518
FXUS66 KOTX 112219
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
319 PM PDT Tue Jun 11 2024

.SYNOPSIS...
This afternoon and evening will be windy raising concerns of
isolated power outages, rough water on area lakes, and the
heightened potential for grass fires. Another cold front is
expected to bring more breezy conditions Friday and Saturday. The
weekend will be cooler along with the chance of mainly mountain
showers.

&&

.DISCUSSION...

Rest of today through Thursday afternoon: Warm, dry, and windy
conditions will continue through the rest of the afternoon and
into the evening hours, raising concerns of rapid spread of new
fire ignitions. Dry grasses and brush in places that haven`t
gotten rain recently like Grant, Chelan, and Douglas counties will
be of particular concern today. GOES low level water vapor
imagery shows very dry air aloft and mountain waves - a sign of
the dry and windy conditions out there. Vigorous showers have
mostly stayed in Canada as dry air entrainment has mostly kept
terrain based cumulus under control. The mid level speed max will
stay in our area this evening, keeping breezy conditions around in
the higher peaks overnight. Still, an isolated lightning strike
cannot be ruled out in northeastern Washington. Fair to poor RH
recoveries are forecasted given little decoupling of the boundary
layer tonight. Sheltered valleys (Deer Park and Priest lake areas)
have the best shot at some decent humidity recoveries tonight.

Tomorrow`s temperatures will be much closer to normal (in the 70s
and low 80s) following the frontal passage. PWATS will drop to 40
to 60% of normal as well. Tomorrow will be even drier but far
less windy. Overall expecting a gorgeous day. My concern for frost
in the sheltered valleys of northeastern Washington tomorrow
night is increasing given very dry air and calm winds forecasted.
Some guidance is explicitly forecasting a low of 32 degrees for
Deer Park (MOS guidance, which handles these situations well
usually). Will hold off on frost products for now but definitely
something to watch.

Temperatures rebound into the lower 80s Thursday as a shortwave
ridge builds in the interior Northwest. Light winds forecasted will
pose a minor HeatRisk - a level of heat that impacts extremely
sensitive populations when outdoors without effective cooling
and/or adequate hydration. /Butler

Thursday night to Tuesday: The next system starts to move in with
cooler temperatures, breezy to windy conditions and, for some, a
chance of showers and thunderstorms and even be some high terrain
snow. Patchy frost is also possible in some of the sheltered
northern valleys in the morning early next week.

First Thursday night into Saturday a couple shortwave
disturbances pivot around the approaching low and cross the
region, thickening clouds and another increase in winds. Winds
start increasing overnight into Friday morning near the Cascades
and increase throughout the region heading through the day,
peaking once in the evening, subsiding some overnight and then
increasing again through Saturday afternoon. Speeds of 15-30 mph,
with gusts of 30 to 40 mph will be possible, strongest around the
lee of the Cascades through the Waterville Plateau and Upper
Columbia Basin. In terms of fire weather concerns, afternoon RH
values will hover near critical values, similar to today
(Tuesday), especially Friday so this will be monitored. Wind
gradually decline late Saturday night into Sunday morning.
Precipitation-wise, the main precipitation chances lay near the
Cascade crest Friday and perhaps skimming near the Canadian
border. By Saturday the atmosphere moistens up some and the
threats of showers expands over most of the Cascades and northern
mountains and central Panhandle mountains, with a risk for snow in
the higher terrain. Some snow may be found near Washington Pass
and a rain/snow mix could even be seen near Stevens and Sherman
Pass. Shower chances were expanded to include the northern Basin
into the Spokane/C`dA area and the northern Palouse. Thunderstorms
are possible around the NE WA and ID Saturday afternoon too. Some
could be locally stronger and could enhance the synoptic scale
winds. All of this combined will be another fire weather concern.

Sunday to Tuesday the area remains in a troughy pattern, but
models still do not have a good handle on the details. Overall it
continues to favor shower chances around the mountain zones and at
least a slight chance around the eastern third of WA and lower
ID, especially late Sunday to Tuesday. As the models start to
settle on a solution confidence in who will have the higher risk
will start to come into focus. A limited risk for t-storms will
linger over the northern mountains too each afternoon. Wind will
still remain a bit breezy, but not as much as previous days with
gusts near 10-20 mph strongest near the Cascades to Waterville
Plateau. Afternoon RH values will be a bit higher than earlier in
this period.

As for temperatures they begin to drop heading into Friday and
especially Saturday into Sunday. Highs on Friday are forecast in
the 70s to near 80, then 60s to mid-70s for the weekend, warming
a couple degrees Monday and Tuesday. Lows are forecast to be in
the 40s and 50s Friday morning, 40s Saturday morning, 30s to
mid-40s Sunday morning, moderating slightly Monday morning. These
latter temperatures could bring some frost to the sheltered
valleys near the Cascades and Canadian border counties. Overnight
Saturday into Sunday has the highest risk. As we get closer we
will have more confidence, but could impact anyone with sensitive
plants or crops. /Solveig

&&

.AVIATION...
00Z TAFS: Sustained 15 to 25 kts winds with gusts to 35kts will
be common for our TAF sites including Wenatchee, Moses Lake,
Spokane, Coeur d`Alene and Pullman. Peak gusts will likely occur
between 00-04z. Winds tomorrow will be much lighter with VFR
conditions.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
There is a low chance of visibility reductions due to blowing dust
at Moses Lake and Spokane International as winds peak late in the
afternoon.

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

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        44  74  46  80  53  75 /   0   0   0   0   0   0
Coeur d`Alene  43  71  45  78  51  74 /   0   0   0   0   0   0
Pullman        42  69  43  78  51  70 /   0   0   0   0   0   0
Lewiston       51  78  51  86  58  82 /   0   0   0   0   0   0
Colville       38  74  41  78  46  77 /   0   0   0   0   0   0
Sandpoint      42  70  42  77  48  74 /   0   0   0   0   0   0
Kellogg        46  68  48  78  55  70 /   0   0   0   0   0   0
Moses Lake     45  79  46  84  51  80 /   0   0   0   0   0   0
Wenatchee      48  78  49  82  54  75 /   0   0   0   0   0   0
Omak           45  79  47  83  51  80 /   0   0   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Wind Advisory until 8 PM PDT this evening for Coeur d`Alene Area-
     Northern Panhandle.

WA...Wind Advisory until 8 PM PDT this evening for Moses Lake Area-
     Northeast Mountains-Okanogan Highlands-Spokane Area-Upper
     Columbia Basin-Waterville Plateau-Wenatchee Area.

&&

$$