Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jul 20 2023 20:02:46 ACUS01 KWNS 202002 SWODY1 SPC AC 202000 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Thu Jul 20 2023 Valid 202000Z - 211200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL HIGH PLAINS...AND THE GREAT LAKES/MIDWEST... ....SUMMARY... Scattered severe thunderstorms are expected near the Colorado Front Range into the central/southern High Plains, with other severe storms across the Midwest/Great Lakes, as well as the Tennessee Valley and Southeast States. ....20Z Update... Severe probabilities have been trimmed behind convection ongoing across the Great Lakes, Midwest, and TN Valley. A substantial threat for damaging winds and large hail remains apparent with these thunderstorms as they spread eastward across IL, OH, and western PA/NY this afternoon and early evening. A tornado or two also remains possible, mainly across portions of southeastern Lower MI and northern OH near Lake Erie. See Mesoscale Discussion 1646 for more details on the near-term severe threat across parts of Lower MI. A separate cluster of convection should continue to pose a threat for mainly damaging winds this afternoon and evening as it moves east-southeastward across parts of the Southeast. See Mesoscale Discussion 1645 for more meteorological details regarding this threat. No changes have been made to the Enhanced Risk across the southern/central High Plains. ...Gleason.. 07/20/2023 ..PREV DISCUSSION... /ISSUED 1058 AM CDT Thu Jul 20 2023/ ....Central High Plains... Water vapor imagery shows a shortwave trough moving across UT this morning. Large scale ascent ahead of this trough, along with strengthening westerly flow aloft will aid in the development of scattered thunderstorms along the foothills of CO by early afternoon. These storms will spread eastward through the afternoon and evening into western KS and parts of the TX/OK Panhandles. Forecast soundings appear quite favorable for supercells capable of very large hail and perhaps a tornado or two. As the activity moves eastward, upscale organization is likely with one or more bowing complexes capable of damaging wind gusts. These storms may persist well after midnight into southern KS/northern OK. ....Upper OH Valley... A strong and progressive upper trough over WI/Upper MI will track southeastward today, with its associated cold front sweeping across Lower MI and into the Upper OH Valley. Thunderstorms have already developed along part of the front over northwest Lower MI. Full sunshine ahead of the front will yield afternoon MLCAPE values of 2500 J/kg, along with steep low and mid-level lapse rates. Supercells and bowing structures are expected, capable of large hail and damaging wind gusts. An isolated tornado or two is also possible. This activity will build southward into northern IN and spread eastward over much of OH and western NY/PA this evening with a continued risk of damaging winds and hail. Refer to MCD #1641 for further short-term details. ....TN Valley... A remnant area of convection is affecting southern MO, with one intense cell along the leading edge near Paducah. More storms are expected to eventually develop along the leading edge as the activity tracks east-southeastward along an outflow boundary/differential heating zone extending into northern TN. Sufficient winds aloft and a very moist/unstable air mass will promote a risk of damaging winds and perhaps hail in the strongest cells this afternoon. $$ = = = 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) .