Richland, Oregon Weather Forecast Discussion

428
FXUS65 KBOI 170827
AFDBOI
Area Forecast Discussion
National Weather Service Boise ID
227 AM MDT Wed Sep 17 2025
.SHORT TERM...Today through Friday night...Sunny, warmer days, and
clear cool nights will continue through Thursday evening under high
pressure aloft. The ridge axis will shift east of our CWA Thursday
night and southwest flow aloft will then draw moisture northward
through the California Sierra Nevada and bring high clouds into
eastern Oregon by Friday morning. The clouds will slightly raise
low temperatures in Oregon. Thursday and Friday will be the
warmest days this week with highs about 10 degrees above normal.
Winds will be light diurnal through the period except southeast
gusts 15 to 20 mph midday today near Mountain Home and Glenns
Ferry, ID. Wildfire smoke will be negligible near the surface.
.LONG TERM...Saturday through Wednesday...Several degrees cooler
(but still above normal) this weekend as a weak upper trough comes
inland from the Gulf of Alaska and another weak upper trough comes
inland across Calif and Nevada. The southern trough will bring a
15-20 percent chance of showers to the ID/NV border Saturday
afternoon. By Sunday both troughs will be east of us but the
southern one will leave clouds near the ID/NV border, while
northern areas become sunny again. Sunday night a stronger north
Pacific upper trough will come inland, with a dry cold front
passing through our CWA overnight and Monday morning. The front
will bring clouds, gusty west/northwest winds, and briefly cooler
temps. By Tuesday forecast models show the trough and cooler air
already well east of us, with the next strong upper ridge
building over the interior western US bringing sunny, warmer
weather again. On Wednesday  GFS and ECM differ on the approach
of the next north Pacific upper trough. GFS brings it strongly
inland to Oregon while ECM allows only a weak trough inland
while keeping the main trough off the coast. For now we will
cautiously allow a 15 to 25 percent chance of showers into our
CWA Wednesday.
&&
.AVIATION...VFR. Layers of smoke aloft. Local IFR in mountain
valley fog until 17/15Z. Surface winds: E-S 5-15kt. Winds aloft
at 10kft MSL: Variable up to 10 kt.
KBOI...VFR with light winds.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.
OR...None.
&&
$$
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SHORT TERM...LC
LONG TERM....LC
AVIATION.....LC

NWS BOI Office Area Forecast Discussion