Mesa, Idaho Weather Forecast Discussion

335
FXUS65 KBOI 300302
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
902 PM MDT Mon Sep 29 2025
.DISCUSSION...Thunderstorms continue ahead of a cold front. The
cold front has moved through Burns and Baker City and will race
across the rest of the forecast area later tonight reaching
Boise around midnight and continue moving east reaching the
Magic Valley by 3 am. Winds will shift to the NW behind the
front. Thunderstorms ahead of the front have been moving rapidly
toward the north east and have been producing very gusty
outflow winds of 40 to 50 mph, with isolated gusts as high as 70
mph. These outflow winds will move through the populated areas
of the Treasure Valley between 9:00 pm and 10:30 pm.
Thunderstorm activity should diminish in intensity and coverage
after 11:00 pm.
&&
.AVIATION...A cold front will move from east to west tonight
reaching the Idaho border by 04Z, KBOI by 06Z, and KTWF by 09Z.
Scattered thunderstorms with gusty winds to 45 kts can be
expected ahead of the front until around 06Z. Areas of rain
after midnight will produce MVFR ceilings visibilities.
Prevailing winds will shift to NW at 10 to 15 kts behind the
cold front.
KBOI...MVFR. Cold frontal passage around 06Z. Scattered
thunderstorms ahead of the front likely impacting the terminal
between 03Z and 05Z. Wind gusts to 40 kts will be associated
with thunderstorms. Prevailing winds will shift to NW at 10 to
15 kts behind the font.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Wednesday night...The main Pacific
cold front will move eastward across the OR/ID border early this
evening, across western Idaho during the night, and exit east
of our CWA by sunrise. Showers and scattered thunderstorms (30
percent areal coverage) with local heavy rain as the front passes,
with a brief windshift to west or northwest 15 to 25 mph, then
several hours of steady moderate rain with light winds. Total
rainfall should be .50 inch to 1.00 inch in the Idaho mountains
(heaviest in the Boise Mountains), and .25 to .50 inch in the
Idaho valleys, with about half those amounts on the Oregon side.
Scattered light rain showers continuing Tuesday through
Wednesday mainly over northern mountains, with a slight chance
of thunderstorms in the afternoon and evening hours. Another
Pacific cold front with more showers expected Wednesday night.
LONG TERM...Thursday through Monday...An upper low over the
coast of British Columbia will slowly break off and dig into
the Northwest region as a longwave trough through Thursday.
Southwest flow will be expected throughout the area Thursday and
Friday, with precipitation mostly concentrated along the western
Idaho side both days. A cooling trend is expected to continue
toward the end of the week, with peak valley temperatures
expected to gradually drop into the mid to lower 60s by Sunday.
Friday through Saturday will generally see the longwave trough
slowly dig southeastward across the region, but not signaling
much precipitation at this time. There is considerable uncertainty
over another upper low digging southward from British Columbia
or a longwave trough over the area Sunday through Monday. For
now, a drier and cooler pattern is expected for the weekend into
Monday.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
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DISCUSSION...JB
AVIATION.....CH
SHORT TERM...LC
LONG TERM....JY

NWS BOI Office Area Forecast Discussion