Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Feb 26 2024 19:36:02 ACUS01 KWNS 261935 SWODY1 SPC AC 261934 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0134 PM CST Mon Feb 26 2024 Valid 262000Z - 271200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE GREAT LAKES AND OHIO VALLEY... ....SUMMARY... Isolated late-night hail is possible across parts of the Great Lakes and Ohio Valley. ....20Z Update... ....Midwest into Lower MI... Conditional threat for elevated supercells capable of large hail described in the previous outlook (appended below) remains valid. Additionally, confidence in thunderstorm development has increased enough across bring the 5% hail probability south into northern KY. Environmental conditions in this area are similar to those farther north, and should support isolated hail with any deeper convective cores. Overall storm coverage is still expected to remain isolated, precluding the need to increase probabilities. ...Mosier.. 02/26/2024 ..PREV DISCUSSION... /ISSUED 1028 AM CST Mon Feb 26 2024/ ....Synopsis... A mid-level trough will dig across the Pacific Northwest today with a mostly zonal mid-level pattern across the eastern CONUS. Within that zonal flow, a weak shortwave trough is forecast to move through the Great Lakes/Ohio Valley late tonight and could result in some thunderstorms capable of large hail. A gradual strengthening of the low-level jet is anticipated through the day today from the Ohio Valley into the Great Lakes as a mid-level trough advances eastward. This will lead to poleward moisture transport centered around 850mb. This moist plume combined with very steep (8-8.5 C/km) mid-level lapse rates will lead to increasing elevated instability during the overnight period. Convective initiation remains the primary question during the overnight period. A trough is present at both 850mb and 500mb in 12Z guidance, but they are not quite phased. This leads to weakening/veering 850mb flow during the period when height falls and 500mb dCVA arrives across the region. This is likely an explanatory factor for the lack of storm coverage by most CAM guidance. Nonetheless, global guidance continues to show significant convective precipitation from southern Michigan to northern Tennessee. Given 1000 to 2000 J/kg MUCAPE and effective shear of 45-50 knots (highest across southern Indiana), a conditional threat for elevated supercells capable of large hail exists tonight. Have expanded the marginal risk farther south in Indiana to account for this threat. It is worth mentioning there is at least some threat farther south into Kentucky where strong instability and shear are present which would support supercells also. However, have confined the marginal risk to areas where better mid-level support is expected early Tuesday morning. $$ = = = 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) .