Aug 24, 2007 2000 UTC Day 1 Convective Outlook
Updated: Fri Aug 24 20:04:16 UTC 2007
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Public Severe Weather Outlook

The SPC is forecasting ...severe thunderstorms expected over parts of the middle mississippi river valley into the lower great later today and tonight....   Please read the latest public statement about this event.

Categorical Graphic
20070824 2000 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20070824 2000 UTC Day 1 Tornado Probabilities Graphic
Probabilistic Damaging Wind Graphic
20070824 2000 UTC Day 1 Damaging Wind Probabilities Graphic
Probabilistic Large Hail Graphic
20070824 2000 UTC Day 1 Large Hail Probabilities Graphic
   SPC AC 241959
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0259 PM CDT FRI AUG 24 2007
   
   VALID 242000Z - 251200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS PORTIONS SRN LOWER
   MI...INDIANA...ILLINOIS...EXTREME EAST-CENTRAL MISSOURI...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS ELSEWHERE FROM LOWER MI TO
   PORTIONS NERN NM/SERN CO...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS CENTRAL HIGH PLAINS...
   
   ...SYNOPSIS...
   UPPER AIR PATTERN AWAY FROM NRN STREAM IS CHARACTERIZED BY RIDGING
   AND WEAK FLOW ALOFT FROM SERN CONUS WWD ACROSS TX THEN WNWWD OVER
   CENTRAL/SRN CA.  MOST SIGNIFICANT NRN STREAM FEATURE IS TROUGH
   INITIALLY OVER CENTRAL/NRN HIGH PLAINS -- COMPOSED OF PHASED
   SHORTWAVES NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER BLACK HILLS
   REGION...ERN CO/WRN KS...AND ERN MN/W TX.  COMBINED TROUGH IS FCST
   TO MOVE EWD ACROSS CENTRAL CONUS TOWARD MS VALLEY THROUGH REMAINDER
   PERIOD.
   
   MEANWHILE...AT SFC...WAVY FRONTAL ZONE IS ANALYZED FROM NRN LOWER MI
   SWWD ACROSS NWRN MO TO VICINITY ERN PORTION CO/NM BORDER.  THIS
   FRONT SHOULD SAG SWD ACROSS S-CENTRAL PLAINS...WHILE MOVING SEWD-EWD
   10-15 KT OVER UPPER GREAT LAKES AND MID MS VALLEY REGIONS. 
   AGGREGATE OF SEVERAL MCS OUTFLOWS IS EVIDENT IN SFC ANALYSIS AND VIS
   IMAGERY AHEAD OF AND LARGELY PARALLEL TO SYNOPTIC FRONT...FROM SWRN
   LOWER MI SWWD ACROSS CENTRAL IL...SWRN MO...SWRN OK.
   
   ...NRN OK TO GREAT LAKES...
   SCATTERED TSTMS IN CLUSTERS ARE EXPECTED TO INCREASE IN COVERAGE AND
   INTENSITY THROUGH REMAINDER AFTERNOON HOURS...RESULT BEING ONE OR
   TWO COMPLEXES WITH POTENTIAL FOR CONCENTRATION OF DAMAGING GUST
   REPORTS.  RELATIVELY DISCRETE TSTMS ALSO MAY EXHIBIT SUPERCELL
   CHARACTERISTICS AND POSE RISK OF LARGE HAIL.
   
   REF WW 647 AND RELATED MESOSCALE DISCUSSIONS FOR NOWCAST GUIDANCE. 
   RELATIVE CONCENTRATION OF CONVECTIVE WIND PROBABILITIES EXISTS
   ACROSS CATEGORICAL MDT RISK AREA...COVERING TERRITORY NEAR AND
   DOWNSTREAM FROM ONGOING MO ACTIVITY.  BOUNDARY LAYER AIR MASS FROM
   SRN MO NEWD ACROSS LOWER MI HAS BEEN EXPERIENCING STG DIABATIC
   HEATING/MIXING FOR SEVERAL HOURS...COINCIDENT WITH PRESENCE OF SFC
   DEW POINTS COMMONLY LOW-MID 70S F.  ASSOCIATED HIGH THETAE AIR MASS
   LIES BENEATH BELT OF 40-50 KT 500 MB WINDS EVIDENT IN
   PROFILER/VWP/RAOB DATA.  DEEP-LAYER SHEAR IS EXPECTED TO WEAKEN
   GRADUALLY WITH SWWD EXTENT FROM MO...CONTRIBUTING TO CORRESPONDING
   REDUCTION IN ORGANIZED SVR PROBABILITIES.
   
   ...CENTRAL HIGH PLAINS...
   CLEARING OF MORNING STRATIFORM CLOUD DECK HAS LED TO SUBSTANTIAL
   HEATING/DESTABILIZATION OF BOUNDARY LAYER.  SFC MESOANALYSIS SHOWS
   MOIST AXIS CURVING FROM S-CENTRAL SD SWWD THROUGH NEB
   PANHANDLE...THEN SEWD OVER NERN CO AND KS...CHARACTERIZED BY SFC DEW
   POINTS GENERALLY 50S F.  VEERING/STRENGTHENING OF FLOW WITH HEIGHT
   WILL CONTRIBUTE TO EFFECTIVE SHEAR 40-50 KT IN SUPPORT OF LATE
   AFTERNOON THROUGH EARLY EVENING SUPERCELL POTENTIAL...WITH LARGE
   HAIL LIKELY AND ISOLATED DAMAGING GUSTS POSSIBLE.
   
   ...SERN CONUS...
   SWATH OF WIDELY SCATTERED TO SCATTERED TSTMS WILL CONTINUE FOR A FEW
    MORE HOURS FROM ERN MOUNTAINS/PIEDMONT OF VA SWWD ACROSS MUCH OF AL
   AND COASTAL PLAIN FROM FL PANHANDLE TO MS.  BOUNDARY INTERACTIONS
   MAY ENHANCE CONVERGENCE AND CONTRIBUTE TO MORE INTENSE UPDRAFTS
   LOCALLY.  ORGANIZED SVR POTENTIAL IS LIMITED BY WEAKNESS OF
   LOW-MIDLEVEL WINDS AND RESULTANT LACK OF SHEAR...HOWEVER STRONG
   HEATING AND RICH BOUNDARY LAYER MOISTURE WILL CONTRIBUTE TO
   POTENTIAL FOR STG/DAMAGING GUSTS IN MOST INTENSE PULSE/MULTICELL
   CORES.
   
   ..EDWARDS.. 08/24/2007
   
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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z