SWODY1
SPC AC 091253
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0753 AM CDT SUN SEP 09 2007
VALID 091300Z - 101200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
A BROAD LOW AMPLITUDE TROUGH WILL PERSIST FROM THE NRN RCKYS TO THE
UPR GRT LKS...N OF ELONGATED SUB-TROPICAL RIDGE EXTENDING FROM THE
SRN RCKYS TO THE GULF CST STATES. COLD FRONTAL SURGE ASSOCIATED
WITH WEAKENING SHORTWAVE IMPULSE NOW CROSSING LK SUPERIOR WILL
CONTINUE S INTO THE SRN PLNS AND REINFORCE EXISTING BOUNDARY THAT
HAS BECOME MORE OR LESS STATIONARY FROM W TX AND SRN/ERN OK THROUGH
THE LWR OH VLY INTO SRN NEW ENGLAND. S OF THE FRONT...T.S.
GABRIELLE IS SLOWLY APPROACHING CAPE LOOKOUT NC ATTM. THE STORM
SHOULD TURN MORE NWD LATER TODAY...CROSSING THE NC OUTER
BANKS/COASTAL SOUNDS DURING THE AFTERNOON.
IN THE WEST...RISING HEIGHTS OVER THE WRN CANADA SHOULD KEEP ID
SHORTWAVE TROUGH FAIRLY STRONG AS IT CONTINUES ESE INTO ERN WY EARLY
MONDAY.
..NY/PA...
SATELLITE AND VWP DATA SHOW AN IMPULSE OVER IND ATTM...IN BELT OF
FLOW IMMEDIATELY N OF SUBTROPICAL RIDGE. THIS FEATURE SHOULD
CONTINUE ENE TODAY...BECOMING ABSORBED IN STRENGTHENING WSW FLOW
OVER THE NERN STATES. WHILE MID/UPR LVL CLOUDS ASSOCIATED WITH UPR
IMPULSE WILL TEMPER DESTABILIZATION...SFC HEATING SHOULD STILL BOOST
SBCAPE TO 1000-1500 J/KG ALONG AFOREMENTIONED FRONT IN NRN PA/SE NY
INTO SRN/CNTRL NEW ENGLAND. COUPLED WITH UPR LVL DIFFLUENCE AND
30-35 KT UNIDIRECTIONAL WSWLY MID LVL FLOW...SETUP MAY SUPPORT A FEW
CLUSTERS OF STRONG STORMS WITH LOCALLY DAMAGING WIND GIVEN WEAK CAP
AND ABUNDANT MOISTURE.
..ERN NC...
A LOW PROBABILITY THREAT WILL EXIST FOR A TORNADO OR TWO AS T.S.
GABRIELLE CROSSES NE NC TODAY. THIS THREAT SHOULD BE GREATEST NEAR
SYSTEM/S CENTER OF CIRCULATION...WHERE TSTMS HAVE PERSISTED
OVERNIGHT. POTENTIAL WILL ALSO EXIST FOR DIURNAL TSTM DEVELOPMENT
IN NRN QUADRANT OF THE T.S. AS SFC HEATING DESTABILIZES REGION ALONG
CONFLUENCE BAND/WARM FRONT OVER NE NC/FAR SE VA. LOW LVL SHEAR IN
THESE AREAS SHOULD BE MORE LIMITED...BUT MAY BE COMPENSATED FOR BY
GREATER LOW LVL INSTABILITY/UPDRAFT STRENGTH.
..N TX ACROSS THE ARKLATEX TO NRN MS/WRN TN...
AXIS OF STRONG DESTABILIZATION EXPECTED ON THE SRN EDGE OF
CLOUD BAND ASSOCIATED WITH LEAD FRONT BECOMING STATIONARY ACROSS THE
SRN PLNS/LWR MS VLY. WEAK LAPSE RATES AND LIMITED
SHEAR WILL LIMIT UPDRAFT ORGANIZATION/LONGEVITY. BUT GIVEN HI
PWS...A COUPLE WET MICROBURST EVENTS CANNOT BE RULED
OUT...ESPECIALLY IN AREAS OF STRONGER SFC HEATING.
..SRN HI PLNS W INTO THE RCKYS...
ENHANCED MOISTURE FLUX AND UPSLOPE FLOW IN THE WAKE OF REINFORCING
FRONTAL SURGE...COUPLED WITH DIURNAL HEATING...SHOULD SUPPORT TSTM
DEVELOPMENT FROM W TX WWD INTO MUCH OF NM THIS AFTERNOON. THIS
REGION WILL LIE BENEATH WEAK MID LEVEL FLOW OF UPR RIDGE. POCKETS OF
STRONGER INSTABILITY...TERRAIN INFLUENCES...AND STORM
MERGERS/INTERACTIONS COULD YIELD A ISOLATED WIND AND/OR MARGINALLY
SVR HAIL REPORTS...BUT THREAT FOR ORGANIZED SVR ACTIVITY WILL REMAIN
LOW.
FARTHER N ACROSS PARTS OF CO/WY...SCTD STORMS SHOULD FORM IN
WEAKLY UNSTABLE BUT MORE STRONGLY SHEARED REGIME DOWNSTREAM FROM ID
IMPULSE. UVV WILL INCREASE AS ID SHORT WAVE TROUGH APPROACHES
..AND THIS MAY SUPPORT DEVELOPMENT OF A FEW STRONGER STORMS THAT
POSE A THREAT FOR ISOLATED HI WIND GUSTS INTO THE EVENING.
.CORFIDI/JEWELL.. 09/09/2007
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