Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Aug 24 2024 19:40:44 ACUS01 KWNS 241940 SWODY1 SPC AC 241938 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sat Aug 24 2024 Valid 242000Z - 251200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE FOUR CORNERS INTO THE CENTRAL HIGH PLAINS...ACROSS NORTHEAST MONTANA AND FAR NORTHWEST NORTH DAKOTA...AND WESTERN OKLAHOMA... ....SUMMARY... Strong to locally severe storms are possible today from the Four Corners region northeastward into the central High Plains, over northeast Montana/northwest North Dakota and also across western Oklahoma. ....20z Update... The primary change for this update was the removal of the Marginal risk area across southern Missouri/northern Arkansas. The ongoing MCS along the MO/AR border has shown a steady weakening trend over the past few hours in early all convective metrics (IR cloud top temperatures, lightning counts, maximum reflectivity, etc...). A sporadic strong updraft pulse or two will remain possible across northern AR given MLCAPE values between 1000-22000 J/kg, but the overall weakening trend is expected to continue as the MCS migrates closer to the center of an upper anti-cyclone where deep-layer wind shear is negligible. Elsewhere, the forecast remains on track with no changes required. See the previous discussion (below) for additional details. ...Moore.. 08/24/2024 ..PREV DISCUSSION... /ISSUED 1128 AM CDT Sat Aug 24 2024/ ....Northeast Montana/northwest North Dakota... Have introduced severe hail/wind probabilities for the potential of isolated severe thunderstorm development beginning potentially as early as late afternoon across northeast Montana, but more likely this evening across the region. This development is possible along/behind a surface wave and eastward-moving front, where moderate buoyancy will coincide with strong shear through the cloud-bearing layer. ....Four Corners to Central High Plains... Widely scattered to scattered thunderstorms are expected by mid/late afternoon. Activity should move northward to northeastward over this corridor, with isolated severe gusts being the main concern, and hail near severe limits also possible over the High Plains. Effective shear will be modest (generally 30 kt or less), but enough cloud-layer shear for a few organized multicell storms, with a well-mixed sub-cloud layer supportive of strong/locally severe wind gusts. ....Southern Missouri/northern Arkansas... A linear convective cluster will continue to progress southward today. Deep-layer/low-level shear will remain weak, with the cluster tending to remain elevated to the east of the main reservoir of surface-based buoyancy and mid-level lapse rates. While some strong gusts and/or sub-severe hail could occur, the overall severe potential should remain isolated and relatively marginal in nature. ....Western/northern Oklahoma.... Isolated to widely scattered thunderstorms are possible by late afternoon through around sunset, with locally strong-severe microbursts possible. A surface moist/buoyancy axis will persist under and near the mid/upper high, with an effective dryline to its west across northwest Texas to northwest Oklahoma. Enough moisture should be present to support a minimally capped, deep, hot, well-mixed boundary layer with around 250-1000 J/kg MLCAPE and DCAPE values of 1000-2000 J/kg. $$ = = = 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) .