902
FXUS65 KPIH 182343
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
543 PM MDT Fri Jul 18 2025

.KEY MESSAGES...

- Red Flag Warning in effect for the southern highlands for scattered
  thunderstorms and gusty outflow winds this afternoon.

- Marginal risk for severe thunderstorms this afternoon over much
  of east Idaho with strong outflow winds as the main threat.

- Critical or near critical winds and humidities across the
  Snake Plain and central mountains Saturday afternoon.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 121 PM MDT Fri Jul 18 2025

Marginal risk of severe thunderstorms in place today with monsoonal
moisture helping to fuel isolated to scattered development this
afternoon and evening ahead of weak cold front. Steep lapse rates
Widespread precipitable water > 0.75" in place for most of East
Idaho with the exception of the Central Mountains, where values drop
off to between 0.5-0.75". DCAPE across the southern highlands around
1200 J/kg will support gusty winds along with small hail, and
localized heavy rainfall. HRRR has been consistent with supporting
potentially long-tracked outflows across both the northern zones and
southern highlands. Activity diminishes this evening, leaving
locally breezy winds behind. Could see redevelopment of some showers
into Saturday as the upper feature shifts through the region, but
there is little agreement even among the high-res solutions, and the
signal is washed out in the Blend. There is enough dry air upstream
on the water vapor imagery, and HREF drops precipitable water
significantly across the region into Saturday. Winds look to be
stronger during the day Saturday particularly across portions of the
Snake Plain, leading to new Fire Weather concerns for critical
wind/humidity combinations.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 121 PM MDT Fri Jul 18 2025

Models and ensembles have remained consistent with development of a
trough along/just off PacNW coast through the extended period. Flow
aloft turns gradually more southwest through the period with East
Idaho caught between trough and developing high pressure near the 4-
corners region. Could see a few pulses of moisture work toward the
region for an occasional isolated thunderstorm threat. Otherwise
daytime highs stay relatively stable in the upper 80s/low 90s across
the region. The warm and generally dry conditions will likely lead
to additional Fire Weather concerns with breezy afternoon winds.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 522 PM MDT Fri Jul 18 2025

Thunderstorms will impact IDA and DIJ the next couple of hours.
Variable outflow gusts around 25 to 35 kts are possible for IDA
and DIJ the next couple of hours. Otherwise, winds will drop off
overnight and skies will clear out. Look for breezy winds
tomorrow afternoon with gusts of 20 to 30 kts likely for all TAF
sites as weak, dry trough moves over our area.


&&

.FIRE WEATHER...
Issued at 121 PM MDT Fri Jul 18 2025

Scattered, mostly dry thunderstorms will impact Fire Weather Zones
427 and 413 today, where fuels are critical and the current Red Flag
Warning remains in effect through Midnight tonight. Outside of those
two Zones, isolated to scattered coverage is also forecast across
Zone 411, and portions of 410 and 476. Storms will be capable of
producing 40 to 50 mph outflows with more isolated gusts over 50
mph. Elevated fire weather conditions are anticipated across the
Snake River Plain and portions of the eastern Magic Valley again
tomorrow, for minimum RH and winds. There is a 50 to 70 percent
probability of gusts over 30 mph across most of Zone 410, coinciding
with RH widely ranging 15 to 20 percent. A Red Flag has been pre-
coordinated with East Idaho for Zone 410, which will be issued
following the expiration of the current RFW. The northern portion of
Zone 425 is also expected to observe near critical to critical winds
and RH tomorrow. There is some potential that conditions could be
supportive of another RFW on Sunday, but winds look to be a bit
lighter and RH slightly higher Sunday.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until midnight MDT tonight for IDZ413-427.

&&

$$

SHORT TERM...DMH
LONG TERM...DMH
AVIATION...TW
FIRE WEATHER...Cropp