Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 280958
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
258 AM PDT Thu Mar 28 2024

.SYNOPSIS...Low pressure spinning off the coast will maintain
scattered showers and isolated thunderstorms today. Showers will
gradually subside through the day Friday giving way warmer and
drier conditions as high pressure builds into the area, resulting
in above normal temperatures by Sunday and Monday. A cold front
is poised to move southward across the Pacific Northwest Tuesday,
bringing a return to a cooler and wetter pattern into the middle
part of next week.

&&

.SHORT TERM /TODAY THROUGH SATURDAY/...A vertically-stacked and
occluded low pressure center continues to spin just west of 130 W
offshore with yesterday`s occluded front having stalled over
eastern Washington. A surface trough will pivot onshore later this
afternoon amidst several shortwave perturbations and vorticity
maxima pivoting around the occluded upper low. These will maintain
scattered and disorganized showers with isolated thunderstorms
through much of the day, largely similar to those observed
yesterday. Hazards from these will once again include small
hail/graupel, brief heavy downpours, gusty winds, and dangerous
cloud-to-ground lightning. Remember, when thunder roars, go
indoors!

Similar temperatures today as to yesterday with highs in the low
to mid 50s. Snow levels today will hover around 3000 to 3500 feet
with light snow accumulations of 1-3 inches at the Cascade Passes
will be possible. Total rainfall amounts today will be on the
lighter side - generally a quarter of an inch or less across the
lowlands, with 1 to 2 inches across the southern Olympics.

Meanwhile, a stronger shortwave trough will pivot southward
through the longwave trough over the eastern Pacific, prompting
cyclogenesis of a new surface low, which will overtake the current
one, pulling the focus for scattered showers and thunderstorms
south of the area through the day Friday as the only remaining
focus for showers isolates to the Cascades and Olympics. High
temperatures begin rising Friday as mid-level heights rise with
mid to upper 50s forecast.

Upper-level ridging will build south and east across the Pacific
Northwest on Saturday with pleasant conditions featuring clear
skies and highs in upper 50s to near 60.

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...Warm and dry weather
will continue Sunday into Monday, with the high temperatures
peaking Monday as the upper-level ridge axis moves overhead. Snow
levels also rise closer to 7000 feet by late Monday. While
forecast highs aren`t nearing any record highs Monday, the
forecast doesn`t look to be a joke of any sorts for April Fools`
Day with a high likelihood for max temperatures above 60 Monday
for the interior and Puget Sound lowlands.

The upper-level ridge begins to flatten into Tuesday as the upper
low previously along the coast cuts off over the Desert Southwest.
While some disagreement continues over how cutoff this low will
become and how long it will linger to our south, better agreement
appears to exist in the amplification of a new developing trough
across British Columbia into the Pacific Northwest by Wednesday.
At the surface, a cold front looks to slide southward across the
region Tuesday into Tuesday night, ushering in a return to cooler
and wetter weather by Wednesday.

Davis

&&

.AVIATION...Southwesterly flow aloft continues as an upper low
meanders just offshore. A mix between VFR/MVFR early this morning
as heavier shower activity brings down ceilings and vsbys
throughout interior terminals. As showers continue throughout the
day, can expect locally lower ceilings and vsbys at times,
especially as heavier showers pass through. VFR will likely
dominate through the day but may lower to MVFR briefly with
showers.

KSEA...VFR/MVFR early this morning with some heavier showers
passing over the terminal, causing reductions in vsbys and lower
ceilings. VFR will likely rebound and persist, with brief drops
to MVFR likely at times throughout the day as showers pass by.
S/SE winds 5 to 10 knots thru the morning, with gusts up to 20 kts
possible around 20z onward.

Mazurkiewicz

&&

.MARINE...A surface low continues to meander offshore, with small
craft south/southeasterlies over the coastal waters this morning.
Elevated S/SE winds will continue throughout majority of the day,
with small craft advisories still in place for the Eastern
Entrance of the Strait, Admiralty Inlet, and the Northern Inland
Waters. Winds over these areas will likely remain at small craft
advisory threshold until Friday, before the surface low drifts
southward, which will let winds over the waters ease into the
weekend.

High pressure looks to return into the weekend, with both winds
and seas easing, headlines will be allowed to expire.

Combined seas this morning around 12 to 14 feet and will generally
maintain that height through the day. Seas look to drop below 10
feet Friday morning, and continue to lower to around 3 to 6 feet
for the weekend.

Mazurkiewicz

&&

.HYDROLOGY...No river flooding is forecast over the next 7 days.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 PM PDT this afternoon for Admiralty
     Inlet-Coastal Waters From Cape Flattery To James Island 10
     To 60 Nm-Coastal Waters From Cape Flattery To James Island
     Out 10 Nm-Coastal Waters From James Island To Point
     Grenville 10 To 60 Nm-Coastal Waters From James Island To
     Point Grenville Out 10 Nm-Coastal Waters From Point
     Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters
     From Point Grenville To Cape Shoalwater Out 10 Nm-East
     Entrance U.S. Waters Strait Of Juan De Fuca-Grays Harbor
     Bar-Northern Inland Waters Including The San Juan Islands-
     West Entrance U.S. Waters Strait Of Juan De Fuca.

&&

$$


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