477
FXUS65 KBOI 191601
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
1001 AM MDT Sun Oct 19 2025
.DISCUSSION...A cold front is on the move through SE Oregon this
morning with showers developing along and ahead of the front.
It is moving southeast at a steady clip (~30mph) and should
continue at this speed as it crosses the region. The back edge
of precipitation has reached Baker City (0830PT) and is timed to
pass through Burns Oregon by 0930PT, McCall/Ontario ~1130MT,
Caldwell/Boise 12-1300MT, reaching Twin/Jerome 1500-1600MT.
Showers will produce locally moderate precipitation and gusty
winds to 40 mph. Post frontal instability will feed another
round of scattered showers late this afternoon into the evening.
Increasing instability and lapse rates aloft along with
lowering freezing levels could support a thunderstorm in the
late afternoon-early evening (1500-2000MT). For now see the
chance at less than 15%. Post frontal winds remain breezy this
afternoon most sites seeing gusts of 25-40 mph. Have touched up
the winds for today.
&&
.AVIATION...LLWS this morning. Precipitation moving NW to SE
through Mon/02Z. Isolated showers continuing over the W-Central
Mountains through Mon night. Snow levels 7-8kft MSL this
morning lowering to around 5kft MSL by Sun night. Low VFR/MVFR
in rain showers, MVFR/LIFR in snow. Mountains obscured. Surface
Winds: SW-SE 5-15 kt, gusts to 15-25 kt. Shifting to SW-NW 10-25
kt gusts to 20-35 kt behind the cold front. Winds aloft at
10kft MSL: SW-W 35-50 kt.
KBOI...VFR through Sunday AM. LLWS possible Sunday morning. A cold
front will bring rain showers between Sun/16z-21z. A 30% chance of
MVFR during rain, with foothills becoming obscured. Surface winds:
southeast 8-15 kt tonight. Shifting to NW-W 8-15 kt gusts to
20-25 kt behind cold front this afternoon.
&&
.PREV DISCUSSION...
SHORT TERM...Today through Tuesday night...Clear conditions
will continue tonight, with cold temperatures in valleys
inhibited slightly from warm southeast winds. A cold front will
move in from the northwest this morning, bringing gusty winds
and a band of precipitation to the region. Winds will be mainly
out of the northwest at 10-20 mph, with gusts up to 40 mph on
higher ridge tops. Heavier precipitation is likely within the
band, with high terrain in southwest Idaho seeing around
0.50-1.0 inches of rain by the late evening. Snow levels will
stay elevated ahead of the frontal passage, near 8000 feet MSL
this morning with the bulk of the precipitation. They will drop
to around 5000-6000 feet MSL by late afternoon, with snow
accumulating to 1-3 inches at higher elevations, especially as
the front moves east. Showers will linger over high terrain into
Monday morning, but conditions should mostly dry out for the
rest of the short term period as the bulk of the moisture moves
east. Temperatures will then drop for the next several days,
with cooler northwest flow dominating the pattern as a ridge of
high pressure begins to slowly build in on Monday and Tuesday.
LONG TERM...Wednesday through Sunday...Warm and dry conditions will
prevail into the weekend under generally west-to-east flow aloft,
with high pressure positioned over the Great Basin. A weak storm
system will move across the area late Wednesday, bringing a mostly
dry cold front. This system may try to combine with a closed low-
pressure center moving across central Nevada Tuesday from west of
the Baja Peninsula. Most forecast models keep this low well south of
the region, and with it, the associated rain with some
increased cloud cover. Overall, these two systems will help
moderate our temperatures, with only a few degrees of warming
each day in most locations. Friday will be the warmest day (5 to
10 degrees above normal) as a brief ridge of high pressure
builds in behind the shortwave and ahead of the next major
storm. No significant changes are seen with the major pattern
shift expected late Friday into early Saturday. Forecast
guidance shows a favorable setup for widespread precipitation. A
deepening trough over the Pacific Northwest will shift the flow
aloft to southwesterly, which taps into a strong plume of
Pacific moisture ahead of a cold front set to push into the area
this weekend. Consequently, confidence is high in the chances
for breezy winds and widespread precipitation starting as early
as Friday afternoon or evening.
Warm air moving into the region will help keep our snow levels
elevated to 8000 to 9000 feet. Once the associated cold front
passes, snow levels will drop, allowing for a better chance of
mountain snow accumulations by late Saturday. This could bring
significant snowfall to the mountain peaks, especially later in the
weekend once the colder air mass moves in.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
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DISCUSSION...DG
AVIATION.....NF
SHORT TERM...SA
LONG TERM....JDS
