SWODY1
SPC AC 092000
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0300 PM CDT SUN SEP 09 2007
VALID 092000Z - 101200Z
..NO SVR TSTM AREAS FORECAST...
..SRN ROCKIES/HIGH PLAINS...
SURFACE ANALYSIS SHOWED BOUNDARY HAS MOVED INTO WRN NM THIS
AFTERNOON WITH DEWPOINTS IN THE 50S ALONG AND EAST OF THIS
BOUNDARY...BUT INTO THE LOWER 60S ACROSS SERN NM/FAR W TX. SURFACE
HEATING WITHIN THIS MOIST AIR MASS IS RESULTING IN MODERATE
INSTABILITY FROM FAR W TX INTO SWRN NM/SERN AZ. ALTHOUGH
INSTABILITY IS WEAKER FARTHER N INTO CENTRAL/NRN NM...GREATER DEEP
LAYER SHEAR ATTENDANT WITH STRONGER MID LEVEL FLOW ACCOMPANYING
SHORT WAVE TROUGH OVER CENTRAL NM MAY SUPPORT AN ISOLATED SEVERE
WIND/HAIL THREAT. FARTHER S...FROM FAR W TX TO FAR SERN AZ...
SEVERE WEATHER THREAT WILL ALSO BE LOW DUE TO WEAK DEEP LAYER
SHEAR...DESPITE STRONGER INSTABILITY. STEEP LOW LEVEL LAPSE RATES
WILL FAVOR AN ISOLATED WIND THREAT.
..PARTS OF SRN OK/N TX EWD INTO LOWER MS/TN VALLEYS...
CLUSTERS OF TSTMS WILL CONTINUE TO DEVELOP ALONG A SURFACE BOUNDARY
WHICH EXTENDED FROM W THROUGH N TX INTO SRN AR TO THE TN/OH VALLEYS.
ADDITIONAL DEVELOPMENT WILL ALSO OCCUR THROUGH THIS AFTERNOON INTO
THE EARLY EVENING ALONG CONVECTIVE OUTFLOW BOUNDARIES ACROSS THESE
AREAS. AIR MASS IN THE VICINITY OF THE SYNOPTIC BOUNDARY REMAINS
VERY MOIST /SURFACE DEWPOINTS IN THE LOWER 70S/. ADDITIONAL SURFACE
HEATING...ALONG AND S OF MAIN ZONE OF ONGOING TSTM ACTIVITY...WILL
MAINTAIN STEEP LOW LEVEL LAPSE RATES. OVERALL WEAK DEEP LAYER SHEAR
AND/OR WEAK INSTABILITY PRECLUDES A FORECAST FOR HIGHER SEVERE
PROBABILITIES. HOWEVER...THE STEEP LOW LEVEL LAPSE RATES WILL HELP
TO PROMOTE LOCALLY STRONG WIND GUSTS WITH WET MICROBURSTS.
..PARTS OF PA/SERN NY INTO SRN NEW ENGLAND...
AFTERNOON SURFACE ANALYSIS INDICATED A LOW LOCATED OVER LAKE ERIE
WITH A WARM FRONT EXTENDING EWD THROUGH FAR NRN PA INTO CT TO SERN
MA. THIS SURFACE LOW...ATTENDANT TO AN EWD MOVING SHORT WAVE
TROUGH...WILL TRACK TOWARD NEW ENGLAND THIS FORECAST PERIOD WITH THE
TRAILING COLD FRONT SPREADING EWD AND EXTENDING FROM ERN NY/PA TO
VA/CENTRAL NC BY 12Z MONDAY. DESPITE 30-35 KT OF EFFECTIVE BULK
SHEAR IN THE VICINITY OF THE WARM FRONT...EXTENSIVE CLOUDINESS AND
WEAK MID LEVEL LAPSE RATES ARE RESULTING IN WEAK INSTABILITY.
VISIBLE SATELLITE IMAGERY INDICATED ADDITIONAL CLOUD COVER
DEVELOPING ACROSS THE WARM SECTOR AND WILL LIKELY NEGATE ANY
ADDITIONAL DESTABILIZATION. THUS...GIVEN WEAK INSTABILITY...ANY
SEVERE THREAT IS EXPECTED TO REMAIN VERY LOW...LESS THAN 5%
PROBABILITY.
..ERN NC...
MID AFTERNOON SATELLITE IMAGERY/SURFACE OBSERVATIONS INDICATED THE
LOW LEVEL CIRCULATION CENTER OF T.S. GABRIELLE WAS LOCATED ACROSS
FAR ERN NC...40 WNW HSE. DEEP MOIST CONVECTION WITH THIS SYSTEM HAS
REMAINED LOCATED S OF THE CENTER OVER AND OFFSHORE OF THE SRN OUTER
BANKS SO FAR TODAY. THE QUADRANT THAT WOULD BE FAVORABLE FOR A
TORNADO THREAT IS MAINLY OFFSHORE AND HAS LACKED CONVECTIVE
DEVELOPMENT THUS FAR. THIS FACTOR AND OFFICIAL NHC TRACK FORECAST
HAS THIS T.S. MOVING OFFSHORE AFTER 10/00Z WILL REDUCE THE POTENTIAL
FOR A BRIEF/WEAK TORNADO THREAT FOR THIS FORECAST PERIOD.
.PETERS.. 09/09/2007
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