textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Frost possible in the Snake Plain through Tuesday night with temperatures 5 to 15 degrees below normal.

- Unsettled conditions through early Tuesday, mainly on the Idaho side, with showers mainly over Magic Valley and Boise Mountains. - Snow levels near 6000-7000 feet in the west central ID mountains through Monday with light accumulations.

- Warm and dry conditions Wednesday through next weekend.

DISCUSSION

Issued 835 PM MDT SUN OCT 11 2026 into s-central Idaho this evening. It has dropped up to 0.10" in the Treasure Valley (Boise area) to nearly 0.25" in the foothills and Boise Mtns. Forecast models have been too quick to dissipate the this feature as it moves east and given continued cooling in IR satellite imagery, would expect it to hold together for the next couple of hours. Low temperatures tonight across Ag areas are another concern. Given current and forecast cloud cover and winds expect temperatures to stay above freezing in lower Snake Plain tonight with lows ranging between 34 and 38 degrees. Made an earlier update to the forecast to capture this change and add frost to sites in the Lower/Upper Treasure Valley. The best chance for frost to develop will be north of I-84 west of Boise. This area, to include Star, Emmett and Fruitland will see lighter winds towards sunrise. Kept frost wording out of the western Magic Valley as sub 36 degree temps would be brief and could be accompanied by light rain or rain/snow early Monday morning. Winds will also remain breezy through the night.

SHORT TERM /Through Tuesday Night/

Issued 246 PM MDT SUN OCT 11 2026 An upper level trough over eastern OR will keep conditions cool and unsettled through Monday. Showers will mainly be confined to southwest Idaho with the highest chances of precipitation over the higher terrain and Magic Valley. Eastern OR will generally remain dry, with a slight chance of showers in far SE Oregon. Similar conditions on Monday as the trough remains nearly stationary. Monday will be the coolest day of the period. By Tuesday the trough will move into southern NV and UT with a chance of showers mainly along the NV border and Magic Valley through Tuesday. Temperatures will warm around 10 degrees as the upper level trough moves SE.

LONG TERM /Wednesday through Sunday/

Issued 246 PM MDT SUN OCT 11 2026 A warming and drying trend will persist Wednesday through the end of the period. As the low that brought all the weather in the short-term departs to our east, a Pacific ridge will build in, shifting east to be over the Great Basin by the weekend. As a result, temperatures will warm to be 5-10 degrees normal come the weekend.

AVIATION /06Z Monday through Tuesday/

Issued 1140 PM MDT SUN OCT 11 2026 Generally VFR. Wrap-around moisture will bring light rain/mtn snow overnight through Mon night, mainly in s-central/central Idaho and NE Oregon. Low-VFR/MVFR in low stratus or rain, IFR-LIFR in mtn snow. Mountains obscured in stratus/precip. Snow Levels: 5-7kft MSL for SW Idaho, 3.5-5kft MSL in E Oregon. Surface winds: SW-NW 5-15 kt, with gusts 20-25 kt from KBKE-KONO, decreasing to 5-10 kt overnight. Winds aloft at 10kft MSL: variable 5-15 kt, then NW 5-15 kt Mon afternoon.

KBOI...VFR and SCT/BKN low clouds. Surface winds: becoming NW 4-12 kt overnight through Monday.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.