Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Nov 30 2023 19:55:38 ACUS01 KWNS 301955 SWODY1 SPC AC 301954 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0154 PM CST Thu Nov 30 2023 Valid 302000Z - 011200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST TEXAS AND SOUTHWEST LOUISIANA... ....SUMMARY... A few severe storms/tornadoes are possible through tonight from southeast Texas into southern Louisiana. Farther north, isolated hail and strong wind gusts will also be possible across parts of East/North Texas and southern Oklahoma. ....20z Update... The only changes with the 20z update were to trim the western edges of the outlook area based on latest observation trends and location of current convection. Widespread cloud cover and scattered convection has limited heating, and combined with poor low-level lapse rates, low-level inhibition is limited surface-based storm development. Some stronger storms may still develop this evening near the Sabine River as the surface cold front tracks southeast. However, overall severe potential will likely remain somewhat subdued due to poor thermodynamics despite favorable vertical shear. ...Leitman.. 11/30/2023 ..PREV DISCUSSION... /ISSUED 1025 AM CST Thu Nov 30 2023/ ....Northwest Gulf coast and southern Plains through tonight... Thunderstorms are forming this morning over southeast TX from Matagorda Bay northeastward through the Houston area to Toledo Bend reservoir. The convection appears to be driven by low-level warm advection, as well as a subtle/lead speed max ejecting aloft, in advance of the primary shortwave trough over NM. Observed and forecast hodographs (with substantial length and curvature) across southeast TX look favorable for right-moving supercells with some tornado potential. However, with widespread cloud cover and warm advection being the primary mode of storm initiation, the updrafts may be rooted slightly above the ground. Thus, the convection may not take full advantage of the shear profiles, compared to a more favorable scenario where fully surface-based storms formed in a warmer environment upstream and moved into the environment expected across southeast TX/upper TX coast this afternoon/evening. Regardless, there will be some potential for supercells and a few tornadoes given the strong low-level shear in a moistening/gradually destabilizing environment, with the aforementioned caveats related to poor low-level lapse rates. This threat will slowly increase across southeast TX/upper TX coast through the afternoon and continue through tonight while spreading eastward into southwest/south central LA. Farther northwest, elevated thunderstorm development is expected from central/north TX into southern OK, in the zone of ascent preceding the primary shortwave trough that will begin to move east-northeastward this afternoon from NM toward OK and north TX. The strongest of these storms will pose some threat for marginally severe hail based on some steepening of midlevel lapse rates and relatively long hodographs aloft. A narrow zone of buoyancy rooted near the surface may develop later this afternoon from western north TX into extreme southwest OK, near the primary surface cyclone. However, the main forcing for ascent will be east/northeast of this zone by late afternoon, and forecast hodographs reflect low-midlevel wave passage with a pronounced veer-back signature relatively close to the ground (as low as 1 km AGL). $$ = = = 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) .