Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
835 FXUS65 KBOI 191538 AFDBOI Area Forecast Discussion National Weather Service Boise ID 938 AM MDT Fri Jul 19 2024 .DISCUSSION...Widespread smoke from area wildfires is creating hazy skies and impacting air quality across the region, but especially near Burns, OR. Hot temperatures and dry conditions will continue through the weekend with intermittent pushes of monsoon moisture bringing afternoon showers and thunderstorms. A small chance exists this afternoon for showers and thunderstorms over the central ID Mountains (<10% chance) and near the ID-NV border (10-20% chance). Gusty outflow winds to 40 mph and frequent lightning are the main threat with this convection. No updates necessary to the forecast. && .AVIATION...Smoky with low VFR, local visibilities to MVFR/IFR. High density altitude due to heat. Low confidence (<20% chance) in thunderstorms over central ID mountains and along ID-NV border this afternoon. Surface winds variable 5-10 kt, except W-NW 5-15 kt by Fri./21Z, gusts up to 25 kt near KBKE, KONO this evening. Storms may produce gusty outflow winds up to 35kt. KBOI...Smoky with low VFR. High density altitude due to heat. Surface winds variable less than 5 kt, becoming NW 5-10 kt by Fri/21Z. Weekend Outlook...Continued smoky with reduced visibilities. Isolated thunderstorms over central ID mountains and along ID/NV border Sat afternoon, and over central OR and central ID mountains Sun afternoon. Gusty erratic outflows and frequent lightning in vicinity of storms. && .PREV DISCUSSION... SHORT TERM...Today through Sunday night...Upper level ridge will continue to strengthen over the area through the short term with hot conditions. The hot conditions will support unstable conditions, with isolated thunderstorms over central ID mountains and along ID/NV border this afternoon. Excessive heat warnings remain in effect. Temperatures will warm to near record levels, around 10-15 degrees above normal by Sunday. A shortwave off the CA coast will support increased chances of thunderstorms on Sunday afternoon, especially across eastern OR as the system moves north along the WA/OR coast. Wildfire smoke could take a few degrees off forecast guidance, but the current forecast used bias corrected temperatures for the past 10 days to account for recent wildfire smoke trends. LONG TERM...Monday through Friday...Hot and smoky conditions to continue over the long term, with Monday being the warmest day of the period. The aforementioned shortwave on Sunday afternoon will slowly move across southwest Idaho on Monday afternoon, bringing a slight chance of thunderstorms. Lower valleys will see near record high temperatures of 104 to 108 on Monday, however smoke may keep temperatures a few degrees below forecast depending on how thick the smoke is. Slightly cooler temperatures for the remainder of the week as the flow turns more west-southwesterly with the influence of a upper level low over western Canada. Monsoonal moisture will keep a slight chance of thunderstorms Tuesday through Friday over the higher terrain. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Excessive Heat Warning until midnight MDT Monday night IDZ012-014-033. Heat Advisory from noon Saturday to midnight MDT Monday night IDZ015-016-029-030. OR...Excessive Heat Warning until midnight MDT /11 PM PDT/ Monday night ORZ063-064. Heat Advisory from 11 AM Saturday to 11 PM PDT Monday ORZ061. Excessive Heat Warning from 11 AM Saturday to 11 PM PDT Monday ORZ062. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise DISCUSSION...SA AVIATION.....SA SHORT TERM...KA LONG TERM....KA