Emmett Weather

000
FXUS65 KBOI 300239
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
838 PM MDT Wed Mar 29 2023

.DISCUSSION...Evening radar imagery shows rain and snow showers
persisting in Idaho north of the Snake Basin under upper trough over
the area. The trough extends to a weakening upper low near San
Francisco. The portion over our CWA is forecast to develop a weak
low center of its own tonight and Thursday, maintaining rain and
snow showers through midday Thursday. Northwest surface winds will
increase Thursday afternoon as the low center shifts to eastern
Idaho. Our CWA will dry out from the west Thursday night into Friday
as the low exits east. After that the next trough from the Gulf of
Alaska will renew pcpn in our CWA Friday night. By Sunday the whole
trough will come inland bringing another surge of cold, moist air to
our CWA that will last through next Thursday. Current forecast is on
track with all this. No updates for now.

&&

.AVIATION...MVFR and IFR conditions with mountain obscuration will
continue with widespread snow across the mountains north of the
Snake River Plain into Thursday. Isolated MVFR/IFR rain showers this
evening in the Western Snake River Plain becoming widespread snow
early Thursday morning. Snow levels around 3500-4500 ft MSL lowering
to 2500-3500 ft MSL after midnight. Surface winds: westerly 10 kt
or less through tonight then increasing to 15 to 25 kt Thursday.
Winds aloft at 10k ft MSL: NW-N 10-20 kt increasing to 20-35 kt
Thursday.

&&

.PREV DISCUSSION...
SHORT TERM...Tonight through Friday night...Tonight will see
drier conditions across SE Oregon and portions of SW Idaho from
the Snake Plain to the ID/NV border. Periods of snow will continue
to the north as an upper low forms over central Idaho. The
moisture will wrap around the upper low late tonight, spreading
into the lower Snake Plain Thursday morning around sunrise as rain
and snow. Snow levels will be 2500-3000 feet MSL with a rough
transition around the Ada/Canyon county line in the lower Snake
Plain. While accumulation will be limited to colder surfaces in
the Boise metro, the higher elevations between Boise and Mountain
Home could see a brief accumulation on roadways. This area of
rain/snow will shift south and eastward, reaching the Western
Magic Valley by late morning. By that time expect temperatures
and late March sun to limit accumulation in those areas. SE
Oregon will remain on the western fringe of the wrap-around with
the focus of precipitation in the mountains. Snow will taper off
in the valleys during the afternoon, while continuing in the
mountains through the evening. Accumulating snow will lift above
5000 feet MSL Thursday afternoon. Expect additional snow amounts
of 1 to 4 inches in mountain valleys and 4 to 8 inches above
valley floors through Thursday. Northwest winds will increase on
Thursday as the low wraps up over eastern Idaho. Wind gusts of 25
to 40 mph will be realized across open terrain Thursday afternoon
and evening. It will remain gusty across the middle Snake Plain
through the day Friday. The upper low will shift east on Friday
with the region remaining in a cool northwest flow. A weakness in
the flow will support continued light showers over the e-central
Oregon and w-central Idaho mountains while lower elevations stay
dry. The break will be shortlived as another cold and wet storm
system moves into the Pac NW late Friday bringing more valley rain
and mountain snow Friday night. Temperatures will remain 5-10
degrees below normal through the period which will close out a
well below normal month of March at all climate sites across SE
Oregon and SW Idaho. For most sites this will go down as a top 10
coldest March on record.

LONG TERM...Saturday through Wednesday...An upper trough will
move over the Pacific Northwest Saturday and Sunday bringing
another round of widespread precipitation and breezy to windy
conditions to the region. Snow levels are forecast to remain
above valley floors, but lower from around 4000-5000 feet MSL
on Saturday to 3000-4000 feet on Sunday. Significant snow
accumulations in the mountains are likely, especially for much of
the west-central and Boise Mountains where total amounts through
the weekend of a foot or more are likely along with gusty westerly
winds causing blowing/drifting snow. The precipitation will
transition to more of a showery regime on Monday as the core of
the trough moves over the area and snow levels lower to valleys
floors. Potential for minor snow accumulations in the lower
valleys. Models continue to diverge beyond Monday so forecast
confidence is low the middle of next week, with a continued
chance of precipitation and below normal temperatures.

&&

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

&&

$$

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DISCUSSION...LC
AVIATION.....JDS
PREV SHORT TERM...DG
PREV LONG TERM....TL