MD 0307 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR MUCH OF LOWER MICHIGAN…NORTHEASTERN INDIANA…NORTHWESTERN OHIO
Mesoscale Discussion 0307
NWS Storm Prediction Center Norman OK
0108 PM CDT Tue Mar 26 2024
Areas affected…much of lower Michigan…northeastern
Indiana…northwestern Ohio
Concerning…Severe potential…Watch unlikely
Valid 261808Z – 262045Z
Probability of Watch Issuance…20 percent
SUMMARY…An increasingly organized band of showers, and developing
thunderstorms, may be accompanied by increasing potential for strong
to locally severe surface gusts by 4-5 PM EDT. It is still not
clear that a severe weather watch is needed, but trends are being
monitored for this possibility.
DISCUSSION…Weak destabilization within a narrow pre-frontal
corridor of low-level warming and moistening, coupled with
large-scale ascent aided by warm advection, has contributed to
increasing showers across western lower Michigan southward toward
the Indianapolis IN vicinity. Some lightning has recently been
noted southeast of South Bend, but low-level lapse rates are still
relatively modest and the moistening is only contributing to very
weak CAPE.
This may be slow to improve, but breaks in cloud cover may allow for
at least some continuing insolation during the next few hours.
Perhaps more notably, within the left exit region of an intensifying
mid-level jet (in excess of 100 kt around 500 mb) nosing
north-northeastward through the lower Ohio Valley, strengthening
low-level frontogenetic forcing is forecast along the eastward
advancing front across central lower Michigan through the
Indiana/Ohio border area by 20-21Z. This may support a
consolidating and deepening band of convection with increasing
potential to produce lightning.
In the presence of fairly strong (and strongly sheared)
south-southwesterly lower/mid-tropospheric flow (including 40-50+ kt
mean ambient flow in the lowest 3-6 km AGL), activity may become
increasingly organized. Downward mixing of momentum may contribute
to potentially damaging wind gusts reaching the surface in
northeastward surging segments, while the line advances eastward
toward the lower Great Lakes region through late afternoon.
..Kerr/Hart.. 03/26/2024
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…CLE…ILN…DTX…APX…IWX…GRR…
LAT…LON 40428544 42978529 44938539 44928356 43948281 41398341
40408392 40428544
