textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Scattered showers and isolated thunderstorms today over the higher terrain with gusts to 45 mph possible.

- Cooler and breezy this weekend with dry conditions, except showers persisting over the central Idaho mountains.

- Temperatures warming to around 10 degrees above normal by the middle of next week.

SHORT TERM /Through Sunday Night/

Issued 308 AM MDT FRI MAY 29 2026 A broad upper level trough will move overhead today as a closed low over the southern Great Basin lifts northeast. Patchy fog in mountain valleys and the basins of Harney County will quickly clear this morning. Temperatures will be 5-10 degrees cooler than yesterday, remaining slightly above normal. Daytime heating will allow scattered showers and isolated thunderstorms to develop over the higher terrain this afternoon and evening, with less than a 20% chance in the lower valleys. Any storms that develop will be weaker than previous days, but outflow gusts to 45 mph, brief heavy rain, and small hail are still possible. West to northwest winds will become breezy late this afternoon through the weekend as the low center moves to our east. Most areas will see gusts 20-40 mph, strongest along the I-84 corridor between Baker City and Ontario each night and in the Magic Valley Saturday afternoon. Temperatures will cool another 5-10 degrees for Saturday and Sunday across southwest Idaho resulting in slightly below normal temperatures. Most areas will be dry as the low center lifts north into Montana, except for showers and embedded thunderstorms across the central Idaho mountains closer to the low center.

LONG TERM /Monday through Friday/

Issued 308 AM MDT FRI MAY 29 2026 A warming trend will develop Monday through Wednesday as high pressure builds overhead. By Wednesday, highs will be around 10 degrees above normal. Winds will be light early in the week with dry conditions. A system moving to our north may clip our area late Wednesday and Thursday, resulting in a 10-20% chance of showers and thunderstorms across northern areas. Afternoon winds will become a bit breezy as the system moves by. By Friday, southwest flow ahead of a Pacific trough should push temperatures even higher, to around 15 degrees above normal.

AVIATION /18Z Friday through Saturday/

Issued 1146 AM MDT FRI MAY 29 2026 VFR with SCT-BKN mid-high clouds over SE Oregon and mountain areas this afternoon. Scattered showers and isolated thunderstorms this afternoon/evening across SE Oregon and the higher terrain of SW Idaho. Gusty outflow winds up to 35 kt and mountain obscuration in brief heavy rain in storms. Surface winds: W-NW 5-15 kt this afternoon. Gusts 20-30 kt after 30/00Z. Winds aloft at 10kft MSL: S 5-15 kt becoming W-NW by 30/00Z.

KBOI...VFR. NW 8-13 kt with gusts to around 20 kt this afternoon through evening. A 20% chance of outflow gusts from distant thunderstorms over southern mtns late this afternoon.

Weekend Outlook...Generally VFR. Lower ceilings will accompany precipitation over the Central ID mtns Saturday and Sunday, obscuring mtns mainly east of Fairfield-Lowman-McCall. Surface winds: W-NW 5-15 kt each day with afternoon gusts to 20-25 kt, except W-NW 10-20 kt with afternoon gusts to 25-35 kt in the Snake Plain east of KBOI.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.