193
FXUS66 KOTX 151932
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
1232 PM PDT Sat Jun 15 2024

.SYNOPSIS...
Breezy to gusty winds along with isolated thunderstorms and rain
showers are expected Saturday afternoon and evening. Snow will be
possible down to 5000 feet. Temperatures will trend cooler into
early next week with the potential for frost in colder pockets
Sunday and Monday morning. Showers and thunderstorms, mainly in
the mountains will be possible each afternoon through midweek.

&&

.UPDATE...
Issued a wind advisory across the Moses Lake Area, the Upper
Columbia Basin, Spokane Area, Washington Palouse, and lower
Garfield and Asotin County through 8 PM this evening. The
combination of a tight pressure gradient with enhanced gusts from
convection this afternoon will result in windy conditions.

&&

.DISCUSSION...

Several locations from Moses Lake to Ritzville to Spokane are
seeing sustained winds up to around 30 mph. Wind gusts are
generally up to around 40 mph, but convection and thunderstorms
are expected to enhance these winds up to 45 mph through the
afternoon. Expect strong cross winds making for hazardous travel,
choppy lakes, and light weight objects will be prone to becoming
airborne with winds today.

&&

.PREV DISCUSSION... /issued 1119 AM PDT Sat Jun 15 2024/

Today through Sunday Night: Closed low over Vancouver Island will
track east across northern Washington and southern British
Columbia today. Cooling aloft associated with the low (500mb temps
dropping to near -28C), combined with afternoon heating will
destabilize the atmosphere. Surface based CAPE increases to
200-400 J/KG over the region, except 400-700 J/KG over NE
Washington into the Idaho Panhandle where the best chances for
thunderstorms will be found. Another story for today will be the
wind. A well mixed atmosphere and cold air advection will promote
breezy to windy conditions regionwide, with the strongest gusts
(30-40 MPH) found across the Columbia Basin into the West Plains
and Palouse. Localized gusts to 45 MPH will be found in the
windiest prone areas include the Waterville Plateau and Alpowa
Summit. Added boost to the gusts will also be found near
thunderstorms. Finally, 850mb temperatures drop to near 0C along
the Cascade crest this morning and near 2C in the Okanogan
Highlands. This will support snow levels near 4500 feet along the
crest and 5500-6000 feet in the Okanogan Highlands. This will
support light snow over Washington Pass, with a rain/snow mix at
Stevens and Sherman Passes. A persistent Puget Sound Convergence
Zone will be aimed at near Stevens Pass this afternoon and evening
producing moderate rain, with snow possibly mixing in at times.

For tonight models continue to advertise clearing skies and
decreasing winds for cooler temperatures. Areas of frost are
expected for the northern mountain valleys, and across the
Upper Columbia Basin, West Plains, and Palouse. There are a couple
wild cards though. Cloud cover associated with a deformation zone
could hold lows up near the Canadian border. And southwest winds
around the Upper Columbia Basin into the West Plains may not
completely decouple making it more difficult for temperatures to
drop into the mid 30s for frost formation. Frost advisories are in
place though given at least patchy frost is likely where winds
decouple and skies clear.

On Sunday another closed low develops over the region for hit and
miss showers. The cold advection comes to an end and pressure
gradients are much lighter equating to much less wind. High
temperatures will make into the 60s for most areas, although cloud
cover over the northern valleys and mountains from a deformation
area may mean temperatures don`t even get out of the 50s in some
spots such as Colville and Republic. JW

Monday through Friday: The Low from Sunday will continue to exit the
region through Monday. Ongoing shower activity is expected over
Northeast Washington and the Idaho Panhandle. Amounts are not
forecast to be more than an additional few hundredths. Weak
convection could bring an isolated lightning strike from these
showers. High for the day will be in the 60s to low 70s.

For the rest of the week, a broad trough will set up over Western
Conus. Weak waves of moisture periodically pass through the Pacific
Northwest bringing spotty showers chances to the Inland Northwest.
The best chances are generally over the mountains. Weak afternoon
convection from daytime heating has around a 20-30% chance of
generating an isolated thunderstorm. The pattern will allow
temperatures to moderate to near normals. Highs will start in the
70s and climb into the 80s and low 90s by the weekend. Overnight
lows will start in the 40s and climb into the upper 50s and 60s for
Friday night. /JDC

&&

.AVIATION...

18Z TAFS: Windy with pop up shower and thunderstorms today.
Sustained winds of 15-23 kts, with gusts to 28-35 kts are forecast
over the region. There is a 30-50% chance of thunderstorms over
Northeast Washington into the Idaho Panhandle, with a 10-20%
chance across the Columbia Basin down into the LC Valley and
Palouse. Chances for thunderstorms for KDEW-KGEG-KSFF-KCOE will be
highest through early afternoon (around 21-22Z). Showers with
embedded thunderstorms will be more likely around mid afternoon after
20Z near KPUW along a west to east boundary. Convection will come
to an end after sunset with loss of daytime heating, with
decreasing winds as well.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
There is high confidence in continued VFR conditions through
Sunday morning. One potential caveat is for low ceilings and MVFR
ceilings to develop at KPUW between 15-18Z. /SVH

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

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        64  40  64  40  67  43 /  50  20  20  20  30  10
Coeur d`Alene  61  38  62  39  64  43 /  60  20  20  20  30  30
Pullman        60  36  60  38  61  40 /  20  20  20  20  30  20
Lewiston       71  44  70  46  69  48 /   0   0  20  20  40  20
Colville       62  32  58  34  66  36 /  90  40  50  30  50  30
Sandpoint      59  37  58  37  63  42 /  70  40  40  20  50  50
Kellogg        55  40  58  41  58  45 /  50  30  20  20  50  40
Moses Lake     69  40  68  44  73  44 /  10   0  20  20  10   0
Wenatchee      65  45  66  47  71  48 /  10  10  20  20  10   0
Omak           68  41  62  43  73  45 /  60  10  40  20  20  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Frost Advisory from 1 AM to 8 AM PDT Sunday for Central
     Panhandle Mountains-Idaho Palouse-Northern Panhandle.

WA...Frost Advisory from 1 AM to 8 AM PDT Sunday for Northeast
     Mountains-Okanogan Highlands-Spokane Area-Upper Columbia
     Basin-Washington Palouse-Western Okanogan County.

     Wind Advisory until 8 PM PDT this evening for Lower Garfield and
     Asotin Counties-Moses Lake Area-Spokane Area-Upper Columbia
     Basin-Washington Palouse.

&&

$$