


Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
062 FXUS65 KBOI 171600 AFDBOI Area Forecast Discussion National Weather Service Boise ID 1000 AM MDT Fri Oct 17 2025 .DISCUSSION...Still expect morning cloud cover break up through the day giving way to mostly clear skies this afternoon. Northwest flow aloft will translate to the surface across higher terrain. Clearer skies tonight and light winds will allow for another chance at frost in the lower Snake Plain. Current forecast is on track for this morning. && .AVIATION...Broken-overcast skies for the area, but VFR outside of mountain obscuration. Cloud cover has dropped any chance of fog this morning/early afternoon. Surface winds: variable less than 10 kt, becoming W-NW 5-15 kt this afternoon. Winds aloft at 10kft MSL: W-NW 15-30 kt. KBOI...VFR with mostly clear skies. Surface winds: SE 4-8 kt becoming NW 6-10 kt this afternoon. Some variability is possible this afternoon and tonight. Weekend Outlook...Mostly clear conditions on Saturday with patchy mountain valley fog and frost in the AM. Sunday clouds increase with scattered showers north of a KBNO-KBOI line after Sun/12Z. Snow levels during precip drop from 8000 ft MSL Sun morning to 5000 ft MSL Sun evening. Surface winds: S-SE 5-15 kt Sat, and SW-SE 5-15 kt with gusts up to 25-35 kt Sun. && .PREV DISCUSSION... SHORT TERM...Today through Sunday night...High clouds associated with an approaching upper level trough have overspread the area this morning. These clouds to not appear thick enough to prevent pockets of frost from developing in the Upper Treasure Valley east of Boise and the Western Magic Valley, with lows still expected to fall into the mid to upper 30s. The trough will move west to east across the Pacific Northwest just to our north later today bringing another day of breezy winds and mostly dry conditions. The only chance for precipitation (10 to 20 percent) will be in the West Central Mountains. High temperatures will increase a few degrees from yesterday, especially in southern areas, and will be near normal. Pockets of frost area again expected Friday night in the lower valleys as the clouds clear out and winds diminish behind the exiting trough.Consequently, the Frost Advisory has been expanded through the entire Treasure Valley into the Western Magic Valley for Saturday morning, with lows forecast between 33 to 37 degrees. On Saturday, an upper level ridge will briefly move overhead, bringing lighter winds and mostly sunny skies. Winds will start to increase Saturday night ahead of the next system. This upper level trough and its associated cold front will reach the area Sunday afternoon, bringing increased winds, cooler temperatures, and precipitation (30 to 60 percent chance) mainly to the central Idaho Mountains. Snow levels will fall to near 6500 feet for light snow, generally less than an inch. LONG TERM...Monday through Friday...A trough will deepen over southern Canada and the Pacific Northwest on Monday, bringing cooler temperatures and high terrain precipitation. Snow levels will drop to 5000-6000 feet MSL, but the extent of the moisture will remain over Baker County and the West Central Mountains. Limited accumulation of precipitation is anticipated by Monday evening. The trough will then weaken and move east as a ridge of high pressure develops over the Western US. This will bring warm and dry conditions to the region through at least Thursday. After Thursday, ensemble variance increases in timing and extent of the next system. All solutions agree on some deep trough or closed low moving onshore late next week and bringing much cooler temperatures and widespread precipitation with an atmospheric river set up. Forecast confidence is low in exact impacts from this system, but the probability of valley rain and mountain snow with much colder temperatures is higher for Friday into the weekend. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Frost Advisory until 9 AM MDT Saturday IDZ012-014-016. OR...Frost Advisory until 9 AM MDT /8 AM PDT/ Saturday ORZ064. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.x.com/NWSBoise DISCUSSION...DG AVIATION.....JM SHORT TERM...JDS LONG TERM....SA