FXUS65 KBOI 270252
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
852 PM MDT Sat Apr 26 2025

.DISCUSSION...Scattered showers and thunderstorms continue over
SE Oregon the w-central Idaho mountains this evening. Have seen
brief heavy rain and wind gusts to around 25 mph (outside of
high-elvation RAWS sites). The chance for showers and
thunderstorms will continue overnight across southern Harney,
Malhuer, and Owyhee County. Locally heavy rain will be the main
attribute to overnight showers and thunderstorms as the gusty
wind threat is minimal. Areas to the north will see activity
diminish through this evening. Forecast has been updated for
showers/storms across the w-central mtns this evening.

&&

.AVIATION...Mostly VFR. Showers/storms producing local IFR in
reduced visibility across SE OR and far SW ID overnight. Local
mtn obscuration. Scattered to numerous showers and isolated
thunderstorms redevelop areawide on Sunday producing local IFR
conditions and obscuring mtns. Surface winds: N-NW 10-20 kt. SE
OR will gust up to 35 kt Sunday afternoon and evening. Winds
aloft at 10kft: E 5-15 kt becoming N-NW Sunday afternoon.

KBOI...VFR. Surface winds remaining N-NW overnight. Showers
Sunday afternoon with a 20-30% of thunderstorms. Brief IFR
conditions in heavy rain would accompany thunderstorms.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Monday night...At 2 PM MDT
showers were developing over higher terrain in our CWA,
mainly in western Owyhee County and in the Boise Mountains.
Meanwhile, the main Pacific upper low has moved toward the
California coast just off SFO. The low is forecast inland
across central California this evening, northeastward across
Nevada overnight, southeast ID Sunday, then western Wyoming
Sunday night. This track will bring significant rain to our
southern zones overnight through Sunday night, heaviest
(up to 1.00 inch) in southern Malheur County, and generally
50 to 1.00 inch along the entire northern Nevada border.
Another area of moderate to heavy pcpn (.50 to .80 inch) is
indicated in the central Idaho mountains east of Idaho City-
McCall. Elsewhere, expect .15 to .30 inch total rainfall in the
Treasure Valley, upper Weiser River Valley, and central Malheur
and Harney Counties in Oregon. Around .10 inch is forecast for
the western Magic Valley. Least rainfall (less than .10 inch) is
slated for Baker County. As the upper low gets into northeast
Nevada Sunday a north-south cold front will take shape in our
Idaho zones, with showers and a 20-40 percent chance of
thunderstorms along the front as it moves east, finally exiting
our CWA Sunday night. West to post-frontal northwest winds will
increase to 15 to 25 mph in Oregon and western Idaho Sunday
afternoon. Temperatures will be mild tonight due to southerly
flow aloft, and again Sunday night due to continuing mixing
winds. High temps Sunday will be a few degrees lower than today
with widespread clouds and showers in our CWA.

LONG TERM...Tuesday through Saturday...As an upper low moves
east Tuesday morning, another trough will move in that night
into Wednesday morning, bringing another round of clouds and
precipitation. This will cool Tuesday to right about normal
temperatures. Wednesday afternoon through Friday morning upper
high pressure dominates, warming temperatures up to 10-15
degrees above normal. Highs in the Snake Plain Thursday and
Friday will be close to just above 80 degrees. Some uncertainty
exists about the timing of our next system later Friday. While
the GFS deterministic brings the precipitation in the afternoon,
potentially limiting the max temperature to the upper 70s;
other deterministic models show a Friday evening arrival which
would allow temperatures to warm up to the mid-low 80s in the
Snake Plain. Confidence is high in the systems track through our
area and thusly the temperature forecast for Saturday dropping
back to near normal. Thunderstorms are possible later Friday and
Saturday.

&&

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

&&

$$

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DISCUSSION...DG
AVIATION.....DG
SHORT TERM...LC
LONG TERM....JM