Day 1 Convective Outlook
Issued: · Valid: –
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000 ACUS01 KWNS 060101 SWODY1 SPC AC 060100 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 PM CDT Fri Jun 05 2026 Valid 060100Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE MID MISSOURI AND MID MISSISSIPPI VALLEYS... ...SUMMARY... Thunderstorms with large hail and severe wind gusts are expected this evening from parts of the central Plains into the mid Missouri and mid Mississippi Valleys. Isolated wind gusts and hail will also be possible in parts of the upper Mississippi Valley and western Great Lakes. ...Central Plains/Mid Missouri and Mid Mississippi Valleys... A mid-level shortwave trough is currently evident on water vapor imagery over the north-central U.S. The southern part of the trough extends southwestward into the central Plains. Ahead of this feature, a moist and unstable airmass is in place from southern Nebraska and northern Missouri northward into much of Iowa, where surface dewpoints are in the upper 60s and lower 70s F. Along the moist axis, the RAP currently has a pocket of strong instability centered over the mid Missouri Valley with MLCAPE in the 3000 to 4500 J/kg range. A front, where low-level convergence is maximized, is evident on surface analysis from northwest Iowa southwestward into south-central Nebraska. Thunderstorms have recently developed near the front in southeast Nebraska. These storms are expected to steadily increase in coverage this evening as the shortwave trough approaches. From southeast Nebraska into southern Iowa early this evening, RAP forecast soundings have 0-6 km shear in the 25 to 35 knot range with 700-500 mb lapse rates around 7 C/km. This environment will support supercells with large hail. Hailstones greater than 2 inches in diameter will be possible with the more dominant supercells...see MCD 992. Short-term model forecasts suggest that a cluster of strong to severe storms will organize during the evening. As this occurs, the wind-damage threat will likely increase. If a line segment can become intense, then wind gusts above 70 mph will be possible. The severe threat will gradually develop eastward across southern Iowa into northern Illinois from mid to late evening. An isolated severe threat may persist into the early overnight period. ...Upper Mississippi Valley/Western Great Lakes... A surface low is evident on surface analysis over northeast Wisconsin with a cold front extending southwestward across central and western Wisconsin. A line of strong thunderstorms is ongoing along the front. Ahead of the front, surface dewpoints in the mid to upper 60s F are contributing to moderate instability, with the RAP showing MLCAPE in the 1000 to 2500 J/kg range. Ahead of the front, the Green Bay and La Crosse WSR-88D VWPs have 0-6 km shear in the 25 to 35 knot range suggesting that deep-layer shear is strong enough for an isolated severe threat. The more organized multicells along the line could have potential for hail and isolated severe gusts for a couple more hours this evening. ..Broyles.. 06/06/2026 $$