DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 161242
SWODY1
SPC AC 161239

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0739 AM CDT TUE APR 16 2013

VALID 161300Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL/SOUTHERN
PLAINS TO THE OH/TN VALLEYS...

...TN/OH VALLEYS...
FIRST FEW MORNING VISIBLE SATELLITE IMAGES SHOW THE POTENTIAL FOR
CONSIDERABLE SUNSHINE TODAY OVER MUCH OF THE TN/OH VALLEY. 12Z
RAOBS SHOW RATHER STEEP MID LEVEL LAPSE RATES AND SUBSTANTIAL LOW
LEVEL MOISTURE IN PLACE ACROSS THE REGION. THE RESULT SHOULD BE A
MODERATELY UNSTABLE AIR MASS OVER THE ENTIRE REGION BY EARLY
AFTERNOON. MODEL GUIDANCE SHOWS CONSIDERABLE VARIABILITY IN THE
EXTENT OF CONVECTION ACROSS THIS REGION TODAY...BUT BELIEVE THE
RECENT HRRR RUNS DEPICT A REASONABLE SCENARIO OF SCATTERED
THUNDERSTORMS FORMING BY NOON OVER WEST KY/TN. THESE STORMS SHOULD
EXPAND EASTWARD THROUGH THE DAY...WHILE OTHER CONVECTION FORMS ALONG
A FRONT LYING ROUGHLY ALONG THE OH RIVER. EFFECTIVE SHEAR OF 30-35
KNOTS WILL BE SUFFICIENT FOR MULTICELL AND OCCASIONAL SUPERCELL
STORM STRUCTURES. LARGE HAIL IS LIKELY TO BE THE MAIN THREAT...BUT
LOCALLY DAMAGING WINDS AND EVEN AN ISOLATED TORNADO ARE POSSIBLE.

...NORTHWEST TX/SOUTHWEST OK...
A COLD FRONT CURRENTLY EXTENDS ACROSS SOUTHERN OK INTO WEST TX.
THIS BOUNDARY IS EXPECTED TO SAG SLOWLY SOUTHWARD TODAY...WHILE THE
DRYLINE BECOMES ESTABLISHED FROM WEST OF ABI SOUTHWARD TO EAST OF
THE BIG BEND REGION. DESPITE WEAK LARGE SCALE FORCING...STRONG
DAYTIME HEATING MAY BE SUFFICIENT TO LOCALLY BREAK THE CAP BY LATE
AFTERNOON IN VICINITY OF THE DRYLINE/COLD FRONT TRIPLE POINT. IF
THIS OCCURS...STRONG INSTABILITY AND STEEP LAPSE RATES...COUPLED
WITH FAVORABLE DEEP LAYER SHEAR WILL PROMOTE SUPERCELL STORMS
CAPABLE OF LARGE HAIL AND DAMAGING WINDS. STORM COVERAGE IS
EXPECTED TO BE VERY SPARSE...WITH ACTIVITY WEAKENING A COUPLE HOURS
AFTER SUNSET.

...SOUTHERN KS/MO...
MODEL GUIDANCE IS IN AGREEMENT THAT THE LOW LEVEL JET WILL
STRENGTHEN CONSIDERABLY AFTER 17/00Z OVER OK. THIS WILL RESULT IN
STRONG WARM ADVECTION AND LIFT ACROSS PARTS OF SOUTHERN KS AND
SOUTHWEST MO. THIS REGION WILL BE WELL NORTH OF A SURFACE
BOUNDARY...BUT SUFFICIENT ELEVATED CAPE MAY YIELD LARGE HAIL IN THE
STRONGER STORMS OVERNIGHT.

..HART/GARNER.. 04/16/2013

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