Oct 18, 2007 0600 UTC Day 1 Convective Outlook
Updated: Thu Oct 18 09:48:21 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 lower ohio and tennessee valleys to southern lake michigan this afternoon and tonight....   Please read the latest public statement about this event.

Categorical Graphic
20071018 1200 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20071018 1200 UTC Day 1 Tornado Probabilities Graphic
Probabilistic Damaging Wind Graphic
20071018 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Probabilistic Large Hail Graphic
20071018 1200 UTC Day 1 Large Hail Probabilities Graphic
   SPC AC 180609
   
   DAY 1 CONVECTIVE OUTLOOK RESENT 1
   NWS STORM PREDICTION CENTER NORMAN OK
   0109 AM CDT THU OCT 18 2007
   
   VALID 181200Z - 191200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE OH VALLEY AND
   GREAT LAKES...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE LOWER MS
   VALLEY THROUGH TN AND OH VALLEYS AND GREAT LAKES...
   
   ...SYNOPSIS...
   
   LEAD SHORTWAVE TROUGH NOW MOVING INTO THE MID MS VALLEY REGION WILL
   LIFT NEWD INTO THE GREAT LAKES EARLY THURSDAY. ATTENDANT SURFACE LOW
   WILL SHIFT NWD AND CONSOLIDATE OVER THE UPPER MS VALLEY WHILE WARM
   FRONT LIFTS NWD THROUGH THE GREAT LAKES. UPSTREAM IMPULSE NOW
   DROPPING INTO THE CNTRL ROCKIES WILL ADVANCE INTO THE MID MS VALLEY
   THURSDAY AFTERNOON AND EVENING...REACHING THE TN AND OH VALLEYS
   THURSDAY NIGHT ACCOMPANIED BY A COLD FRONT.
   
   ...TN VALLEY THROUGH OH VALLEY AND GREAT LAKES REGIONS...
   
   RICHER BOUNDARY LAYER MOISTURE NOW RESIDING OVER THE LOWER MS VALLEY
   WILL ADVECT NWD THROUGH THE BROAD WARM SECTOR ALONG STRONG LOW LEVEL
   JET INTO THE TN AND OH VALLEYS WITH MID TO UPPER 60S DEWPOINTS
   LIKELY. WIDESPREAD CLOUDS AND THUNDERSTORMS WILL LIKELY BE ONGOING
   WITHIN ZONE OF ASCENT ASSOCIATED WITH EJECTING LEAD WAVE FROM THE
   GREAT LAKES THROUGH PARTS OF THE OH AND TN VALLEYS. IN WAKE OF LEAD
   WAVE...MID LEVEL DRY SLOT WILL LIKELY SHIFT NEWD DURING THE
   AFTERNOON OVER A PORTION OF THE WARM SECTOR. THIS ALONG WITH STRONG
   BOUNDARY LAYER FLOW WILL PROMOTE LOW CLOUDS MIXING OUT FROM THE SW
   DURING THE AFTERNOON. THESE PROCESSES SHOULD RESULT IN AN AXIS
   MODERATE INSTABILITY FROM PARTS OF THE GREAT LAKES INTO THE OH...WRN
   TN AND LOWER MS VALLEYS WITH MLCAPE FROM 1000 TO 2000 J/KG. STORMS
   SHOULD REDEVELOP BY LATE AFTERNOON FROM PARTS OF THE LOWER MS VALLEY
   NWD INTO THE OH VALLEY AND GREAT LAKES AHEAD OF COLD FRONT AS THE
   ATMOSPHERE DESTABILIZES AND FORCING FOR ASCENT INCREASES WITH
   APPROACHING SHORTWAVE TROUGH. SOME WEAKENING AND VEERING OF THE LOW
   LEVEL FLOW MAY OCCUR IN WAKE OF LEAD WAVE EARLY THURSDAY.
   HOWEVER...KINEMATIC PROFILES SHOULD STRENGTHEN AGAIN THURSDAY
   AFTERNOON IN ADVANCE OF APPROACHING SHORTWAVE TROUGH. STRONG DEEP
   SHEAR AND LARGE LOW LEVEL HODOGRAPHS WILL PROMOTE A THREAT FOR
   SUPERCELLS CAPABLE OF PRODUCING A FEW TORNADOES...A COUPLE OF WHICH
   COULD BE STRONG. STORMS MAY EVENTUALLY EVOLVE INTO LINES OR A MIX OF
   LINE SEGMENTS AND CELLS AS THEY ADVANCE EWD THROUGH THE EVENING WITH
   A CONTINUED THREAT FOR MAINLY DAMAGING WIND AND ISOLATED TORNADOES.
   
   
   ...ERN NEB...NERN KS AND NWRN MO...
   
   STEEP MID LEVEL LAPSE RATES ASSOCIATED WITH COLD AIR ALOFT AND
   ASCENT ATTENDING VORT MAX ROTATING SEWD THROUGH UPPER TROUGH WILL
   LIKELY PROMOTE THE DEVELOPMENT OF STORMS OVER ERN PARTS OF THE CNTRL
   PLAINS. ACTIVITY MAY INTENSIFY AS THE BOUNDARY LAYER DESTABILIZES
   WITH A THREAT FOR MAINLY HAIL AND STRONG WIND GUSTS. AT THIS TIME IT
   APPEARS INSTABILITY MAY BE TOO MARGINAL FOR A CATEGORICAL RISK AREA.
   
   ..DIAL/GUYER.. 10/18/2007
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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