Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Nov 29 2023 17:08:32 ACUS02 KWNS 291708 SWODY2 SPC AC 291706 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1106 AM CST Wed Nov 29 2023 Valid 301200Z - 011200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST TEXAS... ....SUMMARY... Scattered storms, some severe, will be possible during the day on Thursday, mainly over southeast Texas. A conditional risk for a few tornadoes will be possible during the day. Otherwise, marginal hail will be possible extending northward into parts of Oklahoma. ....Discussion... A rather conditional severe thunderstorm set up is expected on Thursday, mainly during the morning and afternoon hours across southeast Texas. A warm advection regime, resulting in widespread cloudiness and ongoing showers/thunderstorms will be underway at the beginning of the period as a shortwave trough tracks across the central/southern Plains vicinity. Upper 60s F dewpoints will be focused near the Middle and Upper Texas Coast with low to mid-60s F dewpoints extending northward toward the Red River/ArkLaTex vicinity. A surface low will develop and shift east/northeast across OK/MO as a trailing cold front moves southeast across the southern Plains after 00z. Forecast vertical shear profiles are impressive with large, curved low-level hodographs becoming elongated/straight near 3 km. Strong low-level southerly flow, with around 40-50 kt at 850 mb, is expected. Effective SRH values greater than 300 m2/s2 near and north of a warm front across east TX are depicted in forecast guidance as well. This shear space conditionally would support supercell thunderstorms. However, low-level thermodynamics appear problematic. Surface temperatures and dewpoints may struggle to reach higher than 68-69 F (except perhaps near the immediate coast). Furthermore, cloudiness and morning convection will limit heating, and forecast soundings indicate low-level lapse rates remaining quite poor and nearly moist adiabatic. HREF members also continue to depict stronger negative UH tracks than positive UH tracks, which is an indication that storms may struggle to be rooted near the surface, limiting access to better low-level vertical shear. Additionally, forecast guidance shows modest warming through the day in the 850-500 mb layer, while stronger large-scale ascent remains focused north of the region. An outlook downgrade was considered. However, if boundary-layer moisture is greater than forecast, or any stronger heating can occur, low-level thermodynamics would improve and allow convection to access better low-level shear, resulting in an increased risk for a few tornadoes. As such, will maintain the Enhanced (level 3 of 5) risk with only minor changes/eastward adjustments compared to the previous outlook based on latest guidance. Further north across north TX into OK, steeper midlevel lapse rates are forecast closer to the midlevel speed max. Convection will remain elevated, but sufficient elevated instability within a favorable shear environment will support isolated hail in the stronger cells through early evening. ...Leitman.. 11/29/2023 $$ = = = 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) .