textproduct: Boise

KEY MESSAGES

- Fire weather risk continues due to thunderstorm activity today.

- Thunderstorms with heavy rain may also increase the risk for flash flooding, especially for vulnerable burn scars today.

- Temperatures near normal through early next week, then a few degrees of warming expected by late week.

SHORT TERM /Through Monday Night/

Isolated, weak showers and thunderstorms are lingering near the Nevada border early this morning, but are expected to taper off in this area by mid/late morning. A shortwave trough is on track to swing through the PacNW this afternoon, generating the next round of scattered showers/thunderstorms across the forecast area this afternoon and evening due to persisting monsoon moisture. Activity will mainly favor far east Oregon and the higher terrain of southwest Idaho, but a 15-25% chance of storms are also forecast across the SW Idaho valleys. While precipitable water values are anticipated to be lower than Friday afternoon, values will remain supportive of heavy downpours under storm cores...leading to a risk of flash flooding on steep/rocky terrain and vulnerable burn scars. Models are also indicative of gusty outflow winds with stronger storms, with localized gusts to 45 mph possible.

Activity will taper off for the overnight period (tonight) into Sunday, but lingering moisture and Sunday afternoon instability will keep a slight chance of showers/thunderstorms over the higher terrain of central and south-central Idaho. Otherwise, building high pressure with southwest flow aloft is forecast Sunday, bringing a drying and warming trend across much of the area. A new swath of monsoon moisture will pass through the area again on Monday, continuing a chance of showers and thunderstorms over the higher terrain of northeast Oregon, and central/south- central Idaho Monday afternoon. While temperatures will be near normal today, expect temps to rise a couple of degrees above normal for Sunday and Monday under the influence of the upper ridge and southwesterly flow aloft.

LONG TERM /Tuesday through Saturday/

A weak shortwave trough will skirt through the northwestern U.S. Tuesday and Wednesday, flattening the aforementioned upper ridge and nudging the monsoonal moisture toward the east. As a result, dry conditions with slight cooling is forecast for mid- week. The southwest U.S. ridge will make a rapid return by Thursday and Friday, amplifying northward into Canada while a Pacific trough approaches the West Coast. This pattern will support rapid heating and the influx of monsoonal moisture once again, with shower and thunderstorm chances increasing by Friday.

AVIATION /06Z Saturday through Sunday/

Issued 1157 PM MDT FRI AUG 14 2026

Generally VFR. Storm activity has decreased, with isolated showers and tstorms lingering near the NV border through mid morning. Late this morning/aftn, scattered storms re-develop in far E Oregon and SW Idaho. Storms capable of small hail, gusty winds to 40 kt, and MVFR downpours. Surface winds: variable 5-15 kt. Winds aloft at 10kft MSL: SW-S 5-20 kt.

KBOI...VFR. Scattered showers/thunderstorms re-develop in SW Idaho in the afternoon, with a 20% chance of hitting KBOI terminal. Storms capable of 30-40 kt outflow gusts and brief downpours. Surface winds: SE 5-15 kt, with gusts to 15-25 kt possible this morning and early afternoon. Transitioning to erratic/variable mid-afternoon due to nearby storm activity.

Sunday Outlook...Showers and thunderstorms largely taper off Sunday, with isolated coverage across central and south-central ID. Surface winds: SW-NW 5-10 kt Sunday. Periods of smoke near KBKE/KBNO.

BOI WATCHES/WARNINGS/ADVISORIES

ID...Flash Flood Watch through this evening for IDZ013. OR...Red Flag Warning until 7 PM PDT this evening for ORZ674-675.