textproduct: Boise

SHORT TERM...Today through Friday night

A frontal system steering out East will continue precipitation over most areas this morning. Snow levels will remain in the 3500-4500 ft through the morning and early afternoon today, favoring snowfall over the central mountains and rain in the valleys. A shortwave trough will bring a cold front later today through Thursday morning, returning a band of widespread precipitation through the afternoon/evening hours. Moderate to heavy snow showers, graupel and thunder are possible with this feature Wednesday afternoon and evening as cold air aloft moves overhead causing unstable conditions. For now, there remains a slight chance of convective snow/graupel showers mainly over the West-central ID mountains and Western Magic Valley this afternoon/evening. Snow levels are expected to drop further down into the 1500-2500 ft range tonight through Thursday. While continuous snowfall is expected over the mountains, valleys will mostly see rain with snow flurries possible overnight Wednesday through Thursday morning. Snow will taper off in the evening over the valleys, and scattered snow showers continue through Thursday over the mountains. Breezy Northwest winds will be expected over most areas Thursday as the trough moves out East. Friday will be drier as a large high pressure ridge builds in over the region.

LONG TERM...Saturday through Wednesday...High pressure will continue to build into the region on Saturday, bringing clearing skies and dry conditions. A weak trough will move into the Pacific Northwest on Sunday, likely bypassing southern Idaho and southeast Oregon and moving to our north but bringing clouds into the area. There's also a low chance of precipitation on Sunday into Monday over the far reaches of Baker and Valley County, but uncertainty is high in the extent of that line of precipitation due to the northerly track of the trough.

By Monday afternoon, the ridge will continue to build back in over the region, with the Pacific High moving onshore steadily throughout the week. Air stagnation remains the primary concern with this high pressure system as a surface inversion develops over area valleys throughout the week with low mixing heights and light winds. Temperatures will remain generally right around to slightly above normal in higher elevations, with slightly below normal temperatures in sheltered valleys through the long term period.

AVIATION

Mainly VFR with localized IFR/LIFR in mtn snow showers and valley rain showers this morning and again this afternoon. Snow levels remain around 4-5 kft MSL, dropping briefly to valley floors Thurs. morning. A 10-20% chance of lightning exists in heavier showers this afternoon, primarily in SW ID. Areas of LLWS this evening over the Snake River Valley. Mtns obscured in precipitation. Surface winds: SE-SW 5-15 kt, gusts 20-30 kt across ridges and SE OR shifting to W-NW 5-15 kt with gusts to 35 kt after Thurs/00Z. Winds aloft at 10kft MSL: W 30-40 kt.

KBOI...Mainly VFR with brief MVFR ceilings during light rain early this morning and again by late afternoon. Surface winds will generally be SE 5-8 kt shifting to W-NW 5-10 kt after Thurs/00Z.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Winter Weather Advisory until 11 PM MST this evening IDZ011-013. OR...None.