726
ACUS03 KWNS 090730
SWODY3
SPC AC 090728
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0228 AM CDT WED JUL 09 2008
VALID 111200Z - 121200Z
..THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE UPPER MS VALLEY
..SYNOPSIS
COMPACT...BUT DEEP...CLOSED LOW WILL MOVE FROM SRN/CENTRAL
SASKATCHEWAN EWD INTO FAR WRN ONTARIO. THIS WILL RESULT IN AN
ASSOCIATED TROUGH AND 80 TO 120M HEIGHT FALLS TO SPREAD EWD ACROSS
THE NRN PLAINS AND UPPER MS VALLEY. MOST OF THE STRONGER CONVECTION
WILL BE ASSOCIATED ALONG AND AHEAD OF A COLD FRONT...THAT IS PROGGED
TO EXTEND FROM ERN MN SWWD THROUGH CENTRAL NEB/NERN CO BY LATE
FRIDAY AFTERNOON.
..UPPER MS VALLEY
CONVECTION MAY BE ONGOING AT THE START OF THE PERIOD...BUT WARMING
ALOFT...AHEAD OF UPPER TROUGH...SHOULD STRENGTHEN CAP AND LIMIT
SEVERE POTENTIAL DURING THE MORNING HOURS. HOWEVER...THIS CAP WILL
BE BROKEN BY MID AFTERNOON AS STRONG FORCING AND FRONTAL CONVERGENCE
SHIFT EWD INTO THE REGION. HEATING OF A VERY MOIST BOUNDARY LAYER
COMBINED WITH STEEP MID LEVEL LAPSE RATES ARE EXPECTED TO RESULT IN
MLCAPES FROM 3000 TO 4000 J/KG. VEERING WIND PROFILES...THAT
STRENGTHEN TO 50-70 KT IN THE MID LEVELS...ALONG WITH THE EXTREME
INSTABILITY WILL PROVIDE A VERY FAVORABLE ENVIRONMENT FOR
SUPERCELLS. ONCE SURFACE BASED STORMS DEVELOP ACROSS PORTIONS OF
MN/IA...SEVERE HAIL/WINDS ARE LIKELY ALONG WITH A POSSIBLE TORNADO.
THE STORMS MAY CONSOLIDATE INTO 1 OR 2 SEVERE MCS/S AND SPREAD EWD
INTO PORTIONS OF WI AND THE U.P. DURING THE EVENING HOURS.
..MO SEWD INTO GA/SC
DIFFUSE FRONTAL BOUNDARY AND WEAKLY CAPPED ENVIRONMENT WILL ONCE
AGAIN PROVIDE SUFFICIENT LIFT FOR PRIMARILY DIURNAL THUNDERSTORMS.
DEEP LAYER SHEAR WILL REMAIN QUITE WEAK...BUT A VERY MOIST BOUNDARY
LAYER...WITH DEWPOINTS IN THE 70S...AND TEMPERATURES IN THE 90S WILL
SUPPORT A FEW PULSE TYPE SEVERE STORMS WITH STRONG WINDS.
..SWRN AZ/SRN CA AND FAR SRN NV
MID LEVEL WINDS ALOFT ARE FORECAST TO BECOME ELY AND THIS WILL PUSH
TROPICAL MOISTURE WWD. SUFFICIENT INSTABILITY WILL BE PRESENT FOR
HIGH BASED AFTERNOON THUNDERSTORMS AND TEMPERATURE-DEWPOINT SPREADS
AROUND 50F MAY SUPPORT A FEW STRONG WIND GUSTS.
..IMY.. 07/09/2008
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