Day 1 Convective Outlook

This product has been superseded. View the updated product →

Issued: 2026-09-08 19:49 UTC  ·  Valid: 2026-09-08 20:00 – 2026-09-09 12:00 UTC

Summary

Severe thunderstorms capable of producing damaging wind gusts are possible across southeast Nebraska and parts of Iowa this afternoon and evening. Some scattered showers and thunderstorms with gusty winds may also occur across eastern Colorado into western and central Kansas.

Product Text

000 ACUS01 KWNS 081949 SWODY1 SPC AC 081947 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0247 PM CDT Tue Sep 08 2026 Valid 082000Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM SOUTHEAST NEBRASKA ACROSS PARTS OF IOWA... ...SUMMARY... A few severe storms capable of mainly severe wind gusts appear possible across portions of Iowa and eastern Nebraska this afternoon and evening. ...20Z Update... The ongoing forecast remains on track and no changes are needed. ..Wendt.. 09/08/2026 .PREV DISCUSSION... /ISSUED 1115 AM CDT Tue Sep 08 2026/ ...NE/IA... A broad upper ridge remains over much of the central/southern US, with moderately strong westerly flow over the northern tier of states. A baroclinic zone extends across southern NE into central IA. This feature will be sharpened by differential heating through the day, and will be the focus for afternoon and evening thunderstorm development. The strongest cells will be near a 20-30 knot southwesterly low-level jet where warm advection and lift will aid in convective initiation. Sufficient deep-layer shear will promote supercell and eventual bowing structures, with damaging winds be the main concern. Most CAM solutions suggest the majority of convection will be just north of the surface boundary, which may limit the overall severe threat. Also, weak mid-level lapse rates and warm temperatures aloft will tend to diminish the hail risk. ...CO/KS... Farther southwest, hot surface conditions will result in a deeply mixed boundary layer. Scattered high-based showers and thunderstorms are expected to form from eastern CO into western/central KS, with gusty and occasionally damaging wind gusts possible. $$