876
FXUS65 KBOI 281046
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
446 AM MDT Wed Oct 28 2026

.UPDATE...Updated aviation discussion.

&&

.KEY MESSAGES...
- Dry through Thursday, with near normal temperatures.

- Precipitation chances increasing across higher terrain Friday
  afternoon. Becoming widespread Saturday afternoon.

- A drying and warming trend will set in Monday, through at
  least midweek.

&&

.SHORT TERM /Through Friday Night/...
Issued 1253 AM MDT WED OCT 28 2026
Following the departing shortwave, a drying and clearing trend will
continue this morning. These clearing skies will allow for good
radiational cooling; which, when combined with the recent
precipitation, will allow for the development of fog/freezing
fog this morning (especially in sheltered valleys).
Temperatures this afternoon will generally be in the 50s in the
low elevations, and 40s in the Oregon high desert and higher
Idaho Basins. As flow aloft backs to be out of the southwest,
thanks to a deepening low off the west coast, a warming trend
will set in Thursday afternoon (highs around 5 degrees warmer
than today). Before this, clear overnight skies tonight allow
for cooler low temps. The majority of lower elevations will
reach near or below freezing Thursday morning, with lows of
10-20 degrees in the Oregon high desert and higher Idaho basins.


A weak shortwave rotating through this low will bring an increase of
high cloud cover Thursday. Another consequence of this shortwave
will be increasing precipitation chances early Friday over the
central Idaho mountains. The southwesterly flow aloft will keep snow
levels high and snow accumulations low, with a dusting to an inch of
snow expected above 6kft.

&&

.LONG TERM /Saturday through Wednesday/...
Issued 1253 AM MDT WED OCT 28 2026
As the shortwave in the short-term period departs, the main low will
begin moving its way through our area. This trough will have a good
pull of Pacific moisture ahead of it, with precipitable water values
increasing to around the 90th percentile in southwest Idaho. The
better juxtaposition of forcing and moisture will fall over
southwest Idaho, which will lead to increasing precipitation chances
through the day Saturday, reaching 50-80% Saturday evening and night
as a cold front crosses the area. That being said, an umbrella may
be a fine addition to your Halloween costume. Snow levels will
initially begin at 6-8 kft MSL, lowering to 4.5-6.5 kft MSL by
Sunday afternoon. These lowering snow levels will coincide with
decreasing precipitation chances as conditions dry out behind the
front. Overall, the bulk of any snow accumulation will remain above
6.5 kft MSL, with generally 2-5 inches of accumulation (Locally up
to 7 on the highest peaks). The lowering snow levels could allow for
snow or wintry mix as low as 4.5 kft Sunday, although little
accumulation is anticipated as precipitation tapers off behind the
departing system. Ridging will build in behind the departing system,
allowing for dry conditions Monday afternoon through at least mid-
week. Temperatures will be seasonable or below normal throughout the
period.

&&

.AVIATION /12Z Wednesday through Thursday/...
Issued 447 AM MDT WED OCT 28 2026

Generally VFR. Localized LIFR/IFR conditions this morning with
patchy freezing fog and low clouds in high elevation valleys
near KBNO-KMYL-KBKE. Mountains obscured in fog and low clouds.
Conditions improving after sunrise. Surface winds: Variable
less than 10 kt this morning, then SW-SE 5-15 kt this
afternoon. Winds aloft at 10kft MSL: SW 20-30 kt.

KBOI...VFR with clearing skies this morning. Surface winds:
SE 5-10 kt with a period of light and variable winds this
afternoon.

&&

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

OR...None.

&&

$$

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