Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Dec 12 2022 06:01:19 ACUS01 KWNS 120601 SWODY1 SPC AC 120559 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1159 PM CST Sun Dec 11 2022 Valid 121200Z - 131200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF WESTERN KANSAS...OKLAHOMA AND THE TEXAS PANHANDLE... ....SUMMARY... Isolated severe thunderstorms will be possible from western and central Kansas, Oklahoma and into western north Texas, mainly overnight and early Tuesday. Strong wind gusts, isolated hail and a couple of brief tornadoes will be possible. ....Synopsis... Across the CONUS, an active mid-level flow pattern punctuated by an anomalously deep upper-level cyclone over the western States will remain amplified through the forecast period. As the upper cyclone progresses eastward, strong southwesterly flow aloft (H5 90-100 kt) will develop over much of the southern and central Plains by early evening. At the surface, a lee low is forecast to rapidly deepen drawing a partially modified Gulf airmass northward across the southern and central Plains. Thunderstorms are expected to develop near or after dark along a surface trough attendant to the surface low from eastern CO/southwest NE into western portions of KS, OK and TX. Despite marginal destabilization, strong wind fields may support a risk for severe wind gusts, hail and a couple tornadoes overnight tonight and into early Tuesday. ....Portions of western KS/OK and northwest TX... Ahead of the surface trough across the High Plains, low-level convergence is expected to increase rapidly near sunset in response to strong mid-level height falls and intensification of the surface low across eastern CO. Continued northward advection of a partially modified Gulf airmass with dewpoints in the upper 40s to low 50s F should result in marginal destabilization across portions of western KS OK and the TX panhandle. However, the northern extent of surface-based destabilization remains highly uncertain. Driven primarily by differential cold advection aloft, area forecast soundings show steepening mid-level lapse rates near 7.5 C/km and 500-1000 J/kg of MUCAPE peaking between 03 and 09z. Large forecast hodographs with effective shear of 40-50 kt will be favorable for storm organization into supercells or linear clusters. Hi-res models remain split with some showing isolated development near 00z along the surface trough across southwestern KS and the OK/TX Panhandles. Should these more isolated storms develop, a low-end tornado risk may evolve given the likely supercell mode and strong low-level shear. Additional development is expected along the surface cold front as it enters the warm sector after 03z where strong convergence would suggests some upscale growth into a QLCS or broken linear band. A risk for severe wind gusts and perhaps a brief tornado may evolve as convection shifts eastward through western KS/northwestern OK overnight. Cooler and more stable air to the northeast will likely limit the spatial extent of the threat after 10z. Farther south near the Red River, convective development will likely be delayed until after 03z with the arrival of the cold front. Displaced from the coldest mid-level temperatures, low and mid-level lapse rates are expected to be weaker and some convective inhibition will likely remain. Despite richer surface moisture (dewpoints in the mid 50s to low 60s F) the presence of a low-level inversion/surface stable layer may limit severe potential. However, strong shear profiles (0-1 km 30-40 kt) remain supportive of supercells and short bowing segments. While confidence in sustained severe potential is lower, severe wind gusts, isolated hail, and perhaps a brief tornado will be possible as a broken band of storms tracks eastward along the Red River Valley and north TX through early Tuesday morning. ...Lyons/Kerr.. 12/12/2022 $$ = = = 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) .