Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Jun 18 2023 20:01:22 ACUS01 KWNS 182001 SWODY1 SPC AC 181959 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sun Jun 18 2023 Valid 182000Z - 191200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY/SOUTHEAST... ....SUMMARY... Damaging winds, large hail, and a few tornadoes are expected this afternoon into tonight from the lower Mississippi Valley region to the east-central Gulf Coast. ....20Z Update... Convective evolution in the wake of thunderstorms this morning and early afternoon across southern AL and the FL Panhandle remains uncertain. A pronounced MCV and related mid-level circulation is clearly evident in visible satellite imagery across MO this afternoon. An outflow boundary from the morning/early afternoon convection is also draped from far east TX across LA into southern MS. This boundary may serve as a focus for renewed severe thunderstorm development this afternoon/evening, especially where it intersects a weak front in far east TX and vicinity. Have expanded the 10% significant hail area westward to include this region in the event a supercells can form and be sustained, as very large hail appears likely with any supercell given the very favorable thermodynamic and kinematic environment. Of potentially greater concern, multiple supercells may form closer to the MCV this evening across far eastern AR into northern/central MS. Both low-level and deep-layer shear appear very favorable for intense supercells capable of producing a few tornadoes, very large hail, and severe/damaging winds. The primary uncertainty remains convective coverage, as destabilization in the wake of earlier activity is still occurring. Based on recent observational and short-term guidance trends (RAP/HRRR, etc..), have adjusted the eastern extent of the Enhanced Risk, and expanded the 5% tornado area to include more of MS, far southwest TN, and western AL. ...Gleason.. 06/18/2023 ..PREV DISCUSSION... /ISSUED 1129 AM CDT Sun Jun 18 2023/ ....AR/LA/MS/TN/AL... Widespread overnight and morning convection has overturned the air mass across much of the lower MS valley into AL. This leads to a very low-confidence forecast for later today and tonight. Morning model guidance shows wide diversity in where the corridors of highest risk of severe storms will develop, but several solutions continue to show potential. What appears to be the most likely scenario is shown by the morning NAM and recent runs of the RAP/HRRR. This suggests storms will redevelop this afternoon over parts of AR and track eastward into portions of TN/MS/AL. This area will see substantial heating by mid-afternoon as clearing arrives from the west. Forecast soundings in this area show a strengthening low-level jet by late-afternoon, promoting supercell and bowing structures capable of damaging winds, large hail, and a few tornadoes. ....Southern AL to FL Panhandle Today... Multiple clusters of strong/severe storms are ongoing early this afternoon over parts of southern AL and southeast MS. The air mass ahead of these storms is becoming very unstable with dewpoints in the 70s and temperatures warming through the 80s. This is near the core of a 40-50 knot mid level jet max, providing sufficient shear for organized multicell and supercell storm structures. There is uncertainty how this activity will evolve through the afternoon, but they could persist/intensity and track across much of southern AL and the FL Panhandle with a risk of damaging wind gusts and large hail. ....East TX... Several morning CAM solutions show at least isolated intense storms forming along a surface boundary extending across northeast TX. Given the ample moisture/CAPE in this area, have extended the SLGT risk farther west. $$ = = = 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) .