Washington State Forecast Discussion

Western Washington


002
FXUS66 KSEW 281023
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
323 AM PDT Fri Jun 28 2024

.SYNOPSIS...Zonal flow aloft over Western Washington today with
light onshore flow in the lower levels. Weakening front moving by
to the north Saturday. Upper level trough over the area Sunday
keeping a chance of showers in the forecast. Upper level ridge
building offshore Monday moving into the Pacific Northwest Tuesday
through Thursday. Low level flow remaining onshore keeping
temperatures near normal.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...Satellite imagery shows
cloudy skies over most of Western Washington early this morning.
No precipitation echoes on the doppler radar at 3am/10z.
Temperatures with the cloud cover pretty uniform, in the lower to
mid 50s. The exception is around Olympia where a little bit of
clearing has allowed temperatures to drop into the mid 40s.

No much going on today weatherwise. Zonal flow aloft combined with
light onshore flow in the lower levels will keep at least mostly
cloudy skies over the area. With the near solstice daytime
heating working on the low level moisture some sunshine will
develop in the afternoon. Highs near normal with mid 60s along the
coast and upper 60s to mid 70s inland.

Weakening front near 140W early this morning will approach the
coast early Saturday morning. Parent low associated with the front
up in the Gulf of Alaska and moving northwest. This will stretch
out and weaken the front today and tonight. Front close enough for
a chance of showers along the North Coast with just mostly cloudy
skies over the remainder of the area. Lows tonight in the upper
40s to mid 50s.

What is left of the front dragging through Western Washington
Saturday. Best chance for showers will be along the coast, in the
mountains and over the Northwest Interior. Any showers that do
develop will be light. Highs similar to today with mid 60s coast
and upper 60s to mid 70s inland.

Weak upper level trough remaining over Western Washington Saturday
night into Sunday. Not a whole lot with this feature with 500 mb
heights in the lower 570 dms. There will be plenty of low level
moisture so any lift could produce a light shower or perhaps some
morning drizzle. Once again best chances will be along the coast,
in the mountains and over the Northwest Interior. Lows Saturday
night in the upper 40s to mid 50s. Little change in the high
temperatures from the previous two days with mid 60s along the
coast and upper 60s to mid 70s inland.

.LONG TERM /MONDAY THROUGH THURSDAY/...Extended models in good
agreement with an upper level ridge building offshore Monday. The
ridge will weaken slightly as it moves over the Pacific Northwest
Tuesday with the ridge remaining over the area into the 4th of
July. A weak shortwave riding down the backside of the ridge
Monday morning could trigger a shower in the North and Central
Cascades. 500 mb heights rising to the upper 570 dms to the mid
580 dms by the middle of the week but the low level low remains
onshore. This will keep highs in the mid to upper 60s on the coast
and upper 60s to mid 70s inland Monday and Tuesday. A little
warmer Wednesday and on the 4th with highs in the mid 60s to lower
70s along the coast and 70s to lower 80s inland. Felton

&&

.AVIATION...Northwesterly flow turning westerly this afternoon as
weak transient ridging builds over W WA. A mix of VFR/MVFR
conditions over the interior early this morning as residual low
level moisture continues to linger through over the area. Spots
prone to lower cigs (KHQM, KPWT) may see IFR conditions briefly
throughout early morning. Ceilings are expected to improve into
the early afternoon to widespread VFR for the region, with VFR
persisting throughout the remainder of the day.

KSEA...MVFR ceilings early this morning, with northeasterly winds
around 4 to 8 knots. Ceilings will improve to VFR around 17z-19z
as clouds lift, remaining VFR for the rest of the TAF period.
Winds will turn N/NW later this morning and will hover around 6 to
9 knots.

Maz

&&

.MARINE...Weak high pressure offshore will bring generally benign
and calm conditions to the area waters today. Additional weak
systems look to move through the area waters through the weekend,
along with diurnal pushes down the Strait of Juan De Fuca also likely
through early next week. At this time, winds look to be below any
criteria until possibly Monday night.

Coastal seas 4 to 6 feet through the weekend and into early next
week, before building to 6 to 8 feet by the middle of next week.

Maz

&&

.CLIMATE...Today is the three year anniversary of the hottest day
on record in Western Washington. A sample of some of the highs on
June 28, 2021, Seattle 108 degrees at Seattle Tacoma airport and
107 at the forecast office, Renton 109, Olympia, Elma and
Quillayute 110, Everett 100, Bellingham 99.

On the flip side, with three days left to go in the month of June
the average temperature for the month is 60.6 degrees ( 1.2
degrees below normal ). The forecast temperatures for the next
three days would put the average monthly June temperature at 61.0
degrees. This would be the coldest June since 2012 where the
average temperature was 58.3 degrees. The average temperature in
2022 was 61.1 degrees. 2012 was also the last time July
had below normal temperatures in Seattle. Felton

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&