DAY3SVR: Nws Storm Prediction Center Norman Ok

ACUS03 KWNS 180731
SWODY3
SPC AC 180729

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0229 AM CDT WED APR 18 2007

VALID 201200Z - 211200Z

..NO SVR TSTM AREAS FORECAST...

..SYNOPSIS...
LARGE-SCALE RIDGE WILL PREVAIL OVER THE CENTRAL CONUS THIS
PERIOD...UPSTREAM OF A TROUGH CENTERED OVER THE WRN ATLANTIC AND
DOWNSTREAM OF A SECOND TROUGH ADVANCING EWD ACROSS THE WRN CONUS.
THE WRN TROUGH IS FORECAST TO REMAIN TOO FAR W TO DIRECTLY AFFECT
THE CONVECTIVE POTENTIAL OVER THE PLAINS STATES THIS PERIOD...BUT
MODELS HINT THAT A WEAK LEAD IMPULSE WITHIN SWLY FLOW AHEAD OF THIS
FEATURE MAY TRAVERSE THE HIGH PLAINS. THIS COMBINED WITH THE LIKELY
PRESENCE OF A HIGH PLAINS DRYLINE -- AND POSSIBLY A WEAK W-E WARM
FRONT LIFTING NWD ACROSS KS/OK...COULD RESULT IN A FEW
ISOLATED/SEVERE STORMS THIS PERIOD.

..CENTRAL AND SRN HIGH PLAINS INTO SRN KS/NRN OK...
A SLOW NWD INCREASE IN BOUNDARY-LAYER DEWPOINTS SHOULD OCCUR INTO
OK/KS/THE CENTRAL AND SRN HIGH PLAINS THIS PERIOD...AS BROAD AREA OF
LOW-LEVEL SELY FLOW DEVELOPS AHEAD OF APPROACHING LARGE-SCALE
TROUGH. THIS COMBINED WITH DAYTIME HEATING AND STEEPENING LAPSE
RATES -- PARTICULARLY OVER THE HIGH PLAINS -- SUGGESTS MODERATE
DESTABILIZATION WILL OCCUR BY LATE AFTERNOON.

WHILE THE NAM FORECAST SOUNDINGS REVEAL THE MODELS TYPICAL BIAS OF
AGGRESSIVELY ERODING THE CAPPING INVERSION WHILE ALSO
MOISTENING/STEEPENING THE LAPSE RATES WITHIN THE BOUNDARY
LAYER...THE NAMKF SHOWS A STRONGER -- AND LIKELY MORE ACCURATE --
DEPICTION OF A MORE PERSISTENT CAP.

ALONG THESE SAME LINES...THE NAM MUCH MORE AGGRESSIVELY DEVELOPS
PRECIPITATION -- BOTH ALONG THE WARM FRONT OVER NERN OK/SERN
KS...AND ALONG THE DRYLINE. ATTM...IT APPEARS THAT CONVECTIVE
DEVELOPMENT WILL BE QUITE LIMITED -- PERHAPS TO JUST A FEW ISOLATED
CELLS. HAVING SAID THAT...ANY STORMS WHICH DO DEVELOP WOULD FIND
THEMSELVES IN AN ENVIRONMENT -- BOTH THERMODYNAMICALLY AND
KINEMATICALLY -- SUPPORTIVE OF SUPERCELLS. THEREFORE...WILL
INTRODUCE A 5%/CONDITIONAL SEVERE THREAT ACROSS THE CENTRAL AND SRN
HIGH PLAINS...AND EWD INTO OK/KS ALONG THE POSSIBLE WARM FRONT.

.GOSS.. 04/18/2007

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