Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Jul 01 2023 06:02:26 ACUS01 KWNS 010602 SWODY1 SPC AC 010600 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sat Jul 01 2023 Valid 011200Z - 021200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN MISSOURI...CENTRAL AND SOUTHERN ILLINOIS...WESTERN INDIANA AND WESTERN KENTUCKY... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF SOUTHEAST NM INTO WEST TX... ....SUMMARY... Severe thunderstorms are possible today from the central and southern Appalachians region westward through the Ohio/Tennessee Valleys into the mid-Mississippi Valley. Severe winds gusts, hail, and a tornado or two will all be possible. ....Mid MS Valley into parts of the OH Valley and central Appalachians... An active severe-weather day appears possible from parts of the mid MS Valley into the OH Valley, as a mid/upper-level trough moves eastward and impinges upon a moist and favorably unstable environment. However, the details remain uncertain, due to the influence of rather extensive morning convection on the position of an outflow-reinforced surface boundary, and northward extent of the stronger diurnal destabilization. In general, morning storms could pose an isolated hail and wind-damage threat across parts of the OH Valley, and potentially farther west into eastern portions of the central Great Plains. An increase in storm coverage and intensity is expected during the afternoon, including the potential for organized surface-based development in areas where stronger diurnal heating/destabilization can occur. Moderate southwesterly midlevel flow will generally support 30-35 kt of effective shear (potentially higher near any remnant surface boundaries), with organized clusters and a few marginal supercells possible. Instability will be sufficient to support a hail threat with any discrete or clustered cells. A tornado or two will also be possible if any supercells can be sustained, especially near any remnant boundaries. A tendency toward upscale growth is expected with time, but it remains unclear if a larger-scale MCS will develop, or if multiple smaller-scale clusters will move across the region. In either scenario, swaths of damaging wind will be possible this afternoon and evening. Convection will eventually spread east of the more favorable instability, but some threat could spread into the upper OH Valley and central Appalachians this evening before substantially weakening. ....TN Valley into parts of the Southeast/Carolinas/Virginia... A somewhat separate area of storm development will be possible across parts of the TN Valley into the southern Appalachians, potentially near the remnant outflow from morning convection to the north. Deep-layer shear will be increasingly marginal with southward extent, but a few stronger outflow-driven clusters could eventually spread into parts of the Southeast, Carolinas, and Virginia with a threat of locally damaging gusts. ....Parts of the Northeast... Increasing low-level moisture will support potentially moderate buoyancy this afternoon across parts of the Northeast, and scattered thunderstorm development will be possible along/ahead of a weak surface trough. Weak low/midlevel flow and poor midlevel lapse rates should generally limit the severe threat, but stronger upper-level flow may help to support a few weakly organized cells/clusters capable of locally damaging gusts and/or marginal hail. ....TX Trans Pecos/Permian Basin region... Moderate to locally strong buoyancy may develop across parts of the TX Permian Basin and Trans-Pecos regions this afternoon, and scattered thunderstorm development will be possible near an outflow-reinforced front, and also across the higher terrain. Deep-layer shear will generally be rather weak, though somewhat stronger shear will be possible near and immediately north of the surface boundary. A few stronger cells/clusters will be possible, with a threat of hail and localized severe gusts. ...Dean/Weinman.. 07/01/2023 $$ = = = 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) .