SPC AC 070555
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1155 PM CST SUN JAN 06 2008
VALID 071200Z - 081200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS NE TX...ERN OK...WRN
AR...MO AND IL......
...SRN PLAINS/OZARKS/MID MS VALLEY...
A BROAD WRN AND CNTRL U.S. UPPER-LEVEL TROUGH WILL ACCELERATE EWD
TODAY AND TONIGHT AS SEVERAL SHORTWAVE TROUGHS MOVE NEWD ACROSS THE
PLAINS AND MS VALLEY AHEAD OF THE APPROACHING SYSTEM. AT THE
SFC...FRONTOGENESIS WILL TAKE PLACE ACROSS THE CNTRL PLAINS TODAY
AND THIS BOUNDARY WILL MOVE SEWD INTO NCNTRL MO AND SE KS BY LATE
AFTERNOON. SFC DEWPOINTS ARE CURRENTLY AROUND 60 F ACROSS THE SRN
OZARK REGION AND THIS MODIFIED GULF AIR MASS WILL WORK ITS WAY NWD
INTO SRN MO AS THE FRONT MOVES SEWD INTO THE REGION. THUNDERSTORMS
SHOULD INITIATE ALONG THE BOUNDARY LATE THIS AFTERNOON WITH STORM
COVERAGE RAPIDLY EXPANDING FROM WRN IL SWWD ACROSS MO WITH SCATTERED
DEVELOPMENT ALSO LIKELY IN ERN OK...WRN AR AND POSSIBLY NE TX.
THUNDERSTORMS WILL CONTINUE OVERNIGHT ALONG THE AXIS OF THE
LOW-LEVEL JET AND ALONG THE FRONTAL BOUNDARY.
CONCERNING THE STORM ENVIRONMENT...LOW-LEVEL MOISTURE CONTENT WILL
BE UNSEASONABLY HIGH AND FORECAST SOUNDINGS SUGGEST POCKETS OF
MODERATE INSTABILITY SHOULD DEVELOP ALONG THE MOIST AXIS BY LATE
AFTERNOON. THE MODELS DIFFER ON THE TIMING OF INITIATION WITH THE
NAM FOCUSING CONVECTIVE DEVELOPMENT ALONG THE FRONT MAINLY AFTER
00Z. THIS SEEMS REASONABLE AS THE STRONGEST LARGE-SCALE ASCENT IS
TIMED INTO WRN MO EARLY THIS EVENING BY BOTH THE NAM AND GFS.
FORECAST SOUNDINGS ACROSS THE OZARKS SHOW VERY STRONG DEEP LAYER
SHEAR WITH 0-6 KM SHEAR VALUES IN THE 50 TO 70 KT RANGE. THIS WILL
BE MORE THAN SUFFICIENT FOR ORGANIZED STORMS WITH HAIL AND WIND
DAMAGE POTENTIAL. A FEW TORNADOES MAY ALSO OCCUR ACROSS SW AND
SCNTRL MO WITH SUPERCELLS THAT REMAIN DISCRETE. AN ISOLATED TORNADO
THREAT MAY ALSO EXIST AS STORMS INITIATE ALONG THE FRONTAL BOUNDARY
IN WCNTRL MO. ALTHOUGH TRAINING CELLS WILL BE COMMON ALONG THE
BOUNDARY IN THE EVENING...A FEW PERSISTENT SUPERCELLS COULD HAVE
WIND DAMAGE OR TORNADO POTENTIAL.
FURTHER SOUTH SOUTHWEST...THE GFS SOLUTION DEVELOPS NUMEROUS STORMS
WELL TO THE SOUTHEAST OF THE BOUNDARY IN ERN OK...WRN AR AND NE TX.
CONVECTIVE COVERAGE WILL LIKELY BE MUCH LESS IN THIS REGION DUE TO
WEAKER FORCING THAN AREAS FURTHER NORTH. HOWEVER...MODEL FORECASTS
DEVELOP STRONGER INSTABILITY AND AN AXIS OF MODERATE INSTABILITY
SHOULD BE PRESENT BY LATE AFTERNOON. THIS COMBINED WITH 0-1 KM SHEAR
VALUES IN THE 20 TO 30 KT RANGE SHOULD BE FAVORABLE FOR SUPERCELLS
WITH TORNADO AND WIND DAMAGE POTENTIAL. THE SEVERE THREAT SHOULD
DROP OFF QUICKLY ACROSS EAST TX WHERE ASCENT AND SHEAR WILL BE MUCH
WEAKER.
..BROYLES.. 01/07/2008
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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