-- Discussion containing changed information from previous version are highlighted. --
635
FXUS66 KOTX 140432
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
932 PM PDT Thu Jun 13 2024

.SYNOPSIS...
Friday will be dry and breezy as a cold front moves through the
region. Precipitation chances will increase Friday night into
Saturday with light snow down to 5000 feet over the Cascades and
northeast Washington. Breezy to gusty winds along with isolated
thunderstorms and heavy rain showers are expected Saturday
afternoon and evening. Temperatures will trend cooler into early
next week with the potential for frost across much of eastern
Washington and north Idaho.

&&

.DISCUSSION...

-- Changed Discussion --
Minor update to add some sprinkles to the lower Idaho Panhandle
overnight with little to no impact. A stray lightning strike is
possible but comes with extremely low confidence and less than a
5% chance.

Thursday night through Saturday: The extended period of warm weather
across the Inland Northwest will come to an end as a large low
pressure system nears the Pacific Northwest. Clouds will begin to
increase tonight as a mid level upper level wave embedded within the
southwest flow moves in from the southwest.  Winds will increase
Friday morning as a southwest pressure gradient tightens across the
northwest as a surface low moves across British Columbia. Models are
in good agreement of sustained winds 15 to 25 mph with wind gusts 30
to 40 mph across the lee of the Cascades, the Columbia Basin, and
into the Spokane area and the Palouse. The breeziest winds will be
across the Waterville Plateau where there is a 30-50% chance to see
wind gusts of 45 mph. Despite temperatures cooling into the 70s on
Friday, very dry air will allow relative humidity values Friday
afternoon into the teens to lower 20 percent across the region.
These conditions would allow fire to spread quickly through fire or
brush given an ignition.

By Friday night, the upper level low will move over the Pacific
Northwest with continued breezy to gusty winds and increasing
chances primarily over the mountains.

Winds will be stronger on Saturday compared to Friday with a 50-70%
chance for wind gusts 45 mph or above across the Waterville Plateau
and the upper Columbia Basin. Overall fire weather concerns will
decrease on Saturday as temperatures cool into the 60s and minimum
relative humidity values increase above 20 percent, but people
should increase their efforts to prevent creating sparks. This
will also create tricky driving conditions for high profile
vehicles on highways and choppy waters on area lakes.

As this low moves inland Friday night, snow levels will drop to
around 4500-5000 feet. Higher elevation trails and backcountry spots
will see light snow accumulations with low temperatures near to
below freezing. Road temperatures across Washington Pass are too
warm to see road accumulations, but campers and hikers should be
prepared for these cold temperatures Friday night into Saturday
morning. Precipitation will turn convective in nature as these
colder temperatures aloft steepen low to mid level lapse rates. This
combined with surface CAPE upward of 200-300 J/kg in across
northeast Washington and the Idaho Panhandle may support isolated
thunderstorms and heavier showers. /vmt

Sunday through Wednesday: An area of low pressure will drop down
from British Columbia over the weekend bringing breezy winds, cooler
temperatures, and chances for showers and thunderstorms through at
least the first half of next week. Afternoon high temperatures will
generally be in the 60s, around ten degrees cooler than average for
this time of year. Morning lows will start out quite chilly on
Sunday in the 30s and will gradually warm into the upper 40s by the
middle of next week. Patchy frost is likely Sunday morning,
especially for the more sheltered northern valleys. Best chances for
precip will be Monday and Tuesday over the Cascades, the northern WA
mountains, the Blues, the Palouse, and the ID Panhandle. The chance
of showers in these regions ranges from 30 to 60% during the Monday-
Tuesday timeframe. Most models are showing a warming and drying
trend for the second half of the week. /Fewkes
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&&

.AVIATION...
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06Z TAFS: Midlevel front is limping into the region this evening
and will continue to slowly drift east through Friday morning.
Cigs with the front will mainly remain above 10K ft AGL with high
confidence for VFR conditions to prevail. There may be enough
instability aloft for a few elevated showers between Lewiston and
Mullan Idaho from 8-13z. The lower atmosphere is very dry so
main threat will be sprinkles. Otherwise, the incoming trough will
bring cooling and increasing winds. Winds will begin to pick up
early Friday morning across the region. Wind gusts 30 to 40 mph
will be common in the lee of the Cascades around KEAT and then
across the west Plains for Spokane, Felts Field, Coeur d`Alene
Friday afternoon. Winds will decrease around 02z but remain steady
overnight with stronger winds and more widely scattered showers
in the forecast for Saturday.


FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
Two items that could require updates will be a 5% for a stray
lightning strike with the elevated convection over Idaho early
Friday morning. The second will be adjustments and amendments to
timing of wind speeds and gusts Friday. /sb

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

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
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&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        52  73  48  65  39  64 /   0   0   0  40   0   0
Coeur d`Alene  51  71  48  61  39  63 /   0   0   0  60  10  10
Pullman        49  68  45  60  36  61 /   0   0   0  30   0   0
Lewiston       57  79  53  70  45  70 /   0   0   0  20   0   0
Colville       45  74  44  62  33  62 /  10   0   0  90  20  30
Sandpoint      50  71  47  59  38  58 /  10   0   0  80  30  20
Kellogg        54  69  47  56  40  59 /   0   0   0  60  20  10
Moses Lake     51  77  51  68  39  69 /  10   0   0  10   0   0
Wenatchee      54  73  52  65  44  66 /  10   0   0  10   0   0
Omak           50  78  49  69  41  68 /  10   0   0  50   0  20

&&

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

$$