SPC AC 231301
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0801 AM CDT WED AUG 23 2006
VALID 231300Z - 241200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER
MIDWEST AND NRN PLAINS...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE NRN ND...
...UPPER MIDWEST/NRN PLAINS...
A SHORTWAVE TROUGH OVER IL THIS MORNING WILL MOVE SEWD INTO THE OH
VALLEY WITH A SHORTWAVE RIDGE MOVING INTO THE UPPER MIDWEST TODAY.
AT THE SFC...ANALYSIS SHOWS A NEARLY STATIONARY FRONT EXTENDING
ESEWD FROM SRN MN INTO THE CHICAGO IL AREA WITH SFC DEWPOINTS ALONG
THE BOUNDARY IN THE LOWER TO MID 60S F. THIS SHOULD ALLOW MODERATE
TO STRONG INSTABILITY TO DEVELOP ALONG AND TO THE SOUTHWEST OF THE
BOUNDARY. HOWEVER...WARM AIR ALOFT AND A STRONG CAPPING INVERSION
OVER THE WARM SECTOR WILL LIKELY KEEP CONVECTIVE DEVELOPMENT MINIMAL
FROM FAR WRN MN EXTENDING SWD ACROSS ERN SD...WRN IA AND ERN NEB.
THE CAPPING INVERSION SHOULD BE WEAKER JUST NORTH AND EAST OF THE
STATIONARY FRONT ESPECIALLY BY EVENING. THE MOST LIKELY SPOT FOR
INITIATION APPEARS TO BE ACROSS SRN MN AND/OR SCNTRL WI EARLY THIS
EVENING WHERE MODEL FORECASTS SHOW ENHANCED LOW-LEVEL CONVERGENCE.
IF MCS DEVELOPMENT OCCURS...THE MOST LIKELY TRACK WOULD BE SEWD INTO
NRN IL AND POSSIBLY INTO FAR SW LOWER MI LATER TONIGHT. THE
THUNDERSTORM ACTIVITY SHOULD REMAIN MOSTLY ELEVATED.
HOWEVER...FORECAST SOUNDINGS ALONG THIS ZONE SHOW STRONG DEEP LAYER
SHEAR WITH 0-6 KM SHEAR VALUES REACHING 50-60 KT. IN
ADDITION...MID-LEVEL LAPSE RATES ARE FORECAST TO EXCEED 7.5 C/KM
WHICH COMBINED WITH STRONG FLOW FROM THE LOW-LEVEL JET MAY BE
FAVORABLE FOR SUPERCELLS AND/OR BOW ECHOES WITH HAIL AND ISOLATED
WIND DAMAGE POSSIBLE.
FURTHER NORTHWEST ACROSS NRN ND...THE UPPER-LEVEL RIDGE WILL LIKELY
PREVENT CONVECTIVE DEVELOPMENT THIS AFTERNOON.
HOWEVER...THUNDERSTORMS SHOULD DEVELOP EARLY THIS EVENING NEAR A SFC
LOW FORECAST TO BE LOCATED IN FAR SRN SASKATCHEWAN. FORECAST
SOUNDINGS IN THIS AREA SHOW ADEQUATE DIRECTIONAL SHEAR AND STRONG
SPEED SHEAR IN THE LOWER TO MID-LEVELS. THIS COMBINED WITH VERY
STEEP LASE RATES SHOULD RESULT IN A HIGH POTENTIAL FOR ROTATING
STORMS WITH HAIL POTENTIAL. IF SUPERCELLS MOVE SEWD INTO NRN ND
EARLY THIS EVENING...LARGE HAIL WILL BE VERY LIKELY.
...SRN PLAINS...
LATEST ANALYSIS SHOWS A DIFFUSE STATIONARY FRONT LOCATED FROM FAR NE
OK EXTENDING ESEWD ACROSS NE TX AND NRN LA. DEWPOINTS ALONG AND
SOUTH OF THE BOUNDARY ARE IN THE LOWER TO MID 70S F WHICH SHOULD
RESULT IN POCKETS OF MODERATE INSTABILITY BY AFTERNOON. AS
THUNDERSTORMS DEVELOP NEAR THE BOUNDARY THIS AFTERNOON...STEEP
LOW-LEVEL LAPSE RATES ESPECIALLY IN NE TX WILL MAKE STRONG WIND
GUSTS LIKELY WITH THE STRONGER MULTICELL STORMS.
...GA/SC/FL..
SCATTERED THUNDERSTORMS WILL DEVELOP TODAY ALONG AND SOUTH OF A
NEARLY STATIONARY FRONT LOCATED ACROSS CNTRL AL...CNTRL GA AND SC.
DEWPOINTS IN THE LOWER 70S F SHOULD RESULT IN POCKETS OF MODERATE
INSTABILITY. THIS COMBINED WITH STEEPENING LOW-LEVEL LAPSE RATES BY
MID-AFTERNOON SHOULD BE ENOUGH FOR STRONG WIND GUSTS WITH SOME CELLS
NEAR PEAK HEATING.
...AZ...
LATEST SFC ANALYSIS SHOWS A MOIST AXIS EXTENDING NWWD ACROSS SCNTRL
AZ WHERE DEWPOINTS ARE IN THE LOWER TO MID 60S F. THIS SHOULD ALLOW
MODERATE INSTABILITY TO DEVELOP WITH SCATTERED THUNDERSTORM
INITIATION LIKELY OCCURRING ALONG THE MOGOLLON RIM BY LATE
AFTERNOON. ALTHOUGH FORECAST SOUNDINGS SHOW RELATIVELY WEAK SHEAR
PROFILES...0-3 KM LAPSE RATES SHOULD EXCEED 9.0 C/KM IN SOME AREAS
MAKING STRONG WIND GUSTS LIKELY WITH THE SOME CELLS EARLY THIS
EVENING.
..BROYLES/GUYER.. 08/23/2006
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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