Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Aug 31 2024 16:30:36 ACUS01 KWNS 311630 SWODY1 SPC AC 311629 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Sat Aug 31 2024 Valid 311630Z - 011200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL APPALACHIANS AND UPPER OHIO VALLEY... ....SUMMARY... Severe thunderstorms capable of producing mainly damaging winds will be possible today from parts of the central Appalachians into the Ohio and Tennessee Valleys. Isolated severe wind gusts may also occur across parts of the northern Great Lakes. ....Mid-Atlantic into the Ohio and Tennessee Valleys... A mid/upper-level trough will move eastward across Ontario/Quebec and the Great Lakes today while undergoing some amplification. Ahead of this feature, a surface front will move eastward over parts of the Northeast/Mid-Atlantic, and southeastward over the OH Valley before eventually stalling. A warm front will lift north through the period across the mid-Atlantic and northeast states. Late morning visible satellite imagery shows substantial low cloud cover over much of the Northeast and Mid-Atlantic. This will reduce daytime heating and delay destabilization, especially east of the Blue Ridge Mountains. However, with a moist low-level air mass in place, even modest diurnal heating will result in sufficient destabilization to support some risk for strong/severe storms. The stronger mid-level flow associated with the upper trough is expected to remain generally displaced to the north/west of the surface warm sector. Even so, modestly increasing west-southwesterly winds with height through mid levels should support around 20-30 kt of deep-layer shear across parts of the central Appalachians and upper OH Valley vicinity. This shear will be sufficient for loosely organized multicell clusters to develop or intensify and subsequently spread east-southeastward through this afternoon. Isolated to scattered damaging winds should be the main threat with this convection, although some hail may also occur with the strongest cells. Storms should gradually weaken with eastward extent by this evening across the Mid-Atlantic while encountering a less unstable air mass. Weaker deep-layer shear with southward extent into the lower OH Valley and TN Valley will likely limit overall thunderstorm organization. However, occasional damaging winds may still occur with thunderstorms along/south of the front as low-level lapse rates steepen. ....Northern Great Lakes... Strong west-northwesterly mid-level flow will exist over the Upper Midwest and northern Great Lakes in association with a shortwave trough embedded within a broader cyclonic flow. While low-level moisture and related instability are both expected to remain limited, large-scale ascent and strong deep-layer shear may support the development of low-topped thunderstorms this afternoon. If these thunderstorms can be sustained, then isolated strong to severe winds may occur given the forecast strength of the low to mid-level flow in the presence of steepened low-level lapse rates. ...Bunting/Jewell.. 08/31/2024 $$ = = = 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) .