Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Dec 28 2024 06:01:27 ACUS01 KWNS 280601 SWODY1 SPC AC 280559 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1159 PM CST Fri Dec 27 2024 Valid 281200Z - 291200Z ....THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FAR EAST TEXAS...LOUISIANA...CENTRAL AND SOUTHERN MISSISSIPPI...AND FAR WESTERN ALABAMA... ....SUMMARY... An outbreak of severe storms with tornadoes, wind damage, and large hail is expected today from parts of the southern Plains, eastward into the lower Mississippi Valley and central Gulf Coast states. Several long-track strong tornadoes are expected. ....Tornado Outbreak Likely This Afternoon and Evening Across the Lower Mississippi Valley and Central Gulf Coast States... A mid-level trough will move quickly eastward across the southern Plains today, as an associated mid-level jet moves through the base of the trough. A surface low will deepen across northeast Texas as a warm front advances northward into the Ark-La-Tex. Scattered thunderstorms will first develop near the surface low during the morning, as surface temperatures warm and as large-scale ascent rapidly increases due to the approaching system. Isolated large hail will be the initial severe threat across northeast Texas. The exit region of a 60 to 80 knot mid-level jet will overspread much of east Texas around midday, where more vigorous thunderstorms are expected to develop during the early afternoon. These storms will have potential to produce severe wind gusts, isolated large hail and tornadoes. A severe MCS appears likely to intensify and organize as this activity increases in coverage. Further to the east, an axis of maximized low-level moisture is expected to be in place during the early afternoon, oriented from southern Louisiana into western Mississippi. Surface dewpoints along and near the axis will be in the mid to upper 60s F. The moist axis will be aligned with a strengthening low-level jet. Scattered discrete cells are expected to initiate across the undisturbed moist sector during the afternoon, with several vigorous storms moving east-northeastward across the central Gulf Coast states. RAP forecast soundings near the exit region of the mid-level jet, from central Louisiana into central Mississippi, show steep mid-level lapse rates around 8 C/km, with 0-6 km shear in the 45 to 55 knot range. This environment will support supercell development, with a potential for strong tornadoes, wind damage and isolated large hail. Forecast soundings in the early to mid afternoon near the low-level jet from eastern Louisiana into south-central Mississippi show backed surface winds to the southeast, and increase 0-3 km storm-relatively helicity to around 300 m2/s2. This should be favorable for tornadic supercells. The low-level jet is forecast to move east-northeastward across the central Gulf Coast states in the mid to late afternoon. Supercells that can tap the higher surface dewpoints and stay within or near the axis of the low-level jet should be able to produce long-track EF3+ tornadoes, and several of these will be possible. The severe linear MCS further to the west, is expected to move quickly eastward across the lower Mississippi Valley during the afternoon, and will likely be accompanied with widespread severe wind gusts, with potential for gusts above 65 knots along the more intense part of the line. By early evening, this line of severe storms is expected to become the dominant feature across the region. Widespread wind damage is expected along the leading edge of the line from the central Gulf Coast states into southern parts of the Tennessee Valley. Tornadoes will be possible with embedded supercells within the line, and with line echo wave patterns that form. Due to the fast-moving mid-level trough, large-scale ascent is expected to support the severe linear MCS from the evening into the overnight. A potential for wind damage and tornadoes is expected to continue after midnight as the line moves across middle Tennessee and Alabama. The MCS with some severe potential, is expected to move into the southern Appalachians and northern to central Georgia by the end of the period. ...Broyles/Thornton.. 12/28/2024 $$ = = = 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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .