741
FXUS65 KPIH 271944
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
144 PM MDT Wed Aug 27 2025

.KEY MESSAGES...

- A flood watch is in effect for all of eastern Idaho. Slight
  risk that rainfall will exceed flash flood guidance with some
  chance of flash flooding possible, especially near burn scar
  areas.

- Cooler temperatures, increased humidity, and measurable
  rainfall is expected for the next few days.

- Drier and gradually warming as we move towards the holiday
  weekend

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 144 PM MDT Wed Aug 27 2025

Satellite imagery shows center of upper low centered over East idaho
this afternoon. Deep moisture in place with PWAT near or over an
inch across the forecast area. Thunderstorms already redeveloping
across higher elevation areas early this afternoon, expected to fill
in over most of the area, though the best coverage remains over the
higher terrain. For the remainder of today and overnight, NBM
broad-brushes 24-hr precipitation totals ranging from around
0.35 inches across the Magic Valley and the South Hills to
upwards of 1.00 inch across the Divide to the Big Holes. Higher
resolution HREF 24-hr precipitation gets more granular, and
decreases the amounts significantly to less than 0.10 inches
across the Snake Plain generally south/west of US-20. So far the
HREF matches current radar trends, but there is still a lot of
opportunity for additional thunderstorm development throughout
the Snake Plain where some pockets of sunshine were realized
late this morning and early afternoon. Will maintain the Flood
Watch across the entire area with expiration still around
midnight given the best chance for heavy rainfall associated
with thunderstorms this afternoon and evening. Believe that burn
scars and steeper terrain will continue to be the primary
threat areas, with less of a threat across the Snake Plain.

Drier mid level flow pushes into the region from the west as
shortwave lifts northeast into Montana overnight. PWATS drop off
significantly through the day, and though isolated to scattered
thunderstorms remain possible Thursday afternoon, the threat for
very heavy rainfall diminishes drastically. Temperatures remain
cooler than normal Thursday with daytime highs remaining in the
70s. With surface dew points dropping through the day, there
should be a change in the "feel" toward less muggy conditions as
well.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 144 PM MDT Wed Aug 27 2025

Air mass over East Idaho continues to trend drier moving into
Friday, though isolated thunderstorms remain possible mainly over
higher terrain and trending back toward a mix of wet/dry with gusty
wind threat. A ridge of high pressure rebuilds across the Great
Basin for the Labor Day weekend, though the blend maintains a weak
threat of isolated thunderstorms across some areas Labor Day. The
GFS may be the main driver here as it tries to rotate a weak
shortwave around the low parked over off the PacNW coast into East
Idaho.  Daytime highs return to the 80s by Sunday for most lower
elevation areas, remaining there for the remainder of the forecast
period.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 144 PM MDT Wed Aug 27 2025

Widespread cloud cover remains in place throughout the area leading
to a mix of MVFR or low-end VFR CIGs for much of the afternoon and
evening hours. Hi-res models continue to show additional
shower/storm development over the next few hours and with just
enough breaks in cloud cover being seeing across the south, could see
some tstm development impacting terminals. This isn`t a sure thing
however. Synoptic winds remain light through the period and we`ll
begin to start seeing some clearing by the mid-morning hours
tomorrow from west to east over the course of the day as the
prolonged moisture influx begins to subside tomorrow, but especially
Friday.

&&

.FIRE WEATHER...
Issued at 144 PM MDT Wed Aug 27 2025

Widespread clouds remain in place this afternoon with showers and
embedded thunderstorms continuing to move through the region.
Expecting these to increase slightly in coverage over the next few
hours but instability is fairly limited. Today will be the last day
for widespread clouds and precipitation as the pattern will begin to
change tomorrow and especially by Friday. We`ll still see some
scattered precip chances tomorrow, becoming more isolated Friday and
then basically non-existent by the time we get to the Labor Day
holiday weekend and into early next week. Temperatures will slowly
begin to trend upwards once again but not nearly as warm as the
previous week and this will keep RHs above any critical levels into
early next week.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Flood Watch until midnight MDT tonight for IDZ051>075.

&&

$$

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