Mesoscale Discussion 1039
NWS Storm Prediction Center Norman OK
0356 PM CDT Wed Jul 11 2018
Areas affected...Much of northern Minnesota
Concerning...Severe potential...Watch likely
Valid 112056Z - 112330Z
Probability of Watch Issuance...80 percent
SUMMARY...Storms are expected to initiate around 23-00Z across
northwest Minnesota and possibly near the North Dakota border, and
should increase in coverage this evening across northern Minnesota.
Hail, wind, and perhaps a tornado will be possible. A watch is
expected later this evening.
DISCUSSION...Surface analysis shows a cold front extending from
eastern ND into western SD, with a warm front from northwest MN into
western WI. South of these boundaries, a very warm and unstable air
mass continues to develop with dewpoints in the 70s F. Meanwhile,
gradual height falls with a low-amplitude upper trough will continue
to approach the region. While CIN currently exists for surface based
parcels as of 21Z, a few post-frontal showers were already forming
over ND. With time, strong warm advection will develop in the
low-levels near the warm front in MN, and scattered storms will
result. Veering winds with height will favor supercells initially,
with an eventual merger and/or backbuilding tendency. Large hail,
damaging wind, and perhaps a tornado or two will be possible.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 48219681 48609647 48909593 49129525 49179486 49159460
49069427 48979405 48559335 48029316 47499320 47209350
46959399 46849474 46689636 46809690 47219702 48219681