Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Feb 21 2024 19:55:50 ACUS01 KWNS 211955 SWODY1 SPC AC 211954 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0154 PM CST Wed Feb 21 2024 Valid 212000Z - 221200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TONIGHT ACROSS PARTS OF SOUTHEASTERN KANSAS INTO SOUTHWESTERN MISSOURI AND ACROSS PARTS OF CENTRAL ILLINOIS INTO NORTHWESTERN/CENTRAL INDIANA... ....SUMMARY... Isolated to widely scattered strong thunderstorm development is possible tonight across parts of the Ozark Plateau and lower Ohio Valley, perhaps accompanied by some risk for severe hail. ....20Z Update... In advance of a short wave trough which has emerged from the southern mid-latitude/subtropical eastern Pacific, a deep plume of warm/dry air continues to overspread much of the southern Great Plains toward the lower Mississippi Valley, coincident with large-scale mid-level ridging. Beneath this regime, surface dew points have only reach the mid/upper 50sF across much of the northwestern Gulf of Mexico, though they have risen into the lower/mid 60s near the coast of Mexico into parts of the Texas coastal plain. Even where surface dew points are highest, the boundary-layer moistening remains confined to a rather shallow layer based on morning observed and forecast soundings. Still, limited low-level level moistening appears underway on strengthening southerly return flow across southern/eastern Texas toward the Ozark Plateau and lower Ohio Valley, beneath the warm, capping air aloft. Latest model output continues to indicate that associated potential instability will contribute to at least low probabilities for thunderstorm development late this evening and overnight, generally focused along a couple zones of enhanced low/mid-level warm advection and/or weak frontogenetic forcing. Some machine learning forecast guidance continues to suggest low probabilities for severe hail may accompany stronger storms tonight. However, latest available forecast soundings from the NAM and Rapid Refresh do not appear overly supportive of this potential. ...Kerr.. 02/21/2024 ..PREV DISCUSSION... /ISSUED 1030 AM CST Wed Feb 21 2024/ ....Southern MO... Morning water vapor loop shows a fast-moving shortwave trough over southern CA. This feature and its associated mid-level jet max will track across the southern Plains and into the mid MS valley by late tonight. Ahead of this system, strengthening southwesterly low-level winds will enhance warm/moist advection into parts of MO/IL, leading to a zone of modest instability after dark from southeast KS across much of southern MO. Forecast soundings from several 12z models indicate the boundary-layer remains capped, suggesting the prospects for robust thunderstorm development are rather low. However, a few morning CAM solutions do show a storm or two overnight, which given the steep mid-level lapse rates and strong shear would be capable of hail. Therefore, will maintain the ongoing MRGL risk area to denote the conditional risk. ....Northern IL/IN... A surface warm front is expected to become established from central MO into central IL later today. Low-level winds are expected to be rather weak in vicinity of the boundary, but flow into the mid-levels should result in elevated warm-advection and the initiation of a few thunderstorms after midnight. Forecast soundings suggest the potential for hail in the strongest cells, although the potential for severe-caliber hail appears marginal. $$ = = = 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) .