288
FXUS65 KPIH 312029
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
229 PM MDT Thu Jul 31 2025

.KEY MESSAGES...

- Daily, isolated to scattered showers and thunderstorms will
  continue through the weekend, 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 for Idaho Fire Weather Zones
  422/425/427 for scattered thunderstorms and for Idaho Fire
  Weather Zones 410/413 for gusty winds and low RHs this
  afternoon/evening.

- Conditions will remain very dry outside of any showers or
  storms, supporting elevated fire weather conditions due to a
  combination of low relative humidity and breezy winds.

- Temperatures will remain above normal again today, with a
  gradual cooling trend starting Friday into early next week.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 223 PM MDT Thu Jul 31 2025

A series of shortwaves will keep daily chances for isolated to
scattered thunderstorms in the forecast. Greatest chances for
showers and thunder will generally be across the high terrain, with
HREF probability of thunder ranging 30 to 80 percent across the
central mountains and up to a 50 and 60 percent chance in the
Island Park region and South Hills region, respectively. The
Storm Prediction Center`s Convective Outlook has roughly the
western half of the CWA included in a Marginal Risk of severe
weather today due to the potential for thunderstorm outflows to
60 mph or greater as indicated by steep lapse rates and high
DCAPE values. Hi-res models show convection initiating in these
three regions by around 2 PM MDT, with strong to severe gusts
across the eastern Magic Valley expanding up the Snake River
Plain heading further into the afternoon. PWATs will trend
higher heading into Friday as moisture lifts northward, but
PWATs will still generally run below 0.75". While the
probability that storms will be capable of heavy downpours is
low, flash flooding will be possible in areas that more easily
experience runoff. The Weather Prediction Center`s Excessive
Rainfall Outlook includes the central mountains in a marginal
risk (at least 5% chance) and we have coordinated a Flash Flood
Watch with WFO Boise for the Wapiti burn scar from 3 PM this
afternoon through 10 PM MDT this evening due to the
aforementioned potential for flash flooding and debris flow from
moderate to heavy thunderstorm downpours. Outside of
thunderstorm gusts, winds will gust to 20 to 30 mph each
afternoon areawide. Temperatures will run several degrees above
normal again today before dropping to just below climatological
norms heading into the weekend.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Issued at 223 PM MDT Thu Jul 31 2025

The unsettled pattern will keep our daily highs running several
degrees below climatological norms this weekend through the first
half of next week. Daytime highs across the lower elevations will
span the 80s, with 60s and 70s in the mid to high elevations.
Outside of any thunderstorms, winds each afternoon are expected
to gust 20 to 30 mph throughout the period. Conditions will
trend drier during the middle of next week as high pressure
amplifies over the Southwest with the National Blend of Models
(NBM) PoP forecast keeping all chances of precipitation north of
our CWA beginning Tuesday. However, just less than half of the
500mb ensemble cluster solutions indicate another trough
shifting into the PacNW heading into later week.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1124 AM MDT Thu Jul 31 2025

Afternoon/evening thunderstorms are back once again. Main impacts of
a storm passing over a site/gusty outflow winds will be at SUN, BYI,
PIH, and DIJ. Storms today may produce gusts and outflows around
45 kts. IDA may be able to skirt the storms and outflows are
expected to lose a bit of steam as they head up the Snake River
Plain, so will leave PROB30 out of IDA, but kept it in at the
rest of our sites. Expect quieter conditions overnight. The NAM
shows the potential for a few showers near SUN early Friday
morning, though confidence is not high enough to add anything to
the TAF for now. Thunderstorms on Friday should be a bit more
isolated.

&&

.FIRE WEATHER...
Issued at 223 PM MDT Thu Jul 31 2025

A RED FLAG WARNING is in  effect for Idaho Fire Weather Zones 410
and 413 until midnight tonight for gusty winds and low RHs and also
for Idaho Fire Weather Zones 422, 425, and 427 until midnight
tonight for scattered thunderstorms and gusty outflow winds. Storms
today will be capable of producing gusts to 60 mph, small hail, and
brief downpours. Outside of storms, gusty outflow winds will do
their best to make it a bit farther up the Snake River Plain today
in parts of Zone 410. It is in Zones 410 and 413 that wind gusts
(outside of storms) will be in the 25 to 35 mph range with min RHs
this afternoon ranging from 10 to 20 percent. Outside of the Red
Flag Warning, critical fire weather conditions are expected in zones
475 and 476 where scattered thunderstorms will continue this
afternoon.

Min RHs will be very gradually increasing on Friday, but look for
another RED FLAG WARNING from 2 to 10 PM MDT for FWZ 410, 413, 422,
425, and 427 once again for a combo of scattered thunderstorms
(Zones 422 and 427, creeping into 425) and gusty winds and low RHS
(Zones 410, 413, and part of 425). Wind gusts will range from 25 to
35 mph once again in these areas with min RHs ranging from 15 to 20
percent. Look for this RFW to be issued when the current one ends.
Thunderstorm coverage looks to decrease just a bit for Saturday and
min RHs slowly increase closer to 20 percent in Zones 410, 413, and
425. However, we will still need to evaluate Red Flag potential for
Saturday either tomorrow or Saturday morning.

&&

.HYDROLOGY...
Issued at 223 PM MDT Thu Jul 31 2025

A Flash Flood Watch is in effect for the Wapiti burn scar from 3 PM
this afternoon through 10 PM MDT this evening due to the potential
for flash flooding and debris flows from moderate to heavy
thunderstorm downpours. The Weather Prediction Center`s Excessive
Rainfall Outlook includes the central mountains in a marginal risk
(at least 5% chance), meaning isolated flash flooding is possible
for areas that can experience rapid runoff, such as burn scars.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until midnight MDT tonight for IDZ410-413-422-
425-427.

&&

$$

SHORT TERM...Cropp
LONG TERM...Cropp
AVIATION...AMM
FIRE WEATHER...AMM
HYDROLOGY...Cropp