National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS66 KOTX 170515
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1015 PM PDT Tue Apr 16 2024

.SYNOPSIS...
Anticipate cool, brisk, and somewhat showery weather as a low
pressure system aloft drops over the Inland NW and lingers
through Thursday. It will be chilly early in the morning with lows
dipping below freezing for many areas and the threat of frost.
The weather gradually warms and dries by Friday into the weekend
and continues into early next week with above normal temperatures.

&&

.DISCUSSION...
As of 10 PM, shower activity has gradually decreased through the
evening with the loss of afternoon destabilization. Clusters of
light rain and snow showers have more upper level support north of
Omak. A 20 percent chance of showers will persist across northern
Okanogan county into the predawn hours. A weak backdoor cold front
is also expected to hang up along the Montana/Idaho border
overnight bringing a 30 percent chance of snow showers to the high
terrain of north Idaho. Bonners Ferry and Sandpoint may also
experience some light showers overnight. Clearing skies will allow
temperatures to tumble into the low to mid 30s over the majority
of the Inland Northwest. Pockets of upper 20s will also occur in
our sheltered valleys...places like Deer Park, Springdale,
Republic, Priest Lake, and Mazama. /GKoch


.PREVIOUS DISCUSSION...
An amplified upper ridge centered off the coast near 135W will
result in a broad trough with north-northeast flow over the area
through Thursday. Colder air aloft associated with the trough
combined with daytime heating will help generate convective
showers each day, mainly in the afternoon and evening hours. The
coldest air aloft with 500mb temperatures in the -30 to
-34C range will be focused over NE Washington and the Idaho
Panhandle which is where the models are generating the highest
focus of showers. The cold atmosphere and drier low levels with
dew points in the teens and 20s will support higher cloud bases
with the convection that develops, with most of the CAPE layer
composed of ice. This will support mainly graupel showers, with
thunderstorms not expected although can not rule out a stray
lightning strike.

This air mass will also favor cold overnight lows for this time of
the year. For tonight areas that have begun their climatological
growing season (Wenatchee and Moses Lake area, LC valley) will see
temperatures remaining above freezing. For tomorrow night the LC
Valley and Moses Lake area will be near freezing so will have to
keep a close eye on potential frost or freeze highlights. JW

Friday through Tuesday: Conditions look to dry out for Friday and
Saturday with daytime temps warming to near daily normals. Also
expect breezy northeasterly winds on Friday with local gusts of 25
to 35 mph, especially across the Columbia Basin. Enough instability
and moisture with a passing wave will lead to a chance for mountain
showers Sunday, but most locations will remain dry. The gradual
warming trend looks to continue Monday and Tuesday, with forecast
max temperatures ~5+ degrees above normal. /KD

&&

.AVIATION...
06Z TAFS: Showers enhanced by afternoon destabilization have
decreased. Airports for the remainder of the night into the mid
morning will be mainly clear with light winds and good
visibility. On Wednesday, the atmosphere will again destabilize
from afternoon heating with another round of rain/snow/graupel
showers.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: There is high
confidence in VFR conditions through the TAF period, with one
exception. Under localized moderate showers there is a 10-20%
chance of visibilities dropping to MVFR due to snow or graupel
between 20-01z Wednesday. /GKoch

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

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        30  54  31  55  32  56 /  20  20  20  20   0   0
Coeur d`Alene  30  52  31  53  30  54 /  30  20  20  20  10   0
Pullman        29  50  30  54  31  57 /  20  10  10  10   0   0
Lewiston       37  56  34  61  35  63 /  10  10   0   0   0   0
Colville       32  55  32  55  29  57 /  20  30  20  20  10   0
Sandpoint      31  50  33  51  31  52 /  50  30  20  20  10   0
Kellogg        33  48  32  50  29  52 /  30  50  20  30  10   0
Moses Lake     34  60  33  62  36  63 /   0   0   0   0   0   0
Wenatchee      34  58  35  59  35  60 /   0   0  10   0   0   0
Omak           34  59  33  61  34  63 /  10  10   0   0   0   0

&&

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

$$