Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jun 22 2023 06:02:34 ACUS02 KWNS 220602 SWODY2 SPC AC 220600 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Jun 22 2023 Valid 231200Z - 241200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN/CENTRAL HIGH PLAINS INTO PORTIONS OF THE CENTRAL/NORTHERN PLAINS... ....SUMMARY... Severe thunderstorms are expected across portions of the northern and central Plains on Friday. ....Synopsis... Upper ridging is expected to extend from the southern High Plains into the Upper Midwest early Friday morning. This ridging is forecast to shift eastward throughout the day, while also dampening under the influence of a shortwave trough moving from the Four Corners region into northern and central High Plains. This shortwave will be accompanied by enhanced mid-level flow, which will spread northeastward into the northern and central High Plains during evening and overnight. Farther east, a slow-moving upper trough will drift eastward across the eastern CONUS. A very moist air mass will likely be in place across the Plains ahead of the approaching shortwave trough. By the afternoon low 60s dewpoints will likely reach into SD, with mid 60s dewpoints across much of KS, and upper 60s dewpoints across the TX/OK Panhandles and OK. Low 70s dewpoints are expected across much of central and east TX into south-central OK. Diurnal heating within this very moist air mass will contribute to strong to very strong buoyancy and the potential for severe thunderstorms across the Plains. ....Eastern Wyoming into Nebraska and South Dakota... Dewpoints are expected to reach the low 60s across far eastern WY Friday afternoon. This low-level moisture beneath steep mid-level lapse rates will contribute to a very unstable environment across the region during the afternoon and evening. A lee surface low may develop across southeast WY, at the intersection of the deepening lee trough and stalled front. Mesoscale ascent in the vicinity of this low may result in isolated afternoon thunderstorm development before ascent attendant to the approaching shortwave reaches the area, and promotes additional storm development during the evening. 40 to 50 kt of 0-6 km bulk shear within this strongly unstable air mass will help support supercells, with very large hail as the primary threat. A tornado or two does appear possible, particularly if the low deepens enough to support enhanced southeasterly surface winds. Upscale growth into a linear convective system appears possible, with the stalled boundary potentially acting as a favored corridor for forward progression. However, guidance differs on the location and strength of the front, as well as the strength of the low-level jet, which limits predictability. ....Central/Southern High Plains... Large-scale forcing for ascent will likely be more subtle across the central and southern High Plains than farther north, but moderate to strong southwesterly flow across the region will still promote afternoon thunderstorm development. Thunderstorm development is anticipated across the high terrain over the region, as well as along the lee trough. Strong buoyancy and vertical shear will support robust updrafts capable of very large hail and strong downbursts with any mature convection. Some organization/upscale growth into one or more convective lines appears possible, with guidance indicating the most likely location for this organization is across the TX Panhandle. That being said, confidence in storm evolution and duration has limited predictability given the lack of stronger large-scale forcing for ascent. ...Mosier.. 06/22/2023 $$ = = = 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) .