Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Mar 30 2023 17:33:51 ACUS02 KWNS 301733 SWODY2 SPC AC 301732 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1232 PM CDT Thu Mar 30 2023 Valid 311200Z - 011200Z ....THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN IOWA INTO NORTHWEST ILLINOIS AND FAR NORTHEAST MISSOURI...AND ALSO ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...EXTREME WESTERN KENTUCKY...WESTERN TENNESSEE...AND FAR NORTHWEST MISSISSIPPI... ....SUMMARY... Intense and widespread severe thunderstorms are expected Friday afternoon into the overnight hours across portions of the Middle Mississippi Valley and Mid-South vicinity, eastward to the Lower Ohio and Tennessee Valleys. Intense, damaging gusts and several tornadoes (some strong and long-track) are expected. ....A regional outbreak of severe storms is expected on Friday across parts of the Mid-Mississippi Valley and also into the Mid-South... ....Synopsis... A deep mid/upper-level trough and attendant 100 kt midlevel jet will move quickly eastward from the central Plains into parts of the MS Valley and Midwest on Friday. A surface low will deepen as it moves across IA toward the Great Lakes region, as a cold front sweeps eastward through parts of the Great Plains into the mid-MS Valley. In advance of the cold front, low-level moisture will stream northward across a broad warm sector from the ArkLaTex region into parts of the lower/mid MS Valley and Midwest. ....Mid-MS Valley vicinity into IN/lower MI... Rapid destabilization and increasing large-scale ascent will support thunderstorm development by early/mid afternoon across parts of IA into northern MO. Very strong deep-layer shear (effective shear in excess of 60 kt) and MLCAPE increasing to 1000-1500 J/kg (locally greater) will support organized convection, with initial supercell development expected somewhere over central IA into north-central MO. Very large hail will be the initial threat, given steep midlevel lapse rates and cold temperatures aloft. Some uncertainty remains regarding the convective mode evolution with time, but a few semi-discrete supercells are expected to move into an environment with stronger low-level shear/SRH across eastern IA into northwest IL by late afternoon, posing a threat for a couple strong tornadoes. Evolution into small clusters or bowing segments is expected, resulting in an increasing threat of severe/damaging winds in addition to a continued threat of a few tornadoes and sporadic hail. Organized convection will spread eastward into parts of IN/southern MI Friday night. Instability will weaken with eastward extent, but some threat for damaging wind and a couple of tornadoes will persist before a more definitive weakening trend occurs overnight into early Saturday morning. ....ArkLaTex/Mid South vicinity into the TN/lower OH Valleys... A concerning scenario still appears possible across portions of the MO Bootheel, northeast AR, western TN/KY and far northwest MS vicinity during the afternoon/evening. At least mid-60s F dewpoints are expected beneath modest midlevel lapse rates. This will support 1500-2000 J/kg MLCAPE amid intense vertical shear. Forecast soundings indicate 0-1 km SRH increasing to around 400 m2/s2 by early afternoon. Thunderstorms are expected to develop by early afternoon ahead of the cold front within a pre-frontal trough/low-level confluence zone. Storm motion near 50 kt with supercell wind profiles will support cells capable of significant and long-track tornadoes. With time, upscale growth into a QLCS is expected, and intense wind gusts will be possible in addition to mesovortex tornadoes. The threat for damaging gusts and a few line-embedded tornadoes will spread into parts of the TN and lower OH Valleys Friday night, with a gradual weakening trend eventually expected overnight as storms move into increasingly weak buoyancy with eastward extent. ...Dean.. 03/30/2023 $$ = = = 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) .