ACUS11 KWNS 202313
SWOMCD
SPC MCD 202312
KSZ000-COZ000-210045-

Mesoscale Discussion 2317
NWS Storm Prediction Center Norman OK
0612 PM CDT Sun Sep 20 2026

Areas affected...portions of eastern/southeastern Colorado and
extreme west-central Kansas

Concerning...Severe Thunderstorm Watch 673...

Valid 202312Z - 210045Z

The severe weather threat for Severe Thunderstorm Watch 673
continues.

SUMMARY...Damaging hail will be possible for the next 1-2 hours.
Additional thunderstorms capable of large hail are possible this
evening.

DISCUSSION...A mature supercell continues to track southeast across
the Plains of eastern Colorado this afternoon. This supercell has a
history of producing very large hail (in excess of 2.5"). The
environment along and ahead of this supercell remains conducive for
maintaining its current intensity given effective-layer shear around
45 knots and MUCAPE between 1500-2000 J/kg. Absent the development
of additional thunderstorms that may destructively interfere, the
current supercell should continue to pose a threat for
large-to-very-large hail over the next couple of hours, with overall
magnitude of the hail size governed by storm-scale processes.

With time this afternoon and into the evening, the expectation is
that the boundary layer will cool sufficiently with the loss of
diurnal heating that a gradual weakening of the supercell should
commence. As such, the overall magnitude of any potential hail
should wane as well.

Additional thunderstorms capable of large hail and damaging winds
are still possible behind this initial supercell and that potential
will continue to be monitored.

..Marsh.. 09/20/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!5czpKlxmmsKIoEwzPD5WVml5hFkwgGo3w2Fcj_1tfLB3fovgqDfN3ezhYi2maHKzI1D-GxGWjALo1rXb1NkGqgsQqxo$ for graphic product...

ATTN...WFO...DDC...GLD...PUB...BOU...

LAT...LON 38810318 39080296 39060248 38880221 38630199 38240191
38040205 38020250 38280291 38640309 38810318

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 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)