A powerful cold front will sweep through the region tonight, bringing moderate to heavy rain, mountain snow, and isolated thunderstorms before a dramatic warming trend arrives this weekend.
Scott Dorval's video forecast for showers & storms
Cold Front and Thunderstorm Threat Tonight
The cold front will cross the Oregon and Idaho border around midnight, pushing through the Boise metro area between 1 and 2 a.m. Thursday, and reaching Jerome and Twin Falls between 4 and 5 a.m.
As the front passes, it will bring an abrupt wind shift and about an hour of heavy showers and scattered thunderstorms.
Snow Levels Dropping and Mudslide Risks
Cold air behind the front will cause snow levels to rapidly drop to valley floors. Rain will likely change to wet snow before ending in the Upper Treasure Valley, with about an inch of accumulation possible in the Magic Valley.
Mountain areas will see 3 to 6 inches of snow, with up to 15 inches possible on the highest peaks.
Heavy pre-frontal rain creates a risk for rock and mudslides on steep terrain, particularly along routes like the Banks-Lowman Road. Drivers should avoid these areas until precipitation decreases Thursday morning.
Wind Advisory for Thursday
Following the cold front, westerly winds will increase to 45 mph in the Western Magic Valley and Camas Prairie. A Wind Advisory is in effect for these areas from 9 a.m. to 9 p.m. Thursday.
Temperatures will be noticeably colder on Thursday as the system moves through.
Rapid Warming Trend This Weekend
Skies will clear Thursday night, leading to cold overnight temperatures. Friday will be mostly sunny and about 10 degrees warmer than Thursday.
High pressure will build over the weekend, bringing a significant warming and drying trend. Temperatures will climb 5 to 10 degrees above normal this weekend, reaching 10 to 15 degrees above normal by early next week. Valley highs will reach the lower 70s by Monday and Tuesday under clear skies and light winds.
A weak system may bring slightly cooler temperatures and light rain showers by next Wednesday.
Tonight
Showers and possibly a thunderstorm before 2am, then showers likely. Low around 37. Southeast wind 7 to 13 mph becoming west northwest after midnight. Winds could gust as high as 23 mph. Chance of precipitation is 100%. New rainfall amounts between a quarter and half of an inch possible.
Thursday
Scattered rain and snow showers before 8am, then scattered rain showers. Some thunder is also possible. Mostly cloudy, with a high near 50. West northwest wind 8 to 13 mph, with gusts as high as 28 mph. Chance of precipitation is 40%. Little or no snow accumulation expected.
Thursday Night
A 20 percent chance of showers before 9pm. Partly cloudy, with a low around 33. Northwest wind 9 to 14 mph becoming light west after midnight. Winds could gust as high as 29 mph.
Friday
Sunny, with a high near 57. Calm wind becoming west northwest 5 to 7 mph in the afternoon.
Friday Night
Clear, with a low around 36.
Saturday
Sunny & milder, with a high near 66.
Saturday Night
Clear, with a low around 40.
Sunday
Sunny & pleasant, with a high near 72.
Sunday Night
Partly cloudy, with a low around 43.
Monday
Mostly sunny & warmer, with a high near 74.
Monday Night
Partly cloudy, with a low around 46.
Tuesday
Mostly sunny & pleasant, with a high near 74.
Tuesday Night
Mostly cloudy, with a low around 45.
Wednesday
A slight chance of showers. Mostly sunny, with a high near 68.
