American Falls, Idaho 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

972
FXUS65 KPIH 310001
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
601 PM MDT Sun Mar 30 2025

.KEY MESSAGES...

- A warm front lifting north tonight into Monday morning will
  support another round of rain/snow showers, with a cold front
  on Monday bringing more widespread precipitation along with
  isolated thunderstorms.

- Winter Weather Advisories have been issued for a handful of
  mountain zones due to forecast snowfall totals of 4-10
  inches.

- Winds will remain elevated, peaking Tuesday.

- A secondary Pacific system building in midweek will keep
  precipitation chances going ahead of a ridge of high pressure
  building in by the weekend into early next week.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 213 PM MDT Sun Mar 30 2025

Radar and local cameras show light snowfall continuing in parts of
the Central Mountains/Mud Lake area as some wrap-around
moisture slowly dissipates this afternoon and a few showers have
begun lifting north out of Utah into the South Hills. Overall, we`re
still in a little bit of a break from more organized moisture
this afternoon as a weak ridge passes over us, but that will
change this evening and tonight as a warm front lifts northward
through the Great Basin driving our next round of rain and snow
our way. Precipitation will move in from the southwest and lift
northeast overnight and ahead of a cold front that will arrive
tomorrow, so we are expecting several rounds of precipitation
with some dry time in between throughout the day Monday and even
into Tuesday. It`s on Tuesday that we see more of the wrap
around moisture moving through the Eastern Highlands. For
tonight, most of the precipitation will fall as rain in the
eastern Magic Valley and Snake River Plain as temperatures will
be in the mid 30s. However, some light snow is possible in the
upper Snake River Plain where temperatures will be just a bit
closer to freezing, though little to no accumulation is
expected. Winds will pick up on Monday afternoon with gusts of
25 to 35 mph across much of Eastern Idaho. As temperatures warm
on Monday, we will see increasing chances for thunderstorms
across the entire CWA, but especially in the eastern Magic
Valley, South Hills, Snake River Plain, and Southeastern
Highlands. The latest HREF 24-hour thunder probability shows
about a 60 to 80 percent chance of thunderstorms through this
southern half of our CWA. Some storms will produce small hail
and gusty winds.

Snow totals will be a bit higher up in the mountains with totals
closer to 5 to 7 inches around Galena Summit and 3 to 5 inches in
the Island Park area, Monida Pass, and around Emigration Summit
on Monday. Snow totals will be higher in the Eastern Highlands
on Tuesday where we see more of that wrap around moisture and
less snow in the Central Mountains/Sawtooths. This will give the
Island Park area, Big Hole Mountains, and Bear River Range
48-hour snow totals of 6 to 10 inches by Tuesday evening. Given
these forecast snowfall totals, have gone ahead with Winter
Weather Advisories for these areas. It`s a lower-end advisory
event, but overnight snow could impact some morning commutes on
Monday and Tuesday. Morning temperatures on Tuesday will be in
the upper 20s to low 30s in the valleys, which means there is a
small chance for some light snow accumulation for everyone
Tuesday morning with the NBM showing about a 10 to 20 percent
chance for an inch of snow around Idaho Falls and Rexburg on
Tuesday.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 213 PM MDT Sun Mar 30 2025

The area will reside under a broad upper trough for much of the
period with below normal temperatures, widespread cloud cover and
daily precip chances. Tuesday appears to be the best day for precip,
focused mainly across the higher terrain of the eastern highlands
and central mountains, along with gusty winds throughout eastern
Idaho. Could be close to reaching Wind Advisory levels in spots but
right now the forecast remains just shy. This will be something to
monitor over the days ahead however. Wednesday and Thursday the
pattern is a bit messier with precip becoming less organized in
nature but possible at basically any time throughout the day with
broad troughing remaining over the area. Northerly flow aloft will
keep temperatures running below normal with highs mostly in the 30s
and 40s. Things start to change on Friday with models wanting to
develop a cut-off low to our south with a rex-block pattern setting
up over the Pacific NW. H5 height rises will allow for gradually
warming temperatures beginning Friday (closer to normal) and
continuing to warm into the weekend with 60s becoming more
commonplace across our lower elevations by the end of next weekend.
This pattern should also keep things on the drier side from Friday
into early next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 601 PM MDT Sun Mar 30 2025

After a relative...albeit slightly messy...break between systems
today, impactful weather returns to the aviation world tonight and
Monday as multiple rounds of rain/snow are expected, along with
isolated afternoon thunderstorms Monday...all in advance of a large,
slow-moving low pressure storm system currently approaching the
Pacific Coast. This system will keep varying precip/cig/vsby impacts
going Tuesday as well, along with an increase in winds Tuesday. In
the meantime...feeling a bit better (at least moderate confidence)
in timing of the various rounds of rain/snow, and have added much
more detail to the 00z TAFs in trying to time these rounds out and
highlight any organized breaks in between (mileage varies by
terminal). In general, rounds will be more showery and shorter lived
until we get to the 17-21z/11am-3pm FM groups Monday afternoon, at
which time precip should become more widespread for the rest of the
day with embedded thunderstorms. This may end up being the most
impactful period for regional aviation overall. HREF ensemble max
wind gusts do feature just a couple isolated instances of 50-60 MPH
gusts (likely convectively-induced), but given how much cloud cover
and precip will be running around, and given ensemble mean SB/MU
CAPE values of only 100-250 J/kg, we expect storms will generally be
weak and isolated. West winds will be strengthening aloft, but
currently not approaching criteria for LLWS. While we`re feeling a
bit better about timing...we`re not feeling rosy at all with regard
to cig/vsby impacts tied to each round of precipitation. NBM
guidance is VERY VFR with no vis drops and almost non-existent cig
drops associated even with the steadier periods of precip, and even
HRRR and MOS guidance are messy and a bit optimistic. This just
doesn`t make conceptual sense, and this is especially true for KSUN
and KDIJ during periods where temperatures will be cold enough for
all snow (most of the TAF period). Have gone ahead and massaged cigs
down below the guidance consensus for some of these rounds, and
have pushed vsbys to 2-3 SM during organized snow for now. As
these rounds start to impact ASOS stations upstream across
Nevada into SW Idaho...and then our forecast area tonight...we
hope to calibrate the cig/vsby forecast a bit better. NBM probs
suggest about a 20% chance of lower cigs than currently forecast
at any given site during the precipitation periods...for what
it`s worth. Strongest winds Monday afternoon will be at KIDA,
but parallel with the runway for a tailwind there. No organized
crosswinds currently expected at KSUN.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 11 PM this evening to 6 PM MDT
Tuesday for IDZ060-063-064-066-067.
Winter Weather Advisory until 6 PM MDT Monday for IDZ071>074.

&&

$$

SHORT TERM...AMM
LONG TERM...McKaughan
AVIATION...KSmith