textproduct: Boise

UPDATE

Updated aviation discussion.

KEY MESSAGES

- Drier today with normal temperatures.

- Rain and mountain snow Wednesday, then snow level lowering to valley floors before ending late Wednesday night/Thursday morning.

- Subfreezing morning temperatures Thursday through Saturday across the entire area.

SHORT TERM /Through Thursday Night/

Issued 311 AM MDT TUE APR 14 2026 Weak ridging aloft from the north Pacific will pass through our CWA today, bringing drier weather with normal temperatures. The next upper trough from the Gulf of Alaska will spread more rain (snow above 5000 feet MSL north to 6500 feet south) into our CWA tonight through Wednesday night. The system's cold front should pass through eastern OR midday Wednesday and western ID Wednesday afternoon/evening, followed by even colder air than the previous system. Snow level will lower to valley floors late Wednesday night but most models show pcpn ending by then. GFS, however, has a band of moisture behind the front that passes through our CWA toward sunrise Thursday morning when the air is easily cold enough to support snow. For now we'll stay with the model consensus suggesting little or no snow in the lower valleys, but we remain ready for any model changes in the next two cycles. For now, we can offer a 20 percent chance of a half- inch snow accumulation in the Treasure valley early Thursday morning, with a 40 percent chance of up to an inch in the Magic Valley. Thursday looks breezy, drier, and cold, as the upper trough passes through. Thursday night will be clearing and calming and quite cold, with lows in the teens and 20s, cold enough to damage new plants unless they are covered.

LONG TERM /Friday through Tuesday/

Issued 311 AM MDT TUE APR 14 2026 Friday will mark the start of a warming and drying trend to end the week. As the system in the short-term period exits to the east, ridging will begin to build in behind it. High temperatures come Friday will still be below normal, but 5-10 degrees warmer than Thursday. The drying trend will allow for overnight valley lows to be at or near freezing through Saturday morning. A 15-50% chance of precipitation will remain over the Boise Mountains and Valley County Friday (highest in northeastern Valley County), associated with lingering wrap-around moisture as the low moves east. Gusty west/northwest winds will persist in the usual windy areas east of Mountain Home, with gusts up to around 30 mph. The warming trend will continue through the weekend, with temperatures leaning above normal again by Sunday.

Confidence continues to increase on another low digging down from the Gulf of Alaska early next week, although timing continues to be uncertain on exactly when it will impact our area. However, right now ensembles favor the late Sunday/Monday timeframe. With that, precipitation chances will increase from west to east Saturday afternoon into Monday, reaching 30-60% area-wide come Monday afternoon. Precipitation chances will remain elevated through Tuesday. The exact timing, and therefore best precipitation chances, should become more clear in future forecasts. Regardless of the exact timing of the system, temperatures will cool to be near normal when it impacts our area. Winds will also become breezy/gusty, from the south/ southeast ahead of and north/northwest following the system.

AVIATION /18Z Tuesday through Wednesday/

Issued 1152 AM MDT TUE APR 14 2026 VFR today. Band of SCT-BKN high clouds moving in from west. Cold front will bring showers from W-E early Wednesday morning, with MVFR- IFR conditions and mtn obscuration in showers/low ceilings. Snow Levels will be 5-6.5 kft MSL today through Wednesday morning. Surface winds: SW-NW 5-15 kt this afternoon with gusts up to 25 kt near KTWF/KJER. Winds aloft at 10kft MSL: W-NW 10-20 kt

KBOI...VFR. Rain showers returning early Wednesday morning with increasing clouds and lowering ceilings. Surface winds: W-NW 5-10 kt this afternoon, then SE 5-10kt this evening.

BOI WATCHES/WARNINGS/ADVISORIES

ID...None.

OR...None.