255
FXUS65 KPIH 120755
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
155 AM MDT Sat Jul 12 2025

.KEY MESSAGES...

- Temperatures Continue To Warm Into the 90s

- Isolated Dry Storms Sunday and Monday Up North

- Flirting With Critical Fire Weather Conditions Sunday/Monday

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 155 AM MDT Sat Jul 12 2025

We remain on the northern fringes of high pressure across
portions of the southwestern U.S. That puts under constant
northwest flow off the surface through the beginning of next
week. Saturday will remain dry it looks like, although we may
see afternoon cloud build ups WITHOUT virga impacts. A couple
of "weak waves" drifting across the state Sunday and Monday are
expected to bump up dry thunderstorm chances a bit. We have
isolated storms Sunday from Copper Basin to near Island Park,
and similar areas Monday with a better potential of something
drifting across the Snake Plain. Little to no rain is forecast
with gusty outflow winds. Outside of thunderstorms, we are also
forecasting an uptick in overall wind. Gusts in the 20-25 mph
range are possible Sunday across Snake Plain, Magic Valley and
South Hills/Albion Mountains. Those types of gusts are more
widespread Monday, with the potential of gusts to 35 mph across
the Magic Valley and South Hills/Albion Mountains. Probability
forecasts actually show a 40-75% chance (location/elevation
dependent) of exceeding 35 mph in those areas. At the moment, no
wind-related headlines (at least outside of the fire side of
things) are anticipated.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Issued at 155 AM MDT Sat Jul 12 2025

Increasing confidence supports a H5 low working south of British
Columbia and Alberta into the northern PacNW and Montana Tuesday
into Wednesday, with the main circulation staying north of the
Montana Divide. The passage of this system will lead to an uptick in
winds Tuesday afternoon (peaking around 15-30 mph with gusts to
around 25-45 mph) along with isolated to scattered showers and
thunderstorms with best chances in the eastern Central Mountains,
Upper Snake River Plain, and Eastern Highlands in that 15-30% chance
range. Given the track of this system through Montana, best chances
will be further northeast along the Continental Divide as the bulk
of precipitation remain situated further north of our area. As this
system works east through Montana and Wyoming for Wednesday, lighter
winds will return overall with a 10-20% of isolated showers and
thunderstorms along the Montana and Wyoming border regions. Highs in
the 80s and 90s on Tuesday will cool slightly around 4-8 degrees for
Wednesday with highs in the upper 70s to low 90s. It is notable that
there are some differences in the models with respect to the track
and speed of this system, so stay tuned regarding any changes over
the coming days.

Looking ahead towards later in the week, predominant zonal flow will
keep conditions dry as temperatures see a warming trend into the
weekend. Southeast Idaho will remain situated between several
systems during this timeframe: a series of troughs working east
through Canada and northern Idaho/Montana and a plume of monsoonal
moisture over the Desert Southwest to our south. At this time, there
are some differences in the overall track and placement of this
moisture but given a large fetch of dry air building in out of
Oregon from the Pacific during this time, any shower or thunderstorm
coverage should remain more isolated and confined to the mountains
as conditions remain predominantly dry.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1027 PM MDT Fri Jul 11 2025

High pressure is over the area with weak northwest flow aloft.
There is a weak wave over northern California that will slowly
make its way toward our area by early next week, which will
increase winds each day and bring isolated afternoon tstm
chances by early next week.

Models show FEW to SCT mid-level clouds across our northeastern
areas early this evening to include IDA and DIJ. Expect
clearing overnight with overall light winds. Tomorrow afternoon
expect slightly breezy winds with gusts up to around 20 kts for
KIDA and KPIH. There will be some cumulus clouds (FEW070) mainly
in the mountains in the afternoon tomorrow. The HRRR model is
showing some upper level clouds in the afternoon for our
northeastern TAFs (IDA and DIJ) as well.

&&

.FIRE WEATHER...
Issued at 155 AM MDT Sat Jul 12 2025

Hotter temperatures and lowering humidities (including poor
overnight recovery in some areas) are on tap through Monday. We
will also see an uptick in isolated dry thunderstorms to start
out the week. We COULD see some afternoon cumulus and very
isolated virga issues today, but the potential at the moment
looks minimal at best. Isolated dry storms are forecast at the
moment from basically Copper Basin to near Island Park Sunday
and Monday. On Monday, there appears to be a better chance of
storms making out into the Snake Plain...so we expanded that
chance for this morning`s forecast. We MIGHT see a few storms
make into areas south of Twin Falls and Burley (Zone 427) later
Monday evening, but left that out for now. We will also see
winds picking up OUTSIDE of thunderstorms. We currently have
gusts 20-25 mph across Zones 410, 425 and 427 Sunday afternoon
and evening. That does put us close to critical thresholds in
Zone 427 when combined with afternoon humidity of 10-15%. In
fact, humidity values outside of the central mountains Sunday
(except lower valleys) will be in the 10-15% range, with 15-25%
elsewhere. Gusty winds will be more widespread on Monday.
Humidity values do come up a bit, but are still in the general
10-15% for lower elevations and 15-25% elsewhere. Outside of
areas from Island Park to Driggs, gusts of 20-30 mph are
forecast, with some gusts hitting 35 mph across portions of
Zones 425 and 427. In fact, probabilistic forecasts show a
40-75% chance of exceeding that mark in those areas. There is
also a 30-50% chance of gusts higher than 35 mph across the
higher elevations of the central mountains across Zone 413
(south and east of the Snake Plain). We will need to watch
trends for both days to see if we might need Red Flag Warnings.
Beyond that, we should cool down a bit as we end up being
sandwiched between low pressure along the US/Canada border and
high pressure to our south. While it does look continuously
breezy in this pattern, humidities do increase a bit. The Blend
of Models doesn`t have much in the way of thunderstorm chances
daily, nor showing any type of confidence WHERE that might
happen. Stay tuned.

&&

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

&&

$$

SHORT TERM...Keyes
LONG TERM...MacKay
AVIATION...TW
FIRE WEATHER...Keyes