966
FXUS65 KPIH 011720
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
1120 AM MDT Fri Aug 1 2025

.KEY MESSAGES...

- Daily, isolated to scattered showers and thunderstorms will
  continue into early next week, primarily each afternoon and
  evening in the mountains. Stronger storms will be capable of
  producing gusty winds, small hail, and brief heavy rain.

- Red Flag Warnings are in effect today for Idaho Fire Weather
  Zones 410/413/425/427 for gusty winds, low relative humidity,
  and isolated mountain thunderstorms from 2 PM to 10 PM MDT.

- Conditions will remain very dry outside of any showers or
  storms, with near normal to below normal temperatures into
  early next week.

- Warmer and dry conditions will return for mid to late next
  week under the increasing influence of high pressure.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 242 AM MDT Fri Aug 1 2025

Early morning satellite imagery shows a mid/upper-level trough
and closed low centered over eastern Oregon lifting northeast
across the PacNW and northern Rockies as isolated showers
persist in the Central Mountains. As this system continues its
progression northeast over the Continental Divide into Montana,
daily isolated to scattered shower and thunderstorm chances will
continue which will peak each afternoon. The HREF model
probability of thunder today shows a 30-60% chance in the
Central Mountains, Montana Divide, and South Hills west into the
Owyhees, with a 60-90% chance in Lemhi County. Following
isolated showers/virga this morning, convective initiation this
afternoon will begin between 12 PM and 3 PM MDT, continue
through this evening, ahead of subsiding after sunset with only
isolated showers then possible overnight. Stronger storms today
will be capable of producing wind gusts up to 40-50 mph, small
hail, and brief rain. The primary corridors for stronger storms
today will be in the South Hills and Southeast Highlands where
the HREF model probability of winds greater than 35 mph shows a
30-50% chance. Outside of any showers or storms, conditions will
remain dry with highs in the valleys ranging from the mid 70s
to low 90s, with afternoon wind gusts outside of thunderstorms
peaking around 25-40 mph. As a result, another set of Red Flag
Warnings are in effect for Idaho FWZ 410/413/425/427 to capture
a mix of isolated thunderstorms in the mountains along with
gusty winds and low relative humidity. More on that in the fire
weather discussion below.

For Saturday, isolated showers and virga will be possible in
the morning, ahead of another round of isolated to scattered
showers and thunderstorms in the afternoon. Best chances will
remain confined to the mountains with more isolated coverage
across the Snake River Plain. Outside of any showers or storms,
conditions will remain dry with highs in the valleys ranging
from the upper 70s to low 90s, with afternoon wind gusts outside
of thunderstorms peaking around 20-35 mph.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Issued at 242 AM MDT Fri Aug 1 2025

A series of shortwave troughs early next week will keep
isolated to scattered shower and thunderstorm chances going
through Monday, peaking in coverage each afternoon and primarily
remaining confined to the Central Mountains east along the
Montana Divide. Near normal to below normal temperatures will
persist early in the week with highs in the 70s/80s to low 90s
further south. Following lighter winds on Sunday, winds will be
breezy each afternoon starting Monday with gusts peaking around
25-40 mph each day. Under the increasing influence of high
pressure mid to late week, warmer and dry conditions will
prevail with near unanimous agreement amongst 500 mb ensemble
cluster showing eastern Idaho on the northern edge of a broad
region of high pressure. This will keep conditions hot and dry
as temperatures return to near normal to above normal levels to
finish out the week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1118 AM MDT Fri Aug 1 2025

Thunderstorm coverage is decreased a bit today with the ones that do
pop up looking like they will remain outside of most of our TAF
sites. BYI and SUN may be the two exceptions as storms fire up
near SUN this afternoon and come off the mountain terrain in the
south near BYI, so have afternoon VCTS at both sites given
their 20 percent chance of occurrence. Otherwise VFR conditions
are expected for the rest of today with afternoon winds
increasing to gust around 25 kts at IDA and 20 kts at SUN, PIH,
BYI, and DIJ. HI-RES models are hinting at some showery activity
early Saturday morning, so added VCSH in at SUN. Some isolated
thunderstorms return on Saturday afternoon.

&&

.FIRE WEATHER...
Issued at 242 AM MDT Fri Aug 1 2025

Daily, isolated to scattered showers and thunderstorms will
continue into early next week as a series of troughs from the
Pacific support sufficient moisture transport and instability
each day. Coverage of showers and storms will peak in coverage
each afternoon and evening. Red Flag Warnings are in effect
again today for Idaho FWZ 410/413/425/427 for a combination wind
gusts up to 40 mph, low relative humidity, and isolated
mountain thunderstorms that will be capable of producing outflow
wind gusts up to 50 mph. Have held off with any Red Flag issuance
for Idaho FWZ 422 given the bulk of the zone will only see
isolated thunderstorm coverage, with scattered coverage
remaining confined to the Sawtooth Valley region north. Up in
Idaho FWZ 475/476, look for yet another day of scattered showers
and thunderstorms later today but as fuels are not critical,
have held off with any fire weather headlines at this time.

For Saturday, another round of isolated to scattered showers
and thunderstorms are expected in the afternoon and evening with
minimum RHs in the teens/20s and wind gusts of 20-35 mph.
Thunderstorm coverage looks to decrease overall for Saturday as
minimum RHs slowly increase in FWZ 410, 413, and 425. However,
we will still need to evaluate Red Flag potential for Saturday
either today or Saturday morning.

Starting early next week, increasing high pressure to the south
will shift shower and thunderstorm chances back to being
confined in the Central Mountains east along the Montana Divide
as dry conditions prevail further south. As high pressure
continues to build in mid to late week, dry conditions
regionwide are expected starting Tuesday as cooler temperatures
to start the week see a warming trend later in the week. During
this timeframe, we will see breezy afternoon winds each day,
which coupled with low relative humidity, may lead to additional
fire weather headlines next week where the best overlap is.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 10 PM MDT this evening for IDZ410-413-
425-427.

&&

$$

SHORT TERM...MacKay
LONG TERM...MacKay
AVIATION...AMM
FIRE WEATHER...MacKay