Subj : MESO: Mesoscale Discussion 2239 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Oct 12 2023 01:51:31 ACUS11 KWNS 120151 SWOMCD SPC MCD 120150=20 IAZ000-NEZ000-SDZ000-120415- Mesoscale Discussion 2239 NWS Storm Prediction Center Norman OK 0850 PM CDT Wed Oct 11 2023 Areas affected...portions of northern and central Nebraska...southeastern South Dakota and west central Iowa Concerning...Severe potential...Watch unlikely=20 Valid 120150Z - 120415Z Probability of Watch Issuance...20 percent SUMMARY...Increasing low-level warm advection may support additional thunderstorms capable of isolated hail this evening. Confidence in storm coverage and severity is low and a watch is not expected. DISCUSSION...As of 0140 UTC, regional IR satellite imagery showed cooling cloud tops along a band of convection across portions of the central Plains. Located along and north of a warm front emanating from a deepening lee low over eastern CO, convection is expected to continue to slowly deepen and increase in coverage near the frontal corridor through this evening and into the overnight hours. Area VADs and surface obs show low-level mass response ahead of the deepening low, along with a moderately strong low-level jet. Favored by the uptick in low and mid-level warm advection, forcing for ascent should continue to build this evening supporting additional storm development. While not overly robust, sufficient buoyancy (~500-1000 J/kg of MUCAPE) along the warm front should support a few stronger updrafts. Bolstered by a band of westerly mid-level flow associated with the deepening low, 30-40 kt effective shear may also support some organization of these updrafts into sustained multicells or transient supercell structures. Generally north of the surface warm front and with nocturnal cooling ongoing at the surface, storms should remain elevated with the main risk being isolated hail with the more sustained/robust updrafts. Hi-res guidance varies on the degree of storm coverage/intensity through this evening, casting uncertainty on how widespread any severe risk will be. However, current radar and observational trends do suggest a few stronger storms with hail potential may evolve over north-central NE and spread into portions of southern SD and western IA tonight. ...Lyons/Guyer.. 10/12/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!8enZu1JAlNrAqROQ4PzOzghm6M0NKJknxR9KOs03foGKt-LEHTWAo1ZB1BR42tZBhQ9KDmHWc= 2oV8LFSjLzV-bbHE7E$ for graphic product... ATTN...WFO...DMX...FSD...OAX...GID...LBF...UNR... LAT...LON 41389491 41249657 41279934 41540048 41580061 42210136 43050101 43280048 43629845 43569762 43369652 43139586 42669435 42249336 41639310 41429388 41389491=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) .