652
FXUS65 KPIH 020944
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
344 AM MDT Sun Jun 2 2024

.SHORT TERM...Sunday and Monday.
Currently there is zonal flow aloft over southeast Idaho and a
very moist, atmospheric river, system just off the coast of
Washington and Oregon.

For today, the NBM model shows isolated showers and thunderstorms
in upslope flow mainly over the Eastern Highlands along the
Wyoming border. However, other models, like the ECMWF and HREF
models, show very little, if any, chance of showers and
thunderstorms due to the lack of moisture. If any thunderstorms
and showers do occur, very little, if any, moisture is expected.
Today, especially this afternoon and for our northern areas,
winds will be breezy with gusts of 20 to 30 mph. The Arco desert
will see gusts of 30 to 40 mph with slightly higher gusts for a
few hours this afternoon. Temperatures will run near normal today,
60s for mountains and 70s for lower elevations.

For Monday, look for an atmospheric river system to hit our area
in zonal flow hitting mainly the western Central mountains
(mainly the Sawtooths) where 1 to 2 inches (with isolated areas up
to 2.5 inches) of rainfall in a 24 to 30 hour timeframe. Galena
Summit will get around 1 inch of rainfall with Ketchum receiving
around 0.5 inch. The Pioneer mountains will get around 0.75 inch
of rainfall. Snow levels will start around 11k feet dropping to
around 10k feet Monday evening. Currently, the Salmon river and
Big Wood river only look to rise around 1 foot. For the Eastern
Highlands along the Wyoming border, including the Wasatch
mountains and the Big Hole mountains, expect around 0.50 to 1 inch
of rainfall. It will be breezy to windy on Monday. Currently look
at gusts of 25 to 40 mph across the area. Will likely need a wind
advisory for the Arco desert and the Upper Snake plain. Blowing
dust is possible but is not expected to be widespread. A lake wind
advisory will likely be needed for the American Falls reservoir
with moderate to large waves expected. Temperatures Monday will be
cooler than normal, around 8 to 12 degrees below normal. Expect
50s in the mountains and 60s in lower elevations for daytime highs
on Monday.
Wyatt

.LONG TERM...Tuesday through next Sunday.
Tuesday will mark a change from a wet and seasonably cool pattern to
a dry and seasonably warm pattern. A warming trend will continue
through late week courtesy of high pressure building over the
Southwest. Widespread daytime highs will reach 15 degrees above
climatological norms by Friday, with portions of the eastern Magic
Valley and Snake River Plain potentially reaching 90 degrees for the
first time this year. Winds will be breezy Tuesday afternoon, and to
a lesser degree Wednesday afternoon, before becoming light through
the remainder of the extended period. Widespread sustained winds
will range 15 to 25 mph with gusts of 25 to 35 mph. The National
Blend introduces slight chances for precipitation beginning Thursday
and continuing into the weekend, as models show weak signals for
moisture filtering northward into Idaho in the upper level flow.
Cropp

&&

.AVIATION...
Clouds will scatter/clear from NW to SE during the early to late
morning before cloud cover increases again this afternoon and
evening. Upper flow will turn zonal this afternoon with enhanced 700
mb winds creating breezy conditions at the surface. Sustained SW to
W winds will range 15 to 20 kts with gusts 25 to 35 kts. Expect each
afternoon for the next several days to be breezy as the trough works
through. Slight chances for showers and thunderstorms exist this
afternoon, mainly near KDIJ, with widespread precipitation and
isolated thunderstorms on Monday. VFR conditions are forecast
through around 12z Monday, with MVFR CIGs and VIS likely at times in
the afternoon during the heaviest rain.
Cropp

&&

.FIRE WEATHER...
The next system arrives this evening with precipitation reaching the
central mountains tonight. Widespread wetting rains will overspread
the region early Monday with chances for isolated thunderstorms
during the afternoon and evening. The Weather Prediction Center has
included portions of Fire Weather Zones 475, 476, and 422 in their
Excessive Rain Outlook. The most accumulated rainfall will be over
the Sawtooths and Stanley region, where 1 inch to 2.5 inches of QPF
is forecast to fall between this evening and Monday night. During
this 24-hour or so timeframe, 1.25" to 1.75" is forecast over the
eastern half of the Ross Fork burn scar, with 1.75" to 2.25" over
the western half. Elsewhere, generally 0.50" or less is forecast
with higher totals of 0.75" to 1" in the high terrain of the eastern
mountains. Min RH will continue to increase through Monday, ranging
20 to 35 percent for much of the region today before rising to 50
percent and higher. Elevated winds aloft will support breezy
conditions at the surface each afternoon and evening beginning today
and continuing through Tuesday or Wednesday. The strongest SW to W
winds are expected across Fire Weather Zone 410, where SW winds will
range 25 to 35 mph with gusts 35 to 45 mph. The pattern turns dry
and warmer beginning Tuesday as a ridge of high pressure builds in
from the Southwest. Temperatures may even reach into the 90s for
some portions of the Magic Valley and Snake River Plain beginning
Thursday into the weekend. Widespread minimum humidities will begin
to drop below 25 percent during this timeframe, but winds should
remain light.
Cropp

&&

.HYDROLOGY...A special weather statement is in place for the
Sawtooths where 1 to 2 inches of rainfall is expected Sunday
evening through Monday evening. Up to 2.5 inches of rain could
fall for some western slopes of the Sawtooths. High mountain
snowmelt of around 2 inches, if not higher, is expected as well.
The Salmon river is expected to rise around 1 foot currently and
could go higher on Monday into Tuesday. Valley creek in Stanley
could reach bankful, if not higher. Aerial flooding, especially
creeks, in higher elevations of the Sawtooths is likely. The
western Central mountains will get around 1 inch of rainfall and
the Pioneer mountains are expecting around 0.75 inch. The Big
Wood river is expected to rise at least 1 foot on Monday into
Tuesday, if not higher, especially with high mountain snowmelt of
around 2 inches. Currently action stage on the Big Wood at Hailey
is not forecasted, but action stage for the Big Wood at Hailey is
possible depending on actual snowmelt and rainfall. Currently
small rises area are expected with main stem rivers along the
Wyoming border for Monday and Tuesday. Some streams in the
mountains could reach around bankful.
Wyatt

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$