Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Feb 16 2023 16:32:10 ACUS01 KWNS 161632 SWODY1 SPC AC 161630 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1030 AM CST Thu Feb 16 2023 Valid 161630Z - 171200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF MIDDLE TN INTO MS AND AL... ....SUMMARY... Widely scattered severe thunderstorms are likely from the central Gulf Coast states northward into the Ohio Valley. Strong tornadoes are most likely over Mississippi, Alabama and middle Tennessee. ....Synopsis... A 1010 mb elongated surface low, currently positioned over the central MS Valley, should progress across the OH Valley through the day as a longwave upper-level trough continues to overspread the eastern CONUS. A strong low-level jet will overspread the TN/OH Valleys, roughly coinciding with a warm, moist and overall buoyant airmass across the Southeast. Deep-layer ascent in proximity to the low-level jet will supporting scattered to potentially widespread strong thunderstorms, several of which may be severe, particularly south of ongoing thunderstorms across the TN Valley. ....OH Valley... Widespread showers and thunderstorms are ongoing along the northern periphery of a gradually destabilizing warm sector, at the terminus of a 50 kt 850 mb jet. Continued low-level warm-air and moisture advection and increasing upper-support with the approaching mid-level trough will maintain the widespread nature of rain and thunderstorms through the afternoon, limiting diurnal heating and associated destabilization. As such, northern Category 1-2 (Slight-Enhanced) severe probabilities have been trimmed. Nonetheless, adequate low-level moisture, strong deep-layer ascent, and strong vertical shear profiles suggest that a conditional (low-end) damaging gust/tornado threat still exists as far north as the OH Valley, where Category 1/Marginal risk probabilities have been maintained. ....Middle TN into MS, AL, and far western GA... Relatively robust thunderstorm development has occurred well ahead of an approaching cold front in association with a confluence band along the LA/MS border area. Given ample diurnal heating, temperatures have warmed well into the 70s F, with upper 60s F dewpoint beginning to overspread central MS. With 7-8 C/km mid-level lapse rates overspreading this relatively pristine warm sector, 1000 J/kg MLCAPE should become common across the southeast, with patchy areas of 1500+ J/kg MLCAPE possible. 50+ kts of westerly 500 mb flow currently overlaps a 30-40 kt low-level jet, with ample speed increases/veering with height supporting 50+ kts of effective bulk shear, which will support supercell development through the afternoon given the aforementioned thermodynamic profile. Modest low-level elongation and curvature of hodographs (evident in mesoanalysis and regional VADs) suggest that storms that organize in the near-term could become tornadic supercells. However, the low-level jet should gradually shift northward from the warm-sector today, which is expected to temper hodograph length/curvature, serving as the primary reason for withholding a moderate risk upgrade this outlook. Nonetheless, an appreciable risk for tornadoes (a couple of which may be strong) necessitates the maintenance of Category 3/Enhanced probabilities, and a narrow corridor of locally higher tornado potential may briefly occur somewhere across eastern MS into central AL this afternoon. Thereafter, storms should gradually weaken as they cross into GA as buoyancy decreases and low-level winds continue to veer. ...Squitieri/Lyons.. 02/16/2023 $$ = = = 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) .