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afdsew

Area forecast discussion
National Weather Service Seattle Washington
318 PM PST Fri Nov 22 2019

Synopsis...dry weather into early Saturday with high pressure
over the area. Pattern changes by later Saturday into next week as
several weather systems usher in chances for precipitation and
cooler air.

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Short term /today through Sunday/...current satellite shows some
slight improvement...but over all low clouds continue to linger over
the sound from Everett in the north to Olympia in the south and
trailing down into the SW interior toward Chehalis. Hesitant to call
it fog per se...as visibilities have improved to at least 2 miles.
Still some restriction/haziness out there though. Remainder of West Washington
seeing some high clouds starting to move in in advance of upcoming
weather system for Saturday. This system is not likely to bring
precip to the area until Saturday night as it starts to pass through
West Washington with rain continuing into Sunday morning. Models show a general
drying expected for Sunday afternoon...although enough moisture will
linger where a possible shower or two might still be possible for
the remainder of the day. This system will Herald in a pattern
change as more active weather is expected for the long term forecast
period. Overnight lows will be on a bit of a warming trend as clouds
move in to the area tonight and remain in place Saturday night with
lows tonight ranging from the mid 30s in the SW interior to around
40 along the coast. Lows Saturday night will range in the lower to
mid 40s. Highs Saturday expected to be a degree or two warmer for
most locations. Smr

Long term /Monday through Thursday/...another system will move into
the area Monday with the front due through Monday morning and the
following upper level low dipping down starting Monday
night...bringing more Rain/Mountain snow. The main impact from this
will be to drop temps down areawide...with high temperatures Monday
not escaping the 40s. This cooling trend will continue as the low
plunges further south. Models starting to come in line with one
another regarding this system...although some of the finer details
still slightly out of whack. Precip associated with this low will
continue Tuesday and maybe into early Wednesday...although coverage
will be a bit more scattered. With daytime highs for this period
generally in the lower 40s and overnight lows in the upper 20s to
lower 30s...there will be the Prospect of a potential rain/snow mix
in some lowland locations. Models continue to advertise dry
conditions Wednesday and Thursday providing little obstruction to
Holiday travel. Smr

&&

Aviation...low clouds still cover much of the interior lowlands
this afternoon due to light winds and weak mixing, especially near
the sound. Given the trends, will likely see fog redeveloping this
evening for IFR to LIFR conditions. We should see improving
conditions Saturday morning as south winds increase and high/mid
level clouds push in. Rain, from a warm front, will mostly affect
the coast, Olympics and north Cascades Saturday afternoon. 33

Ksea...fog likely redeveloping this evening with light/variable
winds. Should see improving conditions 14-18z Saturday morning as
south winds increase. 33

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Marine...weak offshore flow will continue tonight with seas around
10 to 14 feet. Southerly flow will increase on Saturday with a warm
front. Onshore flow will increase Saturday night as a cold front
moves inland. Gales are possible through the Strait of Juan de Fuca.
A second frontal system will drop down from the northwest Sunday
night and Monday. Northerly offshore flow will develop on Tuesday. 33

&&

Hydrology...precipitation moving into the region over the weekend
into next week will lead to some rises on area rivers, but river
flooding is not expected for the next 7 days. Snow levels will
also drop with each system with snow falling at higher elevations.

&&

Sew watches/warnings/advisories...
Washington...none.

Pz...Small Craft Advisory from 4 am Saturday to 4 am PST Sunday for
coastal waters from Cape Flattery to James Island 10 to 60
nm-coastal waters from Cape Flattery to James Island out 10
nm-coastal waters from James Island to Point Grenville 10
to 60 nm-coastal waters from James Island to Point
Grenville out 10 nm-coastal waters from Point Grenville to
Cape Shoalwater 10 to 60 nm-coastal waters from Point
Grenville to Cape Shoalwater out 10 nm.

Small Craft Advisory for hazardous seas until 5 am PST Saturday
for coastal waters from Cape Flattery to James Island 10 to
60 nm-coastal waters from Cape Flattery to James Island out
10 nm-coastal waters from James Island to Point Grenville
10 to 60 nm-coastal waters from James Island to Point
Grenville out 10 nm-coastal waters from Point Grenville to
Cape Shoalwater 10 to 60 nm-coastal waters from Point
Grenville to Cape Shoalwater out 10 nm.

Small Craft Advisory for rough bar until 4 am PST Sunday for
Grays Harbor bar.

Small Craft Advisory for hazardous seas until 10 PM PST this
evening for West Entrance U.S. Waters Strait of Juan de
Fuca.

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