Sep 22, 2006 0600 UTC Day 1 Convective Outlook
Updated: Fri Sep 22 10:32:15 UTC 2006
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 ozarks into the mid mississippi valley today...tonight and early saturday....   Please read the latest public statement about this event.

Categorical Graphic
20060922 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20060922 1200 UTC Day 1 Tornado Probabilities Graphic
Probabilistic Damaging Wind Graphic
20060922 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Probabilistic Large Hail Graphic
20060922 1200 UTC Day 1 Large Hail Probabilities Graphic
   SPC AC 220548
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1248 AM CDT FRI SEP 22 2006
   
   VALID 221200Z - 231200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER AR...SRN/ERN MO...AND
   CENTRAL/SRN IL...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK OVER
   THE MIDDLE MS AND LOWER OH VALLEYS SWWD INTO NERN TX...
   
   ...SYNOPSIS...
   HIGH AMPLITUDE ENERGETIC FLOW PATTERN IS FORECAST TO CONTINUE
   THROUGH THE PERIOD AS CENTRAL PLAINS OCCLUDED UPPER LOW LIFTS NWD
   TOWARD SD AND BEGINS TO WEAKEN...AS UPSTREAM SHORT WAVE TROUGH OVER
   THE NRN INTERMOUNTAIN REGION DIGS SEWD INTO THE GREAT BASIN.  THIS
   WILL RESULT IN A STRONG MID/UPPER LEVEL JET STREAM BECOMING
   ESTABLISHED FROM THE NRN PARTS OF AZ/NM ACROSS KS/OK AND THE MIDDLE
   MS VALLEY TODAY.
   
   AT THE SURFACE...COMPLEX PATTERN IS FORECAST TO EVOLVE AS OCCLUDED
   LOW LIFTS NWD TOWARD ERN SD/SWRN MN...WITH A COLD FRONT ARCING SWD
   FROM THE LOW INTO THE LOWER MO RIVER VALLEY THEN SWWD INTO THE SRN
   HIGH PLAINS.  THE COLD FRONT IS FORECAST TO MOVE SEWD ACROSS THE SRN
   PLAINS REGION DURING THE NIGHT.  IN ADVANCE OF THE COLD FRONT...A
   DRY LINE IS EXPECTED TO BE LOCATED FROM ERN KS/WRN MO SWD ACROSS ERN
   OK INTO CENTRAL TX.
   
   ...IL/MO/AR AREA...
   ...SIGNFICANT SEVERE THREAT EXPECTED TODAY...
   STRONG NOCTURNAL CONVECTION OVER PARTS OF MO AND AR IS EXPECTED TO
   MOVE EWD/NEWD DURING THE EARLY MORNING HOURS AND POSSIBLY CONTINUE
   INTO THE MS VALLEY PRIOR TO 18Z.  THE MORNING ACTIVITY IN THE MIDDLE
   MS VALLEY WILL LIKELY REMAIN BELOW SEVERE LEVELS AS MOISTURE AND
   INSTABILITY WILL BE MARGINAL...ALTHOUGH THE STORMS MOVING INTO THE
   MID SOUTH REGION MAY HAVE POTENTIAL TO PRODUCE MARGINALLY SEVERE
   HAIL.
   
   LOW LEVEL MOISTURE IS EXPECTED TO INCREASE NWD IN THE WAKE OF THE
   MORNING CONVECTION.  SURFACE DEW POINTS OF 65-70F ARE CURRENTLY OVER
   ERN OK INTO SRN/ERN TX AND LA AND MODEL GUIDANCE INDICATES THAT
   MOISTURE WILL SURGE NWD TOWARD THE MIDDLE MS VALLEY DURING THE LATE
   MORNING AND AFTERNOON HOURS.  ALTHOUGH RESIDUAL CLOUDS AND
   OCCASIONAL CONVECTION WILL INHIBIT DIURNAL HEATING ACROSS PARTS OF
   THIS REGION...STRONGER HEATING IS LIKELY WHERE BREAKS IN THE CLOUD
   COVER DEVELOP...AND ALONG THE WRN PORTIONS OF THE LOW LEVEL MOIST
   AXIS FROM ERN OK/WRN AR INTO WRN MO/IA.  THIS WILL ENHANCE
   DESTABILIZATION WITH MLCAPE RANGING FROM 1500-2000 J/KG OVER AR INTO
   SRN MO TO AROUND 1000 J/KG FROM NRN MO INTO CENTRAL IL.
   
   MULTIPLE BANDS OF CONVECTION ARE EXPECTED TO DEVELOP DURING THE
   AFTERNOON FROM PARTS OF ERN OK/WRN OK NNEWD INTO MO AND IL WITHIN A
   WEAKLY CAPPED ENVIRONMENT.  MODEL FORECAST SOUNDINGS INDICATE WINDS
   WILL VEER AND STRENGTHEN WITH HEIGHT AS 40-50 KT SSWLY LOW LEVEL
   FLOW VEERS TO WLY/SWLY AT 50-75 KT ACROSS AN EXPANSIVE WARM SECTOR. 
   THIS RESULTS IN VERY STRONG DEEP LAYER SHEAR /50-60 KT IN THE LOWEST
   6 KM/ INDICATING A LIKELIHOOD FOR PERSISTENT SUPERCELLS TO DEVELOP. 
   LOW LEVEL SHEAR WILL ALSO BE VERY STRONG WITH 0-1 KM SRH OF 200-400
   M2/S2. GIVEN THE ANTICIPATED LOW LCL HEIGHTS AND POTENTIAL FOR
   DEVELOPMENT OF DISCRETE STORMS AND EMBEDDED SUPERCELLS WITHIN SHORT
   LINE SEGMENTS...THERE IS A THREAT FOR A FEW STRONG TORNADOES TO
   DEVELOP...IN ADDITION TO DAMAGING WIND GUSTS AND LARGE HAIL.  THIS
   ACTIVITY WILL SPREAD NEWD THROUGH THE EVENING HOURS ACROSS THE
   MIDDLE MS VALLEY INTO THE LOWER OH VALLEY.
   
   ..WEISS/GRAMS.. 09/22/2006
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z