FXUS65 KBOI 092018 AFDBOI Area Forecast Discussion National Weather Service Boise ID 218 PM MDT Fri May 9 2025 .SHORT TERM...Tonight through Sunday night...Dry and mild conditions tonight will set up for another unseasonably hot day on Saturday. Some lower elevation sites will see near record highs. Increased southwest flow will draw mid-level moisture into Idaho during the day which will overlap with surface energy and elevated instability to support shower and thunderstorm development. Dry low levels will make strong to locally severe gusty outflow winds the main attribute accompanying showers/storms that develop. Initiation will be favored across s-central Idaho from the southern Boise Mtns to the ID/NV border (Mtn Home and points east in the Snake Plain). For now will continue to carry a 20-30% chance of showers and storms for this area. Some buildups are possible in the w-central mtns, but expect most of the activity to be north of the Salmon if/when it gets going. Not seeing a great 0-6km shear environment across southern areas, but 30+ kts north of the Snake Plain would be enough to enhance development in the mtns. On Sunday areal coverage expands into higher terrain of the w-central ID mtns and SE Oregon (mainly Baker County and northern Harney and Malheur counties) as instability and dynamic support increases ahead of an upper low. Mid-level moisture drops some, but is sufficient enough to support a 30-50% chance of precipitation in these areas. Southwest flow aloft will translate windy conditions to open terrain of SE Oregon and SW Idaho by Sunday afternoon. Gusts of 40-45 mph will be possible along the NV border which could stir up dust. On top of the generally breezy/windy conditions, strong gusty outflow winds remain the most likely threat from showers and storms through Sunday evening. Increased clouds and cooling aloft with take 7-12 degrees off of high temperatures from Saturday to Sunday with a cold frontal passage later in the day/evening. .LONG TERM...Monday through Friday...A deep upper level low will move into the region on Monday, with gusty winds continuing through Tuesday. Much cooler temperatures and widespread precipitation will move in late Monday with periods of rain showers through Thursday. The strongest winds will stay over the Owyhee Mountains with gusts up to 40-50 mph. Cooler temperatures will allow for lowering snow levels, with minimal accumulations anticipated above ~6000 feet. Instability will remain best over Baker County, OR and high terrain in southwest and south central Idaho on Monday. This introduces about a 20-30% chance of thunderstorms on Monday evening. Model agreement remains excellent in the storm track through Wednesday, with high confidence in precipitation, especially over higher terrain. A warming and drying trend will begin by late Thursday, with some model disagreement on extent of the ridge. A few ensemble members are showing a weak trough moving in late Friday, bringing elevated chances of precipitation. && .AVIATION...VFR with high clouds continuing to fill in across the region. Elevated smoke from area burns in the vicinity of KMYL-KONO. Surface winds: E-SE 5-15 kt with gusts to 20 kt in the Snake Plain and Long Valley, elsewhere variable less than 10 kt. Winds aloft at 10kft MSL: SW 15-25 kt. .KBOI...VFR. Surface winds will be E-SE 7-10 kt with gusts to 20 kt this afternoon, becoming SW 10-13 kt by Sat/19Z. .WEEKEND OUTLOOK...Saturday will be warm and dry with increasing clouds and a slight chance of showers and thunderstorms near the Boise Mountains and ID/NV border late afternoon into evening. On Sunday afternoon, a cold front will move from SE OR into SW ID, bringing a chance of showers and thunderstorms (40-50% chance) with gusty westerly winds, lowering ceilings, andmountain obscuration. && .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...DG LONG TERM....SA AVIATION.....SA