DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 161721
SWODY2
SPC AC 161720

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1220 PM CDT WED OCT 16 2013

VALID 171200Z - 181200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
DOWNSTREAM OF A BLOCKING UPPER RIDGE...WHICH HAS BECOME MORE
PROMINENT ACROSS THE NORTHEAST PACIFIC...CYCLONIC MID/UPPER FLOW
WILL PREVAIL FROM THE EASTERN GREAT BASIN AND ROCKIES EAST
NORTHEASTWARD THROUGH THE MIDDLE AND NORTHERN ATLANTIC SEABOARD
DURING THIS FORECAST PERIOD. THIS LATTER REGIME WILL CONTAIN A
NUMBER OF PROGRESSIVE SHORT WAVE IMPULSES...A COUPLE OF WHICH MAY
ENHANCE LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION ALONG A
FRONTAL ZONE SLOWLY ADVANCING EAST OF THE APPALACHIANS THROUGH THE
ATLANTIC SEABOARD...AND NEAR ANOTHER DEVELOPING FRONTAL ZONE ACROSS
THE SOUTH CENTRAL HIGH PLAINS

AT THE SAME TIME...SUBTROPICAL RIDGING TO THE SOUTH APPEARS LIKELY
TO WEAKEN SOME...BUT IS STILL EXPECTED TO MAINTAIN SUBSTANTIVE
INFLUENCE ACROSS THE GULF OF MEXICO AND THE FLORIDA PENINSULA. A
PERTURBATION MIGRATING AROUND THE PERIPHERY OF THIS FEATURE COULD
CONTRIBUTE TO ANOTHER AREA OF ENHANCED MID-LEVEL FORCING FOR ASCENT
ALONG THE STALLED SOUTHWESTERN FLANK OF THE EAST COAST
FRONT...ACROSS PARTS OF DEEP SOUTH TEXAS BY LATE THURSDAY OR
THURSDAY NIGHT.

AT LEAST LOW PROBABILITIES FOR THUNDERSTORM ACTIVITY APPEAR TO EXIST
WITH THE AFOREMENTIONED SCATTERED AREAS OF ENHANCED FORCING FOR
UPWARD VERTICAL MOTION. HOWEVER...DESTABILIZATION IS EXPECTED TO BE
QUITE WEAK...WITH GENERALLY NEGLIGIBLE SEVERE STORM POTENTIAL.

...APPALACHIANS/ATLANTIC SEABOARD...
LOW THUNDERSTORM PROBABILITIES ACROSS PARTS OF CENTRAL ALABAMA INTO
THE SOUTHERN APPALACHIANS APPEAR MOSTLY IN THE 17/12-18Z TIME
FRAME...BEFORE MID-LEVEL FORCING FOR ASCENT WEAKENS/SHIFTS NORTHEAST
OF THE REGION...ASSOCIATED WITH THE EAST NORTHEAST PROGRESSION OF A
SIGNIFICANT SHORT WAVE TROUGH THROUGH THE OHIO VALLEY. MODELS ARE
SUGGESTIVE THAT THIS IMPULSE COULD AGAIN CONTRIBUTE TO MARGINALLY
FAVORABLE PROFILES FOR THUNDERSTORM ACTIVITY TOWARD THE 17/21-18/03Z
TIME FRAME...MAINLY NEAR AND NORTH/EAST OF THE ALLEGHENY MOUNTAINS.

...SOUTH CENTRAL HIGH PLAINS...
IT APPEARS POSSIBLE THAT A WEAK RETURN FLOW OF MOISTURE TO A
STRENGTHENING LOWER/MID TROPOSPHERIC WARM ADVECTION REGIME COULD
CONTRIBUTE TO SUFFICIENT DESTABILIZATION FOR WEAK THUNDERSTORMS
THURSDAY NIGHT...PARTICULARLY TOWARD THE 18/09-12Z TIME FRAME ACROSS
PARTS OF SOUTHWESTERN KANSAS AND NORTHWESTERN OKLAHOMA.

...DEEP SOUTH TEXAS...
THE BEST CHANCE FOR THUNDERSTORMS ACCOMPANYING THE SUBTROPICAL
IMPULSE APPEARS TO EXIST ALONG IMMEDIATE COASTAL AREAS...AND IN THE
OFFSHORE WATERS AFTER 18/06Z.

..KERR.. 10/16/2013

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