DAY3SVR: Nws Storm Prediction Center Norman Ok

ACUS03 KWNS 200732
SWODY3
SPC AC 200730

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT SAT OCT 20 2012

VALID 221200Z - 231200Z

...SYNOPSIS...
A STRONG POLAR JET WILL MOVE INLAND OVER THE WESTERN STATES AS LARGE
SCALE TROUGH AMPLIFICATION CONTINUES TO OCCUR THROUGH MONDAY. THE
UPPER LOW CURRENTLY OFF THE BAJA MEXICO COAST IS EXPECTED TO SPREAD
NORTHEASTWARD OVER THE SOUTHERN PLAINS TO THE OZARKS/MIDDLE MS
VALLEY MONDAY/MONDAY NIGHT.

...SOUTHERN PLAINS/OZARKS TO MIDDLE/UPPER MS VALLEY...
ALTHOUGH SOME SPATIOTEMPORAL DIFFERENCES EXIST AT THE DAY 3
JUNCTURE...AFOREMENTIONED UPPER LOW/SHORTWAVE TROUGH IS EXPECTED TO
STEADILY SPREAD NORTHEASTWARD OVER PORTIONS OF THE REGION ON MONDAY.
WHILE A PARTICULARLY ORGANIZED SEVERE RISK IS NOT CURRENTLY
ANTICIPATED...VERTICAL SHEAR IN ASSOCIATION WITH THE SHORTWAVE
TROUGH AND 60S F SURFACE DEWPOINTS/MODEST DESTABILIZATION MAY
ACCOUNT FOR AT LEAST SPORADIC WIND/HAIL POTENTIAL MONDAY
AFTERNOON/EVENING FOR PORTIONS OF OK/NORTH TX TO THE OZARKS.

FARTHER NORTHEAST ACROSS THE MIDDLE/UPPER MS VALLEY...SCATTERED
ELEVATED CONVECTION WILL LIKELY BE ONGOING MONDAY MORNING. MORNING
HAIL POTENTIAL AFTER 12Z MONDAY WILL LIKELY BE MINIMAL...BUT A FEW
STRONG STORMS MAY NONETHELESS BE POSSIBLE EARLY IN THE PERIOD.
SUBSEQUENT DEVELOP INTO THE AFTERNOON ACROSS AREAS SUCH AS IA AND
THE ADJACENT UPPER MS VALLEY IS UNCERTAIN...AS LARGE SCALE FORCING
FOR ASCENT MAY REMAIN RELATIVELY NEBULOUS. NONETHELESS...AN ISOLATED
SEVERE THREAT MAY BE POSSIBLE WITHIN A MOIST/MODESTLY UNSTABLE
AIRMASS NEAR A WEAK SURFACE LOW AND/OR WARM FRONT.

...COASTAL NORTHERN CA/ORE...
AS AN UPPER TROUGH CONTINUES TO AMPLIFY OVER THE WESTERN
CONUS...LOW-TOPPED CONVECTION INCLUDING SOME TSTMS IS EXPECTED
ACROSS THE REGION...BUT ESPECIALLY THE COASTAL AREAS ORE/NORTHERN CA
AND PERHAPS INTO THE SACRAMENTO VALLEY MONDAY AFTERNOON/EVENING.
RELATIVELY STEEP LAPSE RATES ALOFT MAY ACCOUNT FOR SOME SMALL HAIL
POTENTIAL...BUT ORGANIZED SEVERE TSTMS ARE NOT CURRENTLY EXPECTED.

..GUYER.. 10/20/2012

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