textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Strong thunderstorms capable of wind gusts to 60 mph possible over the west central and Boise Mountains, and the Magic Valley today.

- Breezy northwest winds 30 to 40 mph through I-84 corridor between Baker City and Mountain Home today.

- Additional showers and thunderstorms and periods of gusty winds Wednesday through Sunday.

- Thunderstorms may produce gusty winds 40-60 mph and blowing dust, brief heavy rain, and hail this week.

SHORT TERM /Through Thursday Night/

Issued 254 PM MDT TUE MAY 26 2026 A trough remains over northern CA and western NV this afternoon. Cooler air associated with the trough is funneling cool air down the Snake Basin and I-84 corridor from Baker City to Mountain Home. A convergence zone is setting up over the Magic Valley today, with easterly surface winds. This boundary will be the focus showers and thunderstorm development over the Magic Valley and central ID mountains this afternoon. Storms will track north and then toward the northwest over the central ID mountains this afternoon and evening. Thunderstorms will be capable of wind gusts up to 50-60 mph this evening over the central ID mountains and Magic Valley. Thunderstorms will diminish after sunset this evening with showers continuing in southeast OR. The upper level trough will retrograde from central NV to near Reno on Wednesday. Warmer temperatures expected on Wednesday with easterly flow setting up over the area. Scattered showers and thunderstorms form during the afternoon on Wednesday with easterly storm motion. The best chances for storms will be over eastern OR and the central ID mountains again. Unstable conditions expected Wednesday afternoon with gusty east to southeast winds during the afternoon with gusts of 20-40 mph. The trough does not move much on Thursday with showers and thunderstorms forming again during the afternoon with peak heating in the same places.

LONG TERM /Friday through Tuesday/

Issued 254 PM MDT TUE MAY 26 2026 Active weather will continue on Friday, as the closed upper low hanging over the Great Basin will slowly merge with an incoming longwave trough digging from off the coast of British Columbia. This pattern will continue widespread showers and thunderstorms on Friday. The merged trough system will then swing northward over our area on Saturday. Long-range guidance mostly favors showers/thunderstorms over higher terrain on Saturday. A cooling trend bringing temperatures 5 to 10 degrees below normal will be expected Friday through Saturday.

There is general guidance agreement on a weaker and drier shortwave steering over the area on Sunday. Considerable uncertainty remains over the precipitation intensity and pattern this system will bring; for now, a 20-40% chance of showers/thunderstorms are forecasted for the mountains Sunday. By early Monday, a building ridge will support a warming trend to start next week, likely returning temperatures up to 10 degrees above normal on Tuesday.

AVIATION /00Z Wednesday through Thursday/

Issued 607 PM MDT TUE MAY 26 2026

Generally VFR. Numerous showers through early Wed. Scattered thunderstorms across northeast OR and southwest/central ID through tonight, with strongest storms over central ID/Boise mtns. Storms capable of outflows to 25-40 kt, small hail, and heavy downpours with reduced vis. Periods of MVFR ceilings around KBNO-KBKE-KMYL. Scattered showers and thunderstorms return Wed afternoon.

Surface winds outside of storms: NW-N 10-20 kt with gusts 20-35 kt, becoming variable 5-15 kt overnight. Then, NE-SE 10-25 kt with gusts 20-40 kt beginning late Wed AM. Winds aloft at 10kft MSL: transitioning to E-SE 20-35 kt this evening.

KBOI...VFR. Scattered showers before Wed/06Z. Lightning threat until sunset. A 20% chance of showers/thunderstorms returning to Upper Treasure Valley Wed/20Z-Thu/00Z. Storms in area will be capable of outflow winds to 30-45 kt, along with brief downpours and small hail. Surface winds: NW 10-20 kt with gusts to 25-30 kt through evening. Becoming variable 3-7 kt by Wed/06Z.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.