SWODY1
SPC AC 090529
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1229 AM CDT SUN SEP 09 2007
VALID 091200Z - 101200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
ELONGATED SUB-TROPICAL RIDGE AXIS WILL REMAIN SITUATED WEST-TO-EAST
ACROSS THE SRN U.S. WITH ABUNDANT TROPICAL MOISTURE PERSISTING ALONG
A QUASI-STATIONARY FRONTAL ZONE FROM THE SRN HIGH PLAINS TO THE
NORTHEAST. WRN EXTENSION OF THE FRONT...ACROSS THE SRN HIGH PLAINS
AND ROCKIES...WILL BE REINFORCED BY A SECONDARY FRONTAL SURGE
ASSOCIATED WITH A DEAMPLIFYING SHORT WAVE TROUGH FORECAST TO LIFT
ACROSS THE GREAT LAKES AND INTO SRN CANADA THROUGH THE DAY. IN THE
WAKE OF THIS IMPULSE...NEXT UPSTREAM TROUGH IS FORECAST TO DIG SEWD
ACROSS THE NRN ROCKIES AND NRN GREAT BASIN THROUGH EARLY MONDAY.
A WEAKER DISTURBANCE...EMBEDDED WITHIN WSWLY MID LEVEL FLOW ON THE
NRN EDGE OF THE SUB-TROPICAL RIDGE...IS FORECAST TO TRACK FROM THE
MIDWEST/UPPER OH VALLEY EARLY TODAY TO THE NORTHEAST THROUGH
TONIGHT. WEAK SURFACE REFLECTION/FRONTAL WAVE ASSOCIATED WITH THIS
IMPULSE WILL TRAVEL ALONG STALLED FRONT FROM OH TO NY TODAY...AND
THEN OVER NEW ENGLAND TONIGHT. INCREASING DEEP-LAYER WLY FLOW
ASSOCIATED WITH THE SRN FRINGE OF THIS DISTURBANCE IS EXPECTED TO
PICK UP AND STEER T.S. GABRIELLE CIRCULATION BACK TO THE WRN
ATLANTIC AFTER CENTER OF THE TC CLIPS NC OUTER BANKS TODAY. REFER TO
LATEST TPC GUIDANCE REGARDING TRACK/INTENSITY OF GABRIELLE.
..PA/NY...
AXIS OF MODEST INSTABILITY /MUCAPE TO 1500 J PER KG/ IS EXPECTED TO
DEVELOP AHEAD OF WEAK FRONTAL WAVE DEVELOPING EAST ACROSS THESE
AREAS DURING THE AFTERNOON. STRONGER FORCING WITH THE WAVE/LOW AND
ALONG THE FRONT SHOULD SPUR A FEW STRONG STORMS GIVEN WEAK CAP AND
ABUNDANT MOISTURE. GENERALLY WEAK LAPSE RATES MAY BE OFFSET BY
MODERATE DEEP LAYER WLY FLOW/SHEAR AND ORGANIZING INFLUENCE OF THE
SURFACE WAVE/LOW AND FRONT. ISOLATED DAMAGING WIND GUSTS APPEAR
POSSIBLE ALONG WITH MARGINALLY SEVERE HAIL. OVERALL THREAT APPEARS
LIMITED BY LACK OF STRONGER DESTABILIZATION. HOWEVER...PROBABILITY
OF SEVERE WEATHER MAY INCREASE IF GREATER INSTABILITY CAN DEVELOP.
..ERN NC...
BRIEF/WEAK TORNADO OR WATERSPOUT CANNOT BE RULED OUT NEAR THE CENTER
OF T.S. GABRIELLE AS STORM MAKES LANDFALL OVER ERN NC. THIS THREAT
WOULD BE CONFINED TO THE OUTER BANKS OF NC BASED ON LATEST TPC TRACK
FORECAST. HOWEVER...A MORE INLAND TRACK WOULD BRING ISOLATED/WEAK
TORNADO POTENTIAL WWD. REFER TO LATEST TPC AND LOCAL NWS OFFICE
INFORMATION REGARDING T.S. GABRIELLE.
..NORTH TX ACROSS THE ARKLATEX TO NRN MS/WRN TN...
AXIS OF STRONG DESTABILIZATION IS FORECAST ON THE SRN EDGE OF
DEEP-LAYER CLOUD FIELD ASSOCIATED WITH RESIDUAL QUASI-STATIONARY
BOUNDARY ACROSS THESE AREAS. GENERALLY WEAK LAPSE RATES AND LIMITED
SHEAR WITHIN THE SUB-TROPICAL RIDGE AXIS WILL RESTRICT GREATER STORM
ORGANIZATION. HOWEVER...A COUPLE WET MICROBURST WIND REPORTS CANNOT
BE RULED OUT AS CONVECTION INTENSIFIES FROM LATE AFTERNOON TO EARLY
EVENING.
..SRN HIGH PLAINS WWD TO THE ROCKIES...
ENHANCED MOISTURE FLUX AND UPSLOPE FLOW IN THE WAKE OF REINFORCING
FRONTAL SURGE...COUPLED WITH DIABATIC HEATING...WILL CONTRIBUTE TO
TSTM DEVELOPMENT FROM PARTS OF WEST TX WWD OVER MUCH OF NM THIS
AFTERNOON. THESE AREAS WILL ALSO LIE BENEATH WEAK MID LEVEL FLOW
WITHIN WRN PERIPHERY OF SUB-TROPICAL RIDGE AXIS. POCKETS OF STRONGER
INSTABILITY...TERRAIN INFLUENCES...AND STORM MERGERS/INTERACTIONS
COULD RESULT IN A COUPLE OF WIND AND/OR HAIL REPORTS BUT MORE
ORGANIZED SEVERE POTENTIAL APPEARS LOW.
FARTHER NORTH...ACROSS PARTS OF CO/WY...SCATTERED STORMS SHOULD
DEVELOP WITHIN WEAKLY UNSTABLE BUT INCREASINGLY SHEARED REGIME.
LARGE SCALE FORCING FOR ASCENT ACROSS THIS AREA WILL STRENGTHEN AS
SHORT WAVE TROUGH APPROACHES LATE IN THE DAY AND THIS MAY SUSTAIN A
FEW STRONGER STORMS INTO THE EVENING. ONLY ISOLATED HAIL/WIND
EXPECTED DUE TO LIMITED INSTABILITY.
.CARBIN/JEWELL.. 09/09/2007
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