Mesoscale Discussion 2317
Issued: · Valid: –
Summary
Severe thunderstorms capable of producing large to very large hail and damaging winds are expected through this evening across portions of eastern and southeastern Colorado and extreme west-central Kansas.
Product Text
000 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 www.spc.noaa.gov 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