Western Dakotas Heat Ignites 70 MPH Outflow Gust Potential — SevereWX

Thunderstorms are ramping up across the high terrain of eastern Montana and northeastern Wyoming, poised to deliver clusters of damaging winds into the western Dakotas this afternoon and evening.

The Storm Prediction Center's Mesoscale Discussion 1797 highlights a 60% chance of a severe thunderstorm watch as coverage increases and storms push eastward. Current activity includes gusts to 57 mph in eastern North Dakota, with new development expected downstream.

Western Dakotas are baking under upper 90s to 100°F heat, paired with dewpoints in the upper 50s to 60s°F. Strong capping (MLCIN) is eroding under sunny skies, unlocking moderate instability and steep low-level lapse rates of 7-8°C/km. SPC mesoanalysis points to dry sub-cloud layers that could amplify downdraft gusts to 55-70 mph in organized clusters. Hail up to 1.25 inches is also possible.

Soundings from Bismarck (BIS) and Rapid City (UNR) confirm the volatile setup, with guidance signaling eastward propagation through late afternoon.

Impacts: Expect scattered severe gusts, potentially stronger in storm clusters, impacting travel, power lines, and outdoor activities across eastern Montana, northeastern Wyoming, and western Dakotas (including western North and South Dakota).

Stay weather-aware this evening. Monitor local NWS updates, have a severe weather plan, secure outdoor items, and seek shelter if storms approach.