109
FXUS65 KBOI 261605
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
1005 AM MDT Sat Jul 26 2025

.DISCUSSION...A few small changes to the forecast this morning,
but big picture remains unchanged. Looking at afternoon showers
and thunderstorms initiating along the northern NV border and
across the w-central Idaho mtns. Storm motion is from south to
north today which will bring the NV border storms into e-central
Oregon and the Snake Plain by early evening. Storms across the
w-central mtns will exit that region by early evening. Expect
storms to enter the Snake Plain sometime between 5 and 7PM,
though a bit earlier (3-5PM) in the western Magic Valley. Gusty
outflow winds of 30 to 50 mph are possible from the storms which
could kick up dust. Also potential for brief heavy rain. Made
some changes to thunderstorm coverage, mostly across SE Oregon
this afternoon, and touched up the winds. Otherwise forecast is
on track.

&&

.AVIATION...VFR. Isolated to scattered showers/thunderstorms
across E Oregon and SW Idaho after 20z. Thunderstorms capable
of producing outflows of 45 kt, heavy rain, and localized
blowing dust may result in MVFR/IFR conditions. Mtns obscured in
showers/thunder. Surface winds: Variable up to 10 kt, becoming
SW-NW 5-10 this afternoon with gusts near 15 kts. Winds aloft at
10kft MSL: Variable 5-15 kt.

KBOI...VFR. A 20% chance of showers/thunderstorms between
Sun/00z and Sun/06z. Thunderstorms capable of 45 kt outflows
and localized blowing dust resulting in MVFR visibilities.
Outflows may travel from distant storms. Surface winds: Variable
under 10 kt, becoming NW 5-10 kt this afternoon with gusts near
15-20 kts possible.

Sunday Outlook...Less thunderstorm coverage is expected Sunday
afternoon/evening. Greatest chances for thunderstorms will be in
Valley county, Eastern Oregon, and near the ID/OR/NV border.
Storms will move largely straight S-N, and will be capable of
producing gusty outflow winds with speeds up to 45 kt. Winds
could produce blowing dust. Outside of storms, surface winds
generally W-NW 5-15 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Monday night...Moisture circulating
around an upper level low over northern California will stream
northeastward across the forecast area this afternoon. The
atmosphere will become unstable in the afternoon after mostly
sunny skies in the morning have caused the surface to heat up.
Cumulus clouds will develop across the area in the afternoon and
scattered showers and thunderstorms will form in southern
Oregon near the Nevada border in southwestern Idaho in the
Owyhee Mountains and highlands near the Nevada boarder. The
thunderstorms will spread north of the Snake River in the late
afternoon and there is a slight chance (20 percent) that some of
the storms will reach the Treasure Valley in the early evening
bringing gusty outflow winds. Isolated thunderstorms are also
expected in the higher mountains of central Idaho. Thunderstorms
will diminish after sunset tonight. Lingering moisture in
southwest flow aloft will be enough to forecast a slight chance
of afternoon showers and thunderstorms again on Sunday and
Monday. Temperatures will be near normal today and on Sunday
with a warming trend beginning on Monday.

LONG TERM...Tuesday through Saturday. An active pattern continues
through Saturday. A building ridge over the Great Plains and a low
in the Gulf of Alaska will keep our area under southwest flow aloft
throughout the long term. This southwesterly flow will keep a source
of mid-level moisture across the area; the mid-level moisture,
paired with afternoon destabilization during peak heating, allows
for daily chances of afternoon showers/thunderstorms in eastern
Oregon and south of the Snake River. Chances of precipitation
generally range from 15-30% each afternoon with a 15-20% chance of
thunderstorms across those locations. Chances across lower
elevations remain under 15%. Wednesday/Thursday, deterministic and
ensemble guidance shows a trough lifting across the area. The added
dynamics from this trough could allow for higher coverage in showers
and thunderstorms those afternoons, although it is still to far our
to delve into specifics. Beyond thursday ensemble guidance shows our
area remaining under... you guessed it... southwest flow aloft.
Temperatures will be right around normal for this time of year
through Thursday, before leaning below normal to end the week.


&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning from 4 PM this afternoon to 10 PM MDT this
     evening IDZ423.
OR...Red Flag Warning from 3 PM this afternoon to 9 PM PDT this
     evening ORZ672.

&&

$$

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DISCUSSION...DG
AVIATION.....CH
SHORT TERM...JB
LONG TERM....NF