690
FXUS65 KPIH 280944
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
344 AM MDT Sun Jun 28 2026

.KEY MESSAGES...

- Precipitation Focused North & West: The heaviest moisture
  will remain firmly anchored over the central mountains, along
  the Continental Divide, and northeastward toward Island Park.
  High- resolution model guidance highlights a pronounced dry
  slot panning out across the Snake Plain and Magic Valley
  today, significantly dry-capping precipitation in these areas
  during the daytime hours.

- Overnight Secondary Push: A secondary wave of energy is
  expected to drop southward overnight Sunday into Monday
  morning, bringing a late round of showers and isolated
  thunderstorms down into the lower Snake Plain.

- Unseasonably Chilly Mountain Snow: Wet snow will occasionally
  fall as low as 6,5007,500 feet today. Backcountry travelers
  must prepare for winter-like hazards through Monday, with 3 to
  4 inches of accumulation expected below 9,000 feet and
  several more inches across higher peaks.

&&

.DISCUSSION...
Issued at 334 AM MDT Sun Jun 28 2026

The split upper-level low remains parked over Idaho today,
keeping unseasonably cool and unsettled conditions in place
across the region. However, the latest high-resolution model
trends have introduced a distinct daytime wrinkle: a robust dry
slot is expanding across the Magic Valley and Snake Plain, which
will heavily limit shower activity across the lower elevations
through the day. Instead, the deepest moisture and best lift
today will align from the Wood River Valley north through
Driggs, focusing the brunt of the steady rainfall and mountain
snow over the central mountains, the Continental Divide, and
toward Island Park.

As the core of the low-pressure system pivots tonight, a
secondary push of wrap-around energy will swing back across the
Continental Divide. This will drop a renewed band of showers and
isolated thunderstorms southward into the Snake Plain and
southeast highlands overnight Sunday into early Monday morning.
Total additional liquid precipitation will be around 0.25-0.5"
in the areas with the best precip chances, locally higher up to
0.50 to 1.50 inches across the central mountains and northern
border region, particularly near Lemhi County. Snow levels will
hover between 6,500 and 7,500 feet within heavier precipitation
bands, bringing accumulating wet snow to the high country and
creating hazardous conditions for outdoor recreationists not
properly equipped for late-June winter weather.

Outside of rain bands, it will turn breezy today where any
breaks in the clouds allow the atmosphere to mix. Wind gusts of
25 to 40 mph are expected today and again on Monday,
particularly across wind-prone spots like the American Falls
Reservoir, though conditions are forecast to stay just below
Lake Wind & Wind Advisory thresholds. It`s possible a short-
fused Lake Wind Advisory could be needed for AF Reservoir if
winds overperform the current forecast. Looking ahead, global
models continue to delay any rapid clearing. Expect a very
gradual warming and drying trend through the upcoming workweek,
with temperatures finally returning to seasonal averages by
Friday. Residual mid-level moisture will maintain a daily
baseline potential for light afternoon showers, virga, and
isolated thunderstorms before a cleaner drying trend takes hold
around the Fourth of July.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 334 AM MDT Sun Jun 28 2026

We`re getting a break from the showers and storms at this point, but
more is expected on Sunday. We will see the wrap around moisture
near SUN, IDA, and DIJ on Sunday, so there are periods of -SHRA and
VCSH in the TAFs at these sites. PIH and BYI will likely remain
dry through much of the period but some isolated showers could
push in late Sunday as a more organized push of moisture will
move through the area overnight Sunday into Monday. Winds will
remain breezy, 15 - 20 kts, at the valley terminals and to a
lesser extent around KDIJ with winds closer to 10 kts around
KSUN.

&&

.FIRE WEATHER...
Issued at 334 AM MDT Sun Jun 28 2026

The overarching weather pattern will maintain exceptionally high
relative humidity values and cool temperatures through Monday,
completely mitigating critical fire weather thresholds across
eastern Idaho. Today`s primary update centers on a daytime dry
slot that will keep the Magic Valley and Snake Plain mostly dry
through the day. However, wetting rains remain a certainty for
the northern mountains and the Divide. Convective concerns today
are lower than yesterday, but a few isolated storms capable of
producing erratic wind gusts up to 40 mph remain possible. A
secondary push of energy overnight tonight will drag a final
round of showers and isolated storms through the lower valleys
before a gradual, long-term warming and drying trend initiates
Tuesday as we return to more of a virga / isolated thunderstorm
regime through mid-week.

&&

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

&&

$$

DISCUSSION...McKaughan
AVIATION...McKaughan
FIRE WEATHER...McKaughan