Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Feb 21 2023 19:46:13 ACUS01 KWNS 211946 SWODY1 SPC AC 211944 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0144 PM CST Tue Feb 21 2023 Valid 212000Z - 221200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE MID-ATLANTIC AND THE SOUTHERN PLAINS... ....SUMMARY... Isolated thunderstorms capable of locally damaging winds will be possible across parts of the Mid-Atlantic through late afternoon. Isolated severe wind and hail will be possible after 2 AM CST across a portion of western north Texas into central Oklahoma. ....20z Update... Isolated thunderstorms have developed across portions of the mid-Atlantic and northeast U.S. in advance of a cold front and in association with a mid-level shortwave trough. For additional details on short-term trends please refer to MCD 171 issued at 1901z. Otherwise, an eastward adjustment to the western edge of the 10 percent thunderstorm line was made based on current observations/trends. The previous outlook reasoning and risk area remains on track regarding development of thunderstorms late tonight over the southern Plains and the associated severe potential. ...Bunting.. 02/21/2023 ..PREV DISCUSSION... /ISSUED 0127 PM CST Tue Feb 21 2023/ ....Mid-Atlantic States... A low-amplitude shortwave trough over southern Ontario and the Lower Great Lakes will continue east-northeastward toward New England tonight. Boundary layer moisture will remain limited within the post-coastal frontal environment, but cloud breaks/moderate heating and 40s F surface dewpoints will lead to weak destabilization early this afternoon. This could allow for the development of some low-topped thunderstorms (less than 25k ft) across eastern Pennsylvania to New Jersey and the Delmarva vicinity. A few storms could produce small hail this afternoon along with strong/convectively enhanced wind gusts, particularly given the strength of the background west-southwesterly low/mid-tropospheric winds. ....Southern Great Plains... Influenced by a southern-stream low-latitude trough that will reach eastern New Mexico/far west Texas tonight, late-day lee cyclogenesis and a strengthening of southerly low-level winds will influence additional moistening across the region. Initially modest moisture and residual capping will likely preclude thunderstorm development until later tonight. A narrow corridor of meager boundary-layer destabilization with MLCAPE of 250-500 J/kg is anticipated to evolve late tonight and early Wednesday ahead of a sharpening cold front ejecting eastward from the High Plains. Strengthening forcing for ascent downstream of an elongated shortwave trough over the southern High Plains will support increasing convective development, especially in the 09-12Z time frame. A few instances of severe hail and/or wind may occur across southwest/central Oklahoma and western North Texas. ....East-central Illinois to southwest Ohio... Elevated convection is expected to develop late tonight/early Wednesday amid strengthening lower-level warm theta-e advection. Most of this activity should occur within scant elevated buoyancy, but strong speed shear through the cloud-bearing layer may support small hail in the more robust updrafts. $$ = = = 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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .