Area Forecast Discussion

KEY MESSAGES

- Breezy through tomorrow, with critical fire weather conditions and impacts to travel and boaters on American Falls Reservoir

- Isolated virga showers and mostly dry storms through the weekend.

- Better chance for widespread showers and storms Tuesday into Wednesday along with much cooler temperatures

DISCUSSION

Issued at 1232 PM MDT Sat Jun 6 2026

As expected, a band of virga/sprinkles has developed and continues to slide east this afternoon. We are also expected isolated virga showers to develop across the central mountains through the rest of the afternoon. The band, however, continues to slide east through tonight with the potential for a few thunderstorms. The HREF and REFS indicate a 10-50% chance of gusts over 35 mph with gusts possibly reaching 45-50 mph. Outside of storms, it will be breezy with gusts of 20-40 mph possible across all of central and eastern Idaho. We MIGHT briefly reach WIND ADVISORY criteria across the INL, but certainly not enough of an impact to issue an advisory for this afternoon. For tonight and Sunday, in terms of precipitation, showers and even a few lightning strikes are possible across the central mountains closer to the Montana border, eastern and southeast highlands. We should see precipitation ending during the afternoon as the low pivots away and a fairly substantial dry slot moves into central and eastern Idaho. As the low moves through, we will see wind ramp up overnight and through most of tomorrow, with the strongest from sunrise through mid to late afternoon. Gusts across the Snake Plain, Magic Valley, central mountains and eastern highlands, will be gusting 30-50 mph with some higher gusts possible especially for the Snake Plain. We went ahead and issued a WIND ADVISORY for the Snake Plain and Magic Valley, up through Monida Pass and Island Park.

We should see a break Monday, with an increasing chance of showers and storms midweek. What once looked like a slow moving closed low across the area is trending toward a faster-moving system. While showers and storms are still expected, it seems the pattern remains more breezy and also temperatures NOT QUITE AS COLD, although still BELOW AVERAGE by a few degrees.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1121 AM MDT Sat Jun 6 2026

Shortwave axis working into East Idaho for today and tonight is continuing to produce unsettled conditions across the region. Winds have increased to 15-20kts sustained across the Snake Plain, and band of high altitude convection is apparent on radar, likely producing virga and contributing to isolated gusty outflows. There is still potential for isolated high-based SHRA/TSRA with gusts 40-45kts until around 03-04z this evening. Activity continues at DIJ through the overnight. Winds decrease during the overnight, but ramp up significantly between 10-14z Sunday into the 20-25kt range for IDA, PIH and BYI. Daytime cross winds are expected at SUN both days, generally around 15g25kts.

FIRE WEATHER

Issued at 1232 PM MDT Sat Jun 6 2026

Isolated virga and thunderstorms are expected at some point across most if not all of central and eastern Idaho through Sunday. A band has developed, as expected, from near Monida Pass southwest through the area of the Summit Creek Fire. This band will continue to shift east through this evening. We are also expecting a few showers and storms to move in from Utah. For tonight and Sunday, light showers will continue across portions of Zone 475 and 476 in the central mountains, Zone 411, and areas of 413 closer to the Wyoming border. We cannot rule out a few lightning strikes overnight as the models indicate a 10-15% potential remaining in place. There is also a 10-50% possibility of gusts over 35 mph and possibly 45-50 mph with any "shower" or storm through the overnight hours. This should clear the state by mid to late afternoon. The other issue Sunday will be stronger wind gusts developing before sunrise and continuing through most of the day, along with a substantial dry slot moving through. Gusts of 30-50 mph, and possibly a bit higher across the Snake Plain, are forecast for the Snake Plain (410), Magic Valley (425), Zone 476 in the central mountains, the South Hills and Albion Mountains (427), Zone 422 near the end of the Wood River Valley, and Zone 411. Based on coordination, we are upgrading to a RED FLAG WARNING for Zones 425 and 427. We should see a break Monday, followed by an increasing chance of showers (with wetting rains) and thunderstorms midweek.

PIH WATCHES / WARNINGS / ADVISORIES

Wind Advisory from 6 AM to 9 PM MDT Sunday for IDZ051>055-066- 067. Red Flag Warning from 9 AM to 9 PM MDT Sunday for IDZ425-427.