885
FXUS65 KPIH 172358
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
558 PM MDT Thu Jul 17 2025

.KEY MESSAGES...

- Isolated showers and thunderstorms along the Utah border this
  afternoon and evening with gusty outflow winds.

- Near critical fire conditions today for winds and humidity,
  then critical conditions Friday for thunderstorms and gusty
  outflows.

- Warming trend continues into the weekend.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 200 PM MDT Thu Jul 17 2025

Moisture along the UT border may be enough for isolated thunderstorms
this afternoon and early evening. Gusty outflow winds 40-45 mph will
be possible, but little precipitation is expected with the very
dry air mass in place. HREF shows a 50% chance of exceeding 40
kts across southern Cassia county this evening. Breezy winds
continue to develop across portions of the Snake Plain today as
airmass reaches full mixing potential. Shortwave advancing into
the PacNW should allow for additional moisture to advance into
East Idaho during the day on Friday. Additional thunderstorm
development is expected once again. Steep lapse rates will allow
isolated gust potential over 50 mph. HREF paints a greater than
50% chance of exceeding 40 kts across a much wider swath of the
region, with pockets of a greater than 70% chance. Long term
discussion:

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 200 PM MDT Thu Jul 17 2025

Remnants of shortwave slide north along the Canadian border on
Saturday. A few thunderstorms may still be possible, again with
locally gusty outflows over 40 mph. Outside of the storms, gusty
winds remain possible especially over the Snake Plain, and may
lead to another day of critical or near critical fire conditions.
Similar conditions exist for Sunday. Models amplify the trough
along the PacNW coast into next week, leading to a strengthening
of southerly flow across East Idaho. Moisture does not look to
edge into the region, but is still spotty and uncertain enough
to only lead to isolated thunderstorm chances at best, for now.
Temperatures remain stable in the upper 80s/lower 90s for most of
East Idaho into next week. Expect breezy conditions within the
continued dry air mass for occasional critical or near
critical fire conditions.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 557 PM MDT Thu Jul 17 2025

VFR conditions expected for most of the period. Seeing some
mid/high clouds across the area this evening and these will
likely persist for much of the overnight and into the day
tomorrow but should have no impact to aviation. Breezy winds
will taper off over the next few hours becoming light and
generally variable into the mid morning on Friday. After this
point, expect winds to increase to around 10-15 kts, with higher
gusts, along with some potential late in the period for showers
and thunderstorm development near all TAF sites with the
exception of KSUN. Chances are low, 15-30 percent, but can`t
rule out some impacts so added some VCTS mention at KPIH and
KDIJ where the chances appear to be highest at the moment but
may need to be expanded to include KBYI and KIDA on later
forecasts.

&&

.FIRE WEATHER...
Issued at 200 PM MDT Thu Jul 17 2025

We are looking for near-critical to critical fire weather
conditions for the next 24-36 hours across central and eastern
Idaho. Through this evening, we are expecting some pockets of
critical conditions due to low humidity and gusty winds,
especially across the Snake Plain (410) and 425 (Magic Valley).
Although fuels are not critical right now, gusts of 25-35 mph
are likely with low humidity in the central mountains (475/476).
Isolated thunderstorms with gusts over 40 mph are possible this
evening along the Utah border, especially across Zone 427. We
may see some virga or isolated storms with gusty winds overnight
elsewhere, mainly though along the Utah border. For tomorrow,
thunderstorm potential along with coverage is higher. The
highest chance for storms will be in 2 main areas. The first in
higher elevations south of the Snake Plain (413 and 427). The
other is across the central mountains from around Mackay to
Monida Pass (411 and 476). Elsewhere, look for more isolated
coverage. There is a 70-90% chance of gusts exceeding 40 mph in
those areas already mentioned with some gusts over 50 mph
likely. Storms tomorrow will likely be a mix of wet and dry as
well. We will be issuing a RED FLAG WARNING for Zones 413 and
427 since fuels are critical. We will NOT issue one for Zones
411 and 476 after talking with local fire folks and determining
fuels are not critical enough at the moment. The timeframe will
be 1pm to Midnight. Saturday COULD be another critical fire
weather day, depending on how things trend. Isolated
thunderstorms are possible again across Zones 411, 413 and 427.
We are also looking for increasing winds OUTSIDE of
thunderstorms and lower humidity. If we do reach thresholds, it
will be across the Snake Plain (410) and Magic Valley (425).
Winds will be gusty across the central mountains, but again
fuels are NOT critical in those zones. Heading into early next
week, we are looking at an ongoing potential for isolated
showers and storms closer to the Montana border. Winds outside
of storms remain breezy, but overall humidity forecasts are
trending higher.

&&

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

&&

$$

SHORT TERM...DMH
LONG TERM...DMH
AVIATION...McKaughan
FIRE WEATHER...13