Joyce, Washington Weather Forecast Discussion

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FXUS66 KSEW 261550
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
850 AM PDT Fri Sep 26 2025
.SYNOPSIS...Zonal flow will continue today as several frontal system
approach Western Washington. A frontal system will clip the northern
portion of Washington, bringing the chance of light showers along
the north coast and Whatcom County Friday and Saturday. Widespread
rain on Sunday and Monday as a frontal system moves over the region.
Additional systems will impact the region next week, bringing
additional chances for precipitation.
&&
.SHORT TERM /TODAY THROUGH SUNDAY/...No major changes have been
made to the forecast this morning. See below for the previous
discussion and an updated aviation section.
Zonal flow will continue today ahead of multiple frontal systems
making their way to Western Washington in the coming days. An
upper level low with an associated front situated over the Gulf of
Alaska will move inland into Canada and clip northern portions of
Western Washington. This will bring the chance of light rain to
the north coast and Whatcom County today through Saturday. Latest
guidance suggests that most locations will see less than 0.10
inches of rain, while the north coast may see up to 0.30 inches
through Saturday. A frontal system will move through the region
Sunday bringing widespread rain to the region by the evening
hours. Guidance hints at a very small chance of thunder along the
coast Sunday evening (10%-20%).
Temperatures will be slightly warmer today and Saturday. Today high
temperatures will be in the upper 60s to low 70s in the interior and
low 60s in the coast. Saturday will be slightly warmer than Friday;
temperatures will in the interior will be in low to mid 70s and low
to mid 60s at the coast.
.LONG TERM /MONDAY THROUGH THURSDAY/...The aforementioned frontal
system will continue pushing through the region on Monday. There is
good agreement between ensemble guidance that unsettled weather will
continue into late next with additional systems set to impact the
region. Latest guidance is suggesting a small chance of
thunderstorms on Monday and Tuesday evening along the Cascades (10%-
20%). As for the lowlands (including the coast), probabilities are
around 10%. In addition to low probabilities, confidence is also
low on thunderstorm development as it would be dependent on the
combination of the upper level flow and thermodynamics.
29
&&
.AVIATION...Brief high pressure over the region today with another
cold frontal system passing through tonight/Saturday with a trough.
Flow aloft will be primarily southwest-west. Down at the surface,
most terminals are reporting VFR with a mix of few-sct cigs at
around 3,000 ft (and broken decks higher from 5,000 to 15,000 ft).
There are still some isolated areas of fog/mist in the Kitsap
terminals (and along the coast), with showers moving out of the KBLI
terminal. Remaining low cigs and vis will improve from 18-22Z (with
the coast being the last area to clear). Southwest winds today will
range from 4-8 kt, dropping to under 5 kt overnight, and becoming
more westerly Saturday. Couple showers will be possible this evening
for northern terminals, otherwise it will remain dry elsewhere. Mid
and high cloud coverage tonight should be enough to keep terminals
VFR into Saturday (though there is a slight possibility for IFR/LIFR
cigs/vis in the south interior and coastline Saturday morning).
KSEA...Remains VFR this morning with few cigs at 3,000 ft and higher
cloud decks over the terminal. Dry slot over Puget Sound will likely
prevent cigs from dropping any further this morning (thus the
likelihood of MVFR conditions has decreased substantially this
morning). Cigs will continue to lift and scatter through the day,
with light south winds 4 to 8 kt by this afternoon. Light winds
under 5 kt from the south are expected tonight, becoming west 4-8 kt
Saturday afternoon. Threat of cigs below VFR remains too low to
include in the TAF Saturday morning (mid/high level cloud coverage
will likely prevent lower cigs/vis from forming).
HPR
&&
.MARINE...A stronger frontal system approach area waters
today into the weekend. Seas will build to 9-10 ft this afternoon
into Saturday, with winds still expected to remain below 20 kt with
this frontal system. Small craft advisories were issued for all
outer coastal zones and the northern third of the inner coast. Seas
will ease somewhat Sunday into Monday, but then build into midweek
above 10 feet for the coastal waters with another system Tuesday
into Wednesday potentially bringing in gusty south winds.
Cook/HPR
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 6 AM to 5 PM PDT Saturday for Coastal
     Waters From Cape Flattery To James Island Out 10 Nm.
Small Craft Advisory from noon today to 11 PM PDT Saturday for
     Coastal Waters From Cape Flattery To James Island 10 To 60
     Nm-Coastal Waters From James Island To Point Grenville 10
     To 60 Nm.
Small Craft Advisory from 6 AM to 11 PM PDT Saturday for Coastal
     Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.
&&
$$

NWS SEW Office Area Forecast Discussion