Tacoma, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

239
FXUS66 KSEW 271618
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
918 AM PDT Sun Jul 27 2025

.SYNOPSIS...Upper level trough offshore with southwesterly flow
aloft over the area today. Upper level ridge will begin to build
over Western Washington tonight and continue building into Tuesday
for sunnier and warmer weather. Ridge remaining over the area
Wednesday before moving slowly eastward Thursday into next
weekend. Western Washington will remain on the backside of the
ridge. Southerly flow aloft in the middle of the week could
produce some convection over the Cascades.

&&

.UPDATE...Only minor changes were made to the aviation discussion
below. Otherwise expect clouds to clear through the morning for a
sunny afternoon regionwide.

HPR

&&

.SHORT TERM /TODAY THROUGH TUESDAY/...Satellite imagery has a
band of middle and high level clouds from about Hoquiam to Mount
Baker this morning. Stratus not advecting inland with the light
offshore flow. Instead the stratus is forming in place with a
shallow marine layer. It`s another cool July morning with
temperatures at 3 am/10z in the upper 40s to mid 50s.

It`s deja vu all over again this morning weather wise. Middle and
high clouds will dissipate this morning. With the marine layer
being shallow stratus also dissipating by late morning leaving
sunny skies for the afternoon. Pretty similar to yesterday. Temperatures
aloft have warmed slightly and interior surface gradients go
northerly this afternoon shutting off the cooler southwesterly
winds that have been present for most of the last couple of days
well into the afternoon hours. Highs a little warmer with upper
60s to upper 70s for the interior, mid 60s coast.

Slow changes to the pattern beginning tonight and continuing into
Monday. Deep upper level trough in the Gulf of Alaska will dig a
little south while the strong upper level ridge over the center of
the country begins to back build into the Pacific Northwest.
Surface gradients go flat leaving just a shallow marine layer
mostly on the coast. With more sunshine highs Monday getting back
to normal, in the 70s and lower 80s, for the interior and mid to
upper 60s for the coast. Like the last couple of mornings, Monday
morning the cooler locations will drop into the upper 40s with the
remainder of the area in the lower to mid 50s.

Upper level ridge continues to build over Western Washington
Monday night and Tuesday with 500 mb heights in the mid 580 dms by
late Tuesday afternoon. Surface gradients turning northerly
Tuesday, possibly strong enough to take a couple degrees off the
highs near the Puget Sound due to the afternoon seabreeze. Slight
warming trend remains intact with highs in the mid 70s to mid 80s
interior and near 70 along the coast. Lows in the 50s.

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...Extended models in good
agreement with a slightly negatively tilted upper level ridge
right over Western Washington Wednesday. Southerly flow aloft with
a somewhat unstable air mass over the Cascades in the afternoon
producing a slight chance of thunderstorms. The ridge axis
slides a little east Thursday but southerly flow aloft continues.
Potential for a weak shortwave embedded in the flow aloft to
arrive late in the day keeping the chances for convection over the
Cascades in the forecast. Some of the model solutions have a weak
trough axis moving through Friday so once again will have a
mention of convection over the Cascades. Flow aloft becoming
southwesterly Saturday as a weak upper level trough approaches the
coast and the upper level ridge continues to drift off to the
east. This will bring about an end to the convection threat over
the Cascades.

Temperatures peaking Wednesday and Thursday with highs in the mid
70s to mid 80s interior and mid 60s to lower 70s along the coast.
The upper level ridge moving east and the approaching trough will
eventually turn the low level flow back onshore with cooler high
temperatures along with some morning clouds by the weekend.

Using the forecast temperatures for the remainder of the month,
July in Seattle will end up about a degree above normal. This
will be the 13th July in a row with above normal temperatures.
The last year Seattle had below normal temperatures in July was
2012. Felton

&&

.AVIATION...Predominantly mid-level stratus deck across much of
Western Washington this morning. Expect this to continue to scatter
through the day today and maintain VFR conditions. However, a few
patches of low MVFR to IFR stratus will linger through late morning
around the South Sound and Kitsap Peninsula. Lower stratus likely
redevelops Monday morning, but less widespread coverage across the
interior is expected. SW winds 5-10 kt today, turning more northerly
this evening.

KSEA...VFR conditions continue with broken mid-level stratus around
5000 ft that will continue to scatter this morning. Expect southwest
surface winds to become northwest late this afternoon at 5-6 kt,
before returning southerly again overnight. Only around 20% chance
of stratus to impact the terminal area late tonight/early Monday
morning.

&&

.MARINE...Weak onshore flow to start the new week with diurnal
enhancement through the strait. Winds in the central/eastern Strait
of Juan de Fuca will increase to 15-20 kt this afternoon and Monday
afternoon with a few isolated gusts to 25 kt possible. However,
winds won`t be sustained enough to prompt a SCA but will be closely
monitored. The next best chance of a SCA through the strait appears
to be Tuesday evening. No significant marine weather issues over the
coastal waters through the start of the week with winds and waves
remaining short of any thresholds.

McMillian

&&

.FIRE WEATHER...No fire weather concerns through Monday.
Conditions will start to warm up and dry out early next week as an
upper level ridge builds over the Pacific Northwest. Concerns
begin to increase Tuesday and Wednesday as a trough slowly drifts
south out of the Gulf of Alaska and the flow aloft over the
region turns southerly. This will allow for more moist air from
the Pacific to move into the region. Atmospheric instability will
begin to increase starting Tuesday, followed by the potential for
showers and thunderstorms to develop as early as Wednesday
afternoon. Thunderstorm chances continuing through Thursday and
possibly Friday. Precipitable water anomaly values are high,
pointing towards mostly wet thunderstorms. Fuels will be dry
enough that any lightning could prove problematic. Additionally,
too much mid-level moisture may allow for enough cloudiness to put
a damper on the threat for thunderstorms. More details will be
available as we get into next week. We will continue to closely
monitor how the pattern evolves.

62/Felton

&&

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

$$