SWODY1
SPC AC 300047
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0747 PM CDT WED AUG 29 2007
VALID 300100Z - 301200Z
..NO SVR TSTM AREAS FORECAST...
..SYNOPSIS...
NRN STREAM PATTERN WILL BE DOMINATED BY RIDGING OVER NRN/CANADIAN
ROCKIES AND PROGRESSIVE TROUGH MOVING EWD ACROSS UPPER GREAT LAKES.
ELSEWHERE...UPPER AIR PATTERN WILL BE CHARACTERIZED BY ANTICYCLONES
OVER 4-CORNERS REGION AND NERN GULF OF MEXICO. IN
BETWEEN...QUASISTATIONARY UPPER TROUGH EXTENDS FROM CENTRAL MEX NEWD
ACROSS ARKLATEX REGION...WITH EMBEDDED UPPER LOW EVIDENT ON MOISTURE
CHANNEL IMAGERY INVOF PRX.
AT SFC...COLD FRONT IS ANALYZED FROM SRN QUE SWWD ACROSS
INDIANA...SRN MO...NRN/WRN OK TO NERN NM. FRONT IS FCST TO MOVE
SLOWLY SWD/SEWD ACROSS ST LAWRENCE VALLEY...LOWER GREAT
LAKES...OZARKS...OK...TX PANHANDLE AND NERN NM...MODULATED ON
MESOSCALE BY OUTFLOW BOUNDARIES.
..AZ...
WIDELY SCATTERED TSTMS OVER HIGHER TERRAIN N-E OF PHX SHOULD MOVE
WWD/SWWD ACROSS VALLEYS WITH POTENTIAL FOR STRONG..POSSIBLY DAMAGING
GUSTS TO DEVELOP FOR A FEW MORE HOURS. MODIFIED 21Z-00Z/PHX AND
00Z/TUS RAOBS SHOW DEEP/WELL-MIXED BOUNDARY LAYER WITH VERY STEEP
LAPSE RATES EXTENDING INTO MIDLEVELS...ALONG WITH HIGHLY VARIABLE
200-1200 J/KG MLCAPE. BEFORE SUBSTANTIAL DIABATIC SFC COOLING TAKES
PLACE...TEMPS UPPER 90S/100S F AND LARGE DEW POINT DEPRESSIONS WILL
PERSIST IN PRE-STORM/LOWER-ELEVATION AIR MASS...SUPPORTING THREAT
FOR A FEW CONVECTIVE GUSTS NEAR SVR LEVELS.
..GREAT LAKES REGION TO SRN HIGH PLAINS...
STRONGEST TSTMS SHOULD REMAIN OVER CANADA THROUGH REMAINDER
PERIOD...ALTHOUGH SRN FRINGE OF THIS ACTIVITY MAY AFFECT PORTIONS
LAKES ERIE/ONTARIO AND MAY SKIRT NERN OH/NWRN PA/WRN NY OVERNIGHT.
MODIFIED RAOBS AND RUC FCST SOUNDINGS SUGGEST AIR MASS IN THIS
REGION WILL BE CHARACTERIZED BY FAVORABLE BUOYANCY FOR TSTMS...BUT
ALSO...WEAK AND GENERALLY WLY LOW LEVEL WINDS THAT WILL
SUBSTANTIALLY LIMIT BOTH CONVERGENCE AND VERTICAL SHEAR. FARTHER
SW...IN BROAD PREFRONTAL/FRONTAL SWATH EXTENDING INTO SRN HIGH
PLAINS...WIDELY SCATTERED TO SCATTERED TSTMS IN CLUSTERS GENERALLY
WILL DIMINISH IN COVERAGE AND INTENSITY DURING NEXT FEW HOURS.
PRIND COMBINATION OF DIABATIC SFC COOLING AND OUTFLOW EFFECTS WILL
REDUCE LOW LEVEL CAPE AND INCREASE SBCINH THROUGH REMAINDER EVENING.
ALTHOUGH ISOLATED HAIL/GUSTS NEAR SVR LEVELS CANNOT BE RULED
OUT...SVR POTENTIAL APPEARS TO HAVE WEAKENED TO BELOW 5 PERCENT
PROBABILITIES.
.EDWARDS.. 08/30/2007
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