Subj : DAY1 2/5 Risk Plains To : All From : Mike Powell Date : Thu Apr 24 2025 08:15:00 ACUS01 KWNS 241231 SWODY1 SPC AC 241230 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0730 AM CDT Thu Apr 24 2025 Valid 241300Z - 251200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS... ....SUMMARY... Isolated to scattered severe thunderstorms are possible today and tonight across parts of the southern/central Plains. Large to very large hail and severe wind gusts may occur with this activity. ....Southern/Central Plains... Aided by modest low-level warm/moist advection, an expansive but slow-moving MCS has persisted through the early-morning hours across south-central OK into north-central TX. Isolated damaging winds may occur with this activity through the morning as it spreads southeastward across a moist but weakly unstable airmass. The potential for the MCS to either restrengthen, or for additional robust convection to develop along its outflow this afternoon remains rather uncertain. Even so, the downstream airmass should gradually destabilize through the day, and both damaging winds and hail may occur with the MCS if it can maintain surface-based inflow. Have therefore expanded the Marginal Risk eastward towards the ArkLaTex and east TX to account for this scenario. Greater severe probabilities may need to be considered if it becomes clear that the MCS will produce swaths of damaging winds later today. Otherwise, another day of isolated to widely scattered severe thunderstorms is forecast across the southern/central High Plains. A broad zone of modestly enhanced west-southwesterly mid-flow will persist across these regions though the period, with multiple convectively augmented vorticity maxima present. A front extending northeastward across KS from a weak low in far southeast CO, along with a dryline extending southward from the low across the southern High Plains, should once again help focus convective initiation later today. Even with multiple prior days of convection occurring, the northeastward advection of an EML over the Southwest will provide steepened mid-level lapse rates across the warm sector. Daytime heating of the moist low-level airmass, in concert with the steep lapse rates aloft, will support at least moderate instability along/south of the convectively reinforced front and east of the dryline by mid afternoon. While deep-layer shear should remain fairly modest, it will still be sufficient for organized updrafts. Current expectations are for isolated to widely scattered thunderstorms to form from parts of eastern CO (in a weak low-level upslope flow regime) into the OK/TX Panhandles and west TX along/east of the dryline. Similar to prior days, a mixed mode of supercells and multicells should occur, with large to very large hail possible with any slow-moving supercells. Severe/damaging winds may occur with any clusters that can develop through the evening, although this threat may tend to remain fairly isolated. A tornado or two also appears possible, especially with any sustained supercell this evening near the front/dryline intersection across southwest KS into the eastern OK/TX Panhandle vicinity. Based on extensive convection that occurred overnight across western KS, the northern extent of the Slight Risk has been adjusted some across the central Plains. ....Southeast Nebraska into Iowa... A convectively augmented/low-amplitude shortwave trough will move northeastward from parts of southeast NE into IA and vicinity today. Although low-level moisture should remain fairly limited, it is forecast to gradually increase along/south of a front by this afternoon. Any thunderstorms that can develop and spread northeastward could pose an isolated hail/wind threat given sufficient deep-layer shear for updraft organization. ...Gleason/Broyles.. 04/24/2025 $$ --- SBBSecho 3.20-Linux * Origin: ILink: CCO - capitolcityonline.net (454:3/105) .