textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Isolated to scattered showers and thunderstorms through Tuesday, with lightning and gusty outflow winds the main hazard and a lower chance of brief heavy rain and small hail. - Hot temperatures through the week and into the weekend. - Breezy winds each afternoon.

SHORT TERM /Through Wednesday Night/

Issued 359 AM MDT MON JUL 6 2026 The center of a shortwave trough will track north through eastern Oregon today. The trough will bring virga, along with isolated showers and thunderstorms, to our area this morning. Rainfall amounts will be minimal from this activity with gusts to around 30 mph possible. As the trough lifts north, showers and thunderstorms will increase across the west- central Idaho mountains this afternoon as daytime instability increases. Southwest flow aloft will transport additional moisture and instability into southeast Oregon and far southwest Idaho this afternoon and evening, resulting in scattered showers and thunderstorms developing over the higher terrain. Storms will be capable of lightning, outflow gusts to 50 mph, brief heavy rain, and small hail. Thunderstorms should weaken upon reaching the Snake River Valley as the environment will be less favorable, but outflow gusts will still be possible. The trough will also cool high temperatures by 5-8 degrees and bring breezy northwest winds with gusts 15-25 mph.

Another round of afternoon/evening showers and thunderstorms will develop on Tuesday across the higher terrain, mainly across far southern areas near the Nevada border. Gusty outflow winds 40-60 mph and lightning will be the main hazards from this activity. A low potential exists for storms to send outflow gusts through the Treasure Valley. Highs temperatures will rebound on Tuesday, increasing 4-8 degrees from today under southwesterly flow aloft. On Wednesday, the flow aloft will become westerly as an upper trough moves into British Columbia. This will begin to push moisture to the east, limiting shower and thunderstorm potential to the higher terrain along the Idaho/Nevada border and central Idaho mountains. Breezy northwest winds will arrive late in the day, with gusts 20-35 mph.

LONG TERM /Thursday through Monday/

Issued 359 AM MDT MON JUL 6 2026 On Thursday, an upper trough moving by to our north will cool temperatures to near normal. Breezy conditions with gusts 20-35 mph will continue across southern Idaho. An upper ridge will build over the southern Great Basin on Friday, then shift east to the Rocky Mountains and Northern Plains over the weekend into early next week. Meanwhile, a trough will be nearly stationary off the Pacific Northwest coast. The ridge will bring hotter temperatures starting Friday, although the trough should keep the hottest temperatures east of our area. Highs in the lower valleys are forecast to reach the upper 90s, but a slight shift of the ridge further west would push lower elevations over 100 degrees. Conditions will remain dry with breezy winds under southwest flow aloft. By Monday, monsoon moisture may start to rotate around the ridge into our area. This would reintroduce shower and thunderstorm potential, likely continuing beyond Monday.

AVIATION /12Z Monday through Tuesday/

Issued 543 AM MDT MON JUL 6 2026 Mainly VFR. Virga/showers and isolated thunderstorms will lift north across the area this morning. Isolated to scattered showers and thunderstorms developing this afternoon and evening across SE Oregon and the higher terrain of SW Idaho. Thunderstorms capable of producing outflow gusts 25-45 kt. Surface winds: W-NW 5-15 kt with gusts 15-25 kt, becoming variable less than 10 kt overnight. Winds aloft at 10kft MSL: variable 5-15 kt, then SW-W 10-20 kt after Mon/18Z.

KBOI...VFR. Virga, with a 20% chance of light rain showers early this morning. Surface winds: W-NW 5-10 kt, gusts to 20 kt this afternoon. Variable outflow gusts up to 25 kt from any nearby showers or storms.