174
FXUS65 KPIH 220830
AFDPIH
Area Forecast Discussion
National Weather Service Pocatello ID
230 AM MDT Sun Jun 22 2025
.KEY MESSAGES...
- Cold temperature continue for Sunday with rain/mountain snow
showers, thunderstorms this afternoon, and breezy winds.
- Winter Weather Advisory above 7500 feet continues in the
Central Mountain and Montana Divide today with a Lake Wind
Advisory also in effect for American Falls Reservoir.
- Frost/Freeze headlines likely needed for the Snake River Plain
and eastern Magic Valley for tonight/Monday morning.
- Weekend system departs late today into tonight as warmer and
mostly dry conditions return for next week.
&&
.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 230 AM MDT Sun Jun 22 2025
Early morning satellite imagery shows a closed low pressure
system centered over central Idaho tracking east as a cold front
and wrap around bands of moisture continue to lead to a mix of
rain and mountain snow showers. The main circulation of the low
will continue to track east through the daytime hours before
lifting northeast into Montana this evening, allowing for dry
conditions to return regionwide tonight. Until then,
rain/mountain snow showers will continue throughout the day with
isolated to scattered thunderstorm development expected this
afternoon and evening. This is reflected well in that latest
HREF model probability of thunder for today which shows a 30-70%
chance across all of eastern Idaho.
Additional precipitation will be highest in the Central
Mountains and along the Montana Divide where around 0.25-0.50"
is expected in the valleys with 0.50-1.00" in the mountains.
Elsewhere, amounts will remain lighter in that T-0.25" range.
With respect to snowfall accumulations, snow levels are still
looking like they will drop to 6000-7000 feet this morning with
the bulk of accumulating snow staying above 7000-8000 feet. This
is where a Winter Weather Advisory will remain in effect above
7500 feet through 6 PM MDT where an additional elevation
dependent 2-12" of snow expected.
Winds today will remain breezy with gusts again peaking this
afternoon around 20-40 mph. As a result, another Lake Wind
Advisory is in effect for American Falls Reservoir from 7 AM to
5 PM MDT. Much lighter winds are expected back regionwide for
Monday.
Well below normal temperatures will continue for Sunday with
highs today in the 40s/50s/60s or about 20-25 degrees below
normal for this time of year. Overnight lows tonight are
expected to be the coldest we have seen in several weeks,
dropping to the 20s/30s. A Frost Advisory/Freeze Warning will
likely need to be issued on the day shift today for the Snake
River Plain and eastern Magic Valley due to these colder low
temperatures.
Following the exit of our weekend system, southwest flow will
return to eastern Idaho and lead to warmer and mostly dry
conditions returning for next week. Highs on Monday will climb
into the 60s/70s.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Issued at 230 AM MDT Sun Jun 22 2025
Warmer weather is still expected moving through next week and
into the last weekend of June. We continue to see the potential
for a few showers or storms daily, especially farther north. The
question remains on how warm it will get. Our Blend of Models
forecasts are trending down slightly, each time we crank out a
forecast. We should still see some 90s, but perhaps not more
widespread mid 90s like we were seeing a few days ago. There is
still a 20-50% chance of exceeding 95 across portions of the
Snake Plain, Magic Valley, and lower valleys south toward the
Utah border.
&&
.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 230 AM MDT Sun Jun 22 2025
As an upper low moves overhead today, expect precipitation
becomes more widespread and begin to impact our TAF sites. It
looks like BYI has the "lowest chance" of seeing anything, but
it is still enough for VCSH this morning. We will carry over
from previous forecasts VCSH or -SHRA, along with any wind gusts
(20- 30kts) for all TAFS except SUN. We should see a few
afternoon storms, but the chance is low overall...so we will not
put any mention in the forecasts. As the low shifts this
evening, we will see skies clearing pretty quickly.
&&
.FIRE WEATHER...
Issued at 230 AM MDT Sun Jun 22 2025
As a closed low pressure system continues its progression
across eastern Idaho today, rain/mountain snow showers will
continue throughout the day with isolated to scattered
thunderstorm development this afternoon and evening. This is
when the HREF model probability of thunder shows a 30-70% chance
regionwide later today. We will see another day of breezy
winds, with gusts peaking around 20-40 mph this afternoon. As
this system begins lifting northeast into Montana later today,
progressively drier conditions will return this evening into
tonight. Additional precipitation will be highest in the Central
Mountains and along the Montana Divide where around 0.25-0.50"
is expected in the valleys with 0.50-1.00" in the mountains.
Elsewhere, amounts will remain lighter in that T-0.25" range.
With respect to snowfall accumulations, snow levels are still
looking like they will drop to 6000-7000 feet this morning with
the bulk of accumulating snow staying above 7000-8000 feet. This
is where a Winter Weather Advisory will remain in effect above
7500 feet through 6 PM MDT with an additional elevation
dependent 2-12" of snow expected.
Following the exit of our weekend system, southwest flow will
return to eastern Idaho and lead to warmer and mostly dry
conditions for next week. Several weak shortwave troughs will
also be passing in and around our region which will at least
support the potential for very isolated shower and thunderstorm
development but other than that, conditions are looking dry next
week. Temperatures will climb back to above normal levels by
midweek with highs reaching back into the 70s/80s and perhaps
some low 90s across our lowest elevations. Given this warmer and
drier trend, afternoon RHs will drop back into the teens/20s
each day. Winds will be on the rise starting Wednesday which
will be our next opportunity to see some overlap of low RH and
gusty winds, leading to elevated to near-critical fire weather
conditions.
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM MDT this evening for IDZ066-
067-069>074.
&&
$$
SHORT TERM...MacKay
LONG TERM...Keyes
AVIATION...Keyes
FIRE WEATHER...MacKay
