Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Mar 11 2023 17:19:31 ACUS02 KWNS 111719 SWODY2 SPC AC 111718 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1118 AM CST Sat Mar 11 2023 Valid 121200Z - 131200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE GULF COASTAL STATES... ....SUMMARY... Scattered severe thunderstorms capable of producing large hail, damaging winds, and a couple tornadoes should occur Sunday across parts of the Southeast. Some of the hail could be very large (2+ inches in diameter). ....Synopsis... Strengthening westerly mid-level flow will overspread the Southeast tomorrow/Sunday as an upper trough amplifies across the eastern U.S. A cold front will continue to sag southeastward ahead of the upper trough, trailing a surface low poised to traverse the OH Valley/central Appalachians through the period. However, a weak impulse embedded within the strengthening mid-level westerly flow will aid in the development of a secondary surface low/lee trough near the southeastward-moving cold front over the Gulf Coastal states. The development of this surface low will aid in low-level warm-air/moisture advection across the Gulf Coast states, enhancing low-level lift, shear and buoyancy to support scattered strong to potentially severe storms during the morning and afternoon hours. ....Gulf Coast States... Thunderstorms (perhaps in an organized line) should be ongoing at the start of the period across portions of the TN Valley into the Southeast states. These storms will continue to drift southward, away from the surface cold front and the better deep-layer ascent, supporting weakening convective trends on at least a temporary basis. Sometime during the late morning to mid-afternoon hours though, the development of a secondary surface low will foster greater low-level lift/moisture advection, coincident with modest diurnal heating amid persistent cloud cover. A re-invigoration of convection is expected ahead of the cold front to support a potentially more organized severe threat. Point forecast soundings and high-resolution guidance-member-consensus depicts a warm sector of mid 60s F dewpoints, overspread by mid-level lapse rates (and resultant MLCAPE) of 6-7 C/km (1000 J/kg) from central AL eastward, and 8+ C/km (2000 J/kg) toward eastern LA/southern MS. Modest veering and strengthening winds with height will support elongated hodographs with mild low-level curvature across the warm sector. Transient supercells should be the initial storm mode before storms grow upscale into a line (since the cold front will be roughly aligned with deep-layer westerly flow). During the supercell stage, large hail is possible, with 2+ inch diameter stones possible from southern AL westward given the elongated hodographs, steep lapse rates and near-saturation in the hail-embryo bearing layer. Farther east, both supercells and linear bowing segments will pose both a damaging gust and hail threat. However, a couple of tornadoes are also possible wherever buoyancy can overlap areas of relatively more backed low-level flow ahead of the cold front. Storms should gradually weaken through the evening as they progress into northern FL given weakening ascent/buoyancy. ...Squitieri.. 03/11/2023 $$ = = = 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) .