Mesoscale Discussion 0468
NWS Storm Prediction Center Norman OK
0936 AM CDT Fri Apr 18 2025
Areas affected...portions of Lake Michigan through southern and
central Lower Michigan
Concerning...Severe potential...Watch unlikely
Valid 181436Z - 181630Z
Probability of Watch Issuance...20 percent
SUMMARY...A continuing risk for severe hail and/or increasing
potential for strong, damaging wind gusts appears low, as a small,
organizing cluster of storms, or its remnants, spreads inland of
Lake Michigan across parts of central/southern Lower Michigan
through midday. A new watch is not anticipated, but trends are
being monitored.
DISCUSSION...Strongest convection has become focused above the
convectively generated cold pool, within forcing associated with
low-level warm advection, trailing to the southwest of a weakening
MCV now approaching Michigan coastal areas near/north of Muskegon.
Currently moving eastward at speeds of 45-50 kt, the small,
organizing cluster is on track to overspread the Grand Rapids,
Lansing and Flint vicinities of south central Lower Michigan through
15-17Z.
However, the latest Rapid Refresh suggests that southerly low-level
wind fields and associated forcing for ascent will weaken through
mid to late morning, while warmer and more strongly capping elevated
mixed layer air advects northeastward across the region. So, it
remains uncertain how much longer ongoing activity will be
maintained.
Furthermore, while an initially cool, dry and stable boundary-layer
across southern into central Lower Michigan is in the process of
gradually warming and moistening ahead of the approaching
convection, the extent to which low-level thermodynamic profiles
become unstable to downdrafts and/or downward mixing of stronger
momentum aloft remains unclear. Currently, potential for a
continuing risk for severe hail and/or an increasing risk for
damaging wind gusts appears low, at least in the near term, but
trends will continue to be monitored.
..Kerr/Smith.. 04/18/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...DTX...IWX...GRR...MKX...
LAT...LON 43918706 44048635 43378327 42268295 41998647 42718813
43918706
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
Source link