Tacoma, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

354
FXUS66 KSEW 291725
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
925 AM PST Wed Jan 29 2025

.UPDATE...Areas of fog continue across central Puget Sound with
stratus along the coast and into the Strait of Juan de Fuca.
Temperatures are slowly warming through this morning, with highs
into the mid 40s this afternoon. No major forecast updates this
morning.

&&

.SYNOPSIS...Dry, chilly conditions through early Thursday. A
frontal system will bring increasing lowland rain, heavier
mountain snow later Thursday through Friday. A cooler pattern
will then develop Saturday into next week, allowing for the
potential of wintry precipitation into the lowlands.

&&

.SHORT TERM /TODAY THROUGH FRIDAY/...Clear skies in place over much
of W WA this morning although satellite imagery is showing some fog
development, mainly confined to over water at the time of this
writing, however significant development over the south Sound
suggests that, as per forecast, could see fog coverage
expand...although still mostly impacting either water-adjacent
locations or the SW interior. As one would expect in this stagnant
weather pattern, temps this early morning on par with what has been
seen in the past few days at this time, with obs reporting mainly
temps in the lower to mid 20s, although some areas in the upper 20s
to lower 30s exist as well.

Another day under the ridge offering little in the way of
surprises...or change for that matter. Locations seeing fog should
see it clear up by the afternoon with another day of high temps in
the mid to upper 40s. It is worth noting that as this ridge begins
to break down, a little bit today but mostly on Thursday, will see
clouds begin to creep into the CWA, first along the coast starting
this evening and making their way eastward overnight tonight and
throughout the day Thursday. As one would expect, this will give a
bit of a boost to overnight lows, elevating the lowlands of the
western half into the mid to upper 30 while nudging the remainder of
the area up into the lower 30s.

Deterministic solutions generally remain unchanged, keeping precip
right along the coast for Thursday before pushing inland late
Thursday night/early Friday morning. Ensembles however are starting
to take a more agressive approach, bringing precip to the coast as
early as late Thursday morning. However, ensembles do fall back in
line with deterministic outputs...keeping precip there for the bulk
of Thursday, getting to the Sound area Thursday evening with best
chances for precip area-wide starting in the overnight hours.

Once the switch gets flipped, W WA remains wet and active for the
remainder of the short term, with categorical PoPs throughout the
CWA for all of Friday. For the lowlands, any precip should remain
liquid, however, the duration and amount of precip expected could
give rise to concerns in the higher elevations, especially the
Cascades. In collaboration with WPC, current model data would lean
toward winter weather headlines in the mountains, however there is
still enough uncertainty with position of the parent low...and as
such just how low thicknesses /and resultingly temps/ will go. As
this would impact snow amounts...felt it more prudent to wait for a
little more data before making a decision.

Daytime highs Thursday will not see much difference from those
expected today while Friday will see a bit of a warm up as highs get
into the mid to upper 40s. Overnight lows Thursday night see an
improvement for most locations, ranging in the mid to upper 30s.

18

.LONG TERM /SATURDAY THROUGH TUESDAY/...A cold front passes through
the area late Friday night and into Saturday. This will serve to
keep conditions wet, but dropping temps as well. Not helping the
forecast process any, but models retain a bevvy of solutions as per
positioning of the parent low, with even deterministic models
showing different solutions from previous runs, keeping said low
further north and inland. This uncertainty has a huge impact on the
main forecast problems facing the area: how cold will it get and
what state any precip will take. Although post-front activity will
be more showery in nature, abundant moisture suggests that this
change will likely not impact coverage all that much. At this time,
majority of ensemble members echo prior runs, favoring liquid precip
for the lowlands for Saturday...even though high temps that day will
take a hit compared to those of Friday with majority of lowland
locations topping out in the lower 40s. Overnight lows Saturday
night into Sunday morning do raise eyebrows when it comes to precip
however, as they dip down into the lower 30s with even a few spots
getting down to 28 or 29. This, at the very least, would allow for
mixed precip but latest ensemble data shows now a majority of
solutions now favor snow being the dominant precip form. Having
shown the opposite 24 hours ago, along with the aforementioned
alteration of the position of the low, it is difficult to assign any
degree of confidence not only to Saturday, but the remainder of the
long term forecast as well. High temps Sunday are akin to those of
Saturday, however the overnight lows begin to sink further into the
20s. Even as PoPs do gradually diminish through the day...they still
remain high end chance to likely /50-80 pct/...which would continue
to at least favor a wintery mix. Monday and Tuesday see temps sink
even further with daytime highs only in the mid to upper 30s...but
by this point, PoPs shrink down into the chance range /30-50 pct/.
This lowering is likely due to models outputs still showing the
parent low shifting west as it continues southward and even tapping
into a band of moisture running through northern CA and much of OR.
However, while previous solutions showed a clear-cut case of this
moisture remaining to the south of the CWA and shunting up into E
WA, latest runs are a bit more muddled...showing some spillover PoPs
throughout much of W WA. As has been said in past discussions, the
situation and thus the forecast continues to evolve. If planning on
outdoor activities or travel during this time period, stay tuned to
latest forecasts to remain informed on latest information.

18

&&

.AVIATION...Localized IFR/LIFR in fog and freezing fog for terminals
along the Puget Sound. Otherwise, VFR with clear skies and calm
winds for the other terminals. Conditions are on track to improve by
the late morning with increasing high clouds as high pressure aloft
begins to break down. Surface winds generally S to SE 5 kt or less
throughout the day.

KSEA...Fog made it to the terminal this morning and currently LIFR.
Expecting the fog to begin lifting after 18Z-19Z. Otherwise, calm
and mostly clear conditions will persist throughout the day, with
increasing cloud cover tonight with an incoming system. S/SE winds 5
kt or less throughout the day.

15/MGF

&&

.MARINE...Calm conditions over area waters will continue today under
high pressure, with areas of fog mainly over the outer coastal
waters early this morning. A frontal system will move across the
region Thursday night into Friday, generating southerly winds
nearing Small Craft criteria offshore and through the east entrance
of the Strait of Juan de Fuca. Winds will remain elevated at SCA
levels through Saturday before easing towards the end of the weekend.

Combined seas generally 3 to 5 feet through Thursday, building to 10
to 12 feet by Friday. Seas will remain elevated through Saturday,
then gradually decrease to 5 to 7 feet by late Sunday where they
will stay heading into next week.

15

&&

.HYDROLOGY...No river flooding is expected over the next 7 days
as abnormally dry conditions continue. However, with the
precipitation coming towards the end of the week, the Skokomish
River is forecast to rise substantially above Action Stage. There
will be much uncertainty with the river forecast all the way into
the event given the current below normal flows and the snow and
ice build up in the basin over this recent dry but cold period. As
far as other rivers, only low elevation basins like the Chehalis,
Samish, and Stillaguamish Rivers will see much response at all.

&&

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

$$