Mesoscale Discussion 1033
NWS Storm Prediction Center Norman OK
0459 PM CDT Wed Jun 14 2017
Areas affected...Portions of far eastern Wisconsin...northeast
Illinois...and lower Michigan
Concerning...Severe Thunderstorm Watch 328...330...
Valid 142159Z - 142330Z
The severe weather threat for Severe Thunderstorm Watch 328, 330
SUMMARY...Several clusters of strong/severe storms will continue
east across Watches 328 and 330 this evening. Storms currently
crossing Lake Michigan may pose a threat of locally gusty winds and
marginally severe hail across parts of Lower Michigan. However,
downstream watch issuance is not currently expected.
DISCUSSION...Numerous strong/severe storms have evolved eastward
across Watches 328 and 330 this afternoon, driven largely by merged
cold pools and advancing outflow boundaries. In pockets where the
air mass has not been convectively overturned, a warm/moist boundary
layer will maintain a threat of strong/damaging winds and marginally
severe hail. However, as storms progress east, they will become
increasingly displaced from stronger mid-level flow (and related
deep-layer shear) to the west. In turn, as storms reach western
Lower Michigan, they will probably have weakened sufficiently to
preclude downstream watch issuance. Nonetheless, MLCAPE around
1000-1500 J/kg may encourage a few loosely organized cores capable
of gusty winds and marginally severe hail this evening. Convective
trends will be monitored, however, in case storms exhibit greater
overall organization than is currently expected.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 43418836 44828758 45188677 45138567 44018488 42278475
41338535 40458617 40478742 41028854 41498870 42158865