MESOSCALE DISCUSSION 1642
   NWS STORM PREDICTION CENTER NORMAN OK
   0149 PM CDT SAT AUG 08 2015

   AREAS AFFECTED...PARTS OF NORTHERN AND CENTRAL MN/FAR NORTHWEST WI

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 081849Z - 082115Z

   PROBABILITY OF WATCH ISSUANCE...20 PERCENT

   SUMMARY...ADDITIONAL TSTMS ARE EXPECTED TO DEVELOP THIS AFTERNOON
   ACROSS CENTRAL INTO NORTHEAST MN...AND PERHAPS SPREADING INTO
   NORTHWEST WI.  A FEW OF THESE STORMS MAY BECOME STRONG TO SEVERE
   WITH AN ISOLATED THREAT FOR HAIL AND GUSTY WINDS.  WW ISSUANCE IS
   UNLIKELY...THOUGH CONVECTIVE TRENDS WILL BE MONITORED.

   DISCUSSION...EARLY AFTERNOON TRENDS IN MOSAIC RADAR IMAGERY AND
   LIGHTNING DATA SHOWED TSTMS DEVELOPING FROM HUBBARD/WADENA AND
   NORTHERN CASS COUNTIES MN INTO AITKIN COUNTY.  THIS CONVECTION IS
   FORMING IN VICINITY OF A POLEWARD-MOVING CONVECTIVE OUTFLOW BOUNDARY
   WHICH EXTENDED FROM NEAR DLH WWD TO AN INTERSECTION WITH A SLOW
   EASTWARD-MOVING FRONT...WHICH EXTENDED FROM NORTH-CENTRAL TO
   WEST-CENTRAL MN.  DESPITE WEAK MIDLEVEL LAPSE RATES...DIABATIC
   HEATING WITHIN THE WARM SECTOR WHERE SURFACE TEMPERATURES HAVE
   REACHED AROUND 80 F COMBINED WITH SURFACE DEW POINTS IN THE MIDDLE
   60S IS RESULTING IN MODERATE INSTABILITY /MLCAPE 1000-1500 J PER
   KG/...THUS FAR.

   THERE ARE SUBTLE HEIGHT RISES ONGOING PER OBJECTIVE ANALYSES AND
   TRENDS IN WATER VAPOR IMAGERY ACROSS THE UPPER MIDWEST.  DESPITE
   THIS FACTOR...SOME FORCING FOR ASCENT AND STRONGER WLY MIDLEVEL
   WINDS...ATTENDANT TO A LOW-AMPLITUDE SHORTWAVE TROUGH MOVING EAST
   ACROSS NORTHERN MN...AND CONVERGENCE IN VICINITY OF THE
   AFOREMENTIONED BOUNDARIES SUGGEST STORMS WILL CONTINUE TO FORM. 
   EFFECTIVE BULK SHEAR EXCEEDING 35-40 KT OVER THE NORTHERN HALF OF MN
   WILL SUPPORT STORM ORGANIZATION WITH HAIL AND STRONG WIND GUSTS THE
   PRIMARY THREATS.  THE WEAK MIDLEVEL LAPSE RATES AND HEIGHT RISES MAY
   LIMIT UPDRAFT STRENGTH SUCH THAT THE COVERAGE OF STRONGER TO SEVERE
   STORMS WILL TEND TO BE CONFINED TO AREAS WITH STRONGER/SUSTAINED
   LOW-LEVEL CONVERGENCE.

   ..PETERS/GUYER.. 08/08/2015


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

   LAT...LON   46929530 48349417 48309330 47949210 47309203 46499224
               45719257 45709419 45869502 46039564 46929530