921
FXUS66 KOTX 040813
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
113 AM PDT Fri Jul 4 2025

.KEY MESSAGES...

- Breezy winds, and a chance of showers on Independence Day.

- Small thunderstorm chances in far southeastern Washington,
  southern and central Idaho Panhandle, and the North Cascades
  on Independence Day.

- Hot temperatures arrive Monday and continue into at least
  Wednesday.

&&

.SYNOPSIS...
Independence Day will increasing clouds and periods of
breezy winds late in the day into the evening. Some areas
will have a chance for showers. Thunderstorm potential also
exists on for far southeastern Washington, the central and
southern Idaho Panhandle, and the North Cascades. Hot
temperatures arrive on Monday and may persist through the
remainder of next week.

&&

.DISCUSSION...
Today - Saturday: A pair of low pressure systems (one over N CA
and second off the coast along 130W) are beginning to phase
together and will move through the NW over the next 48 hours.
Mid-level moisture drawn northward ahead of the system is
evident on the 1AM satellite over southern WA but the main band
of showers and thunderstorms is lagging south and currently over
Central OR. This complex but slow moving system will continue
to lift north and east over the next 24 hours limping through
the region delivering bands of clouds, higher humidities, cooler
temperatures, and chance for showers but not a tremendous
amount of precipitation. The first chance for showers will
arrive in far SE WA and the lower ID Panhandle Friday afternoon
and evening. Rainfall amounts will largely be under a tenth of
an inch. The Camas Prairie and Blue Mountains come with a 50-70%
chance for a tenth of rain or more. These areas will also have
a 10-20% chance for lightning with the threat increasing as you
go further south of Asotin and Lewis Counties. A few of the hi-
res models continue to bring the showers further north toward
Spokane-Cd`A Friday afternoon but this comes with very low
confidence and little support from the ensemble package and
probabilities.

One caveat will be a 10-20% chance for cumulus buildups and threat
for isolated showers or t-storms over the N Cascades. Roughly 2
of 6 cam models support enough instability and low-level
moistening for a few cells in the mountains around the upper
Methow Valley northward to the Canadian Border. The SREF and
HREF come with less than a 5% chance for lightning in these
areas leading to very low confidence.

For the remainder of the Inland NW, the main sensible weather will
be increasing mid and high clouds before midnight and breezy to
gusty winds. As the band of showers approaches the WA/OR
border, several hi-res models are indicating outflow winds from
the rain cooled air into our antecedent dry atmosphere. It does
not look like the convection will be strong enough to produce
damaging winds but a noticeable push of wind gusts 20-25 mph
coming in from the south late Friday afternoon and into the
evening, especially as the cooler marine air catches up and
begins to flood in from the west. Those of you enjoying the
outdoors this Independence day should be cautious of these
increased winds and make sure to secure light weight objects
like umbrellas, floats, and use caution with grills and BBQ`s
around dry grasses. The latest HRRR has this push of southerly
winds punching northward through the Basin as early as 4-6PM and
then remaining breezy into the night. Meanwhile, Cascade gap
winds will increase from the northwest (this is the marine air
squeezing through). These winds will have the potential for
isolated gusts closer to 30 mph. All things considered, a period
of elevated fire weather conditions will be in place as these
winds increase and please use caution. Confidence in exact
timing and strength will be very dependent where we find the
best clusters of showers or thunderstorms to drive these winds.
Would not rule out a push of southeast winds coming across the
Camas Prairie into Lewiston if the best rainfall is falling just
south of these areas.

By late Friday night and into early Saturday, the system will
continue to drift inland with wrap around moisture and showers
expanding into North Idaho and Eastern WA. Probabilities for a
tenth of rain increase toward 30-60% for locations like St
Maries, Sandpoint, Ione, Spokane, and Cd`A. Much of shower
activity will be overnight into Saturday morning. By Saturday
afternoon, clouds begin breaking and partial sunshine will allow
temps to warm back into the 80s. With ample clearing, there
will be a renewed threat for afternoon convection over the
mountains of NE WA and N ID with a 10-20% chance for a few
t-storms between Colville, Ione, and Bonners Ferry.

Unfortunately, this system will deliver little to no rainfall
for Central WA outside a few rogue showers or sprinkles that develop
Friday afternoon.

Sunday - Tuesday:  Zonal flow on Sunday will give way to subtle height
rises for early next week promoting our next warming and drying
trend. 85H temps increase 2-3C each consecutive day through
Tuesday with summer heat returning. High temperatures by Tuesday
will be surging back into the 90s with lower 100s in the Snake
River Valley, lower Basin, and stretches of Hwy 97 between Omak
and Wenatchee. The ridge will be slow to amplify and placement
of the ridge axis is favored to be closer to the spine of the
Rockies thus I do anticipate some local westerly breezes through
the Cascade gaps and Basin each afternoon and evening with wind
speeds closer to 20 mph. Thinking these winds will be breeziest
Sunday and Monday and lowest Tuesday as this would be the
warmest day for the west side which is forecast to reach into
the 80s. Heat risk charts are indicating a return to moderate to
locally major heat risk for much of the Inland NW.


Wednesday - weekend:  Uncertainty in the forecast increases around
mid to late week, heading into the weekend. Above normal
temperatures seem a strong possibility but to what degree is far
from certain and there is a 10-15 degree spread in potential
high temperatures from the upper 80s to lower 100s. NBM is only
lowering temperatures 1-3 degrees from Tuesday through Wednesday
then another handful of degrees for Thursday and Friday. Looks
to be a tied to models struggling with the depth and timing of a
broad shortwave swinging through British Columbia and how much
this will dent the ridge. More importantly, this could be our
next bout of winds and fire weather concerns. Something we will
be paying close attention to as we enter the second week of
July. /sb

&&

.AVIATION...
06Z TAFS: VFR conditions will continue through the TAF period.
Low pressure approaching from the south will bring increasing
mid and high clouds. Shower chances develop after 18Z, with the
best risk over southeast WA and lower ID. Chances were includes
near LWS and PUW. Better chances for showers around Spokane,
Coeur D Alene, Bonners Ferry, and Colville will come after 06z
Saturday. A slight risk for t-storms will be found south of LWS
Friday afternoon. Potentially the greatest impact will be gusty
winds of 15-25 kts from outflow of showers along the WA/OR
border. Exact timing and speed comes with moderate uncertainty
given the nature of this wind from rain-cooled air but it
definitely showing up late in the day or evening on several hi-
res models. Trends have been slower on the latest HRRR and HREF
and TAFS were adjusted slightly to delay the stronger speeds.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
in conditions remaining VFR. Low to moderate confidence in exact
timing of showers near LWS/PUW along with speed and duration of
gusts of 20kts or greater. Moderate confidence speeds will
remain below 30kts given the weak nature of the convection.
There is also a 10-20% chance for isolated thunderstorms over
the far N Cascades Friday afternoon between 22-03z. /sb

-----------------------

Confidence descriptors:
Low - Less than a 30 percent chance
Moderate - 30 to 70 percent chance
High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane
airports, please refer to the Aviation Dashboard on our
webpage: https:/www.weather.gov/otx/avndashboard

&&

.Preliminary Point Temps/PoPs...
Spokane        80  57  82  55  87  56 /  20  20  10   0   0   0
Coeur d`Alene  78  56  79  56  86  56 /  20  30  10   0   0   0
Pullman        73  54  78  50  84  53 /  40  30   0   0   0   0
Lewiston       80  58  86  60  92  62 /  50  30   0   0   0   0
Colville       83  57  81  47  86  49 /  10  20  10   0   0   0
Sandpoint      78  54  75  52  82  51 /  10  40  30   0   0   0
Kellogg        75  53  75  57  82  59 /  30  40  20   0   0   0
Moses Lake     84  58  88  55  91  58 /  20  20   0   0   0   0
Wenatchee      86  61  88  60  91  64 /  10  20   0   0   0   0
Omak           88  59  88  57  90  59 /  10  20   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...None.
ID...None.

&&

$$