Area Forecast Discussion
Issued by NWS Boise, ID
Issued by NWS Boise, ID
533 FXUS65 KBOI 061550 AFDBOI Area Forecast Discussion National Weather Service Boise ID 950 AM MDT Thu Jun 6 2024 .DISCUSSION...Showers got going earlier than expected, and one thunderstorm was able to put down some lightning in Harney county. Forecast was updated to boost precipitation chances in SE Oregon and near the ID-OR border. Still on track for an active afternoon/evening in far SW Idaho and the ID-NV Border as the environment in that region has the most conducive thunderstorm elements. Storms and showers will generally disorganize as they traverse into the Snake Plain, but showers may continue along outflow boundaries. Outflow winds this evening could be up to 40-50 mph, with the greatest chance in the Magic Valley and along the Nevada border. Friday and Saturday continue to see convection along the ID-NV border, and the whole region continues to be hot with temperatures roughly 15-20 degrees above normal. While Saturday will be the hottest day, the most active day is looking to be Sunday. An upper trough moves inland, and even though it loses energy quickly after landfall, it will bring enough to our area to get showers and thunderstorms going throughout the day. && .AVIATION...VFR with high clouds. Isolated to scattered showers/thunderstorms south of KBNO-KONO-KSNT line, mainly after Thu/18Z. Stronger storms may be capable of erratic outflow wind gusts of 35-45 kt. Surface winds: variable 10 kt or less, except gusty near storm outflows. Winds aloft at 10kft MSL: W to SW 10-15 kt. KBOI...VFR. Isolated showers and thunderstorms mostly south and east of the terminal between 20Z and Fri/04Z, but there is a 10-15% chance of thunderstorms within 5 miles even this morning. Erratic outflow wind gusts are also possible from nearby storms, otherwise surface winds remaining less than 10 kt. Weekend Outlook...VFR outside of thunderstorms/showers. Afternoon showers and thunderstorms Saturday mostly across SE Oregon and higher terrain south of the Snake Plain in Idaho. Greater coverage shower/storm coverage, including lower valleys on Sunday. Gusty outflow winds will be possible from showers and storms. Otherwise surface winds generally 5-15 kt. Winds aloft variable to 15 kt on Saturday becoming westerly 15-25 kt on Sunday. && .PREV DISCUSSION... SHORT TERM...Today through Saturday night...Heat will build through Saturday as an upper ridge amplifies over the interior NW. Highs today are 5-10 degrees warmer than Wednesday with 3-8 degrees of further warming through Saturday. This will put lower valleys between 95 and 100 degrees on Saturday while mtn valleys push into the lower 80s. An increase in mid-level moisture today will support a high-based showers and thunderstorms this afternoon/evening. The deepest moisture and best chance of development will be across southern Harney and Malheur Counties in Oregon into southwest Idaho, generally south of a line from Caldwell to Stanley. Southwest flow aloft will direct showers/storms into the portions of Snake Plain, but confidence in storms holding together as they cross the Snake Plain is low (10-20%). Gusty outflow winds to 40 mph are possible with isolated stronger storms capable of 50 mph gusts. Friday and Saturday will see further rounds of afternoon showers and thunderstorms carrying the same gusty outflow threat. Focus of development both days be across higher terrain of SE Oregon and SW Idaho south of the Snake Plain. LONG TERM...Sunday through Thursday...The heat pulls back some on Sunday as an upper trough pushes into the West injecting clouds and increasing the chance for precipitation. Lower elevations will see a 15-25% chance of showers and thunderstorms while mtns hold a slightly higher chance (25-40%) through Sunday evening. Lower elevations will see dew points push above 50F and precipitable water values over an inch (95th-99th percentile) making it feel humid and increasing the chance for locally heavy rain from showers/storms. A drier westerly flow on Monday will bring a few more degrees of cooling and limit any lingering chance of showers to higher elevations of w-central Idaho. There is good model agreement on a west- southeast flow setting up Tuesday and remaining in place through the end of the week. This will keep dry weather in place with temperatures around 10 degrees above normal, or highs near 90 in the valleys. && .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...JM AVIATION.....JM SHORT TERM...DG LONG TERM....DG