Hartline, Washington Weather Forecast Discussion

590
FXUS66 KOTX 052206
AFDOTX
Area Forecast Discussion
National Weather Service Spokane WA
306 PM PDT Fri Sep 5 2025
.KEY MESSAGES...
- Temperatures trending cooler heading into this weekend and
  next week.
- Smoke and haze expected to continue through the weekend
- Unsettled weather returning to the region over the weekend and
  into next week with increasing threat for showers and
  thunderstorms.
&&
.SYNOPSIS...
Smoke and haze is expected to continue over the weekend while
temperatures gradually trend cooler. Precipitation chances will
be on the gradual increase next week, along with more significant
cooling across the region as high temperatures drop into the
70s.
&&
.DISCUSSION...
Tonight through Sunday: As a trough digs in along the coast,
the ridge finally begins to move East. It allows shortwaves
circulating around an embedded Low to push through the Pacific
Northwest. There is still uncertainty with timing and placement
of the Low. Overall the region finally have begin to trend to
moderate near normal temperatures and increasing shower chances
for the Inland Northwest. An initial pulse of instability along
the Cascades could generate a weak thunderstorm (5-15% chance)
Friday evening. It will be followed by a more robust wave late
Saturday into Sunday (20-40% thunderstorm chance). One concern
are the winds ahead of the wave. Some models are showing winds
sustained in the teens with gusts near 30 to 35 MPH. While the
shower chances increase across the region, the amounts are not
expected to be much for the most of the lowland locations with a
few hundredths at most. The mountains will fare much better
with at least a tenth and potentially up to three quarters of an
inch through Wednesday. Instability parameters are strongest on
Sunday and weaken through the start of next week. Temperatures
will be pleasant compared to the last few days with highs in the
70s and low 80s. Lows will be in the 50s. /JDC
Monday-Thursday: There is increasing confidence for a significant
pattern change over the Northwest with the low slowly migrating
through the region. This leads to high confidence for cooler
temperatures and higher humidities which is great news for the
fires. The low will also bring increasing chances for on and off
periods of showers and thunderstorms. Shower and thunderstorm
activity will trend wetter with time with NBM indicated a 30-80%
chance for wetting rains by midweek. Given the convective
nature of the precipitation bands, it conceivable that some
areas miss out, thus the 30% which found across the lower Basin,
but many areas where the fires are burning are closer to 50-80%
chances. Temperatures will be cooling back into the 80s and
then 70s as the low moves inland. At this time, we do not
anticipate a significant wind event with this changing air mass
as this system slowly meanders inland but locally breezy
conditions are not out of the question, especially near any
convection.
Heading into Friday and next weekend, there is a lot more
uncertainty with the forecast. A second low approaches from the
E Pac. This will help kick the first low to the east. Likely
there will be a period of dry and warm conditions between these
features but how long is uncertain. Consensus amongst the
ensembles is for 2-3 days. We will need to closely monitor the
evolution of the offshore low. Some of the ensembles sweep this
wave through swiftly which could be a wind maker while others
develop split flow and would yield far less wind. More to come
on this in the coming days. /sb
&&
.AVIATION...
18Z TAFS: Visibility is expected to be restricted from wildfire
smoke regionwide for the next several days. Visibility is
expected to range from 4-7 miles for most of Central and Eastern
Washington and north Idaho, but areas near fires including
Colville will see restrictions as low as 1 mile.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
Low confidence in precise visibilities at the TAF sites due to
shifting winds out of the northeast into Friday morning for the
Columbia Basin, Palouse, and north Idaho. The wind shift could
shift the surface smoke around with fluctuating visibility.
-----------------------
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:/weather.gov/otx/avndashboard
&&
.Preliminary Point Temps/PoPs...
Spokane        60  94  63  85  58  83 /   0   0  10  20  20  10
Coeur d`Alene  60  94  63  85  59  84 /   0   0  10  20  20  10
Pullman        58  90  58  82  53  81 /   0  10  30  30  30  10
Lewiston       67  95  67  89  63  87 /   0  10  30  30  30  10
Colville       51  94  53  85  49  82 /   0   0  20  40  40  30
Sandpoint      55  90  57  83  54  81 /   0   0  20  30  40  20
Kellogg        63  91  64  83  60  82 /   0   0  20  30  30  10
Moses Lake     63  93  61  86  56  82 /   0  20  20  40  10  10
Wenatchee      71  92  68  85  62  81 /  10  20  40  50  20  20
Omak           66  96  65  88  60  84 /   0  10  20  40  30  20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Air Quality Alert until noon PDT Monday for Central Chelan
     County-Lower Garfield and Asotin Counties-Moses Lake Area-
     Northeast Blue Mountains-Northeast Mountains-Okanogan
     Highlands-Okanogan Valley-Spokane Area-Upper Columbia
     Basin-Washington Palouse-Waterville Plateau-Wenatchee
     Area-Western Chelan County-Western Okanogan County.
ID...Air Quality Alert until noon PDT Monday for Central Panhandle
     Mountains-Coeur d`Alene Area-Idaho Palouse-Lewis and
     Southern Nez Perce Counties-Lewiston Area-Northern
     Panhandle.
&&
$$

NWS OTX Office Area Forecast Discussion