MESOSCALE DISCUSSION 1798
   NWS STORM PREDICTION CENTER NORMAN OK
   0403 PM CDT THU AUG 29 2013

   AREAS AFFECTED...PORTIONS CENTRAL/NRN MN...NWRN WI.

   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

   VALID 292103Z - 292300Z

   PROBABILITY OF WATCH ISSUANCE...40 PERCENT

   SUMMARY...ENVIRONMENT MAY BECOME MORE FAVORABLE FOR SVR THROUGH
   REMAINDER AFTN...INVOF OUTFLOW BOUNDARY THAT ARCS ACROSS NRN MN
   BEHIND INITIAL MCS.  SUPERCELLS ARE POSSIBLE WITH LARGE HAIL AND
   DAMAGING GUSTS...AND A TORNADO CANNOT BE RULED OUT.

   DISCUSSION...SFC MESOANALYSIS SHOWED OUTFLOW BOUNDARY EXTENDING FROM
   TAIL END OF WI/MI BORDER MCS WNWWD ACROSS NRN WI AND MN NEAR HYR-BRD
   LINE...THEN ARCHING NWWD BETWEEN PKD-BJI AND NWD TO SFC LOW OVER
   NWRN BELTRAMI COUNTY.  WRN PORTION OF THIS BOUNDARY HAS BEN
   RETREATING NEWD AHEAD OF SFC COLD FRONT THAT WAS ANALYZED FROM LOW
   SSWWD ACROSS EXTREME SERN ND.  A FEW HOURS OF SUSTAINED INSOLATION
   BEHIND MCS CLOUD COVER HAS LED TO FAVORABLE DESTABILIZATION ALONG
   AND SSW OF OUTFLOW BOUNDARY.  

   WARM SECTOR IS VERY NARROW FOR ABOUT 100 NM S OF SFC LOW...THEN IS
   CHARACTERIZED BY POCKETS OF SUFFICIENTLY STG MIXING FOR MID-60S F
   SFC DEW POINTS FARTHER S OVER CENTRAL MN...AROUND LXL. 
   HOWEVER...DEEPER/SOMEWHAT CONVERGENT BOUNDARY LAYER NEAR OUTFLOW
   BOUNDARY IS MAINTAINING UPPER-60S TO MID-70S F SFC DEW
   POINTS...CONTRIBUTING TO MLCAPE 2000-3000 J/KG ALONG NERN EDGE OF
   EML AND RELATED STEEP LAPSE RATE PLUME.  THIS SEGMENT OF OUTFLOW
   BOUNDARY ALSO RESIDES BENEATH 35-50 KT EFFECTIVE SHEAR MAGNITUDE. 
   LOW-LEVEL SRH AND LOW-MIDDLE LEVEL SHEAR EACH INCREASE WITH EWD
   EXTENT INTO OUTFLOW AIR...WHERE FLOW IS MORE BACKED NEAR
   SFC...HOWEVER BUOYANCY DECREASES AND CINH STRENGTHENS...WITH BILLOW
   CLOUDS SEEN IN VIS IMAGERY OVER ITASCA COUNTY.  ACTIVITY THAT HAS
   FORMED ON BOUNDARY OVER BELTRAMI COUNTY MAY HAVE NARROW CORRIDOR OF
   SFC-BASED EFFECTIVE INFLOW...BUT SHOULD OUTPACE FAVORABLE
   DESTABILIZATION AS IT MOVES EWD INTO OUTFLOW AIR.  MORE SUBSTANTIAL
   SVR POTENTIAL MAY BE FARTHER S FROM LXL/BRD AREA EWD INTO NWRN
   WI...WHERE INITIALLY ELEVATED CONVECTION ROOTED IN ACCAS LAYER MAY
   EVOLVE INTO SFC-BASED TSTMS. EFFECTIVE SRH DECREASES SHARPLY S OF
   BOUNDARY...SO ANY SUSTAINED SUPERCELL POTENTIAL APPEARS TO BE
   CONFINED TO BOUNDARY ITSELF AND 30-50 NM BAND TO ITS N.

   ..EDWARDS/THOMPSON.. 08/29/2013


   ATTN...WFO...DLH...MPX...FGF...

   LAT...LON   47929428 47309430 46789385 46249207 45799178 45119231
               45489468 45699574 45929613 46949542 47749496 47929428