SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Tue Sep 05 2023 Valid 060100Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE UPPER MS VALLEY AND WESTERN UPPER GREAT LAKES...AND FROM MO SOUTHWEST THROUGH CENTRAL OK... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening over parts of the upper Mississippi Valley/Lake Superior region, and across the Ozarks and parts of Oklahoma. Severe wind gusts and isolated large hail are possible. ...01Z Update... Recent surface analysis places a low near the central MN/WI border, with a cold front extending south-southwestward into northwest MO and then back more southwestward through far southeast KS and central OK into southwest TX. Thunderstorms have developed along the front from northwest MO into southwest TX, as well as farther north closer to the low across MN and WI. ...Upper MS Valley... Thunderstorm coverage is expected to increase over the next few hours as the front continues eastward into the moderate buoyancy in place downstream. Some additional development is also possible ahead of the front in an area of pre-frontal confluence. The strongest shear will remain over northern portions of the region, but widespread precipitation and limited buoyancy will likely limit overall storm strength in that region. However, large hail (1-1.75 in.) and damaging winds (50-60 mph) will remain possible farther south, where moderate buoyancy and vertical shear will be in place for the next several hours. ...Central MO...Southwest/Central/Eastern OK...Northwest TX... 00Z SGF sounding sampled strong buoyancy ahead of the approaching cold front. As such, thunderstorm coverage and intensity will likely increase across central and southern MO over the next few hours as the front moves through. Vertical shear is modest, but overall buoyancy is strong enough for robust updrafts. Hail is possible with any initial, more cellular development, with outflow-dominant storm structures then supporting upscale growth into one or more bowing segments capable of damaging gusts. Farther south, storms have already trended towards outflow-dominant structures, with most of the activity now well behind the outflow. Isolated development is possible along the outflow for the next hour or two, with an attendant threat for hail and damaging gusts. Post-outflow development will likely persist for the next few hours as well. Cooler temperatures and resulting limited buoyancy should keep these storms below severe thresholds. ..Mosier.. 09/06/2023
