292
ACUS01 KWNS 290541
SWODY1
SPC AC 290539
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1239 AM CDT FRI AUG 29 2008
VALID 291200Z - 301200Z
..NO SVR TSTM AREAS FORECAST
..SYNOPSIS
IN MID-UPPER LEVELS...SYNOPTIC-SCALE/NRN-STREAM TROUGHING IS FCST TO
SHIFT EWD FROM UPPER GREAT LAKES ACROSS ONT THROUGH PERIOD.
SHORTWAVE TROUGH INITIALLY OVER NWRN ONT...LS AND WI IS FCST TO
EJECT ENEWD THEN NEWD ACROSS NERN ONT AND JAMES BAY REGION AND
WEAKEN. MEANWHILE...UPSTREAM PERTURBATION -- NOW EVIDENT IN
MOISTURE CHANNEL IMAGERY OVER SASK -- IS FCST TO DIG SEWD TO LS BY
30/00Z AND TO SWRN QUE BY END OF PERIOD.
AT SFC...COLD FRONT ASSOCIATED WITH LEADING SHORTWAVE TROUGH IS
EXPECTED TO CONTINUE MOVING EWD ACROSS GREAT LAKES REGION AND SEWD
OVER PORTIONS OH VALLEY AND MID-SOUTH. WESTERN PORTION OF FRONT
FROM AR ACROSS OK TO TX HIGH PLAINS WILL BECOME
QUASISTATIONARY...AND HEAVILY MODULATED ON MESOSCALE BY CONVECTIVE
OUTFLOWS.
OTHERWISE...MID-UPPER RIDGING WILL PERSIST FROM OZARKS WWD ACROSS
4-CORNERS REGION AND CENTRAL CA. BROAD/DIFFUSE TROUGHING WILL
REMAIN OVER SERN CONUS AND OVER MEX BORDER WITH AZ/NM/FAR W TX.
..OH VALLEY TO SRN HIGH PLAINS
OUTFLOW BOUNDARY FROM ONGOING MO MCS SHOULD SETTLE SWD OVER PORTIONS
TN/AR DURING DAY. THIS...ALONG WITH FRONTAL ZONE AND ADDITIONAL
BOUNDARIES GENERATED BY INITIAL CONVECTION...WILL SERVE AS FOCI FOR
DEVELOPMENT THROUGH AFTERNOON/EVENING HOURS. SCATTERED TO LOCALLY
NUMEROUS TSTMS IN CLUSTERS ARE FCST...WITH OUTFLOW-DOMINANT
MULTICELLULAR MODES BEING MOST COMMON. STRONGEST HEATING AND LOW
LEVEL MOISTURE WILL BE FROM MID-SOUTH WWD ACROSS OK...WHERE 70S F
SFC DEW POINTS AND STEEP LOW-MIDLEVEL LAPSE RATES WILL CONTRIBUTE TO
MLCAPES POTENTIALLY IN 2500-3000 J/KG RANGE. FARTHER W OVER
PORTIONS CO/NM..CONVECTIVE COVERAGE SHOULD BE SOMEWHAT LESS...BUT
WELL-MIXED BOUNDARY LAYERS MAY CONTRIBUTE LOCALLY ENHANCED POTENTIAL
FOR GUSTS NEAR SVR LEVELS.
A FEW RELATIVELY CONCENTRATED AREAS OF CONVECTIVE COVERAGE AND SVR
POTENTIAL MAY DEVELOP WITHIN THIS CORRIDOR...BUT LIKELY ARE
DEPENDENT ON MESOSCALE BOUNDARY DEVELOPMENT/INTERACTION. GIVEN THAT
FACTOR...AND WEAKNESS OF WIND AND SHEAR PROFILES BENEATH UPPER RIDGE
WHERE INSTABILITY WILL BE STRONGEST...SVR POTENTIAL APPEARS TOO
MRGL/CONDITIONAL FOR CATEGORICAL OUTLOOK ATTM.
..AZ
SVR POTENTIAL APPEARS MORE UNCERTAIN AND CONDITIONAL TODAY...GIVEN
PASSAGE OF SVR TSTM COMPLEX ACROSS PARTS OF THIS REGION DURING PRIOR
OVERNIGHT HOURS. ELY-ENELY FLOW REGIME WILL BE MAINTAINED
ALOFT...BETWEEN UPPER RIDGE AND BORDERLANDS HEIGHT
WEAKNESS...FAVORING PROPAGATION OVER DESERTS OF STORMS DEVELOPING
OVER HIGHER TERRAIN. HOWEVER...LOW-MIDLEVEL INSTABILITY IS A
CONCERN...AND MAY NOT SUPPORT CONVECTION AS EXTENSIVE OR
WELL-ORGANIZED AS ON THURSDAY NIGHT.
..EDWARDS/BOTHWELL.. 08/29/2008
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