Hayden, Idaho 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

848
FXUS66 KOTX 231000
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
200 AM PST Sat Nov 23 2024

.SYNOPSIS...
The weekend into early next week will feature seasonably cool
temperatures and chances for valley rain and brief snow and
periods of mountain snow. Moderate rain amounts for portions of
eastern Washington and the Idaho Panhandle will lead to the threat
of rock and mud slides near steep terrain.

&&

.DISCUSSION...
Saturday through Monday: An unsettled weather pattern will persist
over the Inland NW as an area of low pressure continues to spin
along the WA Coast slinging disturbances inland. The remnants of
Friday`s front remains draped over southeastern WA and North Idaho
this morning. This front will begin to slowly drift east through
the day but not before delivering light to moderate QPF for
locations from Lookout Pass to the Blue Mountains and points
south. Meanwhile the air mass aloft is cooling with precipitation
likely to transition back to snow for elevations above 3000 feet.
This includes Lookout Pass within the Central Panhandle Mountains,
Blue Mountains, and higher benches of the Camas Prairie. If you
are traveling Saturday morning in these areas, be prepared for
variable conditions and return to winter driving conditions in the
next few hours. Additional QPF amounts of a quarter to half an
inch are expected through the afternoon. Using a conservative 10:1
ratio, Lookout Pass has a 50% for 4" or more with the most likely
range between 3 to 6 inches. Lower snow levels will be slower to
arrive in Winchester which is calling for around of an inch or so.
There is a 10-30% chance for lighter showers to build westward
into Central and Eastern WA with minimal QPF amounts. A lot of
this activity could be more in the form of drizzle with an
abundance of low clouds now in place following Friday`s rain.

The consistent rain over SE WA and NC Idaho will continue to bring a
threat for rock-slides. There were two confirmed on Friday in NC
Idaho. Unfortunately, its near impossible to determine exactly
where these may occur. Flood advisory remains in effect for the
Gwen Burn scar for this threat given its sensitive nature to even
light precipitation.

On Sunday into Monday, a weak but more organized frontal system will
pass through with light rain and mountain snow. Thinking many
communities will escape Sunday morning and early afternoon
precipitation free with shortwave ridging coming through ahead of
the system then precipitation will start in the Cascades Sunday
afternoon and expand eastward Sunday evening into Monday morning.
Snow levels will start off lower with an increased threat for
light snow in the Cascade mountains, upper river valleys, and into
the Okanogan Highlands. NBM has a 40% chance for at least 4" of
snow at Stevens Pass with the most likely range from 3 to 6
inches. It will be a challenging forecast for precipitation type
for the lowlands in the Cascade Valleys down toward the Columbia
River and into Ferry County. Deterministic models indicate the
layer is cold enough for snow with moderate to high confidence for
850mb temperatures below 0C and 0-4km wetbulb temperatures below
0C. However, models may be struggling with how the low stratus
will evolve over the next 36 hours which could act to trap
afternoon warmth and keep surface temperatures 32-35F. Needless to
say, snow is in the forecast but amounts which could vary from a
trace to 4 inches come with low confidence. Travelers should be
prepared for snowy travel over Stevens, Loup Loup, and Sherman
Passes; 30-40% chance for light snow in the aforementioned
lowlands.

As the system tracks east Monday morning, light snow will be possible
down to the valley floors along and north of Hwy 2 into
Northeastern WA and North Idaho. This also comes with low
confidence for meaningful accumulations given earlier reasoning
stated above with low stratus. Probabilities remain around 20-30%
for an 1". Anything falling early Monday morning would be of more
concern for slick travel vs after 10AM which is more likely to
melt on pavement surfaces given the light nature of this event.

The next few days will bring areas of fog and low clouds with periodic
drizzle when rain or snow is not falling. Fog could be dense at
times producing visibility of 1/4 mile or less. Temperatures will
vary from the 30s and 40s in the afternoon to upper 20s to 30s at
night. Many areas may be getting close or just below the freezing
mark so be cautious of black ice. /sb

Tuesday through Friday: Tuesday, an upper-level low will move
southeast, reaching the OR/CA border. Precipitation chances will
decrease, mainly affecting the Cascades and eastern WA. Temperatures
will be warmest on Tuesday, with highs hovering around 40. A cool
northwesterly flow will develop for the second half of the week, as
a high pressure ridge strengthens offshore. Temperatures will drop,
with highs in the 30s and lows in the teens to 20s. Precipitation
uncertainty remains due to varying model predictions about the
ridge`s position. If the ridge is near the coast, disturbances will
likely miss eastern WA and ID. If it remains further offshore, more
precipitation could occur. Precip chances for the Cascades, ID
Panhandle, and eastern WA are currently forecast at 20-50% but may
change as we get closer and models dial in better. /KM

&&

.AVIATION...
06Z TAFS: A persistent band of light to moderate rain won`t move
much until 18-21z when the models finally push it out of eastern
Washington and the Coeur d`Alene area. Soaking rain has been
common region-wide over the last 24 hours. The combination of wet
ground, decreasing winds in the boundary layer, the continued
influx of rain, should lead to decreasing visibility and lower
ceilings region-wide through mid morning. Drier and cooler air
aloft and a modest increase in post-frontal winds should lead to
improvements between 18-00z Saturday as the Inland Northwest
finally dries out. /GKoch

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
Moisture laden environments like this are tough as they produce
variable low cloud and visibility conditions. Amendments will be
necessary as rain intensity varies. /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        42  33  42  31  39  30 /  80  20  20  20  50  30
Coeur d`Alene  41  33  41  29  36  31 / 100  40  20  20  50  50
Pullman        41  32  42  31  40  31 / 100  40  10  10  40  40
Lewiston       47  33  47  31  43  36 / 100  30  10  10  20  30
Colville       42  31  39  30  35  24 /  50  10  20  40  60  30
Sandpoint      37  30  37  27  34  29 /  90  60  40  30  60  60
Kellogg        38  33  39  25  36  32 / 100  60  30  20  70  60
Moses Lake     45  32  44  35  41  30 /  20   0  20  30  30  20
Wenatchee      40  30  38  33  38  31 /  10   0  30  40  20  20
Omak           39  30  39  34  38  29 /  10   0  40  60  20  10

&&

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

$$