007
FXUS65 KBOI 172037
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
237 PM MDT Sun Aug 17 2025

.SHORT TERM...Tonight through Tuesday night...Thunderstorms
will remain the main concern across the region through late
tonight, developing first along the IdahoNevada border and then
expanding into southeast Oregon. Atmospheric conditions are
favorable for heavy rainfall, with precipitable water values
near 1.0 incharound the 95th percentile for mid- August.
Combined with an approaching shortwave providing lift and modest
instability near 600 J/kg, storms are expected to be better
organized and longer-lived than those observed yesterday. Heavy
rain and gusty outflow winds will be the primary hazards.

Storms are already developing along the IdahoNevada border and
will drift north-northeast into the Magic Valley by around 4 PM
MDT. The drier boundary layer in this region increases the
potential for stronger outflow winds with the more intense
storms.

Farther west, additional thunderstorms are expected to initiate
around 5 PM MDT across southeast Oregon ahead of the shortwave.
These storms will move north-northeast through the evening,
spreading across southeast Oregon into the West Central
Mountains and possibly reaching the Treasure Valley later
tonight. There is about a 20 percent chance of storms reaching
the Treasure Valley between 7 and 11 PM MDT. The greatest flash
flood risk will continue to be over recent burn scar areas,
where Flash Flood Watches remain in effect.

Hotter and drier upper ridge will begin building westward from
the Rockies and Great Basin on Monday. By Tuesday afternoon,
circulation around the high may draw monsoon moisture northward
into southern Idaho, though model guidance remains inconsistent.
For now, Tuesday remains dry in the forecast.

.LONG TERM...Wednesday through Sunday...Enough monsoon moisture
should reach southern Idaho to support at least a 15 percent
chance of thunderstorms near the IdahoNevada border on
Wednesday, with low chances continuing through the remainder of
the week. The entire period will remain hot, with high
temperatures running 5 to 10 degrees above normal as the upper
high remains centered over the Great Basin. Afternoon highs in
the southern valleys will push well into the 90s, with some
locations approaching 100 degrees at times. Aside from the
limited storm potential, conditions will generally be dry, with
the ridge keeping most of the region under stable and hot
weather.

&&

.AVIATION...Mostly VFR. Scattered thunderstorms this afternoon
and evening. Storms will produce heavy rainfall, small hail, and
gusty outflows. Local visibility restrictions due to wildfire
smoke in the W-Central ID Mtns. Surface winds: Light and
variable this morning, becoming mostly NW 5-15 kt this
afternoon. Winds aloft at 10kft MSL: SW 10-20 kt.

KBOI...VFR. A 20% chance for thunderstorms later this evening.
Storms could produce heavy rainfall, hail, and 35 kt outflows.
Surface winds outside outflows: NW 5-15 kt.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Flash Flood Watch until midnight MDT tonight
     IDZ011-012-015-029-033.
OR...Flash Flood Watch until midnight MDT /11 PM PDT/ tonight
     ORZ061>064.

&&

$$

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