Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 271559

Area Forecast Discussion
National Weather Service Seattle WA
859 AM PDT Tue Oct 27 2020

.SYNOPSIS...Mainly dry conditions across the region this week with
high pressure. The exception is near the Canadian border where
there`s a chance of rain due to a front in British Columbia. A
cold front will bring showers to western Washington on Friday. The
weekend is looking dry with high pressure.


remains offshore today, yielding dry conditions under northerly
flow. Temperatures warming across the area today through Thursday,
with Thursday on track to be the warmest day of the week as
temperatures climb back into the upper 50s and low 60s.

A stalled frontal system over southern B.C. tonight into Wednesday
will increase POPs along the northern border and potentially along
the northern slopes of the Olympics. Light rain is possible in
these regions.


.LONG TERM /FRIDAY THROUGH MONDAY/...Wetter weather returns on
Friday as a cold front clips through western WA (average looking
front). Snow levels in the Cascades will lower to around
4500-5000 feet behind this system Friday night but showers will
also taper off. High pressure will rebuild over the region
Saturday and Sunday for another break in the weather. A wetter,
stronger system may track inland Monday or Tuesday as the ridge
exits. 33


.AVIATION...Upper ridge offshore will gradually weaken over the next
24 hours as stalled frontal boundary well to the northwest of the
region sags southward. Northwest flow aloft to continue today with
light flow in the low levels. The air mass remains somewhat moist
below about 6000 feet and expect mostly VFR ceilings to persist
across the region through the day ahead. Light surface flow will
allow ceilings to lower tonight with widespread low MVFR or IFR
likely on Wednesday morning.

KSEA...VFR ceilings expected to persist today. Some improvement
expected this afternoon, but broken to overcast 5000 to 6000 feet is
likely to remain in place this afternoon. Ceilings lowering down to
1000-2000 feet around 12z Wednesday. Surface winds light southerly.



.MARINE...High pressure over the waters will gradually weaken
through Thursday as a frontal boundary near Haida Gwaii gradually
sags southward toward northern Vancouver Island and stalls. A
somewhat stronger front will arrive Friday with small craft
advisory winds possible over most of the waters. Winds will ease
Friday night and Saturday as high pressure rebuilds over the
area. Felton


.HYDROLOGY...No river flooding expected over the next 7 days.



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