DAY3SVR: Nws Storm Prediction Center Norman Ok

ACUS03 KWNS 280732
SWODY3
SPC AC 280730

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT MON OCT 28 2013

VALID 301200Z - 311200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE
SOUTH-CENTRAL PLAINS TO LOWER MO RIVER VALLEY...

...SOUTHERN/CENTRAL PLAINS TO LOWER/MIDDLE MO VALLEY ...
A CONSIDERABLE UPPER TROUGH/ASSOCIATED STRONG POLAR JET ARE EXPECTED
TO MAKE AN EAST-NORTHEASTWARD TRANSITION FROM THE ROCKIES TO MUCH OF
THE PLAINS/MO VALLEY ON WEDNESDAY. AS THE PRIMARY SURFACE LOW
DEEPENS ACROSS THE MIDDLE MO VALLEY...A COLD FRONT WILL GENERALLY
SPREAD EASTWARD ACROSS THE CENTRAL PLAINS/MO VALLEY...WHILE
ADVANCING SOUTHEASTWARD AND GRADUALLY OVERTAKING A DRYLINE ACROSS
THE SOUTHERN HIGH PLAINS. FACTORS SUCH AS CONTINUED NUMERICAL
GUIDANCE VARIABILITY AND THE POTENTIAL EXTENSIVENESS OF EARLY-DAY
CONVECTION COMPLICATES THE DETAILS AT THE DAY 3 JUNCTURE.
REGARDLESS...THE ADVANCEMENT OF THE UPPER TROUGH...A STRENGTHENING
DEEP LAYER WIND FIELD...AND A SEASONALLY MOIST AIRMASS IMPLY AT SOME
SEVERE RISK WILL EXIST ACROSS A BROAD REGIONAL EXTENT WEDNESDAY.

ALTHOUGH GUIDANCE SOLUTIONS VARY...IT SEEMS LIKELY THAT SCATTERED
TSTMS WILL BE ONGOING WEDNESDAY MORNING TO THE EAST OF A COLD
FRONT/DRY LINE ACROSS THE SOUTHERN INTO CENTRAL PLAINS...INCLUDING A
CORRIDOR FROM NORTH TX AND PORTIONS OF OK INTO KS/MO. THE UNCERTAIN
TIMING/COVERAGE OF SUCH CONVECTION AND ASSOCIATED CLOUD COVER
COMPLICATES THE DETAILS. BUT A VERY MOIST AIRMASS...WEAK TO MODERATE
DESTABILIZATION AND RELATIVELY STRONG SHEAR WOULD SUPPORT
MULTI-FACETED STORM MODES INCLUDING RISKS FOR HAIL/WIND AND POSSIBLY
A TORNADO.

FARTHER NORTH INTO THE MIDDLE MO VALLEY/UPPER MIDWEST...LOW-LEVEL
MOISTURE WILL STEADILY INCREASE ACROSS THE REGION...BUT THE DEGREE
OF DESTABILIZATION IS UNCERTAIN NEAR/EAST OF THE DEEPENING SURFACE
LOW AND EASTWARD-ACCELERATING COLD FRONT. THIS IS ESPECIALLY GIVEN
THE POTENTIAL FOR EXTENSIVE CONVECTION TO THE SOUTH.
REGARDLESS...SHOULD CONFIDENCE INCREASE IN TERMS OF EVEN MODEST
DESTABILIZATION...A NORTHWARD EXPANSION OF THE CATEGORICAL SLIGHT
RISK WOULD LIKELY BE WARRANTED GIVEN AMPLE FORCING FOR
ASCENT/VERTICAL SHEAR.

..GUYER.. 10/28/2013

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