THE CENTRAL PLAINS VICINITY AS A FEW STRONGER CELLS ARE
LIKELY TO EVOLVE THROUGH THE AFTERNOON AND EARLY EVENING BEFORE
STORMS DIURNALLY WEAKEN.

..GOSS.. 05/15/2013

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