429
FXUS66 KOTX 200940
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
240 AM PDT Thu Jun 20 2024

.SYNOPSIS...
A warming trend is expected through the week, with high
temperatures rebounding into the mid 80s to mid 90s on Saturday. A
dry cold front on Sunday will create elevated fire weather
concerns with widespread breezy winds across the region. This will
likely be followed by temperatures cooling back down towards
normal values by Monday.

&&

.DISCUSSION...
Today through Friday Night: Astronomical summer offically arrives
at 150 PM PDT this afternoon with warmer temperatures the main
story for the remainder of this week.

An upper trough lingers over the region this morning with a
couple weak areas of elevated instability. One area is near the
Canadian border although clouds are gradually dissipating with
slightly drier air in the mid levels lifting north. A second area
was located from the Blue Mountains into the southern Idaho
Panhandle with radar showing some high based weak echoes. Models
shows this area of mid level moisture and weak mid level
instability will continue through much of the day into tonight and
thus have added a chance of sprinkles to the forecast. The other
area to watch this afternoon will be the north Cascades where
there is a 20% chance of surface based convection to develop over
the mountainous terrain as a mid level wave passes during peak
heating. The CAM`s models show the best potential for isolated
thunderstorm development in the mountains surrounding the Methow
Valley, but can`t rule out a few cells further south across Chelan
county. On Friday the trough finally begins to push out of the
region with drier air aloft moving in. This will limit convection
chances on Friday, with a 10-20% chance limited to the mountainous
terrain near the North ID/MT border. Despite the trough over the
region, temperatures will continue to warm into Friday with the
high sun angle of mid to late June, and most places seeing an
abundance of it. JW

Saturday through Wednesday: The ridge of high pressure bringing our
end-of-week warming trend will be stationed directly over the Inland
Northwest Saturday, likely bringing the highest temperatures we`ve
seen yet this season. Daytime highs will be in the upper 80s to mid
90s regionwide. Hitting 100 degrees is not out of the question for
some of our warmer locations including Lewiston and the lower
Columbia Basin. Remember to stay hydrated and take breaks in the
shade as needed if you`re outdoors!

By Sunday the ridge will begin to push eastward into Montana and a
trough will move in behind it from the Pacific, stalling just
offshore. While the trough is not looking to carry any moisture with
it, it will create a pressure gradient resulting in winds picking up
for Central and Eastern Washington Sunday afternoon. Gusts ranging
from 25 to 35 mph are expected with potential for gusts up to 40 mph
through the Cascade gaps and over the Waterville Plateau.
Temperatures will be 5 to 15 degrees cooler than Saturday`s, but
with widespread breezy conditions and relative humidity values below
20 percent, rapid fire spread will be a concern.

Model consensus breaks down at the start of next workweek. Some
models keep the trough offshore while others bring it inland. If it
stays offshore, temperatures will cool only slightly and conditions
will remain dry. If it moves inland, temperatures will cool more
noticeably and chances of showers and thunderstorms may pop up along
the Canadian border. /Fewkes


&&

.AVIATION...
06z TAFS: Convective showers are ongoing across the North Cascades
and portions of the Okanogan Highlands. This activity will wane
with the loss of heating but there is some uncertainty exactly
when the shower activity will completely end with a weak midlevel
circulation noted on the satellite. Precipitation from this
afternoon will bring a threat for fog or stratus in the valleys
around Republic, Curlew, and Conconully. Would not rule out patchy
coverage around Colville, Deer Park, and Ione but this comes with
low confidence. Otherwise, breezy north winds are channeling down
the Okanogan Valley through Omak and will continue to spread
toward Chelan, Wenatchee, and Moses Lake 6-7z. Wednesday will
feature more cumulus build ups across the Cascades with isolated
showers. A stray T-storm will be possible near the immediate
Canadian border. For most terminals in the Columbia Basin, L-C
Valley, and Palouse, dry conditions with fair cumulus and
scattered cirrus. Winds will generally be light with speeds below
10kts. The exception will be a few hours of easterly winds for KCOE
and KPUW mainly 14-19Z.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
in VFR conditions for TAF sites. Main uncertainty will be fog
development where the showers occurred today in the northern
mountain valleys around Colville, Deer Park, Republic, and Bonners
Ferry but most areas are running 20% lower RH as of 2200 pdt. /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

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        81  52  85  55  88  59 /   0   0   0   0   0   0
Coeur d`Alene  80  51  83  52  85  55 /   0  10   0   0   0   0
Pullman        80  51  82  53  86  57 /   0  10   0   0   0   0
Lewiston       88  59  91  60  95  64 /  10  10   0   0   0   0
Colville       80  44  84  47  86  49 /   0   0   0   0   0   0
Sandpoint      78  51  80  49  82  52 /   0   0  10   0   0   0
Kellogg        78  56  80  57  83  59 /   0  10  10   0   0   0
Moses Lake     87  53  91  57  93  59 /   0   0   0   0   0   0
Wenatchee      85  61  90  64  92  61 /   0   0   0   0   0   0
Omak           85  54  90  57  91  56 /   0   0   0   0   0   0

&&

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

$$