135
FXUS65 KBOI 140309
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
909 PM MDT Wed Aug 13 2025

.DISCUSSION...Isolated showers and thunderstorms near the ID/NV
border south of Twin Falls will continue to diminish and end by
late this evening. The same area could have another round of
showers/thunderstorms Thursday afternoon, but the chance is less
than 25 percent. A weak front will result in 5 to 10 degrees of
lower temperatures on Thursday with highs close to normal. No
updates.

&&

.AVIATION...VFR. Isolated thunderstorms south of KTWF, ending by
Thu/04Z. Gusts to 30 kt near storms. Smoke from wildfires over
West Central Mtns and near KMYL. Surface winds: W-NW 5-15 kt.
Winds aloft at 10kft MSL: W-NW 10-20 kt.

KBOI...VFR. Surface winds: W-NW less than 10 kt.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Friday night...The upper high
that`s brought the recent heat will shift further east on
Thursday, placing the region in dry west-southwest flow aloft.
In response, high temperatures will drop 5 to 8 degrees from
today to Thursday, then hold steady into Friday. South-central
Idaho remains on the fringe of monsoon moisture and keeps enough
daytime instability to support a slight chance of afternoon
thunderstorms along the ID/NV south of the western Magic Valley
Thursday and Friday. A deepening trough off the West Coast will
turn winds more SWly and begin increasing moisture across SE
Oregon and the w-central ID mtns on Friday. The air mass
remains too stable aloft for shower/storm development but will
see an increase surface dew points and RH. Winds are breezy on
Thursday relaxing some on Friday as the surface pressure
gradient weakens.

LONG TERM...Saturday through Wednesday...Southwest flow will
dominate through Wednesday, thanks to an upper-level low over
the Gulf of Alaska and a building ridge over the Four Corners
region. Saturday afternoon, a cold front will enter our area
from the northwest and stall out in eastern Oregon. This front
will coincide with a good stream of Pacific moisture, which will
increase PWATs to near the 90th percentile (ensemble mean
values surpass an inch in some areas). While it still looks like
the better axis of moisture will set up west of our area, there
will be enough to support chances of precipitation west of a
line roughly from Rome to McCall. For now, the chances of
precipitation range from 15-50% with a 15-20% chance of
thunder, increasing as you move west from the aforementioned
line. However, if the stream of Pacific moisture shifts east,
chances may need to be increased. Come Sunday afternoon, height
falls aloft and PWATs near the 70th percentile will allow for a
more widespread chance of showers/thunder as peak heating
destabilizes the atmosphere. Chances of showers outside of the
Snake Plane Sunday afternoon range from 15-40% with a 15-30%
chance of thunderstorms. The chances of showers/thunderstorms
within the Snake Plane are non-zero...but keeping them under 15%
for now.

There is a 15-20% chance of showers/thunder in far western Baker
county come Monday afternoon. However, aside from that, dry air
advecting across our area will keep us dry beyond Sunday.
Temperatures will be near normal on Saturday, before warming a
couple of degrees each day through Tuesday. Temperatures Tuesday
and Wednesday will be similar and lean a few degrees above
normal.

&&

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

&&

$$

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DISCUSSION...BW
AVIATION.....BW
SHORT TERM...DG
LONG TERM....NF