FXUS65 KBOI 281525
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
925 AM MDT Mon Apr 28 2025

.DISCUSSION...Upper low has moved to western Utah this morning
with moisture still wrapping around the northern and western
sides and causing light rain showers in south-central Idaho.
Current forecast has showers there and also has a slight chance
of thunderstorms from the Camas Prairie southward through Twin
Falls County this afternoon and early evening. Latest hi-res
models do show evidence of convection but SPC has downplayed
it. After clearing and cooler wx tonight, the next upper
trough will approach from the northwest Tuesday with light
rain showers in northern areas but only sprinkles to the south.
Then clearing and breezy Wednesday followed by sunny and warmer
weather Thursday and most of Friday under strong high pressure
aloft. Overall, no eventful weather through early Friday. After
that another north Pacific upper trough/low is forecast to move
inland along roughly the same track as this past weekend's
system, leading to showers and chance of thunderstorms, and
cooler temps. No updates.

&&

.AVIATION...Mostly VFR. Patchy mist and low ceilings clearing this
morning. Light showers/virga near the ID/NV border moving south
of the area this afternoon. Storm development north of KTWF/KJER
this afternoon is expected with a 30% chance for them to move
south into the TAF sites. Surface winds: NW 5-15 kt, with some
local gusts to 25 kt this afternoon. Winds aloft at 10kft:
N 10-20 kt.

KBOI...VFR and partly cloudy. 5-15 kt NW winds with gusts up to
25 kt this afternoon, calming to SE 3-8 kt tonight.

&&

.PREV DISCUSSION...
SHORT TERM...Today through Wednesday night...The closed upper
low is now off to our SE, and will still influence the weather
in our SE today. As the low moves SE into southern UT today,
there will be enough residual moisture and instability for
showers and a slight chance of thunderstorms near and south of
Fairfield. This chance extends until roughly 9 PM MDT this
evening. An upper level ridge will build in from the NW and
bring clearing skies tonight and early Tuesday. This will be
followed rapidly by a relatively dry short wave trough. Showers
will move back into the area from NW to southeast from late
Tuesday morning through Tuesday night, with the best chance in
the West Central Mountains. Rainfall/snowfall amounts are
expected to be light due to limited moisture, with even the
higher elevations seeing around a tenth of an inch or less of
liquid equivalent. Snow levels should be 7000 to 8000 ft MSL.
A stronger upper ridge will follow this trough into the PacNW,
bringing dry conditions Wednesday and Wednesday night, and start
a warming trend that will last through the workweek.


LONG TERM...Thursday through Monday...A warm and dry upper-level
ridge will amplify over the northwestern U.S. on Thursday, boosting
daytime temperatures by 5-10 degrees from Wednesday. Additional
warming from strengthening southerly flow is anticipated Friday, as
the ridge axis shifts east of the forecast area ahead of a deep
Pacific trough. As the trough approaches, the chance for showers and
thunderstorms will increase Friday afternoon and evening (30-60%),
then increase further on Saturday (60-80%) associated with the
arrival of a cold front. Temperatures will become notably cooler on
Saturday in the wake of the cold front, but should remain within a
few degrees of normal. In addition, surface winds will transition
from southerly to northwesterly behind the front, remaining gusty
throughout the weekend. Models depict that the trough will evolve
into a cut-off low by late Saturday/Sunday, with the center of the
low forecast to track through northern CA and NV during this time.
As a result, wrap-around moisture will support continued chances of
showers and thunderstorms, breezy winds, and slightly cooler than
normal temperatures into Monday.

&&

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

&&

$$

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DISCUSSION...LC
AVIATION.....JM
SHORT TERM...SP
LONG TERM....SH