textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Afternoon rain and snow showers over higher terrain through Wednesday.

- Gradual warming trend through the week.

- Thunderstorms possible this weekend.

SHORT TERM /Through Wednesday Night/

Issued 234 AM MDT MON APR 27 2026 A very slow moving trough keeps conditions cool and unsettled through Wednesday. Shortwaves embedded in the trough provide sufficient forcing for afternoon showers in Eastern Oregon and Central Idaho. Modest CAPE could see a few showers become thunderstorms each day. As the trough exits, shower activity becomes limited to Central and Southern Idaho Wednesday afternoon. Temperatures rise through the forecast, starting at 5 degrees below normal today and warming to just above normal Wednesday.

LONG TERM /Thursday through Monday/

Issued 234 AM MDT MON APR 27 2026 A broad upper level ridge will move over the area Thursday and Friday, continuing a warming trend. Temperatures Thursday will increase to around 5-8 degrees above normal, then rise by another 3- 5 degrees on Friday with similar temperatures over the weekend. This translates to lower valley highs in the upper 70s to lower 80s. Dry conditions with light winds are expected Thursday and Friday. On Saturday, ensemble guidance indicates that an upper low will dive south along or near the coast and become cut off and nearly stationary Sunday and Monday, but location of the low is uncertain. A more inland track over California and the Great Basin would bring showers and thunderstorms to our area, but models also indicate the potential for the low to remain offshore, which would keep our area warmer and drier. The net result in the uncertainty is a 10-30% chance of showers and thunderstorms on Saturday, increasing to a 20- 50% chance Sunday and Monday, highest in the mountains and near the Nevada border. The forecast calls for above normal temperatures through Monday, but would trend cooler if the wetter pattern becomes more likely.

AVIATION /12Z Monday through Tuesday/

Issued 543 AM MDT MON APR 27 2026

Mainly VFR. Scattered showers and isolated thunderstorms will develop over the higher terrain this afternoon into early this evening, mainly across eastern OR and the west-central ID mtns. Snow levels 4500-5500 ft MSL. Localized MVFR/IFR conditions and mountain obscuration in showers. Showers/storms capable of erratic gusts to 30 kt. Surface winds: variable less than 12 kt this morning, becoming W-NW 10-15 kt this afternoon, gusts 20-30 kt east of KBOI. Winds aloft at 10kft MSL: NW 15-25 kt.

KBOI...VFR. Surface winds: light and variable this morning, becoming NW 8-13 kt with gusts up to 20 kt this afternoon.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.