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Mesoscale Discussion 1583
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   MESOSCALE DISCUSSION 1583
   NWS STORM PREDICTION CENTER NORMAN OK
   0751 AM CDT SUN AUG 02 2015

   AREAS AFFECTED...PORTIONS OF E-CNTRL MN...NRN/CNTRL WI...UPPER
   PENINSULA OF MI...NRN LOWER MI

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

   VALID 021251Z - 021515Z

   PROBABILITY OF WATCH ISSUANCE...40 PERCENT

   SUMMARY...MULTIPLE CONVECTIVE CLUSTERS EVOLVING WITHIN A CORRIDOR
   FROM CNTRL MN INTO NRN LOWER MI ARE BEING MONITORED FOR ISOLATED SVR
   POTENTIAL. WHILE WW ISSUANCE IS NOT IMMINENTLY EXPECTED...THERE IS
   SOME CONCERN THAT A GREATER SVR RISK COULD DEVELOP THIS MORNING --
   DURING THE NEXT FEW HOURS -- AND THIS MAY WARRANT WW ISSUANCE ACROSS
   A PART OF THE REGION.

   DISCUSSION...SFC OBSERVATIONS INDICATE A QUASI-STATIONARY BOUNDARY
   EXTENDING FROM LOW PRESSURE ANALYZED OVER W-CNTRL MN TO LOW PRESSURE
   N OF EAU...WITH THE SAME BOUNDARY ARCING EWD/SEWD INTO WRN LOWER MI.
   CLUSTERS OF CONVECTION BEING FED BY UNSTABLE AIR ABOVE THE
   NOCTURNALLY COOLED PBL ARE ONGOING N OF THE BOUNDARY IN A WAA
   REGIME. RELATED ISENTROPIC ASCENT IS BEING ENHANCED IN CONJUNCTION
   WITH A MID-LEVEL SPEED MAX CROSSING THE REGION AND IN ADVANCE OF A
   SHORTWAVE TROUGH PROGRESSING ESE FROM THE SRN CANADIAN PRAIRIE
   PROVINCES PER MOISTURE-CHANNEL IMAGERY.

   THE 12Z RAOBS AT MPX AND ABR SAMPLED AN EML PLUME WITH H7-H5 LAPSE
   RATES AROUND 8 C/KM...WHICH WILL CONTINUE TO BE ADVECTED OVER THE
   UPPER MIDWEST AND UPPER GREAT LAKES REGION. MEANWHILE...RELATIVELY
   RICHER PBL MOISTURE S OF THE SFC BOUNDARY -- ASSOCIATED WITH
   LOWER/MIDDLE 60S SFC DEWPOINTS -- WILL CONTINUE TO SPREAD NEWD TO
   THE E OF THE WI SFC CYCLONE. THIS WILL ESTABLISH AN INCREASE IN
   SFC-BASED BUOYANCY ACROSS PARTS OF THE REGION...ESPECIALLY AS AREAS
   OF INSOLATION ENCOURAGE SFC HEATING. AS SUCH...ONGOING CONVECTION
   MAY CONTINUE TO INCREASE IN COVERAGE AND INTENSITY. ADDITIONAL TSTM
   DEVELOPMENT WILL BE POSSIBLE GIVEN THE ALREADY-PRESENT FORCING FOR
   ASCENT MARKED BY 2-HOURLY SFC PRESSURE FALLS AROUND 1.5-2 MB ACROSS
   THE REGION. GIVEN 40-50 KT OF DEEP SHEAR SAMPLED BY AREA VWPS AND
   12Z RAOBS...UPSCALE CONVECTIVE GROWTH WILL BE POSSIBLE...WITH
   25-40-KT WLYS AROUND H85 FACILITATING FAST-MOVING COLD POOLS WITH
   SVR-WIND POTENTIAL. SVR-WIND POTENTIAL ASIDE...THE STEEP LAPSE
   RATES/MODERATE SHEAR WILL SUPPORT HAIL POTENTIAL...ESPECIALLY WITH
   ANY MORE DISCRETE UPDRAFTS.

   ULTIMATELY...CONFIDENCE IN UPSCALE CONVECTIVE GROWTH AND A
   GREATER-COVERAGE SVR RISK -- IN THE SHORT-TERM -- IS LIMITED...AS
   STRONGER DCVA IS STILL DISPLACED UPSTREAM AT PRESENT.
   REGARDLESS...AT LEAST ISOLATED SVR RISK WILL CONTINUE THROUGH THE
   MORNING HOURS. THE ONGOING INCREASE IN CONVECTIVE COVERAGE SUGGESTS
   SOME POSSIBILITY IN WW ISSUANCE THIS MORNING. THIS WOULD ESPECIALLY
   BE THE CASE IF A MORE ORGANIZED CONVECTIVE CLUSTER/BOWING SEGMENT
   WERE TO BECOME EVIDENT AND JUXTAPOSED WITH HIGHER THETA-E AIR IN
   CLOSER PROXIMITY TO THE SFC BOUNDARY.

   ..COHEN/EDWARDS.. 08/02/2015


   ATTN...WFO...APX...GRR...MQT...GRB...DLH...ARX...MPX...

   LAT...LON   45018360 44238435 43978638 44048948 44679304 45289505
               45819531 46319405 46208824 45798520 45018360 

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