Fort Flagler, Washington Weather Forecast Discussion

539
FXUS66 KSEW 030348
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
848 PM PDT Thu Oct 2 2025
.UPDATE...Doppler radar shows most of the shower activity has
dissipated with the end of daytime heating. Only batch left
between Bonney Lake and Issaquah. These showers will move north
and die out in the next couple of hours. Clearing skies along with
a cool upper level trough over the area and light surface winds
will make for a brisk start Friday morning. Forecast low for
Seattle 50 degrees. The last time Seattle had a low below 50
degrees was June 14th ( 49 degrees ). Even if Seattle doesn`t drop
into the 40s Friday morning good chance lows will be in the 40s
Sunday morning through next Thursday morning.
Elongated upper level trough over the area tonight will shift
east Friday. Weak system embedded in the northwesterly flow aloft
behind the trough will keep shower chances in the forecast Friday
night into Saturday. Ridge building offshore Saturday night with
dry northerly flow Sunday. Current forecast on track. No update
this evening. Previous discussion with updated aviation and marine
sections below. Felton
&&
.SYNOPSIS...An upper level low just offshore will get pushed
southward tonight into tomorrow, wrapping up precipitation
chances for most of the area tonight. Another upper level wave
will move across the area Friday night into Saturday, bringing
another round of light precipitation chances. Slightly cooler
conditions Saturday and Saturday night. Upper level ridging will
build over the area for the first half of next week, though there
is considerable uncertainty with the potential for additional
systems by mid-week.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...A low pressure system that
has been sitting just offshore of Vancouver Island slowly begin to
weaken and sink southward this evening as it beings to lose upper
level support due to the upper level trough aloft getting
stretched southward down towards California. Showers will
continue, mostly along the western half of the area, through the
rest of the day before tapering off after sunset this evening.
There`s a slim (10-15%) chances of an isolated lightning strike or
two near the coast/over the waters, but we have yet to see any
lightning so far today.
Clearing skies tonight should allow us to dip back into the 40s
to near 50 in the metro area tonight. Areas of fog and low stratus are
possible by Friday morning. A weak cold front will move across
the area from the northwest Friday night into Saturday. Some light
precipitation chances are possible Friday night, but amounts will
be slim to none. What it will bring is slightly cooler
conditions, with highs on Saturday in low 60s with lows in the low
to mid 40s. 30s will be possible in the foothills with low
temperatures below freezing possible for elevations above 5000 ft
in the North Cascades. This will be short lived, however, as an
upper level ridge begins to nose in on Sunday and starting a
warming trend into next week.
.LONG TERM /MONDAY THROUGH THURSDAY/...The aforementioned upper
level ridge will continue to amplify and build over the Pacific
Northwest through the beginning of the week. Temperatures are
expected to warm into the upper 60s to low 70s by Tuesday. Model
solutions diverge quite a bit from Wednesday and beyond. Some
solutions are bringing in an upper level low or a shortwave trough
through the area--which would keep precipitation chances in the
forecast--while others keep the ridge overhead. As such, the full
distribution for highs in Wednesday ranges form the low 60s to
low 70s. The mean solution keeps temperatures in the mid 60s with
chance PoPs from Wednesday morning beyond.
62
&&
.AVIATION...Southwest flow aloft will transition to more northerly
on Friday as ridging offshore nudges into Western Washington. Dry
conditions will return tonight. Cigs will lower tonight into Friday
morning, with areas of LIFR/IFR cigs, especially along the coast and
into portions of southern and central Puget Sound. In addition,
light winds and residual moisture may promote fog development,
particularly in the aforementioned areas. Otherwise, cigs will
slowly improve to VFR for Friday afternoon. S/SW surface winds will
become light tonight.
KSEA...A few showers may be around the terminal, mainly through 03z-
04z. Some clearing early tonight before cigs lower Friday morning.
There remains uncertainty in regards to the extent of low stratus or
fog in the morning. At this time, however, IFR cigs are forecast.
Current probabilities for IFR/LIFR cigs are 25% and 20% respectively
between 13 and 18z. S/SW surface winds will continue, becoming light
tonight. JD/21
&&
.MARINE...Southerly winds will continue to dissipate into this
evening as the weather system offshore weakens. Otherwise, weak
onshore flow expected into Saturday. Northerly winds will then
increase over the weekend, with high pressure building into early
next week. Winds expected to be below SCA threshold Friday into
early next week.
Combined seas of 9 to 12 feet will subside below 10 feet tonight.
Seas generally of 4 to 6 feet are expected Friday into the weekend.
JD/21
$$
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$

NWS SEW Office Area Forecast Discussion