DAY3SVR: Nws Storm Prediction Center Norman Ok

ACUS03 KWNS 150831
SWODY3
SPC AC 150830

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CST SAT DEC 15 2012

VALID 171200Z - 181200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...

BROAD SYNOPTIC TROUGH WILL ADVANCE THROUGH THE ERN STATES MONDAY. A
SERIES OF VORT MAXES EMBEDDED WITHIN THIS REGIME WILL MOVE ACROSS
THE OH VALLEY AND SERN U.S. SURFACE LOW IS FORECAST TO DEVELOP AND
LIFT NEWD THROUGH THE OH VALLEY IN ASSOCIATION WITH AN EJECTING
SHORTWAVE TROUGH. COLD FRONT TRAILING FROM THE LOW WILL SWEEP
SEWD...LIKELY EXTENDING FROM NEAR THE NERN U.S. COAST SWWD INTO THE
NRN GULF BY THE END OF THE PERIOD.

...GA THROUGH THE ERN CAROLINAS...

SWLY LOW LEVEL JET IS FORECAST TO STRENGTHEN FROM GA THROUGH ERN
CAROLINAS IN ASSOCIATION WITH HEIGHT FALLS ATTENDING THE PROGRESSIVE
SHORTWAVE TROUGH. THIS FEATURE WILL TRANSPORT MODIFIED CP AIR WITH
LOW 60S DEWPOINTS THROUGH THE PRE-FRONTAL WARM SECTOR CONTRIBUTING
TO DESTABILIZATION. INSTABILITY WILL REMAIN MARGINAL /MLCAPE AOB 500
J/KG/ ESPECIALLY WITH NWD EXTENT INTO WARM SECTOR OWING TO
WIDESPREAD CLOUDS AND WEAK LAPSE RATES. CONVECTION SHOULD CONTINUE
DEVELOPING WITHIN ZONE OF ASCENT ALONG CONVEYOR BELT...AND MAY
UNDERGO SOME INTENSIFICATION AS THE BOUNDARY LAYER MOISTENS AND
DESTABILIZES. ACTIVITY WILL BE EMBEDDED WITHIN STRONG DEEP LAYER
WIND PROFILES...WITH LARGE HODOGRAPHS AND STRONG VERTICAL SHEAR
SUPPORTIVE OF ORGANIZED STORMS INCLUDING BOWING STRUCTURES AND
SUPERCELLS. WILL INTRODUCE A 5% SEVERE COVERAGE AREA AT THIS TIME
DUE TO POTENTIAL LIMITING FACTORS IMPOSED BY THE EXPECTED MARGINAL
THERMODYNAMIC ENVIRONMENT. HOWEVER...AREA WILL BE RE-EVALUATED FOR A
POSSIBLE SLIGHT RISK ON THE DAY 2 UPDATE.

...OH VALLEY REGION...

MOISTURE WILL BE MORE LIMITED IN THIS REGION WITH DEWPOINTS
GENERALLY IN THE 40S. HOWEVER...COLD TEMPERATURES ALOFT...STEEPER
LAPSE RATES AND POTENTIAL FOR BOUNDARY LAYER WARMING MAY YIELD AT
LEAST MARGINAL INSTABILITY WITH MLCAPE AOB 300 J/KG. A FEW STORMS
MAY DEVELOP AS THE ATMOSPHERE DESTABILIZES...POSSIBLY AIDED BY AT
LEAST MODEST FORCING FOR ASCENT ATTENDING AN EJECTING SHORTWAVE
TROUGH. IF SUFFICIENT INSTABILITY DEVELOPS...STRONG EFFECTIVE SHEAR
WILL SUPPORT POTENTIAL FOR ORGANIZED STORMS AND AT LEAST A MODEST
SEVERE THREAT. LIKELIHOOD OF WEAK INSTABILITY PRECLUDES INTRODUCING
MORE THAN 5% SEVERE PROBABILITIES AT THIS TIME.

..DIAL.. 12/15/2012

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