ACUS11 KWNS 210452
SWOMCD
SPC MCD 210452
KSZ000-COZ000-210615-

Mesoscale Discussion 2321
NWS Storm Prediction Center Norman OK
1152 PM CDT Sun Sep 20 2026

Areas affected...portions of eastern Colorado and extreme western
Kansas

Concerning...Severe Thunderstorm Watch 674...

Valid 210452Z - 210615Z

The severe weather threat for Severe Thunderstorm Watch 674
continues.

SUMMARY...Strong-to-severe thunderstorms will continue this evening
into the early morning hours. Large hail and strong damaging
thunderstorm winds will be possible.

DISCUSSION...Scattered strong-to-severe thunderstorms, including
severe supercells, are ongoing this evening across eastern Colorado.
These supercells are capable of producing large-to-very-large hail,
with MRMS MESH episodically exceeding 2 inches across many of these
storms. Additionally, the supercell across Crowley County, Colorado,
is exhibiting signs of strong, perhaps damaging, convective outflow
winds. Overall, these storms will continue to move southeast, with
the storms having the strongest mesocyclones favoring a more
southerly direction.

The background environment remains conducive for severe
thunderstorms. MUCAPE is in excess of 1000 J/kg with effective layer
shear exceeding 40 knots is more than sufficient to sustain ongoing
supercells and an attendant large-hail threat into the early morning
hours. With time, however, increasing precipitation coverage should
weaken the overall instability and lead to a decrease in the overall
severe threat. Until that happens, large hail and damaging
thunderstorm winds will continue as individual storms move southeast
across the area.

..Marsh.. 09/21/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!7fA4z9iI-GXLZkhn1Q75ucp98MPUomgAdQpUDbRLpoTs2vum95AVxkQUux5MKWuLyJPNMaYtfH-voVWZy4hT48xD1mc$ for graphic product...

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

LAT...LON 37840462 38010503 38840504 39840504 40130505 40420458
40170364 39840281 39440213 39060183 38470171 37970165
37590191 37620347 37840462

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN


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--- scorpsmtpd
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