textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Windy and cold today, with scattered snow showers and isolated afternoon thunderstorms. Snow level on valley floors.

- Areas of subfreezing temperatures in the agricultural valleys this morning, but widespread subfreezing temperatures late tonight and Friday morning.

- Steadily warming days but only gradually warming nights Friday through Monday.

- Next precipitation Monday through Wednesday..

SHORT TERM /Through Saturday Night/

Issued 314 AM MDT THU APR 16 2026 At 2 AM MDT the cold front and nearly all the rain and snow extended from near Twin Falls through Owyhee County into northwestern Nevada, moving slowly southeastward. Snow levels have lowered to the valley floors and any showers that form in our CWA later today will be snow or graupel, although little accumulation is expected. Post-frontal west/northwest winds will blow 20 to 30 mph, with afternoon gusts to 40 mph in the western Magic Valley and south to the Nevada border.

Temperatures at 2 AM MDT were still above freezing in the agricultural valleys of southern Idaho, and should stay above freezing in the Treasure Valley, but dip slightly below freezing in the Magic Valley between 6 AM and 10 AM MDT. The Freeze Warning for today has been adjusted accordingly.

The Freeze Warning for late tonight and Friday morning will be more impactful, with low temps Friday morning between 23 to 28 degrees everywhere, i.e., a hard freeze. Even Saturday morning will be below freezing, but not as cold as Friday morning. Low temps will moderate only gradually through Sunday, but high temps, only in the 30s and 40s today, will warm about 10 degrees per day Friday through Sunday, getting back to the 60s and 70s Sunday. Skies will be mostly clear and winds will be light, as high pressure aloft replaces today's cold upper level trough.

LONG TERM /Sunday through Thursday/

Issued 314 AM MDT THU APR 16 2026 Cluster analysis continues to show some form of a closed-off low in the 500mb pattern come Monday. The ensemble consensus continues to lean toward a mid-week arrival (Tuesday/Wednesday); however, it could arrive in eastern Oregon as early as Monday. This is leading to a 20 to 30 percent chance of precipitation in E-Oregon Monday afternoon. Precipitation chances will increase to 30-60% area-wide come Tuesday and Wednesday, which is the time frame the majority of ensemble guidance favors. The convective threat will increase mid-week next week as the low moves inland, with ensembles hinting at building instability Tuesday/Wednesday. Right now it appears that Tuesday and Wednesday afternoons will have the best chance for thunderstorms in the forecast area. However, the day of greatest likelihood will depend on how soon the system impacts our area. Confidence is low on the pattern progression beyond Wednesday, but unsettled conditions will likely continue. A 20 to 40 percent chance of precipitation will continue area-wide come Thursday. Temperatures Monday will continue to be around 10 degrees above normal, cooling to near normal following the low.

AVIATION /18Z Thursday through Friday/

Issued 1141 AM MDT THU APR 16 2026 Scattered snow showers will produce brief MVFR/IFR conditions and obscure mountains through sunset. Local mtn valley fog overnight. VFR on Friday, with scattered cumulus over mtns. Snow levels: At valley floors. Surface winds: W-NW 10-20 kt with gusts to 20-35 kt through sunset. Lighter winds overnight and Friday. Winds aloft at 10 kft MSL: W-NW 15-25 kt.

KBOI...VFR with scattered to broken cumulus through sunset. Scattered rain/snow showers this afternoon with a 25% chance of impacting the terminal. Gusty northwest surface winds will weaken this evening, becoming light and variable overnight.

Weekend Outlook...VFR. It will be dry with periods of mid-high cloud cover. Local mtn valley fog is possible Saturday morning. S-SE Surface winds of 5-15 kt Saturday increasing to 10-20 kt with gusts 20-30 kt on Sunday. Strongest winds on Sunday in the Snake Plain east of KBOI. Variable up to 15 kt overnight Sat/Sun night.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Freeze Warning from midnight tonight to 10 AM MDT Friday for IDZ012-014-016. OR...Freeze Warning from midnight MDT /11 PM PDT/ tonight to 10 AM MDT /9 AM PDT/ Friday for ORZ064.