MESOSCALE DISCUSSION 1656
   NWS STORM PREDICTION CENTER NORMAN OK
   0145 PM CDT MON SEP 01 2014

   AREAS AFFECTED...MI

   CONCERNING...SEVERE THUNDERSTORM WATCH 485...

   VALID 011845Z - 012015Z

   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 485
   CONTINUES.

   SUMMARY...SCATTERED DAMAGING WINDS ASSOCIATED WITH FAST-MOVING TSTMS
   AND POSSIBLY BRIEF TORNADO CIRCULATIONS WILL CONTINUE ACROSS EASTERN
   PARTS OF NORTHERN LOWER MI...AND PERHAPS EXTREME EASTERN PORTIONS OF
   THE UPPER PENINSULA. A NARROW SQUALL LINE WILL ALSO PROGRESS ACROSS
   SOUTH-CENTRAL LOWER MI WITH AN ISOLATED WIND DAMAGE THREAT
   DEVELOPING EAST INTO SOUTHEAST LOWER MI THROUGH LATE AFTERNOON.

   DISCUSSION...BROKEN PRE-FRONTAL SQUALL LINE HAS DEVELOPED ACROSS
   MUCH OF CENTRAL LOWER MI THIS AFTERNOON. EMBEDDED SUPERCELL
   STRUCTURES ASSOCIATED WITH BREAKS IN THE LINE HAVE EXHIBITED
   OCCASIONAL STRONGER LOW-LEVEL CIRCULATIONS IN PARTS OF KALKASKA AND
   CRAWFORD COUNTIES IN THE NRN LOWER PENINSULA. IN ADDITION TO
   ISOLATED/BRIEF TORNADO POTENTIAL WITH THESE STORMS...OTHER STRONGER
   SEGMENTS WITHIN THE CONVECTIVE LINE COULD PRODUCE WINDS GUSTS TO
   NEAR SEVERE LEVELS AS THE ENTIRE SQUALL LINE MOVES ACROSS THE REST
   OF NORTHERN LOWER MI OVER THE NEXT 1-2 HOURS.

   LOW LEVEL CONVERGENCE AND DEEP-LAYER SHEAR WEAKEN WITH SRN EXTENT
   ACROSS SRN LOWER MI. HOWEVER...SUPPORTIVE LARGE SCALE FORCING FOR
   ASCENT ASSOCIATED WITH MID/UPPER TROUGH AND 50-60KT MID-LEVEL WIND
   MAX EJECTING ACROSS LAKE MI ATTM...AND A MAXIMUM IN DIURNAL
   INSTABILITY ACROSS THE REGION...HAVE CONTRIBUTED TO THE DEVELOPMENT
   OF A NARROW CONVECTIVE LINE. THE MOST ORGANIZED STRUCTURE WITHIN
   THIS PORTION OF THE LINE WAS MOVING FROM NORTHWEST GRATIOT AND
   EASTERN ISABELLA COUNTIES INTO MIDLAND COUNTY NOW. KMOP...MT.
   PLEASANT ASOS...NEAR THE APEX OF THE SMALL-SCALE BOWING SEGMENT OF
   CONVECTION...RECENTLY REPORTED A GUST NEAR 30KT. THE REMAINDER OF
   THE CONVECTIVE LINE TO THE SOUTH APPEARS LESS ORGANIZED/INTENSE AND
   A WATCH IS NOT CURRENTLY EXPECTED IF STORMS CONTINUE TO EXHIBIT
   MARGINAL/TRANSIENT STRUCTURE WHERE DEEP SHEAR AND FORCING WEAKEN
   WITH SOUTHERN EXTENT.

   ..CARBIN/HART.. 09/01/2014


   ATTN...WFO...DTX...APX...IWX...GRR...

   LAT...LON   44938491 46638512 46698453 46408373 45288294 44508279
               43748269 43018261 42358324 41848359 41798416 41818502
               41908590 42498582 43608497 44268489 44938491