Subj : MESO: Mesoscale Discussion 2080 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Sep 04 2023 21:53:21 ACUS11 KWNS 042153 SWOMCD SPC MCD 042152=20 NDZ000-SDZ000-042345- Mesoscale Discussion 2080 NWS Storm Prediction Center Norman OK 0452 PM CDT Mon Sep 04 2023 Areas affected...northwest and north-central SD...southern and central ND Concerning...Severe Thunderstorm Watch 666... Valid 042152Z - 042345Z The severe weather threat for Severe Thunderstorm Watch 666 continues. SUMMARY...Scattered severe gusts are probable across the northeast part of severe thunderstorm watch #666 as a band of storms moves northeastward. A downstream severe thunderstorm watch is expected within the next hour in parts of northern SD and southern ND. Peak gusts with the most intense downdrafts are forecast to range 70-90 mph through 01 UTC (8pm CDT/7pm MDT) over northern SD and southern ND. DISCUSSION...Radar mosaic late this afternoon shows an intensifying band of storms over western SD. Surface analysis ahead of this activity indicates temperatures are in the 95-100 deg F range south of a southwest-northeast oriented surface trough. The airmass where the ongoing storms are located in western SD is adequately moist (mid 50s deg F dewpoints) but relatively dry compared to south-central ND where dewpoints are in the lower 60s. As a result, PW increases from southwest to northeast. This increase in moisture will probably result in both storms moving in a more favorable environment of buoyancy and moisture for evaporatively cooled downdrafts.=20=20 It appears the most intense phase of the developing squall line will commence over the next few hours as storms move into northern SD and into southern ND. The negatively tilted mid-level shortwave trough over WY will continue to pivot eastward towards the Dakotas this evening. The combination of very steep low to mid-level lapse rates, a linear storm mode, and appreciable large-scale forcing for ascent will favor scattered severe gusts through the evening across the Dakotas with the squall line. Peak gusts are forecast to range from 70-90 mph. ...Smith.. 09/04/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!4M9ErsRzBVTUNsQE_mUb6KubLintIFS3upjOvZyvyNXaljt0e8UaoRIyUZIs7lpzEezvlsqfi= V1QtvciDEsmRHN7tEQ$ for graphic product... ATTN...WFO...FGF...ABR...BIS...UNR... LAT...LON 44300172 44250220 44340250 45460364 45700370 45950357 47300105 47409982 47229892 46789830 46129834 45419893 44300172=20 =3D =3D =3D 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. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .