Day 3 Convective Outlook

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Issued: 2026-09-09 19:32 UTC  ·  Valid: 2026-09-11 12:00 – 2026-09-12 12:00 UTC

Summary

Severe thunderstorms are possible across eastern South Dakota, western Minnesota, and central Nebraska from late Friday afternoon through Friday night. These storms may produce large hail, brief tornadoes, and damaging winds.

Product Text

000 ACUS03 KWNS 091932 SWODY3 SPC AC 091930 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Wed Sep 09 2026 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN SOUTH DAKOTA INTO MUCH OF WESTERN MINNESOTA...AND INTO CENTRAL NEBRASKA... ...SUMMARY... Severe thunderstorms are possible across portions of the Upper Midwest late Friday afternoon into Friday night. ...Discussion... A leading shortwave trough will move into the Northern Plains on Friday, as an upper low drops south along the Pacific Northwest. A pre-frontal trough will develop into northern MN, extending into eastern SD and central NE by late afternoon. Ahead of this trough, strong heating will occur from NE into SD, with a cooler boundary layer into central MN. Temperatures aloft will cool with the upper wave, resulting in moderately steep lapse rates aloft. Midlevel wind speeds of 20-40 kt, combined with low-level southerlies (including 40 kt at 850 mb late in the day) will favor a few supercells initially before storms become linear along the advancing cold front. Forecast soundings indicate large hail will be likely with the initial cellular activity, though shear in the mid to upper levels will not be particularly strong. As such, will not add any sig hatching for hail. A brief tornado may occur with initial supercells, particularly from eastern SD into western MN where low-level shear will be strongest. Otherwise, damaging winds will be possible through the evening as storms move northeast across MN. ..Jewell.. 09/09/2026 $$