textproduct: Boise

KEY MESSAGES

- Warmer and generally dry Thursday, except a slight chance of afternoon thunderstorms in Harney County and along the Nevada border. - Showers and afternoon/evening thunderstorms developing Friday, most numerous in eastern Oregon.

- Widespread showers and a chance of thunderstorms area-wide Friday night through Saturday with locally heavy rain.

SHORT TERM /Through Friday Night/

Pacific upper low near 40/131 will take until Friday to reach the coast, while another upper low in sw Alaska moves rapidly southeastward and overtakes the first low by Friday. The combined upper low will circulate moisture inland and northward into our CWA Friday through Saturday, with widespread showers and a chance of afternoon/evening thunderstorms. Southeast Oregon will be the wettest area on Friday, with western Idaho becoming the wetter area Friday night through Saturday, with the upper low then centered in northern California. Greatest instability for strong thunderstorms will occur Friday evening, but showers will be more numerous Friday night and Saturday. By then the air will be cooler and instability weaker resulting in fewer thunderstorms. As for temperatures, after today's brief cooling Thursday will be warmer again, with Friday just as warm in Idaho but cooling in Oregon. Saturday will be 5 to 10 degrees cooler everywhere. Breezy northwest winds this afternoon will become light and variable tonight and Thursday, and remain below 15 mph through Saturday except stronger near thunderstorms, especially Friday afternoon and evening.

LONG TERM /Saturday through Wednesday/

Active weather is expected to continue. Another upper-level low will move in quickly behind the quickly eroding low from Friday night. Models show widespread precipitation over the region from Saturday through Monday. Saturday afternoon looks to have an increased chance of stronger thunderstorms and showers as the stronger cut off low moves onshore. The stronger thunderstorms are possible from upper- level lapse rates rising to near 8 degrees C/km, with surface to 6 km shear values of 20-30 kts. Gusty winds, small hail, and brief heavy rain are the main hazards with these storms, however the instability and shear aloft could lead to a few severe storms with strong winds. Thunderstorms are less likely Sunday from increased overturn from Saturday and a cold air moving in, but still possible. The two day rainfall total (18z/Sat-18z/Mon) is estimated with valleys seeing anywhere from 0.25-0.75 inches of rain and mountains accumulating 0.75-1.5 inches. Tracks of stronger thunderstorms will also strongly determine where localized greater accumulations occur. At higher elevations, some of the accumulations will turn into snow Sunday and Monday. Uncertainty is higher among this, as the position of the low will determine temperatures, and therefore, snow levels. The current forecast has snow levels dipping from 7000-8000 feet on Saturday to around 4000-5000 feet during the overnight-early morning hours on Monday and Tuesday. Two day snowfall totals look to be less than 3 inches for mountain valleys, with localized higher amounts up to 8 inches over high peaks.

Precipitation chances will begin to trend lower on Monday and especially Tuesday as the trough moves east of the area and an upper- level ridge builds in. Another shortwave trough passage looks to pass to our north late Wednesday, bringing precipitation back into the picture.

AVIATION /18Z Wednesday through Thursday/

Issued 1150 AM MDT WED APR 8 2026 VFR. Scattered showers and a 20% chance of thunderstorms near KBNO and along the OR/NV border this afternoon. The threat of showers and thunderstorms will spread further north Thursday- Sunday. Surface winds: mostly W-NW 5-15 kt with gusts to 25 kt in the Camas Prairie and Magic Valley. Winds aloft at 10 kft MSL: W-SW 10-20 kt.

KBOI...VFR. NW 5-10 kt this afternoon, becoming light and variable after sunset.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.