TL;DR
The Storm Prediction Center has issued a Marginal Risk for isolated severe thunderstorms across portions of Montana this afternoon and evening. The primary hazard is isolated damaging wind gusts. Storms should remain disorganized, with the strongest activity expected between 2pm and 7pm local time in affected areas.
Where is the highest risk today?
The Marginal Risk—the lowest tier on the SPC's five-level scale—covers Montana today:
Montana: Portions of southwest and central Montana face a Marginal Risk for high-based thunderstorms capable of producing occasional strong to severe wind gusts through the early evening.
No tornado or severe thunderstorm watches are currently active nationwide.
What's driving today's weather?
Montana setup
Mid- and upper-level ridging will extend from the southern and central Rockies to the northern Plains and Upper Midwest through the period, with a belt of enhanced southwesterly mid-level flow over western and central Montana.
High-based thunderstorms may develop this afternoon across parts of southwest into central Montana amid a deeply mixed boundary layer. While low-level moisture and related instability are both expected to remain limited, the SPC warns that "some risk for occasional strong to severe gusts may accompany this convection as it spreads northward through the early evening before weakening."
When will the storms hit?
Montana: High-based storms should develop this afternoon across southwest and central Montana, spreading northward through the early evening before weakening. Peak activity is expected between 2pm and 7pm Mountain Time.
What happened yesterday?
Sunday saw widespread wind damage but no tornadoes. The SPC received 113 wind reports and 3 hail reports across 11 states, with the bulk of the activity concentrated in the Southeast.
In Michigan, golf ball-sized hail was reported in two locations—Malone Bay and Herman—during the afternoon hours.
No tornado reports were received in the last 24 hours.
Tomorrow's outlook
The SPC Day 2 outlook shows an Enhanced Risk—the third of five severity levels—developing for portions of Montana and New York on Tuesday. This represents an uptick in severe weather potential compared to today's Marginal Risk, with better wind shear and instability parameters expected in those regions.
If you're in the Enhanced Risk area for Tuesday, monitor updates from the SPC and your local National Weather Service office throughout the day Monday.
Staying weather-aware this week
Marginal Risk days like today rarely produce widespread severe weather, but isolated strong to severe storms can still cause localized damage. If you're in Montana, keep an eye on radar this afternoon and evening, especially if you hear thunder nearby.
The National Weather Service will issue severe thunderstorm warnings for individual storms that meet warning criteria. Third-party weather apps are silenced by Do Not Disturb, though Wireless Emergency Alerts for severe thunderstorm warnings still break through on most phones by default.
VORTEX is a free web app at vortexintel.app that monitors severe weather nationwide. Pro ($4.99/month) places phone calls to your phone when a tornado or flash flood warning is issued for a location you care about — calls can ring through Do Not Disturb once you enable Emergency Bypass for the number, unlike most third-party app notifications.