SWODY1
SPC AC 170559
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT MON OCT 17 2011
VALID 171200Z - 181200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
THE UPPER FLOW PATTERN OVER THE CONUS WILL CONTINUE TO QUICKLY
AMPLIFY THROUGH THE PERIOD...HIGHLIGHTED BY THE EVOLUTION OF A
LONGWAVE TROUGH OVER THE EASTERN TWO-THIRDS OF THE CONUS. AS THIS
OCCURS...SURFACE CYCLOGENESIS IS ANTICIPATED ACROSS THE SOUTHERN
HIGH PLAINS/RED RIVER VICINITY...WITH MODEST MOISTURE RETURN
OCCURRING ACROSS THE SOUTHERN PLAINS/ARKLATEX AHEAD OF AN
EAST-SOUTHEASTWARD ACCELERATING COLD FRONT. THIS FRONT WILL BE A
GENERAL FOCUS FOR TSTMS /SOME POTENTIALLY STRONG TO SEVERE/ THIS
AFTERNOON INTO TONIGHT.
ELSEWHERE...EASTERLY LOW-LEVELS WINDS OFF THE ATLANTIC WILL HELP TO
INCREASE MOISTURE ACROSS FL...WITH MINIMAL INSTABILITY PRESENT FOR A
FEW AFTERNOON THUNDERSTORMS. COOL/STABLE CONDITIONS ACROSS THE
REMAINDER OF THE CONUS WILL OTHERWISE GENERALLY PRECLUDE TSTMS.
...NORTH TX AND EASTERN/SOUTHERN OK TO OZARKS...
GIVEN THE SCENARIO PREVIOUSLY DESCRIBED...STEADY BUT MODEST MOISTURE
RETURN IS EXPECTED AHEAD OF AN ACCELERATING COLD FRONT LATER
TODAY...WITH MIDDLE/UPPER 50S F SURFACE DEWPOINTS BECOMING
INCREASINGLY ESTABLISHED AHEAD OF THE FRONT ACROSS SOUTHERN/EASTERN
OK AND NORTH TX TO THE ARKLATEX/PORTIONS OF THE OZARKS. WHILE
CAPPING WILL BE PREVALENT AHEAD OF THE FRONT...STORMS SHOULD DEVELOP
WITHIN A NORTHEAST-SOUTHWEST ORIENTED NEAR-FRONTAL CORRIDOR
TOWARD/AFTER 00Z...WITH THE AID OF DPVA/UPPER JET EXIT REGION AND
INCREASING NEAR-FRONTAL CONVERGENCE.
WHILE MOISTURE CONTENT/TOTAL BUOYANCY WILL BE MODEST...WITH MLCAPE
500-1000 J/KG OR LESS -- RELATIVELY HIGHEST ACROSS PORTIONS OF
OK/NORTH TX...STEEP LAPSE RATES/LONG HODOGRAPHS WILL SUPPORT
MULTICELLS/PERHAPS A FEW INITIAL SUPERCELLS CAPABLE OF SEVERE
HAIL...WITH A WELL-MIXED BOUNDARY LAYER/STRONG MEAN FLOW SUGGESTIVE
OF A DAMAGING WIND THREAT AS WELL. STORMS ARE LIKELY TO
INCREASE/CONGEAL AFTER DARK WHILE GRADUALLY BEING UNDERCUT BY THE
FRONT THIS EVENING. ANY SEVERE HAIL AND/OR WIND THREAT WILL TEND TO
WANE BY LATE EVENING AS THE STORMS ENCOUNTER A DECOUPLING BOUNDARY
LAYER/PROGRESSIVE ELEVATED INFLOW.
...SOUTH FL/FL KEYS...
ITS LIKELY THAT THE BAROCLINIC ZONE CURRENTLY IN VICINITY OF THE FL
STRAITS SHOULD SLOWLY SHIFT NORTHWARD THROUGH THE PERIOD. A FEW
MINI-SUPERCELLS MAY REMAIN POSSIBLE MAINLY EARLY IN THE PERIOD NEAR
THE KEYS/OFFSHORE WATERS. HOWEVER...WEAK LAPSE RATES/LIMITED
BUOYANCY ASIDE...LOW LEVEL SHEAR IS EXPECTED TO GRADUALLY WEAKEN
WITH TIME SUCH THAT ANY TORNADO/WATERSPOUT THREAT SHOULD REMAIN VERY
LOW.
..GUYER/GARNER.. 10/17/2011
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