Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Aug 17 2024 07:29:37 ACUS03 KWNS 170729 SWODY3 SPC AC 170728 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Sat Aug 17 2024 Valid 191200Z - 201200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS FROM THE MID-ATLANTIC INTO NORTH CAROLINA...AND ACROSS PARTS OF THE CENTRAL AND NORTHERN HIGH PLAINS... ....SUMMARY... Thunderstorms, associated with a marginal severe threat, will be possible on Monday in parts of the Mid-Atlantic, North Carolina, and from the central to the northern High Plains. ....Mid-Atlantic/North Carolina... An upper-level trough will move slowly eastward across the southern and central Appalachians on Monday, as a cold front advances southeastward toward the middle Atlantic Coast. Surface dewpoints across most of the Mid-Atlantic into North Carolina are forecast to be in the 60s F, with 70+ surface dewpoints confined to the immediate Atlantic coast. As surface temperatures warm, a pocket of instability will likely develop near and ahead of the front, and in the post-frontal airmass. Scattered thunderstorms are expected to form within these areas as surface temperatures warm during the day. Although low-level lapse rates will become steep in many areas by afternoon, deep-layer shear is forecast to remain relatively weak. The instability could still be strong enough for a marginal severe threat. Isolated strong to severe wind gusts could occur near and around peak heating. ....Central to Northern High Plains... An upper-level ridge is forecast to move across the Central High Plains and northern Plains on Monday. An axis of instability will likely develop during the day to the west of the ridge, from eastern Colorado northward into eastern Montana and western North Dakota. Although large-scale ascent will be weak along this corridor, thunderstorms are expected to form in some areas due to topographical forcing in the central and northern Rockies. More isolated storms will be possible in the lower elevations of the central and northern High Plains. Forecast soundings across the central and northern High Plains have steep low to mid-level lapse rates and sufficient deep-layer shear for a marginal severe threat. Relatively large surface temperature-dewpoint spreads could enhance downdrafts associated with high-based storms. Hail could also accompany the stronger cells, especially further west near the higher terrain. ....Ark-La-Tex... North-northwesterly mid-level flow will be in place across the Ark-La-Tex on Monday. At the surface, a quasi-stationary front is forecast from northeast Texas into Louisiana, where surface dewpoints should be in the lower 70s F. As surface temperatures warm during the day, low-level lapse rates will become steep. This combined with moderate deep-layer shear may support an isolated severe threat. Although there is some uncertainty concerning convective coverage, the forecast environment should be enough for a few marginally severe storms. ...Broyles.. 08/17/2024 $$ = = = 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) .