The Heat Advisory remains in effect for the Treasure Valley, western Magic Valley, and Upper Weiser River Valley through Friday as a high-amplitude upper ridge holds strong over the Four Corners region. Relief is on the way, with temperatures dropping 5 to 10 degrees Saturday and continuing to moderate through the weekend.
Intense heat breaks for the weekend in Scott Dorval's video forecast
Heat Advisory: Friday's Intense Heat
Friday will bring another day of intense heat to the Treasure Valley, with highs near 100 degrees. High clouds streaming in from the Pacific subtropics will help keep temperatures from reaching even higher levels, as some weather models were showing the potential for temperatures approaching 105 degrees without the cloud cover. Overnight lows will remain warm near 72 degrees Friday night, providing only limited relief and increasing cumulative heat stress.
Residents should continue to take heat precautions Friday. Stay hydrated, limit strenuous outdoor activities to the early morning hours, use air conditioning or visit a cooling center, and check on vulnerable neighbors and family members. Never leave children or pets in parked vehicles.
Weekend Cooldown and Thunderstorm Chances
Saturday will bring a welcome change, with temperatures dropping 5 to 10 degrees from Friday's highs to near 96 degrees. Deeper monsoon moisture from the south will allow thunderstorms to be more effective rain producers Saturday, while continuing cloudiness and the approach of a weak surface cold front will aid in the cooling. A 15 to 25 percent chance of thunderstorms will develop over higher terrain Friday through Saturday, with gusty winds and lightning as the primary concerns Friday and heavier rain possible Saturday.
Sunday will be noticeably more comfortable with highs near 89 degrees as the front moves through. Frontal winds will bring 20 to 30 mph gusts to higher terrain in the central Idaho mountains Sunday afternoon. Relative humidity values will remain low in the drier airmass, so fire weather awareness will still be warranted.
Mountain Travel Weather This Weekend
For those heading into the central Idaho mountains this weekend, conditions will be active Saturday and Sunday. Thunderstorms Saturday will be capable of producing heavy rain, lightning, and gusty winds. Sunday will bring frontal winds with gusts of 20 to 30 mph to higher terrain in the afternoon. Mountain travelers should monitor conditions closely and be prepared for rapidly changing weather.
Looking Ahead to Next Week
As the upper ridge builds back in following the front and trough, temperatures will slowly climb into next week, holding steady around normal to a few degrees above normal. The building ridge will also allow monsoon moisture to continue streaming into the region, leading to a daily slight chance of afternoon showers and thunderstorms in south-central and central Idaho Monday and Tuesday. Highs will climb from 92 degrees Monday to 94 degrees Tuesday before moderating slightly Wednesday.
Tonight
Mostly cloudy, with a low around 67. Northwest wind 5 to 8 mph becoming calm after midnight.
Friday
Patchy smoke before 3pm. Mostly sunny and hot, with a high near 101. Gusty late-day & evening wind.
Friday Night
Mostly cloudy, with a low around 73. Southwest wind 7 to 13 mph becoming southeast after midnight. Winds could gust as high as 26 mph.
Saturday
Mostly cloudy and hot, with a high near 97. East wind 6 to 8 mph becoming west southwest in the afternoon.
Saturday Night
Partly cloudy, with a low around 64. South southwest wind 5 to 8 mph.
Sunday
Sunny and not as hot, with a high near 90.
Sunday Night
Partly cloudy, with a low around 62.
Monday
Mostly sunny and hot, with a high near 92.
Monday Night
Partly cloudy, with a low around 64.
Tuesday
Mostly sunny and hot, with a high near 94.
Tuesday Night
Partly cloudy, with a low around 64.
Wednesday
Mostly sunny and hot, with a high near 93.
Wednesday Night
Partly cloudy, with a low around 63.
Thursday
Mostly sunny and hot, with a high near 92.
