314
FXUS66 KOTX 171843
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1142 AM PDT Thu Sep 17 2026

.KEY MESSAGES...
- 30-60 percent chance of showers and 20 percent chance of
  thunderstorms over southeastern WA and the central ID
  Panhandle Thursday evening into Friday.

- Warm temperatures Thursday through Monday with afternoon
  highs in the mid 70s to low 80s. Temperatures cool to near
  normal by the middle of next week.

&&

.SYNOPSIS...
Shower and thunderstorm chances return to the forecast over
southeast WA and the central ID Panhandle Thursday evening into
Friday. Otherwise, conditions will be dry through the weekend
and into early next week. Afternoon temperatures will be warm
Thursday through Monday with highs in the mid 70s to low 80s.
Overnight lows will fall into the 40s to low 50s.

&&

.DISCUSSION...
Thursday and Friday: A closed upper level low over northern
California wobbles northeastward into eastern Oregon Thursday,
increasing moisture over southeastern WA and the central ID
Panhandle and bringing in cooler air aloft. Meanwhile, surface
temperatures will run 3-8 degrees warmer than on Wednesday. The
combination of more moisture, cooler temperatures aloft, and
warmer temperatures at the surface will result in steeper lapse
rates and a more unstable atmosphere over the southeastern
portion of the region during the afternoon and evening hours
Thursday. A 30-60 percent chance of showers will move in over
southeastern WA and central ID Thursday evening with shower
chances decreasing to around 20-40 percent late Thursday night
into Friday morning. There will also be a 20 percent chance for
elevated thunderstorms primarily Thursday evening with the
threat of thunderstorms waning overnight as surface temperatures
cool and CAPE values decrease.

Downdraft CAPE of 800-1000 J/kg indicates outflow winds will be
the primary concern with convection Thursday. The HRRR model
depicts outflow winds up to 35-40 mph with convection, and
these gusts may extend far out away from the parent
thunderstorm(s). One thing to watch for with these winds will be
blowing dust, as planting season is well underway. Blowing dust
may lead to rapid changes to visibility across southeastern
Washington. Secondary hazards will include brief downpours,
small hail, and occasional cloud to ground lightning strikes.

By Friday, the upper level low tracks eastward into southern ID,
moving chances for showers and thunderstorms largely out of the
region.

Saturday through Wednesday: Conditions look drier through the
weekend and into early next week. The Inland Northwest will be
under a flat ridge with dry westerly flow bringing mostly sunny
skies. Temperatures will be around five degrees warmer than
average for mid September with highs in the upper 70s to around
80 for most valley locations through Monday. Temperatures cool
into the low to mid 70s by the middle of next week as a trough
approaches the West Coast. /Fewkes

&&

.AVIATION...
18Z TAFS: A low pressure system spinning over eastern Oregon will
spread scattered showers with a isolated embedded thunderstorms into
southeast Washington and the southern Idaho Panhandle today. Timing
for showers and thunderstorms into KLWS looks to be mid to late
afternoon into the evening hours (after 22Z). Instability parameters
are less likely to support thunderstorms as far north as KPUW with
chances decreasing to a 15% chance. Chances decrease further north
and west into KMWH/KGEG/KSFF/KCOE where spread mid to high level
clouds from convection is all that is expected at these airport
terminals. Thunderstorms will be capable of gusty outflows of up to
20-25 kts and brief heavy downpours. Isolated showers in the
vicinity of KLWS and KPUW will continue overnight, but convection is
expected to weaken.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence in
VFR conditions. Low to moderate confidence for thunderstorms to
impact KLWS and KPUW airport terminals this afternoon and evening.
/SVH

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

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        78  52  76  51  77  52 /   0  10   0   0   0   0
Coeur d`Alene  78  50  75  48  76  49 /   0  10   0   0   0   0
Pullman        72  49  72  47  75  46 /  10  50  10   0   0   0
Lewiston       76  56  77  54  80  54 /  10  50  10   0   0   0
Colville       80  43  78  43  81  45 /   0   0   0   0   0   0
Sandpoint      76  45  73  44  76  44 /   0   0   0   0   0   0
Kellogg        78  50  72  46  74  47 /   0  40   0   0   0   0
Moses Lake     79  49  77  48  77  48 /   0   0   0   0   0   0
Wenatchee      79  56  77  55  77  55 /   0   0   0   0   0   0
Omak           80  50  78  49  79  50 /   0   0   0   0   0   0

&&

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

&&

$$