Area Forecast Discussion

KEY MESSAGES

-Fire Weather Watch continues for Sunday due to low relative humidity and strong, gusty winds.

-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 318 AM MDT Sat Jun 6 2026

An area of low pressure is moving through the Pacific Northwest and southwestern Canada this weekend which will bring a slow-moving cold front through eastern Idaho. This cold front will bring gusty winds, isolated virga showers/dry thunderstorms, and cooler temperatures for Sunday. The probability of these virga showers and isolated dry storms remains around 10 to 15 percent for much of the area, but does increase to closer to 20 percent the farther north and northeast you go, nearer to the Montana state line. With any virga showers, the potential is there for gusts around 45 mph. Even outside of any shower or storm activity, wind gusts will be around 20 to 35 mph with stronger gusts near 40 mph on ridge tops and out across the Arco desert/Mud Lake area. Highs today will be a couple of degrees cooler than yesterday, but still topping out around 80 degrees or so. Winds will be stronger on Sunday with more widespread gusts of 40 to 50 mph, so we will likely need a WIND ADVISORY for most of the Snake River Plain. In addition to the gusty winds, it remains quite dry overall, so the FIRE WEATHER WATCH remains in effect for Sunday at this point which will likely be converted into a RED FLAG WARNING by the day shift crew today. Highs drop quite a bit for Sunday with many of us not making it out of the 60s!

This system and cold front will be out of here by Monday and that will be a bit of a "break" in between systems for us. Highs will rebound into the 70s, dry conditions persist, and wind gusts return to a more "typical" 20-30 mph. Tuesday into Wednesday another low will move through the PNW and southwestern Canada to bring a better chance for measurable rainfall to much of eastern Idaho and drop afternoon highs into the 60s for Tuesday through Thursday. Winds will remain breezy through this time, too.

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 318 AM MDT Sat Jun 6 2026

A FIRE WEATHER WATCH remains in effect for fire weather zones 425 and 425 on Sunday at this point, but will most likely be upgraded to a RED FLAG WARNING later today. This is due to a slow-moving cold front that is passing through eastern Idaho this weekend and bringing strong, gusty winds. It will bring some isolated virga showers/dry thunderstorms this afternoon and into Sunday, but little to no liquid precipitation is expected out of any of this. Even min RHs are generally in the 15 to 25 percent range today, which means we will see NEAR CRITICAL fire weather conditions, but min RHs drop significantly on Sunday, in the 10 to 15 percent range for most of zones 425 and 427, hence the current headlines. Through parts of zones 410, 413, and 476 we will remain near critical on Sunday, too. With any isolated showers or storms we see today, there is the potential for gusts of around 45 mph. Even outside of any of this activity, it will be breezy with gusts of 30 to 40 mph in the Central Mountains and across the Arco desert. Strong wind gusts arrive on Sunday with more widespread gusts of 35 to nearly 50 mph in zones 410, 411, 425, 427, and 476. It's not until next Tuesday into Wednesday that we see the potential for more widespread wetting rains as a stronger system arrives.

PIH WATCHES / WARNINGS / ADVISORIES

Fire Weather Watch from Sunday morning through Sunday evening for IDZ425-427.