Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Dec 16 2024 00:51:53 ACUS01 KWNS 160051 SWODY1 SPC AC 160050 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0650 PM CST Sun Dec 15 2024 Valid 160100Z - 161200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN OK INTO THE OZARKS... ....SUMMARY... Isolated severe hail, strong/gusty winds, and perhaps a brief tornado may occur tonight through early Monday morning from parts of eastern Oklahoma and the Ozarks. ....Synopsis... Early evening water-vapor imagery shows a pronounced shortwave trough embedded within mostly zonal westerly flow slowly amplifying across the central and northern Plains states. Stronger westerly flow south of the main shortwave is expected to expand eastward this evening, as a subtle perturbation crosses the southern Plains and moves into the Ozarks tonight. This subtle forcing for ascent will allow increasingly strong northward advection of a partially modified Gulf air mass into portions of the southern Plains, Ozarks and lower OH River Valley ahead of a cold front. ....Eastern OK and the Ozark Plateau... Weak low-level warm advection is occurring across the ArkLaTex early this evening as evidenced by showers and several weak thunderstorms from northeast TX into western AR. This should continue before intensifying with the approach of the stronger deep-layer ascent tonight. A 30-45 kt low-level jet will support moderate isentropic ascent centered over eastern OK and western AR mainly after 03z. Low to mid 60s F surface dewpoints should reach as far north as the AR/OK/MO border region supporting moderate destabilization despite poor low-level lapse rates. Delayed by the late arrival of modest large-scale forcing for ascent, convective initiation is expected late this evening into the overnight hours near the cold front from northeast OK into southwest MO, and farther southeast within the warm sector. Initial activity may be supercellullar, given 35-40 kt of deep-layer shear and 1000-2000 J/kg of MUCAPE. This suggests the stronger storms may initially be capable of some severe hail, especially with any persistent rotating updrafts. Strong low-level shear is also suggestive of a non-zero tornado and damaging wind gust threat through early Monday morning. However, this is conditional upon more unstable near-surface based parcels, which, given the poor low-level lapse rates and saturated air mass, is uncertain. Overall, the severe threat with any convection that develops should remain rather isolated, will maintain level 1 Marginal with low-end probabilities for all hazards. ...Lyons.. 12/16/2024 $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .