DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 280555
SWODY2
SPC AC 280553

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1253 AM CDT SAT APR 28 2012

VALID 291200Z - 301200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF ERN NM INTO
WRN TX...

...SYNOPSIS...

BLOCKING SYNOPTIC PATTERN WILL PERSIST SUNDAY WITH AN UPPER RIDGE
FROM ONTARIO SWD THROUGH THE GREAT LAKES AND OH VALLEYS FLANKED BY
TROUGHS OVER THE ROCKIES AND PLAINS AS WELL AS OVER ERN CANADA.
EARLY SUNDAY A FRONT WILL LIKELY STRETCH FROM THE CAROLINAS WWD INTO
NRN AND WRN TX. A LARGE AREA OF HIGH PRESSURE WILL SETTLE SWD INTO
THE OH VALLEY RESULTING IN SWD ADVANCE OF ERN PORTION OF THIS
BOUNDARY...WHILE WRN EXTENT REMAINS NEARLY STATIONARY OR DEVELOPS
SLOWLY NWD. DRYLINE WILL EXTEND FROM NEAR THE BIG BEND AREA NWD INTO
ERN NM WHERE IT WILL INTERSECT THE FRONT.

...SRN HIGH PLAINS AREA...

NUMEROUS THUNDERSTORMS WILL LIKELY BE ONGOING FROM PORTIONS OF OK
INTO KS WITHIN ZONE OF ISENTROPIC ASCENT NORTH OF QUASI-STATIONARY
FRONT. THESE STORMS MAY POSE A MARGINAL THREAT FOR HAIL AS THEY
SHIFT NEWD DURING THE MORNING. FARTHER SOUTH LOW UPPER 50S TO NEAR
60 DEWPOINTS WILL EXIST IN WARM SECTOR OVER WRN TX BENEATH STEEP
LAPSE RATES RESULTING IN 1500-2000 J/KG MLCAPE AS THE BOUNDARY LAYER
WARMS DURING THE AFTERNOON. IT STILL APPEARS MUCH OF THIS AREA WILL
REMAIN CAPPED MUCH OF THE DAY. HOWEVER...STORMS MAY DEVELOP OVER THE
HIGHER TERRAIN AND MORE DEEPLY MIXED BOUNDARY LAYER OF ERN NM AS
WELL AS NEAR THE FRONT/DRYLINE INTERSECTION WHERE CONVERGENCE SHOULD
BE MAXIMIZED. SOME OF THIS ACTIVITY WILL INITIALLY BE WEST OF THE
MOIST AXIS AND HIGH BASED...BUT STORMS SHOULD INTENSIFY AS THEY
DEVELOP EWD INTO THE INSTABILITY AXIS ACROSS THE SRN HALF OF WRN TX.
EFFECTIVE VERTICAL SHEAR OF 40-50 KT WILL BE SUFFICIENT FOR
SUPERCELLS.

FARTHER NORTH OTHER STORMS MAY DEVELOP OVER THE HIGHER TERRAIN FROM
NERN NM INTO SCNTRL CO WHERE A NARROW AXIS OF MARGINAL INSTABILITY
COULD DEVELOP WEST OF CNTRL PLAINS MCS. SHEAR PROFILES WILL SUPPORT
SUPERCELLS...BUT OVERALL DESTABILIZATION POTENTIAL AND SEVERE THREAT
IN THIS REGION IS MORE UNCERTAIN AND CONDITIONAL UPON EVOLUTION OF
EARLY CLOUDS AND CONVECTION.

WILL MAINTAIN LOWER SEVERE PROBABILITIES FROM OK THROUGH KS DUE TO
WIDESPREAD ONGOING CONVECTION WHICH WILL PROBABLY LIMIT THE
POTENTIAL FOR SIGNIFICANT DESTABILIZATION.

...MID MS VALLEY...TN AND KY INTO NC...

ISOLATED STORMS MAY DEVELOP DURING THE AFTERNOON IN VICINITY OF E-W
FRONT WHERE THE ATMOSPHERE MAY BECOME MODERATELY UNSTABLE AS THE
BOUNDARY LAYER WARMS. SHEAR PROFILES FROM 35-45 KT WILL BE
SUFFICIENT FOR ORGANIZED STORMS. THIS ENVIRONMENT WILL SUPPORT A
THREAT FOR ISOLATED DAMAGING WIND AND HAIL. IT STILL APPEARS THAT
SHALLOW AND WEAK FRONTAL CONVERGENCE AND SHORTWAVE RIDGING MAY LIMIT
STORM COVERAGE SO WILL MAINTAIN 5% SEVERE PROBABILITIES AT THIS
TIME.

..DIAL.. 04/28/2012

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