SWODY1
SPC AC 250044
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0744 PM CDT FRI OCT 24 2008
VALID 250100Z - 251200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
IN RESPONSE TO THE APPROACH OF A STRONG POLAR JET STREAK EMANATING
FROM THE PACIFIC...THE CENTRAL STATES CLOSED LOW IS IN THE PROCESS
OF ACCELERATING NORTHEASTWARD TOWARD THE GREAT LAKES REGION. A
BROAD CYCLONIC FLOW CURVES AROUND THIS FEATURE...EAST OF THE ROCKIES
INTO THE APPALACHIANS...WITH ONE BAND OF STRONGER FORCING FOR UPWARD
VERTICAL MOTION PIVOTING NORTHEASTWARD ACROSS PARTS OF THE GREAT
LAKES/UPPER OHIO VALLEY REGION. THE NEXT SIGNIFICANT IMPULSE IS
JUST NOW SHIFTING THROUGH THE OZARK PLATEAU REGION...BUT THIS COULD
APPROACH THE UPPER OHIO VALLEY/CENTRAL APPALACHIANS REGION BY 12Z
SATURDAY...AS THE NEXT IMPULSE DIGS SOUTHEAST OF THE CENTRAL PLAINS.
ACROSS THE SOUTHEASTERN STATES...ONCE AN IMPULSE ASSOCIATED WITH THE
SUBTROPICAL JET SHIFTS EAST OF CAROLINA COASTAL AREAS THIS
EVENING...LARGE-SCALE FORCING FOR UPWARD VERTICAL MOTION IS EXPECTED
TO REMAIN FAIRLY WEAK. A SURFACE LOW PROBABLY WILL MIGRATE OR
REDEVELOP NORTHEASTWARD FROM THE VICINITY OF THE FLORIDA BIG BEND
INTO THE NORTH CAROLINA PIEDMONT...BENEATH A DIFLUENT UPPER FLOW
REGIME ASSOCIATED WITH COUPLED SUBTROPICAL AND POLAR JET
STREAKS...BUT MODELS SUGGEST LITTLE IF ANY DEEPENING WILL OCCUR.
WHILE THIS MAY BE ACCOMPANIED BY BOUNDARY LAYER MOISTENING IN A
NARROW WARM SECTOR WEDGE IN THE WAKE OF THE RETREATING LARGE SURFACE
RIDGE OFF THE ATLANTIC SEABOARD...CONVECTIVE POTENTIAL IS EXPECTED
TO REMAIN LOW TO THE LEE OF THE CENTRAL/SOUTHERN APPALACHIANS
THROUGH THE REMAINDER OF THE NIGHT. WEAK MID-LEVEL LAPSE RATES HAVE
ALREADY BEEN INHIBITIVE TO THE DEVELOPMENT OF THUNDERSTORMS...AND A
DEVELOPING INVERSION ASSOCIATED WITH MID-LEVEL SUBSIDENCE IS
EXPECTED TO LOWER THUNDERSTORM PROBABILITIES FURTHER.
...SOUTH ATLANTIC COASTAL AREAS...
A CONVECTIVE CLUSTER APPEARS TO BE STRENGTHENING AND BECOMING
INCREASINGLY ORGANIZED ALONG A FRONTAL ZONE NEAR THE GEORGIA/SOUTH
CAROLINA COAST. THIS APPEARS TO BE SUPPORTED BY THE FORCING
ASSOCIATED WITH SUBTROPICAL IMPULSE...AND THE MOST VIGOROUS
CONVECTION ALREADY APPEARS TO BE DEVELOPING OFFSHORE. LOW POTENTIAL
FOR DAMAGING WIND GUSTS WITH CONVECTION INLAND OF COASTAL AREAS IS
EXPECTED TO LOWER FURTHER BY LATE EVENING.
...APPALACHIANS/UPPER OHIO VALLEY...
IT IS POSSIBLE THAT LOW-LEVEL WARMING/MOISTENING ALONG THE
APPALACHIANS COULD CONTRIBUTE TO SUFFICIENT DESTABILIZATION FOR
SCATTERED WEAK THUNDERSTORMS LATER THIS EVENING/OVERNIGHT...
PARTICULARLY BENEATH THE COOLER MID-LEVEL ENVIRONMENT ACROSS PARTS
OF WEST VIRGINIA INTO WESTERN PENNSYLVANIA.
...GREAT LAKES...
WEAK THUNDERSTORMS NEAR THE COLD CORE OF THE CLOSED LOW ARE
BEGINNING TO WEAKEN/DECREASE IN COVERAGE. HOWEVER...ACTIVITY COULD
LINGER INTO/THROUGH THE OVERNIGHT HOURS ACROSS THE LAKE MICHIGAN
VICINITY...WHERE THE BOUNDARY LAYER OVER THE WARMER LAKE WATERS WILL
BE SLOWER TO COOL/STABILIZE.
..KERR.. 10/25/2008
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