MESOSCALE DISCUSSION 1671
   NWS STORM PREDICTION CENTER NORMAN OK
   0957 PM CDT WED AUG 12 2015

   AREAS AFFECTED...NERN ND THROUGH NWRN MN

   CONCERNING...SEVERE THUNDERSTORM WATCH 485...

   VALID 130257Z - 130400Z

   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 485
   CONTINUES.

   SUMMARY...SEVERE THREAT MAY PERSIST PRIMARILY OVER NWRN MN THROUGH
   04-05Z. WHILE OVERALL THREAT IS NOT SUFFICIENT FOR ANOTHER WW
   ISSUANCE...A LOCAL EXTENSION IN TIME MIGHT BE NEEDED FOR A PORTION
   OF THIS AREA DEPENDING ON CONVECTIVE TRENDS.

   DISCUSSION...STORMS /INCLUDING A PERSISTENT SUPERCELL/ CONTINUE
   WITHIN ZONE OF ISENTROPIC ASCENT RESULTING FROM A STRENGTHENING SWLY
   LLJ INTERACTING WITH A WWD MOVING OUTFLOW BOUNDARY. STORMS WILL
   PERSIST ALONG COOL SIDE OF THIS BOUNDARY AND ARE SLIGHTLY
   ELEVATED...BUT EFFECTIVE SHEAR REMAINS FAVORABLE FOR SUPERCELLS WITH
   A THREAT FOR LARGE HAIL AND DAMAGING WIND. AS TEMPERATURES ALOFT
   CONTINUE TO WARM...THE ENVIRONMENT SHOULD EVENTUALLY BECOME
   INCREASINGLY HOSTILE TO DEVELOPING STORMS...RESULTING IN A WEAKENING
   TREND. IN THE MEANTIME THE SEVERE THREAT WILL PERSIST...POSSIBLY AN
   HOUR OR SO BEYOND WW EXPIRATION TIME.

   ..DIAL.. 08/13/2015


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

   LAT...LON   46759533 47839639 48289585 47569493 46769457 46759533