Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jan 01 2023 17:30:22 ACUS02 KWNS 011730 SWODY2 SPC AC 011728 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CST Sun Jan 01 2023 Valid 021200Z - 031200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EAST TEXAS...SOUTHEASTERN OKLAHOMA...ARKANSAS...AND NORTHERN LOUISIANA... ....SUMMARY... Severe thunderstorms are expected Monday and Monday night from eastern Oklahoma and Texas into Louisiana/Arkansas and vicinity. Tornadoes and scattered damaging winds will be the main hazards with these storms. Some of the tornadoes could be strong. ....Eastern Oklahoma/Texas into the Lower Mississippi Valley... A potent upper trough will pivot from the Southwest/Four Corners region across the southern/central Rockies and Plains on Monday, while acquiring a negative tilt as it ejects over the Plains Monday night. This trough will be accompanied by enhanced low/mid-level winds overspreading much of the southern/central Plains into the lower MS Valley and Mid-South through the period. Strong low-level southerly winds associated with a 40-50+ kt low-level jet will advect Gulf moisture northward across east TX/OK into the lower/mid MS Valley, with mid to upper 60s surface dewpoints becoming common from east TX into southeastern OK, LA, and AR by Monday evening. A surface low is forecast to consolidate over the southern/central High Plains as pronounced large-scale ascent preceding the upper trough overspreads this region. This surface low should develop quickly northeastward across OK/KS and into northern MO/IA through Monday night. An attendant cold front will sweep quickly eastward over the southern Plains and towards the lower/mid MS Valley through the period. Fairly widespread cloud cover will probably tend to hinder robust daytime heating across much of the warm sector. Even with this potential limitation, cooling mid-level temperatures and steepening lapse rates aloft should help compensate to some extent. Most guidance suggests that sufficient instability will develop east of the cold front by Monday afternoon, with MLCAPE around 1000-1500 J/kg possible where at least mid 60s surface dewpoints are in place. Weaker boundary-layer instability should exist farther north into eastern KS and MO, with a more isolated/marginal severe threat possible. Most high-resolution guidance indicates that scattered convection will develop within the strong low-level warm advection regime around midday across the ArkLaTex vicinity as the cap erodes, and subsequently spread northeastward into a somewhat less favorable thermodynamic environment. These thunderstorms may pose a threat for all severe hazards initially, before becoming mainly elevated. The prospect for additional robust convective development in the open warm sector ahead of the front Monday afternoon/evening remains uncertain. A southerly low-level jet is expected to continue strengthening through the day from the ArkLaTex into the lower MS Valley in tandem with the approaching upper trough. Enhanced deep-layer flow and 40-50+ kt of effective bulk shear will easily support supercell structures. The primary uncertainty is how many supercells will actually develop before convection grows upscale along the front Monday evening/night. Even with this uncertainty, the potential for tornadoes remains apparent, as low-level shear will be more than adequate for updraft rotation. If a supercell can be maintained, then a strong tornado also appears possible. Otherwise, isolated large hail may occur with initially semi-discrete convection. A transition to more of a damaging wind threat appears probable as thunderstorms gradually congeal into one or more bowing line segments along or just ahead of the front Monday night. But, a threat for tornadoes embedded within the line will likely continue across the lower MS Valley through early Tuesday morning. ...Gleason.. 01/01/2023 $$ = = = 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) .