Day 1 Convective Outlook
Issued: · Valid: –
Summary
Isolated strong to severe thunderstorms are possible tonight across the Great Basin, central Rockies, and Northern Plains, including parts of the Desert Southwest. These storms may bring damaging wind gusts or hail through the overnight hours.
Product Text
000 ACUS01 KWNS 290100 SWODY1 SPC AC 290058 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0758 PM CDT Fri Aug 28 2026 Valid 290100Z - 291200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE GREAT BASIN...TO THE CENTRAL ROCKIES AND NORTHERN PLAINS... ...SUMMARY... Isolated strong to severe storms are possible across the northern Plains, and from parts of the Great Basin and Desert Southwest into the Rockies. ...Great Basin/Rockies... Evening water vapor imagery showed an expansive area of high pressure centered over the Four Corners with broad southwesterly flow aloft ongoing over much of the Great Basin and Rockies. To the west of the ridge, an upper low and broad trough were moving onshore across the Pacific Northwest and CA respectively. Ahead of these features, several weaker perturbations and a plume of mid-level moisture were contributing to widely scattered thunderstorms over the Great Basin and central Rockies this evening. Despite limited buoyancy owing to expansive cloud cover, plentiful monsoon moisture should continue to support widely scattered high-based thunderstorms this evening and into the overnight hours. At least isolated strong to severe gusts are possible owing to dry low-levels suitable for strong downdrafts with the established storms/clusters. This appears most likely from far eastern NV, across northern UT, and into central WY where the air mass remains the warmest. ...Northern Plains... The first of the mid-level shortwave troughs embedded within the broader southwest flow are expected to eject eastward over the northern Plains tonight. As ascent from the wave overspreads a warm front, the low-level jet is forecast to strengthen (40-50 kt), supporting a broad area of low-level warm air advection across the eastern Dakotas into MN/IA. Elevated storms should develop near the front with moderate buoyancy and deep-layer shear supportive of supercells. Some hail risk is possible with these storms overnight. Given the increasing forcing for ascent, upscale growth into a cluster or MCS is possible, which could result in a low-probability risk for damaging gusts over southwest MN and adjacent northwest IA through 12z Saturday. ...Mid Atlantic to the Southeast... Several clusters of scattered thunderstorms remain ongoing ahead of a weak front from VA to the northern Gulf Coast. These storms have slowly weakened through the evening and should continue to do so with the loss of diurnal heating. Ahead of the front, high PWAT content (2-2.5 inches) may still support a sporadic downbursts with the stronger clusters this evening. However, weak shear and waning diurnal buoyancy suggest an organized or expansive severe threat is unlikely. ..Lyons.. 08/29/2026 $$