Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
024 FXUS65 KBOI 092009 AFDBOI Area Forecast Discussion National Weather Service Boise ID 209 PM MDT Sun Mar 9 2025 .SHORT TERM...Tonight through Tuesday night...Warm, mild conditions will persist across our region ahead of the next storm system expected Wednesday. Tonight, the upper-level ridge weakens, transitioning to westerly flow aloft as a weak trough passes to our north. This brings a 20-40% chance of showers to northern Baker County and the West Central Mountains of Idaho on Monday. Precipitation amounts will be light, with less than an inch of snow expected above 5000 feet. Monday`s temperatures will cool slightly but remain approximately 5 degrees above normal. Tuesday will see southwest flow developing aloft as the next storm system approaches the Pacific Northwest coast. Despite increasing high clouds, temperatures will warm a few degrees, with highs reaching the 60s across the lower valleys. Moisture will be limited and primarily stay to our north, though Baker County and the West Central Mountains of Idaho still have a 15-30% chance of showers. .LONG TERM...Wednesday through Sunday...Active weather expected throughout the extended period. A high amplitude trough will kick off the active weather Wednesday night, and last through about Friday morning. This system will bring widespread precipitation as well as gusty winds. Snow levels drop from 5-6kft MSL Wednesday to valley floors by Friday morning. From 4.5 to 5.5 kft MSL snow amounts of 1 to 8 inches are possible, and potentially greater than a foot of snow along mountain ridges and high elevation passes including Banner Summit. There is still a 20% chance of a dusting of snow in valley floors Friday morning, but precipitation will have largely tapered off by that point. Liquid equivalents in central ID higher elevations of around an inch, and less than half an inch in lower valleys and SE Oregon. Temps cool from near normal to 5-10 degrees below normal by Thursday. After a brief lull in precipitation Friday, very moist zonal flow and a series of shortwaves will pick things up for the weekend. With the colder airmass in place, snow amounts will be near to just above the previous system over the course of Saturday and Sunday. Up to an inch of snow possible around 3kft, 1 to 6 inches between 3-4kft, up to a foot between 4-5kft, and up to 2 feet above 5kft. The warm zonal flow means lower elevation snow will fall near the beginning of this system, while the later onset of the peak moisture means much of the higher elevation snowfall will occur Sunday. Liquid equivalents will be very similar to the Wednesday-Thursday system. Temperatures remain below normal and winds gusty each day. The two very moist systems in the long term and ongoing flooding in the short term introduces some hydrologic concern. Rain and snowmelt in lower to middle elevations will result in increased river flows and increased potential for flooding impacts in some rivers. See the Hydrology section for more information. && .AVIATION...VFR with high clouds. Isolated light snow and rain in the far north Monday. Surface winds: SE-SW 5 to 15 kt with gusts to 25 kt in the lower Snake Plain and Baker County. Winds aloft at 10kft MSL: SW 15-30 kt. KBOI...VFR and partly cloudy. Surface winds SE 10-16 kt with gusts up to 25 kt. Winds calming to 5-10 kt around Mon/02z. && .HYDROLOGY...Flood Warnings remain active for minor flooding on the Malheur River near Vale and the Owyhee River below Owyhee Dam as snowmelt mitigation releases continue. Several additional waterways require monitoring for potential flooding later this week, including the Silvies River near Burns and the Weiser River near Weiser. The combination of milder temperatures accelerating snowmelt and moderate precipitation expected later in the week is contributing to the elevated flood risk throughout the region. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise SHORT TERM...JDS LONG TERM....JM AVIATION.....JM HYDROLOGY....JDS