963
FXUS65 KBOI 190245
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
845 PM MDT Fri Jul 18 2025

.DISCUSSION...Isolated showers and thunderstorms continue to
move ENE near the NV/OR border, and also over Owyhee and Twin
Falls counties as of 8:30 PM PDT. Activity has been decreasing
over the past hour, and we expect that downward trend in both
coverage and intensity to continue. Smoke from area wildfires
continues to contribute to hazy skies. A relatively new fire
near Adrian, OR is currently emitting a great deal of smoke that
is headed to the east (into much of the Treasure Valley). This
smoke is likely to be trapped in the boundary layer overnight in
the populated I-84 corridor from Caldwell to Boise.

Otherwise, a weak "less hot" front will move through Saturday,
taking temps back down to near normal. This front will be dry.
The next chance of storms still appears to be Monday. Minor
changes were made to indicate where smoke is expected to be
overnight and tomorrow morning from the new fire.

&&

.AVIATION...VFR. Smoke aloft in West Treasure Valley and ID/OR
border. Few isolated showers/thunderstorms near ID/NV border
expected to dissipate later this evening. Surface winds: W/NW 5-15
kt. Gusts to 25 kt in SE OR and south of Snake River in ID until
sunset.

KBOI...mainly VFR. Some smoke aloft from fire near KONO. Surface
winds: NW 5-10 kt, then variable less than 7 kt tonight.

Sunday Outlook...VFR. Areas of smoke aloft. Surface winds: W-NW
5-15 kt with afternoon gusts 20-30 kt for most areas.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Sunday night...A disturbance in
the zonal flow aloft is moving over the CWA this afternoon.
Cumulus fields and convection are ongoing over much of our
southern zones. This activity is expected to continue for the
next few hours and weaken during the evening. Thunderstorm
outflows from these scattered thunderstorms south of Twin Falls
may produce wind gusts near 45 mph. After this evening,
northwesterly flow aloft will keep conditions dry. The first
push of cooler air, from the upper-level trough over British
Colombia, will bring a "cold" front that will stall out across
a SW-NE line from Burns, OR to McCall, ID. Late Sunday night,
the upper-level trough that had been unmoving will finally drift
south and begin to bring precipitation chances back in behind
another "cold" front. Temperatures will be 5 degrees cooler than
normal with these fronts on Saturday and Sunday. Winds will be
breezy from the northwest over the area on Saturday, gusting to
around 20 mph.

LONG TERM...Monday through Friday...The upper-level trough
moving south from British Colombia is the main story over the
long term period. To begin Monday morning, PoPs range from
15-20% currently over our northern zones. The ECMWF and GFS
largely disagree on precipitation amounts at the moment, so that
will be a forecast point to watch over the next few model runs.
Afternoon to evening thunderstorms are possible (15-20%) on
Monday. For Tuesday, more southwesterly flow will dominate,
bringing drier air and lower PoPs. Temperatures through Monday
and Tuesday will be 5 degrees below normal. Depending on the
trough movement trend, PoPs may rise to mentionable amounts
again Tuesday. Late Tuesday into Wednesday, the negatively
tilted trough over the Pacific NW will cut off over the
California coast, with the rest of the trough moving east.
Wednesday and Thursday, the cut off low will stall, putting the
CWA in southerly flow aloft. This will bring warmer air back
into the area. Moisture and lift from the nearby upper-level
low look to be increasing PoP chances again late Thursday in SE
OR. On Friday, another upper-level trough looks to come from
Canada again, although timing and amplitude is not well agreed
upon at this time.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.

&&

$$

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DISCUSSION...SP
AVIATION.....JY
SHORT TERM...CH
LONG TERM....CH