Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jul 29 2024 17:36:39 ACUS02 KWNS 291736 SWODY2 SPC AC 291734 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1234 PM CDT Mon Jul 29 2024 Valid 301200Z - 311200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY AS WELL AS ACROSS THE CENTRAL DAKOTAS... ....SUMMARY... Scattered strong to severe storms will be possible across a broad region from the northern Plains to the Midwest, Ohio Valley, and Carolinas. A more concentrated severe threat is possible across portions of the Middle Mississippi Valley as well as across the central Dakotas. ....Synopsis... Upper ridging is forecast to remain centered over the southern Plains on Tuesday, with moderate westerly flow aloft extended throughout much of the northern third of the CONUS. Several shortwave troughs will be embedded within these westerlies, the strongest of which is expected to be the shortwave progressing across the northern Rockies and into the northern High Plains. Another shortwave trough is expected to begin the period in the MN vicinity, before progressing east-southeastward through WI and the Mid MS Valley into Upper Great Lakes and lower/middle OH Valley. Yet another shortwave trough is forecast to track slowly northeastward across the upper OH Valley. At the surface, a broad area of low pressure is expected to remain over the Plains, with a moist airmass covering the central and eastern CONUS to its east. The surface pattern will likely be free of notable synoptic features, although a weak frontal zone, demarcated predominantly by a wind shift, may extend from a weak low near the northern IN/OH border southwestward into southern IL and then back northwestward with a more warm-front-like character through IA to another low in the SD/IA/MN border intersection vicinity. Sharpening and/or progression of these boundaries will depend largely on convective evolution of antecedent showers and thunderstorms, leading to low forecast confidence. Two, potentially three, convective clusters could be ongoing early Tuesday, including one in the northern/central IA vicinity, which could then progress into a very moist and buoyant airmass downstream while also interacting with the warm front. ....Mid MS Valley into the Lower OH and TN Valleys... As mentioned in the synopsis, thunderstorms will likely be ongoing over the region Tuesday morning, likely in the northern/central IA vicinity. Guidance varies on how these storms evolve, with much of the CAM guidance suggesting the early storms weaken before then restrengthening during the afternoon as the strongly buoyant airmass downstream destabilizes. MLCAPE over 3000 J/kg is possible across the Lower OH Valley, supporting very strong updrafts capable of producing large hail. Shear will be modest, with most storms likely remaining multicellular and outflow dominant. Damaging gusts will be the primary risk with these storms. A supercell or two is still possible, with low potential for a tornado along the warm front. Another solution, which is offered by the NAM and ECMWF, suggests these storms have organized into a linear MCS, which then continues quickly southeastward, supported by the organized character of the line and ample downstream moisture and buoyancy. Damaging gusts would be the primary risk in this scenario, with a low-probability tornado risk as well. Significant wind gusts over 65 kt would be possible with the MCS solution, but forecast confidence is too low to introduce an area with this outlook. Additionally, overnight development is possible across IA amid warm-air advection supported by a moderate low-level jet. Given the uncertainty regarding the convection evolution throughout the day, the thermodynamic environment that will be in place Tuesday night is difficult to ascertain. There is some potential for preceding storms to be far enough east and/or south that strong to severe storms can be supported across IA overnight. ....Northern Plains... Weak height falls amid moderate to strong instability may lead to some thunderstorm development along a surface trough/dryline across the Dakotas Tuesday afternoon. The shortwave trough will remain west of the region, displacing the stronger mid-level flow to the west. Even so, moderate westerlies atop southeasterly surface wind should support moderate deep-layer vertical shear around 30 to 35 kt from 0-6 km. Strong buoyancy will likely be in place, with the resulting combination of shear and buoyancy supporting a few organized storms capable of both large hail and damaging gusts. A trend towards a more outflow-dominant character is anticipated with eastern extent, with damaging gusts becoming the most likely severe threat. ....Central Appalachians to the Carolinas... Showers and thunderstorms will likely be ongoing from WV into eastern TN early Tuesday morning. This storms (and associated outflow) should progress southeastward throughout the day, with additional development anticipated downstream across the western Carolinas (and potential northern GA) as the airmass destabilizes. Outflow-dominant storms could result in a few damaging gusts. ...Mosier.. 07/29/2024 $$ = = = 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) .