Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Oct 11 2023 04:55:56 ACUS01 KWNS 110455 SWODY1 SPC AC 110454 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1154 PM CDT Tue Oct 10 2023 Valid 111200Z - 121200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE COASTAL FLORIDA PANHANDLE AND WESTERN PENINSULA... ....SUMMARY... Strong to severe storms may threaten parts of the Florida Gulf Coast this evening and into tonight, with damaging gusts or brief tornadoes. A few storms may produce hail late in the day from eastern Nebraska into parts of Illinois. ....Synopsis... An upper trough will deepen over the West as an intense, cyclonically curved speed max noses east across the Four Corners area. The trough will move across CO overnight, with 60-80 kt midlevel winds and height falls into the central High Plains by 12Z Thursday. Meanwhile, an upper low will fill slightly as it drifts east out of Ontario and into Quebec, with moderate cyclonic flow aloft across the Great Lakes and Northeast. To the south, a southern-stream disturbance will develop northeastward across the Gulf of Mexico through the period, aiding thunderstorm potential. At the surface, low pressure will develop over the central High Plains during the day, with a warm front extending eastward roughly near the NE/KS border and toward the mid MS Valley at 00Z. A cool and stable air mass will exist north of this boundary, but southerly winds across the warm sector will aid destabilization along and north of the front. To the south, easterly surface winds over the eastern Gulf of Mexico and FL will veer through the period as low pressure and thunderstorm coverage increases to the west. Substantial southwest flow just off the surface will aid both moisture advection and low-level shear, with a possible severe risk developing late in day and overnight. ....Coastal FL Panhandle to the western FL Peninsula late... A surface ridge will remain entrenched across the Southeast, with axis from the lower MS valley into GA and SC. To the south, low pressure associated with widespread convection is expected to develop over the northern Gulf of Mexico, and may approach the coastal FL Panhandle by 12Z Thursday. This steepening pressure gradient will result in strong low-level shear over the area, with SRH also increasing into the Tampa Bay area overnight. The quality of the boundary layer will increase throughout the night as shear increases, with a conditional risk of a few supercells possibly affecting land prior to 12Z Thursday. Widespread rain and elevated thunderstorms may hamper surface-based instability over northern parts of FL, but any storms that threaten coastal areas may produce brief tornadoes or damaging gusts. ....Eastern NE into IA...IL...and northern MO... Scattered showers and thunderstorms may be present over northeast MO, southern IA and western IL north of the surface warm front this morning. Weak instability at that time should preclude much of a severe risk. Later in the day, heating will occur over the warm sector, with the temperature gradient near the front tightening as it eventually becomes stationary. Winds around 850 mb are forecast to become diffluent late in the day and overnight, as flow over the Plains backs and responds to the approaching upper trough and surface low. Still, lift along the boundary and influx of warmer air from the south may still yield a band of convection, with isolated, marginally severe hail from eastern NE into northern IL. Cool temperatures aloft and elongated hodographs in the mid to high levels may further support marginal hail. ...Jewell/Weinman.. 10/11/2023 $$ = = = 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) .