FXUS65 KBOI 070922 AFDBOI Area Forecast Discussion National Weather Service Boise ID 322 AM MDT Mon Apr 7 2025 .SHORT TERM...Today through Wednesday night...North-south Pacific cold front and associated rain showers have reached Harney County as of 2 AM PDT and were moving steadily eastward. Radar coverage in that part of Oregon is poor but some pcpn echoes can be seen from Boise's radar, suggesting showers exist along the whole frontal zone. Latest models, however, have lowered QPF and PoPs on the southern part of the front. We therefore also lowered QPF and PoP from previous forecast but not as much as the models. The northern part of the front still looks wet and QPF and PoPs remain high there today and tonight. For today the cold front and initial showers should pass through western Idaho this morning and south-central Idaho this afternoon. The air mass will destabilize this afternoon due to moistening at low levels and cooling aloft, leading to more showers and isolated thunderstorms lasting until sunset. Total rainfall today and tonight should be .25 to .50 inch in Idaho north of the Snake Basin, .10 to .25 inch in Baker County, .05 to .15 inch in southwest Idaho and Harney and Malheur Counties, and less than .05 inch near the Nevada border. High temps will be about 10 degrees cooler than yesterday in eastern OR, 5 to 7 degrees cooler in western ID, and zero to 3 degrees cooler in south-central ID, with the rest of the cooling occurring there on Tuesday. Snow level will stay above 7000 feet MSL today, then lower to 6000 feet tonight, with minimal snow accumulation. East or southeast winds ahead of the cold front will shift to west or northwest behind the front, with afternoon gusts to 35 mph in southern Harney and Malheur Counties. Tuesday will be the coolest day over the next several days with temps lowering only to normal. Another warming trend and increasing high-level snowmelt and runoff will begin Wednesday. .LONG TERM...Thursday through Monday...The axis of an upper level ridge will move overhead on Thursday as southwest flow aloft develops. This will push temperatures to around 15-20 degrees above normal, with highs in the upper 70s to around 80 degrees in the lower valleys. On Friday, an upper level trough will move into the Pacific Northwest. A 20% chance of showers will develop across the northern mountains, but temperatures are expected to remain warm ahead of the cold front. Ensembles have come into better agreement about the passage of the trough over the weekend, although some uncertainty remains. The cold front is favored to arrive on Saturday with temperatures dropping 10-15 degrees from Friday. Precipitation chances will increase to 10-40%, highest over the northern mountains, and winds will be gusty as the front pushes through. Overall, only light precipitation amounts are expected with this system. Temperatures are forecast to fall several more degrees on Sunday and end up a few degrees below normal. Precipitation chances will decrease Sunday night and Monday as the trough departs with temperatures rebounding by several degrees. && .AVIATION...Areas of MVFR and possible IFR conditions in showers will move into SE Oregon early this morning and SW Idaho after 07/12Z. Mainly VFR conditions outside of showers. Snow levels 6500-7500 ft MSL. Mountains obscured occasionally in precipitation. Isolated thunderstorms developing late this morning through the evening. Gusts to 35 kt near thunderstorms. Surface winds: SE- SW 5-15 kt, except increasing to 10-20 kt with gusts to 35 kt after 07/18Z across SE Oregon and far SW Idaho. Winds aloft at 10kft: SW 25-45 kt. KBOI...Mainly VFR. Rain showers after 07/14Z, heavier showers may bring brief MVFR conditions. A 20% chance of thunderstorms after 07/16Z. Winds SE 10-20 kt this morning, becoming variable 10 kt or less after 07/22Z. && .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...LC LONG TERM....ST AVIATION.....ST