DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 101729
SWODY2
SPC AC 101728

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT THU OCT 10 2013

VALID 111200Z - 121200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE
DAKOTAS/MN...

...SYNOPSIS...
THE UPPER TROUGH CURRENTLY APPROACHING THE SOUTHERN ROCKIES IS
EXPECTED TO BECOME INCREASINGLY NEGATIVE-TILT AND BEGIN TO
DECELERATE AS IT MOVES NORTHEASTWARD OVER THE NORTHERN PLAINS AND
UPPER MIDWEST ON FRIDAY. A CORRESPONDING SURFACE LOW WILL SPREAD
NORTHEASTWARD FROM NEB TO THE EASTERN DAKOTAS ON FRIDAY...WITH AN
EAST/NORTHEASTWARD-MOVING FRONT ACROSS THE MIDDLE MO VALLEY/UPPER
MIDWEST...WITH THE FRONT ADVANCING IN A MORE SOUTHEASTWARD-FASHION
ACROSS THE SOUTH-CENTRAL PLAINS/LOWER MO VALLEY THROUGH FRIDAY
NIGHT.

...DAKOTAS/MN...
IN ADVANCE OF THE APPROACHING UPPER TROUGH...SHOWERS/TSTMS ARE
LIKELY TO BE ONGOING FRIDAY MORNING ACROSS PORTIONS OF THE
DAKOTAS/ADJACENT MIDDLE MO VALLEY IN ASSOCIATION WITH A WARM
CONVEYOR. IN THE WAKE OF THIS EARLY DAY CLOUD
COVER/PRECIPITATION...THE AIRMASS SHOULD MODESTLY DESTABILIZE WITHIN
A RELATIVELY NARROW CORRIDOR NEAR/IMMEDIATELY AHEAD OF THE
EAST-NORTHEASTWARD ADVANCING OCCLUDED/COLD FRONT ACROSS THE EASTERN
DAKOTAS INTO WESTERN/SOUTHERN MN...POTENTIALLY AS FAR WEST AS THE
SURFACE LOW AND NEARBY NORTH-SOUTH ORIENTED WARM/STATIONARY FRONT
ACROSS THE EAST-CENTRAL DAKOTAS.

WITH SURFACE DEWPOINTS LIKELY TO BE LIMITED TO THE LOWER/SOME MIDDLE
50S F...STEEPENING LAPSE RATES/COOL THERMAL PROFILES ALOFT AND
AFOREMENTIONED RELATIVELY NARROW CORRIDOR OF INSOLATION/HEATING
SHOULD ALLOW FOR SBCAPE TO NEAR/ABOVE 500 J/KG BY EARLY/MID
AFTERNOON. SUFFICIENT WIND PROFILES/INSTABILITY COULD ALLOW FOR
STRONG/POTENTIALLY SEVERE LOW-TOPPED SURFACE-BASED STORMS FRIDAY
AFTERNOON. THIS INCLUDES THE POTENTIAL FOR A WEAK TORNADO OR
TWO...SEVERE HAIL...AND POSSIBLY DAMAGING TSTM WINDS AS STORMS
INCREASE/MERGE INTO BANDS BY LATE AFTERNOON/EARLY EVENING.
THEREAFTER...AN INCREASINGLY STABLE BOUNDARY LAYER BY MID/LATE
EVENING SHOULD ACCOUNT FOR A DIMINISHED CONVECTIVE INTENSITY/SEVERE
RISK FRIDAY NIGHT.

...LOWER MO VALLEY/SOUTH-CENTRAL PLAINS...
IN ASSOCIATION WITH THE NORTHERN PLAINS/UPPER MIDWEST UPPER
TROUGH...THE MAJORITY OF HEIGHT FALLS AND VERTICAL SHEAR /RELATIVE
TO THE WARM SECTOR/ WILL BE RELEGATED TO AREAS NORTH OF THE LOWER MO
RIVER VALLEY. REGARDLESS...TSTM DEVELOPMENT WILL INITIALLY BE
POSSIBLE NEAR THE COLD FRONT ACROSS IA AND NORTHERN/WESTERN MO
VICINITIES FRIDAY AFTERNOON...AND A BIT LATER INTO FRIDAY EVENING
/MAINLY POST-SUNSET/ FARTHER SOUTH-SOUTHWEST INTO OK/TX MAINLY AS A
COLD FRONT OVERTAKES A DRYLINE. WHILE LOW-LEVEL MOISTURE/VERTICAL
SHEAR WOULD BE ADEQUATE FOR SOME STRONG/POTENTIALLY SEVERE TSTMS
INCLUDING A SUPERCELL OR TWO...FACTORS SUCH AS WEAK LAPSE RATES
ALOFT AND THE NOCTURNAL TENDENCY FOR MUCH OF THE EXPECTED
DEVELOPMENT SHOULD LIMIT THE OVERALL SEVERE POTENTIAL/LIKELIHOOD.

..GUYER.. 10/10/2013

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