Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Sep 22 2025 16:27:12 ACUS01 KWNS 221627 SWODY1 SPC AC 221625 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 AM CDT Mon Sep 22 2025 Valid 221630Z - 231200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN/CENTRAL PLAINS...LOWER/MID MISSOURI VALLEY...AND OHIO VALLEY... ....SUMMARY... Scattered severe thunderstorms will be possible this afternoon into tonight across portions of the southern/central Plains, lower/mid Missouri Valley, and Ohio Valley. Large to very large hail and severe/damaging winds should be the main threats. ....Synopsis... Water-vapor imagery late this morning shows a mid- to upper-level low and associated troughing over the Upper Midwest to the north of a mid-level trough moving east across confluence of the OH-MS Rivers and into the OH Valley. Additionally, a minor disturbance is moving east across NE, a mid-level ridge extends from northern Mexico into the central High Plains, and larger-scale troughing persists over the West. ....Southern/Central Plains... Little change in the forecast scenario for mainly tonight across the central and southern Great Plains. A moist airmass characterized by 60s to lower 70s deg F dewpoints resides across OK northward into NE-IA. Initially flattened mid-level ridging/neutral height change will act to suppress thunderstorm development during the day and perhaps into the early evening across the Great Plains. However, a lead mid-level vort max ahead of the north-central Rockies trough, will move across the Sangre de Cristos into the central High Plains by early evening. The intensification of a southerly low-level jet this evening and associated moist advection to the east of a weak lee trough and surface low over the central High Plains, will favor scattered thunderstorms eventually developing over the central High Plains and in proximity to a frontal zone farther north in NE. Ample buoyancy per forecast soundings and an elongated upper portion of hodographs will support storm organization, including supercells. Large to very large hail is a possibility with supercells this evening into the early overnight over eastern NE and if cells can develop ahead of an evolving thunderstorm cluster/MCS over northern OK/southern KS. Severe gusts will likely become the primary hazard later tonight but a risk for a brief tornado could develop with the OK-KS activity given moist low levels and a linear mode. ....IA-WI... Isolated to scattered storms are forecast to form along a front in northern IA this afternoon/evening. With cool temperatures aloft and modestly steepened mid-level lapse rates, this activity could pose a threat for mainly severe hail given gradually strengthening westerly winds with height through mid/upper levels. ....Tennessee/Ohio Valleys to the Lower Great Lakes... A shortwave trough associated with ongoing convection over the Mid-South/lower OH Valley this morning will translate northeastward today across much of the OH Valley. Modestly enhanced southwesterly low/mid-level winds will exist this afternoon over this region, with 20-30 kt of deep-layer shear supporting mainly loosely organized multicells. Multiple clusters should develop and gradually strengthen through the afternoon as they spread northeastward across a weakly unstable airmass. Isolated to scattered damaging winds may occur with the more intense portion of these thunderstorm clusters. ....Far Eastern Arizona into New Mexico... Moisture remains limited this morning across eastern AZ and much of southern/central NM, with surface dewpoints generally ranging from the 40s to mid 50s. Westerly mid/upper-level flow across this region is expected to gradually strengthen through the day as an upper trough/low digs southward from the northern Rockies across the Great Basin and towards the Four Corners region by late tonight. A weak perturbation embedded within the mid-level westerly flow may aid initial convective development this afternoon across the higher terrain of east-central AZ and vicinity. This activity will spread eastward across much of central NM through the remainder of the afternoon and into the evening. While instability will likely remain weak owing to limited low-level moisture, steepened low-level lapse rates with daytime heating and moderate to strong deep-layer shear should promote outflow-dominant convection with an isolated threat for severe wind gusts. ...Smith/Wendt.. 09/22/2025 $$ = = = 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 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .