Dangerous fire weather conditions are expected Tuesday and Wednesday as temperatures approach 98 degrees, gusty winds reach 40 mph, and relative humidity values plummet to critically low levels across south-central Idaho.
Critical Fire Weather Conditions as temps ramp up to the upper 90s in Scott Dorval's video forecast
The heat will reach its peak on Tuesday with high temperatures in the mid to upper 90s across the lower Snake River Plain. A few sites could approach 100 degrees along the Idaho-Oregon border and around Hagerman. Winds will ramp up Tuesday afternoon, reaching 15 to 25 mph with gusts of 30 to 40 mph. A passing upper wave will bring a weak front across the area Tuesday night, with post-frontal winds maintaining breezy conditions along the Interstate 84 corridor through the night.
While Tuesday will be dry, even drier air will move in behind the front on Wednesday, with precipitable water values dropping to the 5th percentile. Winds will remain gusty across the Snake River Plain in response to a deepening surface low over eastern Idaho. Areas from Mountain Home to Twin Falls and Jerome will see gusts around 40 mph Wednesday afternoon and evening. The combination of dry and windy conditions will result in critical fire weather conditions in the south-central Snake River Plain. Wednesday will be 5 to 10 degrees cooler than Tuesday, though still about 5 degrees above normal.
As the high-pressure ridge builds, temperatures will climb Thursday and Friday to 10 to 15 degrees above normal by Friday, making Juneteenth very comparable to Tuesday's dangerous heat. The heat on Friday will bring very low afternoon minimum relative humidity values of 5 to 10 percent across the area, especially at lower elevations.
An upper-level trough will move into the area for the weekend, introducing slightly cooler temperatures and a chance of precipitation. Thunderstorms in southeast Oregon and along the Idaho-Nevada border Friday evening pose a critical fire weather threat and could produce outflow winds up to 40 mph. Showers and thunderstorms will move into Idaho on Saturday. Temperatures will begin climbing Monday again as a ridge builds behind the trough.
Residents should take this heat seriously and take precautions to stay cool, stay hydrated, and check on vulnerable neighbors and family members. Anyone working or recreating outdoors should be aware of the critical fire weather conditions and avoid any potential ignition sources.
Tonight
Partly cloudy, with a low around 60. Northwest wind 5 to 8 mph becoming calm in the evening.
Tuesday
Sunny, breezy and very hot, with a high near 98. Light and variable wind becoming NW 10 to 15 mph in the morning. Winds could gust as high as 25 mph.
Tuesday Night
Mostly clear, with a low around 61. Northwest wind 10 to 18 mph, with gusts as high as 30 mph in the evening.
Wednesday
Sunny and not as hot, with a high near 88. WNW wind 10 to 15 mph.
Wednesday Night
Clear, with a low around 55. Diminishing wind.
Thursday
Sunny and hotter, with a high near 92.
Thursday Night
Mostly clear, with a low around 58.
Friday
Sunny and very hot, with a high near 98.
Friday Night
Mostly cloudy, with a low around 64.
Saturday
Partly sunny and not as hot, with a high near 91.
Saturday Night
Partly cloudy, with a low around 59.
Sunday
Sunny and hot, with a high near 91.
Sunday Night
Clear, with a low around 57.
Monday
Sunny and hot, with a high near 94.
