056
FXUS65 KBOI 131814
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
1214 PM MDT Thu Aug 13 2026

.UPDATE...Updated aviation discussion.

&&

.KEY MESSAGES...
- Fire weather concerns increase due to threat of thunderstorms
  this afternoon into Friday.

- Thunderstorms with heavy rain may also increase the risk for
  flash flooding especially for recent burn scars on Friday and
  Saturday.

- Temperatures cooling to around 5 degrees below normal come
  Friday.

&&

.SHORT TERM /Through Saturday Night/...
Issued 253 AM MDT THU AUG 13 2026
A more active pattern will kick off today, continuing into
Saturday. Current water vapor imagery shows a deepening trough
over the west coast, with an embedded shortwave out ahead of it.
This shortwave will continue to eject around the trough through
the day, leading to scattered showers and thunderstorms this
afternoon into Friday morning. Storms will initially take on
more of a dry posture, leading to elevated fire weather concerns
when combined with the lightning potential. Thunderstorms this
afternoon will also be capable of wind gusts to 40-45 mph.

With a more saturated atmosphere come Friday, the threat
associated with thunderstorms will transition from dry lightning
and gusty winds to heavy rain. Heavy rain will increase the
risk for flash floods and debris flows, especially across
steep/rocky areas and recently burned areas (including the
Wapiti burn scar). The better dynamical forcing at this point
will be over southwest Idaho, with the highest chances of
precipitation (60-95%) over the Central ID Mountains, with
scattered thunderstorms continuing. With moisture remaining
elevated (80-90th percentile PWATs) in the southwest flow aloft
come Saturday, hazards similar to that of Friday will present
themselves yet again over the same area. Temperatures come
Friday will be around 5 degrees below normal.

&&

.LONG TERM /Sunday through Thursday/...
Issued 253 AM MDT THU AUG 13 2026
Ridging will build back in over the Great Basin come Sunday,
leading to near normal temperatures and generally dry conditions
through Monday. Barring a slight chance (10-20%) of afternoon
showers and thunderstorms over the Central ID Mountains. Come
Tuesday, a quick short-wave looks to approach from the
northwest, reintroducing breezy conditions and precipitation
chances. Moisture looks to be more limited this time around,
with the best chances of precipitation (15-35%) over higher
terrain. Beyond Wednesday, guidance hints at a ridge building
back in over the great basin, support another warming and drying
trend.

&&

.AVIATION /18Z Thursday through Friday/...
Issued 1210 PM MDT THU AUG 13 2026
Generally VFR. Isolated to scattered showers and thunderstorms
across the area through late this evening. Outflow gusts up to
around 40 kt near thunderstorms. Surface winds: SW- NW 5-15 kt.
Variable and gusty winds to 25 kt near showers. Winds aloft at
10kft MSL: W-SW 5- 15 kt.

KBOI...VFR with reduction in visibility due to wildfire smoke
at times. Foothills obscured by smoke. Smoke improving this
afternoon. A 20% chance of showers and thunderstorms by late
evening, continuing overnight. Surface winds: Light and
variable becoming SE 10-20 kt after 22z.

Weekend Outlook...Isolated to scattered showers and
thunderstorms continuing Saturday. Storms Saturday capable of
heavy rain, gusty outflows, and MVFR conditions. Showers taper
off come Sunday with clearing skies. Surface winds: SW-SE 5-15
kt Saturday, then SW-NW 5-10 kt Sunday. Light and variable
overnight.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning until 6 AM MDT Friday for IDZ400>403-420-421-
     423-424-426.
     Flash Flood Watch from Friday afternoon through Saturday
     evening for IDZ013.
OR...Red Flag Warning until 5 AM PDT Friday for ORZ670>672.
     Air Quality Alert until 1 PM MDT /noon PDT/ Friday for ORZ061-
     063-064.
     Red Flag Warning until 9 AM MDT /8 AM PDT/ Friday for
     ORZ673>675.
&&

$$

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AVIATION.....JDS
SHORT TERM...NF
LONG TERM....NF