SWODY1
SPC AC 141259
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0759 AM CDT SUN SEP 14 2008
VALID 141300Z - 151200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE TN VLY NE INTO THE OH
VLY/LWR GRT LKS...
...SYNOPSIS...
AMPLIFIED PATTERN WILL CONTINUE INTO MONDAY...WITH BUILDING RIDGE IN
THE WEST...PROGRESSIVE TROUGH ACROSS THE PLNS AND MS/OH VLYS...AND
PERSISTENT RIDGE ALONG THE ERN SEABOARD. T.D. IKE IS ACCELERATING
NE ACROSS SE MO ATTM. THE REMNANT CIRCULATION SHOULD REACH LK ERIE
EARLY THIS EVE AS IT IS RAPIDLY ABSORBED WITHIN STRENGTHENING SW
FLOW AHEAD OF APPROACHING TROUGH.
...TN VLY NE INTO OH VLY/LWR GRT LKS...
VERY STRONG LOW TO MID LVL WIND FIELD WILL PERSIST TODAY AS IKE IS
ABSORBED WITHIN THE WLYS OVER THE OH VLY. NARROW SSWLY 850 MB
JET...WITH CORE SPEEDS AOA 60 KTS...MOVING IN TANDEM WITH 75 KT SW
FLOW AT 700 MB WILL YIELD PROFILES VERY FAVORABLE FOR LOW LVL STORM
ROTATION AS IKE MOVES NE UP THE OH VLY. AT THE SAME TIME...EXPECT
BAND OF 80+ KT 500 MB FLOW OVER THE OH VLY/LWR GRT LKS TO EXPAND AS
THE SYSTEM MERGES WITH UPSTREAM MID LATITUDE TROUGH.
OFFSETTING THE FAVORABLE WIND ENVIRONMENT FOR TORNADOES/SUPERCELLS
WILL BE PERSISTENT POCKET OF VERY WARM MID LVL TEMPERATURES /AROUND
0 TO MINUS 2 C AT 500 MB/ ACCOMPANYING IKE. THIS WILL TEND TO LIMIT
UPDRAFT STRENGTH...DESPITE LIKELIHOOD FOR MODERATE SFC HEATING AHEAD
OF SYSTEM. MOISTURE-WISE...SATELLITE AND GPS PW DATA SHOW AN AREA
OF RELATIVELY DRY AIR /PW AROUND 1.50 IN VS. VALUES AOA 2.0 IN
FARTHER N AND W/ CENTERED OVER ERN KY ATTM THAT LIKELY WILL MOVE N
INTO OH LATER TODAY. WHILE THE SOMEWHAT DRIER AIR MAY SERVE TO
RAISE THE BASE OF CONVECTIVE CLOUDS...IT MAY ALSO ALLOW FOR
INCREASED SFC HEATING AND POTENTIALLY STRONGER CONVECTIVE
DOWNDRAFTS.
TAKEN TOGETHER...THE SETUP DESCRIBED ABOVE COULD YIELD A BAND OR TWO
OF FAST-MOVING STORMS AHEAD OF IKE THAT POTENTIALLY COULD YIELD BOTH
ISOLD TORNADOES...AND BOWING SEGMENTS WITH HIGH WIND. THERE IS ALSO
THE POSSIBILITY THAT THE MID LVL WARMING WILL PROVE SO HOSTILE TO
DEEP CONVECTION THAT ANY SVR SFC GUSTS THAT DO OCCUR WILL BE MORE
DIRECTLY ASSOCIATED WITH THE REMNANT WIND FIELD OF IKE...RATHER THAN
WITH CONVECTION.
FARTHER NE...PARTS OF NY AND WRN NEW ENGLAND WILL HAVE AT
LEAST A CONDITIONAL SUPERCELL/TORNADO RISK THIS AFTN/EVE INVOF WARM
FRONT/ZONE OF DIFFERENTIAL HEATING. THE 12Z BUF SOUNDING SHOWS
FAVORABLE DEEP WIND FIELD ALREADY IN PLACE. WHILE PREVIOUSLY
MENTIONED MID LVL WARMING MAY LIMIT POTENTIAL FOR STORM
DEVELOPMENT IN WRN NY...DEVELOPMENT MAY BE REALIZED FARTHER E AS
CLEARING SKIES SPREAD E TO THE HUDSON VLY.
...MID-SOUTH/CNTRL GULF CST...
LOW TO MID TROPOSPHERIC FLOW WILL STEADILY WEAKEN TODAY AS IKE
CONTINUES TO MOVE NE AWAY FROM REGION. DESPITE DIMINISHING LARGE
SCALE SUPPORT...SCTD CLUSTERS OF STORMS LIKELY WILL DEVELOP/
INCREASE WITH HEATING OF WARM/VERY MOIST AIR ALONG/AHEAD OF
SE-MOVING COLD FRONT NOW IN E TX/LA. STEEP LOW LVL LAPSE RATES AND
HIGH PWS MAY SUPPORT ISOLD DMGG WIND GUSTS THROUGH SUNSET.
..CORFIDI/HURLBUT.. 09/14/2008
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