412
FXUS65 KPIH 011117
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
517 AM MDT Sun Jun 1 2025

.KEY MESSAGES...

- Isolated light showers and dry thunderstorms for Sunday
  afternoon/Sunday night. Breezy in the Snake River plain.

- Cooling trend to afternoon highs starts Sunday, continues
  through Tuesday.

- Slight chance to chance of light showers Monday in eastern
  mountains, showers and thunderstorms on Tuesday afternoon.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 149 AM MDT Sun Jun 1 2025

Upper level trof moves east through Idaho today and tonight and
expect showers and thunderstorms mainly along the Montana border
today with a marginal risk of severe again also near the Montana
border in the Upper Snake River Highlands. There is at least a
chance or slight chance everywhere else. Do not expect
significant precipitation but main threat will be gusty winds
near storms and also hail potential. Winds will pick up in the
Snake River Plain with some 15 to 25 mph sustained winds. Will
hold off locally on Lake Wind Advisory as strongest winds should
be further north. Showers will continue overnight in the eastern
mountains for the most part. It will remain very warm today with
highs 70 mountains and 80s valleys. It will begin to cool off
substantially tonight with lows back into the 30s and 40
mountains and 40s to lower 50s valleys. Highs Monday much
cooler in the 60s and 70s. It will be mainly dry with morning
showers in the Upper snake Highlands again but dry elsewhere and
mainly dry Monday afternoon and night. Lows Monday night will
be in the 30s mountains and 40s valleys. 10 to 15 mph winds will
be present Monday and not expected to be as breezy as today.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Issued at 149 AM MDT Sun Jun 1 2025

Persistent longwave troughing remains forecast throughout next week,
with a few individual disturbances/shortwave troughs cutting through
the region at times. These features continue to look very low-impact
for southeast Idaho with day-to-day PoPs generally confined to the
eastern highlands and Island Park areas. Tuesday and Tuesday night
continue to look like the best shot at better coverage of a few
showers and thunderstorms, although the eastern Magic Valley and
Raft River regions may yet stay completely dry. Daily winds have
trended lighter in the forecast with the breeziest conditions
holding off until Friday and Saturday as the pressure gradient
tightens in response to a more organized low pressure system to our
northeast dropping out of Canada. Temperatures will modestly trend
warmer over the course of the week...starting in the 60s to low 70s
Tuesday and eventually reaching the upper 70s to mid 80s by
Saturday.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 517 AM MDT Sun Jun 1 2025

A trough of low pressure will induce increasing WSW winds this
morning (then continuing right into the overnight tonight), followed
by a chance of showers and thunderstorms this afternoon and evening.
The most favored corridors for thunderstorm development remain from
the eastern Central Mountains northeast along the Montana border
(north of KIDA and KDIJ), and also across the Raft River region and
Utah border (south of KBYI and KPIH), but our concern is that storms
may either be in close enough proximity to all of these terminals...
or additional cells not well modeled by high-res guidance may fire
along storm-induced outflow boundaries...to bring some impacts
starting around 23z/5pm at KBYI and 01z/7pm at KPIH/KIDA/KDIJ (late
show by local standards), so have gone ahead and defined VCTS
periods in the 12z TAF package. Overall forecast confidence in
occurrence and timing of nearby storms is moderate at best...some
"nowcasting" may be required as we monitor real-time trends this
afternoon. The primary hazard with storms today will be
gusty/erratic downdraft and outflow winds potentially reaching 50-60
MPH in a cell or two (as hinted at in the HREF wind gust
ensemble max), while other hazards such as hail will be more
significant north of KIDA and KDIJ where better deep-layer
shear resides. KSUN should be just far enough west to stay away
from thunderstorm issues, but all guidance strongly supports a
wind shift from the normal SE diurnal flow to a SW (gusty)
runway crosswind this afternoon...a few models go as early as
20z/2pm but have nudged this to 21z based on climatology. Clouds
look to remain strongly VFR...may see some areas of BKN develop
late this afternoon into the first half of the night if storm
coverage is decent and spreading cumulonimbus anvils are
prominent.

&&

.FIRE WEATHER...
Issued at 149 AM MDT Sun May 31 2025

An upper level trof approaching will bring a chance for showers
and thunderstorms with the potential for strong storms mainly in
zones 475, 476 and 411 and northern parts of 410. Winds will
increase with 15 to 25 mph winds in parts of zone 410 as well
this afternoon and parts of 425 and 475 and 476. Minimum
humidity will be increased today with slightly cooler
temperatures and most locations above 20 percent. Cooler
temperatures will move in Monday with about a 10 degree drop
from today but humidity will decrease with substantially drier
air moving in. Most convective activity limited to zone 411.
Showers likely a bit more widespread on Tuesday with another
upper trof sliding south.

&&

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

&&

$$

SHORT TERM...GK
LONG TERM...KSmith
AVIATION...KSmith
FIRE WEATHER...GK