MESOSCALE DISCUSSION 2026
   NWS STORM PREDICTION CENTER NORMAN OK
   1104 AM CDT SAT AUG 20 2011
   
   AREAS AFFECTED...SRN LWR MI...NRN IND...NW OH
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 201604Z - 201800Z
   
   THE NEED FOR A WW IS NOT ANTICIPATED IN THE NEAR TERM...BUT TRENDS
   ARE BEING MONITORED FOR AN INCREASING SEVERE THREAT THAT COULD
   REQUIRE A WW LATER THIS AFTERNOON.  THE 1630Z OUTLOOK UPDATE WILL
   INCREASE SEVERE PROBABILITIES ACROSS THE REGION TO SUPPORT A
   CATEGORICAL SLIGHT RISK OF SEVERE STORMS.
   
   SOUTHERN PORTIONS OF THE GREAT LAKES REGION REMAIN SOUTH OF THE
   STRONGER MID-LEVEL WESTERLIES...BUT FORCING FOR ASCENT AND MODEST
   DEEP LAYER SHEAR ASSOCIATED WITH A WEAK SHORT WAVE IMPULSE APPEAR TO
   BE PROVIDING THE SUPPORT FOR AN ORGANIZED AND SUSTAINED STORM
   CLUSTER NOW SPREADING INTO/THROUGH THE SOUTHERN LAKE MICHIGAN
   VICINITY.  DOWNSTREAM...A SLOWLY MOISTENING PRE-FRONTAL BOUNDARY
   LAYER IS DESTABILIZING WITH DAYTIME HEATING...AND...THOUGH
   INSOLATION MAY CONTINUE TO BECOME INCREASING FILTERED BY
   MID/HIGH-LEVEL CLOUD COVER FROM UPSTREAM CONVECTION...MIXED LAYER
   CAPE COULD INCREASE IN EXCESS OF 2000 J/KG THIS AFTERNOON.  THIS
   SHOULD BE SUFFICIENT TO MAINTAIN CONVECTIVE DEVELOPMENT EASTWARD
   INTO THE LOWER GREAT LAKES REGION...WITH AT LEAST SOME
   INTENSIFICATION OF UPDRAFTS PROBABLE AS THE AFTERNOON WEARS ON.  
   
   THERMODYNAMIC PROFILES APPEAR FAVORABLE FOR THE RISK OF AT LEAST
   MARGINALLY SEVERE HAIL IN STRONGER STORMS...WHILE DAMAGING WIND
   POTENTIAL REMAINS A BIT MORE UNCERTAIN.  MEAN FLOW FIELDS IN THE
   LOWEST 3 TO 5 KM AGL APPEAR LIKELY TO REMAIN RELATIVELY WEAK...AT OR
   BELOW 20 KTS...AND THE EXTENT TO WHICH LOW-LEVEL LAPSE RATES STEEPEN
   REMAINS IN QUESTION DUE TO THE INFLUENCE OF CLOUD COVER. 
   HOWEVER...IT APPEARS AT LEAST A POSSIBILITY THAT AS THE CONVECTIVELY
   GENERATED COLD POOL CONTINUES TO STRENGTHEN...A MORE SUBSTANTIVE
   INCREASE IN DAMAGING WIND POTENTIAL COULD DEVELOP ALONG THE GUST
   FRONT IN THE PEAK LATE AFTERNOON HEATING...AS IT APPROACHES THE
   DETROIT METROPOLITAN AREA...AS WELL AS TOLEDO AND ADJACENT AREAS OF
   NORTHWEST OHIO...TOWARD 20-22Z.
   
   ..KERR.. 08/20/2011
   
   
   ATTN...WFO...CLE...DTX...IWX...GRR...LOT...
   
   LAT...LON   43208556 43298419 43678279 43638196 41928193 41098268
               40828391 40748533 40758692 40838787 41088848 41558759
               41918653 43208556