South Dakota's Scorching Airmass Sparks 100 MPH Wind Threat — SevereWX

South Dakota's Scorching Airmass Sparks 100 MPH Wind Threat

Extreme heat is supercharging thunderstorms in south-central and southeast South Dakota, setting the stage for damaging wind gusts up to 100 mph this afternoon and evening.

The SPC's Mesoscale Discussion 1729 highlights a volatile setup: surface temps of 105-110°F, MLCAPE around 2000 J/kg, and steep lapse rates. Storms are firing on the edge of a mid-level cirrus deck ahead of a weak shortwave trough, with 50°F dewpoint depressions favoring outflow-dominant modes.

Coverage is increasing, and forecasters expect these to congeal into a mesoscale convective system (MCS). The hot, unstable airmass to the west clashes with moist air from the east, plus moderate shear, priming intense downdrafts. Peak gusts of 85-100 mph are most probable, with hail up to 1.25 inches possible.

A severe thunderstorm watch is 95% likely within 1-2 hours, and a Particularly Dangerous Situation (PDS) watch isn't off the table for the wind damage potential.

This comes amid broader Plains storm activity, but South Dakota's heat-fueled evolution stands out. Track updates via SPC and local NWS offices (FSD, ABR).

Stay prepared: Secure outdoor items, avoid flooded roads, and have a severe weather plan. Monitor radar and alerts closely this evening.