Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Aug 23 2024 05:59:56 ACUS01 KWNS 230559 SWODY1 SPC AC 230558 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Fri Aug 23 2024 Valid 231200Z - 241200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF MT INTO THE INTERMOUNTAIN WEST/EASTERN GREAT BASIN...PARTS OF THE CENTRAL/NORTHERN HIGH PLAINS...AND SOUTHEAST AZ INTO EXTREME SOUTHWEST NM... ....SUMMARY... Strong to severe storms with severe gusts and possibly some hail are possible across Montana, the Intermountain West and central Rockies, southeast Arizona, and the central and northern High Plains. ....Synopsis... A seasonably deep mid/upper-level trough will persist over the West today. A strong embedded shortwave trough and attendant midlevel jet maximum will move quickly northeastward from the Great Basin into the interior Northwest/northern Rockies through the day. A surface low is forecast to deepen across western MT through the day, in conjunction with the passage of the shortwave trough. A weaker surface low may move gradually northeastward across the southern High Plains. Relatively rich low-level moisture will extend from TX/OK into the central/northern High Plains, while a plume of monsoonal moisture will persist from the Southwest/southern Rockies into eastern parts of the Great Basin. ....Parts of UT/western CO into the interior Northwest and western/central MT... Stronger ascent related to the ejecting shortwave trough over the interior Northwest may remain somewhat displaced from better moisture/instability through the day. However, it will likely aid in the development of scattered thunderstorms across a broad region from UT/western CO into parts of the Northwest/northern Rockies. The combination of relatively high-based convection and increasing low/midlevel flow will support a threat of at least isolated severe gusts across a broad region from the eastern Great Basin into parts of ID/MT. Steep lapse rates and sufficient deep-layer shear could also support an isolated hail threat, where sufficient pre-convective buoyancy can be realized. The Marginal Risk has been expanded across much of western/central MT, due to increased confidence in sufficiently deep convection to support a severe-wind threat. Portions of the Marginal Risk may eventually need greater wind probabilities, if confidence increases in one or more corridors where a greater coverage of severe gusts will be possible. Some severe-wind threat could also evolve west of the current Marginal across parts of OR/WA/western ID, in closer proximity to the shortwave trough, but confidence is lower at this time due to very limited forecast buoyancy in this area. ....Parts of the High Plains... Moderate to locally strong buoyancy is forecast to develop this afternoon across much of the High Plains, along/east of a wavy surface trough extending between the surface lows across MT and the southern High Plains. However, large-scale ascent will likely remain rather nebulous across this region, and the details of storm development and coverage remain uncertain. While midlevel flow will be somewhat weaker compared to areas farther west, it will remain sufficient to support effective shear of 30+ kt, conditionally supporting organized convection. Any sustained storms that can develop and be maintained during the afternoon/evening would pose a threat of isolated hail and severe gusts. ....Southeast AZ vicinity... Scattered thunderstorms are again expected across southeast AZ into adjacent southwest NM. A modest increase in midlevel flow could support somewhat more organized storms compared to Thursday. Moderate buoyancy and effective shear increasing into the 20-25 kt range will support a threat of localized strong/severe gusts and possibly some hail with the strongest storms. ...Dean.. 08/23/2024 $$ = = = 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) .