ACUS11 KWNS 202215
SWOMCD
SPC MCD 202215
MIZ000-WIZ000-210015-

Mesoscale Discussion 1677
NWS Storm Prediction Center Norman OK
0515 PM CDT Mon Jul 20 2026

Areas affected...western U.P. of Michigan

Concerning...Tornado Watch 501...

Valid 202215Z - 210015Z

The severe weather threat for Tornado Watch 501 continues.

SUMMARY...The threat for a few tornadoes appears to be increasing
across the discussion area.

DISCUSSION...Over the past hour, several discrete supercells have
developed over the western U.P. of MI within a moist and moderate
environment with MLCAPE as high as 2500-3000 J/kg, per latest
objective analysis. The KMQT VWP currently resides within the
eastern fringe of stronger instability, where locally backed
near-surface winds are resulting in relatively strong low-level and
deep-layer shear with 0-1 km SRH of over 200 m2/s2 and 0-6 km shear
of 50 kt, respectively.

Current radar observations indicate the supercells maturing near the
eastern edge of greater instability (around the longitude of
Marquette) and within the zone of enhanced vertical shear.
Non-hydrostatic pressure perturbations existing with the ongoing
supercells will sustain the storms farther east into the central
U.P.; however, the tornado threat may be muted by the higher
convective inhibition with eastward extent, at least in the short
term.

As of 2205Z, the best tornado potential appears to exist with the
supercells near the MI-WI state line, northwest of Iron Mountain,
and over far northeast Dickinson and southeast Marquette Counties.
In addition to the tornado threat, the potential will exist for
large hail with the strongest supercells.

..Mead.. 07/20/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!8dO6IAcqf9Fz85s6b1lPpEZdNMan9zFaVbUpwYM_oCDA1tC2cZbEYZWKZqDK9jhmgCyD2LJsP3tdJr559Ghb1ZM-GDU$ for graphic product...

ATTN...WFO...MQT...GRB...

LAT...LON 46108986 46498971 46738899 46718797 46608687 46208660
45658678 45528777 45488871 45638936 45818975 46108986

MOST PROBABLE PEAK TORNADO INTENSITY...120-145 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN


= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)