Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
371 FXUS65 KBOI 160256 AFDBOI Area Forecast Discussion National Weather Service Boise ID 856 PM MDT Mon Jul 15 2024 .DISCUSSION... This afternoon and evening, several thunderstorms developed along the Idaho-Nevada border, producing approximately 20 lightning strikes. While satellite imagery has not detected any new fire starts as of 830 PM MDT. Storms have dissipated with the loss of daytime heating and dynamic support. The Falls Fire, located north of Burns, Oregon, became plume- dominated again this afternoon, generating lightning near the fire and producing a long, thick plume of smoke that extended through Valley County. Overnight, smoke will once again filter back through the lower valleys, leading to low visibility and poor air quality, particularly across southeast Oregon. Tuesday afternoon, another round of thunderstorms is expected to develop across southeast Oregon due to the passage of an upper- level low along the Pacific Northwest Coast. High- resolution models consistently show most of the convection occurring across Harney County and along the Nevada-Oregon border tomorrow. As the low tracks north-northeast on Tuesday night into Wednesday morning, there is a 20 percent chance of thunderstorms moving north-northeast through Malheur and Baker Counties into parts of southwest Idaho overnight. The strongest storms could bring gusty winds, lightning, and little to no rainfall. Adjustments have been made to thunderstorm coverage from tonight through Tuesday. An updated forecast will be released shortly. && AVIATION...Wildfire smoke from active fires in Eastern Oregon will filter into the region, with the thickest smoke over KMYL- KONO-KBNO from the Falls Fire. Isolated showers and t-storms with gusty outflow winds will move into SE OR tomorrow evening, then into SW ID overnight. High density altitude due to hot daytime temperatures. Surface winds: SW-NW 5 to 15 kt, then NE 10-20 kt after Wed./00Z. Gusts 30-40 kt in outflows. Winds aloft W to NW 10-20 kt becoming SE 5-15kt after Tues./16Z . KBOI...VFR but continued hazy from area wild fires. Visibility could drop below 6 miles, but thicker smoke expected to stay northwest of KBOI. High density altitude due to hot daytime temperatures. Light winds overnight, becoming NW 8 to 11 kt by Tues./15Z. && .PREV DISCUSSION... SHORT TERM...Tonight through Wednesday night...After today`s slight cool-down hotter weather will begin again Tuesday as high pressure aloft over the southern Rockies begins to shift westward to the Great Basin. Meanwhile, a Pacific trough will move northeastward through Oregon Tuesday and Tuesday night triggering afternoon and nighttime thunderstorms there. In our CWA Harney County will be most vulnerable, with a 30-50 percent chance of thunderstorms Tuesday evening. The trough and thunderstorms will move into WA Wednesday, but later Wednesday limited monsoon moisture will move northward through Nevada for a 20 to 40 percent percent chance of thunderstorms in Owyhee and Twin Falls Counties Wednesday afternoon and evening. Skies will continue smoky mainly due to the Falls and Cow Valley wildfires in eastern Oregon. LONG TERM...Thursday through Monday...Extreme heat will return to our CWA beginning Thursday, especially in Idaho, as the hot upper high re-centers itself over the Great Basin and also amplifies northward in response to a deepening upper trough in the Gulf of Alaska. Latest models show Sunday and Monday as the hottest days with high temps of 105 to 110 degrees at lowest elevations on those days. An Excessive Heat Watch has been issued for zones listed below. GFS shows limited monsoon moisture approaching from the south, especially on Sunday. Thunderstorms may develop in Owyhee and Twin Falls Counties later Sunday. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Excessive Heat Watch from Thursday afternoon through Monday evening IDZ012-014-016-030-033. OR...Excessive Heat Watch from Thursday afternoon through Monday evening ORZ063-064. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise DISCUSSION...JDS AVIATION.....SA SHORT TERM...LC LONG TERM....LC