Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
190 FXUS65 KBOI 141558 AFDBOI Area Forecast Discussion National Weather Service Boise ID 958 AM MDT Fri Jun 14 2024 .DISCUSSION...Breezy westerly winds are increasing across the region this morning ahead of a frontal passage expected later this evening. Recent hi-res model guidance indicates that showers and weak thunderstorms will form over the Steens Mountains around 3-5pm MDT, so have updated probability of precipitation and thunderstorm coverage to reflect changes. Otherwise, light showers and high based thunderstorms will likely move into southwest Idaho by later this evening (7-9pm MDT) bringing a chance of strong outflow winds. Temperatures will be a few degrees above normal today ahead of the cooler system coming in this weekend. Other than precipitation chance changes, no updates necessary to the current forecast. && .AVIATION...VFR and mostly clear. A slight chance of showers thunderstorms Fri/22Z through Sat/06Z, though confidence is low (less than 20 percent). Patchy smoke from the Owyhee mountains. Surface winds: W-NW 5-15 kt with gusts to 25 kt. Winds aloft at 10kft MSL: W-SW 15-25 kt. KBOI...VFR. Low confidence (10 percent chance) of showers/thunderstorms between Sat/01Z and Sat/06Z. Hazy skies from fires in Owyhee mountains. Surface winds: W to NW 8-12 kt with gusts to around 20 kt. Weekend Outlook...VFR. Increasing high clouds Saturday, with 15 percent chance of showers in NE Oregon and w-central Idaho mountains north of KBKE-KMYL. Afternoon winds increasing to W-NW 10- 20 kt with gusts to 20-30 kt. Mid and high clouds Sunday, with a 30 percent chance of rain/snow showers in SE Oregon and w-central Idaho mountains late Sunday night. Snow levels 5500-6500 ft MSL. Surface winds on Sunday W-NW 5-15 kt with afternoon gusts to 15-25 kt. && .PREV DISCUSSION... SHORT TERM...Today through Sunday night...A weak shortwave has moved through the area this morning, with isolated showers and thunderstorms from the lower Treasure Valley through the west central ID mountains. Drier air will move into the area this morning ending the shower threat through the day. Another shortwave moves through on Friday night into early Saturday morning, with a slight chance of showers and thunderstorms. A cold front will move through on Saturday, lowering temperatures 10-15 degrees from today, and another 3-5 degrees of cooling on Sunday. An unseasonably cool upper level trough over southwest Canada will strengthen the pressure gradient on Saturday and Sunday, with breezy northwest winds during the afternoon both days. Showers will generally stay north of the area on Saturday and Sunday. The trough over the Pacific NW will begin to move southeastward on Sunday night with a slight chance of showers developing. LONG TERM...Monday through Friday...An upper low is still forecast to move through our area Monday through Tuesday. There is some model variation in the depth of the low and whether it becomes closed or not. However, cooler and wetter weather overall is likely. Precipitation chances Monday through Tuesday are 20-30% for lower valleys and 30-50% for higher terrain. As some models are beginning to show a closed low forming, snow levels have been reduced slightly from the NBM and are currently 6000-7000 ft MSL. This change increased the coverage of mixed/snowy precipitation for mountains. Thunderstorms will be possible in afternoon instability on Monday. A cold front associated with the low will bring windy conditions Monday afternoon, with gusts to 30-40 mph. The front will cool temps all the way down to 15-20 degrees below normal on Monday, before a warming trend kicks in for the rest of the long term. Following the exit of the low, the flow becomes briefly zonal on Wednesday before becoming southwesterly through the rest of the long term. The drier southwesterly flow will warm us up to 5-10 degrees above normal by Friday. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise DISCUSSION...SA AVIATION.....BW SHORT TERM...KA LONG TERM....JM