Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Mar 30 2023 16:24:22 ACUS01 KWNS 301624 SWODY1 SPC AC 301622 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1122 AM CDT Thu Mar 30 2023 Valid 301630Z - 311200Z ....THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE CENTRAL AND SOUTHERN PLAINS... ....SUMMARY... Isolated severe thunderstorms are possible over parts of the Great Plains this afternoon and evening. ....Synopsis... A robust upper wave is evident in mid-morning water-vapor imagery slowly shifting to the southeast across central/southern CA. Ahead of this wave, a broad swath of 50+ knot 500 mb flow is slowly overspreading the central/southern Rockies and the western Plains. A southerly low-level flow regime is noted across the Plains with a plume of 50+ F dewpoints advecting poleward through the southern Plains. This moisture will continue to move north through the period as a surface low deepens across parts of western KS/NE amid continued height falls and the approach of an upper-level jet streak late this afternoon into tonight. Broad isentropic ascent over the southern Plains and more focused ascent in the vicinity of the synoptic warm front and deepening surface low over the central Plains will support isolated to severe thunderstorms this afternoon and evening. ....Southern Plains... Regional radar mosaics over the past few hours show a steady increase in stratiform clouds and precipitation across parts of southwest TX. This is indicative of a broad warm advection regime that is expected to spread northeast into northern TX, eastern OK, and adjacent areas of AR/MO later this afternoon/evening. While 12 UTC soundings from OUN and FWD show marginal mid-level lapse rates, differential warming in the 850-700 mb layer through the day will support increasing buoyancy adequate for deep convection. Effective shear will generally increase through the period and may support a few organized elevated thunderstorms capable of large hail across eastern OK into AR/MO. Further west across northwest TX and southwest OK, a diffuse lee trough/dryline is expected to sharpen through the day as the deepening cyclone over the central Plains aids in advecting high-quality moisture northward from south TX and southwest downslope flow increases out of eastern NM. Initially capped soundings across northwest TX may see adequate daytime heating through broken clouds to allow for mixed-layer parcels to reach their LFCs within a weak dryline circulation. While this threat is highly conditional, the thermodynamic and kinematic environment would be supportive of supercells with all associated hazards. ....Central Plains... Surface pressure falls on the order of 2-3 mb/3 hours are noted across NE/IA this morning in the vicinity of a weak surface low and diffuse warm frontal zone across south-central NE to central IA. Steep mid-level lapse rates noted in 12 UTC soundings across the High Plains will advect westward through the day. The combination of increasing moisture, steepening lapse rates, and increasing ascent along the warm front should be favorable for isolated to scattered elevated convection across central NE into southeast SD late this afternoon/evening. Elongating hodographs will feature sufficient deep-layer shear for organized convection with an associated hail threat. Additional convection is expected to overspread much of the Mid-West during the overnight hours within a strengthening warm advection regime. Strong cells in this regime may produce small hail, but less favorable buoyancy/deep-layer shear with eastward extent and the potential for numerous storm interactions casts uncertainty into the severe threat. ...Moore/Hart.. 03/30/2023 $$ = = = 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) .