The broad upper-level trough that has influenced the region for the past several days will begin its inland trek tonight, bringing one final round of scattered snow showers before a significant warming trend develops this weekend ahead of another active weather system early next week.
Tonight Through Friday: Last of Current System
A weak shortwave moving along the Oregon coast and into California will bring scattered snow showers across southeast Oregon and along the Idaho and Nevada border later this afternoon through this evening. Localized accumulations of up to 2 inches remain possible in higher terrain, however most locations should see less than half an inch.
As the core of the trough shifts east into the Great Basin, one final round of light, scattered snow showers is possible Friday morning through afternoon as the trailing edge moves through. The best chance for snow in the Treasure Valley will be Friday morning during the commute, though accumulations are expected to be minimal with less than 0.2 inches. By Friday afternoon, atmospheric heights begin to rise as a shortwave ridge builds in from the west, marking the beginning of a drying trend and notable clearing of skies from west to east.
Weekend: Ridge Amplifies and Warming Begins
Saturday and Saturday night will see the ridge amplify over the Pacific Northwest, leading to a period of quiet weather and a steady warming trend. High temperatures Saturday will climb back to near seasonal normals with mostly sunny skies and breezy southeasterly winds reaching 9 to 14 mph with gusts as high as 23 mph. Clear skies and light winds Saturday night may once again allow for cold valley bottoms as temperatures drop to around 30 degrees.
The warming trend continues Sunday as southwesterly flow strengthens ahead of a deep trough positioned off the Pacific Northwest coast. Sunday will be mostly sunny with highs near 57 degrees, representing a significant temperature increase from recent below-normal readings.
Next Week: Major System Approaches
The warming trend peaks Monday with temperatures rising to 5 to 10 degrees above normal, reaching near 60 degrees. At the same time, clouds will increase beginning Monday afternoon as the offshore low moves inland. Rain and snow showers on the western fringe of the forecast area will begin moving into the rest of the region Monday night.
The warmer temperatures will bring snow levels up to 5,000 to 6,000 feet for the onset of precipitation, and much of the heavier precipitation will occur during this onset period and on Tuesday. This will bring heavy snow to many mountains, with light to moderate rain for mountain valleys and low-lying areas.
Tuesday evening, the bulk of the moisture moves east of the area and precipitation chances decrease to 20 to 40% every six-hour period through Wednesday. By Wednesday night, weather models heavily favor a mostly dry solution with only a 10% chance of light showers lingering in central Idaho Thursday.
Mountain Snow Conditions for Ski Areas
The current system will provide minimal additional accumulations through Friday, with up to 2 inches possible in higher terrain. However, the major system arriving Monday night through Tuesday will bring heavy mountain snow with snow levels at 5,000 to 6,000 feet initially. This should provide substantial fresh snowfall for most ski areas, particularly those at higher elevations, following the brief weekend warming period.
The pattern continues to show alternating periods of warming and active weather, maintaining excellent overall conditions for winter recreation despite the temperature fluctuations.
Tonight
Mostly cloudy, with a low around 25. East wind around 5 mph becoming calm in the evening.
Friday
A 20 percent chance of snow showers before 11am. Cloudy through mid morning, then gradual clearing, with a high near 40. Light wind.
Friday Night
Partly cloudy, with a low around 24. Light wind.
Saturday
Increasing clouds breezy & milder, with a high near 49. SE wind 10 to 15 mph, with gusts as high as 25 mph.
Saturday Night
Mostly cloudy, with a low around 30. East southeast wind 11 to 13 mph.
Sunday
Mostly sunny, breezy & unseasonably mild, with a high near 57.
Sunday Night
Mostly cloudy, with a low around 37.
Monday
Partly sunny & continued very mild, with a high near 60.
Monday Night
A 50 percent chance of rain. Mostly cloudy, with a low around 42.
Tuesday
Rain likely. Mostly cloudy, with a high near 54. Chance of precipitation is 70%.
Tuesday Night
A 50 percent chance of rain. Mostly cloudy, with a low around 35.
Wednesday
A chance of rain and snow. Partly sunny, with a high near 52. Chance of precipitation is 30%.
Wednesday Night
A chance of rain and snow. Mostly cloudy, with a low around 34. Chance of precipitation is 30%.
Thursday
A chance of rain and snow. Partly sunny, with a high near 55. Chance of precipitation is 30%.
