656
FXUS66 KOTX 040546
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1046 PM PDT Thu Jul 3 2025

.KEY MESSAGES...

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

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

- Hot temperatures arrive Monday, possibly persisting through
  the remainder of next week.

&&

.SYNOPSIS...
Independence Day will bring breezy winds and a chance of showers
across the region. 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...
Tonight through Friday Night: Satellite imagery this afternoon
shows a couple features of interest. The first is a large low
pressure system moving into Alberta providing a cooler, westerly
flow over the region today. The second and more important
feature in terms of Independence Day weather is a smaller low
approaching the southern Oregon and northern California coast
this afternoon. Models are in good agreement of increasing
showers and thunderstorms developing south of our area across
Central and Eastern Oregon tonight. Friday morning some of this
moisture begins to lift north towards SE Washington and the
Lewiston area and Camas Prairie for a 20-30% chance of showers.
As the low continues to push east the chances for showers in
these areas increase to 60% in the afternoon, while a 20% chance
pushes north into the Columbia Basin and Spokane/Coeur d`Alene
area, and over the ridges in the northern mountains.

Heading into Friday evening, as moisture continues to push
north and there being a broad area of weak mid level instability
all areas will be under a threat of showers, but ensembles
currently depict coverage of rain reaching the surface to be
isolated in nature (20% coverage) over most of the region, with
the best chances over SE Washington, the ID Panhandle, and over
the northern mountains (30-40%). Yet despite the somewhat low
POP`s, the increased lift with the incoming low and some weak
mid level instability to work with could yield localized areas
with moderate rain showers, putting a damper on outdoor
festivities.

Regarding thunderstorms, the limited instability over
Washington and North Idaho continues to look unfavorable for
thunderstorms with a couple exceptions. One being SE Washington
into the Central Panhandle Mountains (including the LC Valley)
Friday afternoon and evening with 850-500mb MU CAPE of 200-400
J/KG potentially yielding a few storms. The second is over the
North Cascades during the late afternoon and evening where some
of the CAM`s models continue to show isolated storms forming
over the mountains around and to the north of Lake Chelan.

Cloud cover will yield a day of below normal temperatures for
the Palouse and Lewiston area for Independence Day with highs in
the mid 70s to low 80s. Elsewhere highs will be in the 80s.
Differential heating between the warmer northern valleys and
cooler portions of northern OR/southern WA had the potential to
produce a period of breezy south winds Friday afternoon into the
early evening. Brief gusts in the 20-30 MPH range are possible
from the Columbia Basin, Palouse, LC Valley, and Spokane area
Friday afternoon, and then across the northern valleys Friday
evening. High res models also show breezy Cascade gaps winds
Friday evening with gusts up to 30 MPH around Wenatchee, Chelan,
and Vantage. JW

Saturday: A passing shortwave will bring unsettled weather to
the region on Saturday. As this system moves through, it will
interact with lingering moisture and modest instability to
trigger scattered showers and isolated thunderstorms in the
afternoon over the higher terrain in northeast WA and the ID
Panhandle. Any storms that do form could be capable of brief
heavy rainfall, gusty winds and lightning. While the overall
coverage is expected to remain limited, conditions will be
monitored closely due to the holiday weekend.

Sunday through Wednesday: Following the exit of Saturday`s
system, a strong ridge of high pressure is expected to build
into the region. This will mark the beginning of another warming
trend, with dry, unstable conditions returning. Each day will
increase in temperatures, with Tuesday and Wednesday being the
warmest days. Ensembles are indicating that yet again we could
see warmer temperatures than the last heat wave. Temperatures in
the high 90s to 105 are expected as of this forecast, with the
hottest temperatures being down in the LC Valley and Columbia
Basin. This could bring the potential for widespread impacts
from heat stress to increased fire danger. Winds will begin to
increase Wednesday afternoon as another system begins to push in
offshore. Overnight temperatures will be warm was well, with
most areas remaining in the upper 50s to around 70. Keep an eye
on the forecast as we get closer. /KK

&&

.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        55  82  58  82  55  88 /   0  20  20  10   0   0
Coeur d`Alene  56  82  56  79  56  86 /   0  20  30  10   0   0
Pullman        51  73  51  79  50  85 /   0  40  30   0   0   0
Lewiston       62  80  61  86  61  94 /   0  60  30   0   0   0
Colville       46  84  56  82  48  86 /   0  10  30  10   0   0
Sandpoint      51  81  55  77  51  83 /   0  10  50  20   0   0
Kellogg        58  77  54  75  57  83 /   0  30  40  20   0   0
Moses Lake     55  84  58  87  55  91 /   0  20  20   0   0   0
Wenatchee      60  86  62  88  61  91 /   0  10  20   0   0   0
Omak           56  88  59  87  57  91 /   0  10  20   0   0   0

&&

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

&&

$$