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000
FXUS66 KOTX 211130
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
430 AM PDT Sun Apr 21 2024

.SYNOPSIS...
Today will be breezy with persistent westerly winds. Mild and dry
weather returns for the start of work week with 60s and 70s by
Tuesday. A subtle cooling trend arrives Wednesday into Thursday
with small chances for mountain showers.

&&

.DISCUSSION...
Today and tonight: A potent cold front is sweeping across the Inland
Northwest this morning and has recently reached North Idaho as of
2AM. Wind gusts have been on track so far with spotty reports of
40-45 mph but on a widespread basis, more in the 30-40 mph range.
Sustained speeds have varied from 20-30 mph. Rainfall has been
light along the front with just a few hundredths measured on some
of the RAWS in Northeastern WA/far North Idaho and along the
Cascade Crest. Cold air advection will continue through the day
promoting windy conditions across the region. Winds will generally
be from the west and southwest with speeds of 15-25 mph. Gusts
will approach 30-35 mph at times but this seems to be the upper
limit given the modeled wind aloft. Water vapor is showing a lot
of dry air behind the front so despite cooler temperatures,
humidity levels will remain quite low dipping into the 20-30%
range. This will keep skies mostly clear away from the Cascade
Crest and across much of the Basin. Some shallow cumulus buildups
are expected under a more pronounced 500 mb cold pool that will be
skirting along the International border with a small chance for
spotty sprinkles or a brief shower. Winds will decrease slowly
Sunday evening and further overnight with chilly conditions for
Monday morning. Timing of the winds decreasing below 5 mph will be
key to areas that can dip below freezing and backed off slightly
on coverage of freezing temperatures with winds remaining between
5-10 mph till closer to sunrise.

Monday and Tuesday: Shortwave ridging returns to the region early
in the work-week delivering a period of warming and drying. The
only exception will be a few cumulus buildups along the Canadian
Border with a 10% chance for showers. Otherwise, chilly
temperatures are expected each morning with potential for near
freezing temperatures, especially in the sheltered northern
valleys and typical "cold spots". Afternoon temperatures rebound
into the 60s Monday and 60s-70s Tuesday. Winds will be light and
terrain driven Monday through early Tuesday. By Tuesday afternoon,
the next system approaching the coast will draw increasing south
to southeast winds across the landscape with locally breezy
conditions for the Okanogan Valley.

Tuesday night through Saturday: The ridge will flatten with the
return of upper-level troughing. The first shortwave dents the
ridge Tuesday night into Wednesday promoting breezy conditions but
little in the way of precipitation. Best chance for showers will
come in the mountains with generally light precipitation amounts.
NBM currently only has 10-15% chance for a tenth of rainfall. The
incoming trough will not be particularly cold with temperatures
only falling around 5F from Tuesday to Wednesday then another 4F
or so by Thursday which places most readings close to 30-year
averages. The air mass will slowly moisten with time as PWATS
increase from 0.25" on Monday toward 0.45" Wednesday through
Saturday. This will keep a small threat for showers over the
mountains each afternoon largely driven by afternoon heating.
Shower chances expand into the lowlands on Friday as a reinforcing
shortwave drops in the mean trough. Again, this does not look
like a soaker by any means but we do see probabilities for a tenth
increase closer to 40-50% in the mountains and 10-30% in the
lowlands.

Sunday into next week: The large scale pattern is trending toward
another drying period but the exact details are far from certain.
Roughly 70% of the ensemble members are showing either split flow
or ridging, both supporting dry weather. The other 30% hold on to
a weak trough which could support additional mountain showers.
There are little to no signs for any significant weather impacts
or temperature anomalies. /sb


&&

.AVIATION...
12z TAFS: Gusty winds will persist through the day with VFR
conditions. There is some cloud groups given the mid-level
breaking wave clouds on satellite.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Low confidence in
mid-level breaking wave clouds this morning.
-----------------------

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        56  34  60  37  68  43 /   0   0   0   0   0   0
Coeur d`Alene  53  33  58  34  67  42 /   0   0   0   0   0  10
Pullman        52  32  56  34  67  44 /   0   0   0   0   0  10
Lewiston       60  38  64  39  74  49 /   0   0   0   0   0  10
Colville       57  28  62  31  68  39 /  10   0   0   0   0   0
Sandpoint      52  32  57  34  64  40 /  20  10   0   0   0  10
Kellogg        50  34  56  37  67  45 /  10   0   0   0   0  10
Moses Lake     62  35  64  37  71  44 /   0   0   0   0   0   0
Wenatchee      58  38  63  43  68  46 /   0   0   0   0   0   0
Omak           61  34  65  38  70  43 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory until 7 AM PDT this morning for Idaho Palouse-
     Lewis and Southern Nez Perce Counties-Lewiston Area.

WA...Wind Advisory until 7 AM PDT this morning for Lower Garfield and
     Asotin Counties-Spokane Area-Upper Columbia Basin-
     Washington Palouse-Waterville Plateau.

&&

$$