Mesoscale Discussion 0507 NWS Storm Prediction Center Norman OK 0746 PM CDT Sun Apr 20 2025 Areas affected...eastern Missouri into Illinois Concerning...Tornado Watch 155... Valid 210046Z - 210215Z The severe weather threat for Tornado Watch 155 continues. SUMMARY...The severe threat continues across Tornado Watch 155. Strong to severe gusts appear to be the main threat along most of the line, though tornadoes remain possible, particularly with supercells. DISCUSSION...A mature squall line continues to progress eastward amid a strongly sheared, adequately unstable airmass. A line-embedded mesovortex across far west-central IL has supported several estimated/measured severe gusts. While buoyancy ahead of this portion of the line is beginning to diminish considerably, strong synoptic forcing and ambient flow aloft will continue to support mesovortex maintenance and associated strong/severe gust potential, at least in the near-term. Farther south in southeast MO, supercells have entered the southwestern-most portions of the watch, and it is here where short-term tornado potential is greatest. Given strong kinematic fields in place, despite waning buoyancy, at least damaging gust potential may persist with the line downstream, east of the current Tornado Watch, so either a new WW issuance may be needed, or a spatial extension of the ongoing watch may be warranted. ..Squitieri/Guyer.. 04/21/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PAH...LOT...ILX...MEG...LSX...DVN... LAT...LON 36589107 37449084 39749049 40189062 40929107 41439127 41759097 41739019 41378915 40918861 39968815 38858800 37828812 37018841 36488904 36478985 36499042 36589107 MOST PROBABLE PEAK TORNADO INTENSITY...100-130 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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