Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Aug 12 2024 20:01:30 ACUS01 KWNS 122001 SWODY1 SPC AC 122000 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Mon Aug 12 2024 Valid 122000Z - 131200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE COASTAL CAROLINAS...CENTRAL HIGH PLAINS...EASTERN GREAT BASIN NORTHWARD INTO PARTS OF THE NORTH-CENTRAL ROCKIES...AND NORTHERN MONTANA... ....SUMMARY... Isolated severe thunderstorms are possible today over parts of the coastal Carolinas, central High Plains, the eastern Great Basin northward into parts of the north-central Rockies, and northern Montana. ....20z Update... No changes are needed to the Day 1 Outlook. Marginal risk for strong to severe gusts and large hail will continue through the afternoon across the central High Plains/Central Plains as well as the Intermountain West into the northern High Plains. See MCD#1186 and MCD#1885 for more information. Additional thunderstorm development is expected across a front portions of South Carolina this afternoon. Ahead of this boundary, the air mass has destabilized, with around 2000 J/kg of MLCAPE and 20-30 kts of deep layer shear. Thunderstorms will be capable of instances of strong to severe wind. ...Thornton/Mosier.. 08/12/2024 ..PREV DISCUSSION... /ISSUED 1129 AM CDT Mon Aug 12 2024/ ....Central High Plains/Central Plains... Upslope flow will persist across the central High Plains, helping to maintain moderate low-level moisture across region. Afternoon dewpoints are expected to range from the upper 60s in the southeast CO/northeast NM/western Panhandles vicinity to the mid to upper 50s across eastern WY. This low-level moisture will help support moderate buoyancy during the afternoon/evening, although some limited capping may linger. Thunderstorms are expected to develop across the higher terrain before then progressing eastward into the more moist and buoyant airmass downstream. Generally moderate deep-layer vertical shear coupled with the potential for some remaining convective inhibition suggest the severe potential will remain isolated, with damaging gusts and/or large hail as the primary severe risks. Thunderstorms will likely persist eastward into more of the central Plains, supported by moderate buoyancy and shear and the development of modest low-level jet. Isolated instances of large hail are possible, but the overall storm severity will likely be tempered by limited instability. ....Intermountain West into the Northern High Plains... Morning satellite imagery depicts upper ridging centered over TX covering much of the southern third of the CONUS and also extending northward into MT. Several shortwave troughs are moving through the westerlies within the northern periphery of this ridging, including a low-amplitude shortwave currently moving into ID and northern/central NV and another, more defined shortwave farther west off the northern CA coast. Eastward/northeastward progression of these waves will bring greater mid-level moisture and increased large-scale forcing for ascent, supporting the development of scattered to numerous thunderstorms across the region. Mid-level flow will remain modest, but a few more organized/persistent updrafts are possible. High cloud bases atop steep low-level lapse rates could result in a few stronger gusts as these more persistent storms form into clusters, particularly from northern/central UT into far eastern ID and far western WY and northern MT. ....Coastal Carolinas... Far southern periphery of an upper trough currently extending from Quebec through the Upper OH Valley will glance this region today as it progresses eastward. Modest (i.e. 20-30kt) mid-level flow will overspread a moisture-rich airmass (i.e. PWs over 2") in place south of a front. Scattered thunderstorms should develop along this boundary by early afternoon then propagate toward and off the coast by early evening. A few water-loaded downbursts capable of damaging gusts could be noted with the strongest storms. $$ = = = 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) .