Forecast Discussion for SEW NWS Office
035
FXUS66 KSEW 212157
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
257 PM PDT Thu Mar 21 2019

.SYNOPSIS...Cooler temperatures have returned as onshore flow
increases. A weak system will bring showers and breezy conditions
later Friday into Saturday. Unsettled weather continues next week.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...Onshore flow returned today
in advance of frontal system out across the Pacific. Temperatures
are running some 5 to 15 degrees cooler than this time yesterday.
Stratus deck also present along the coast and southwest interior
this afternoon. This cloud cover will continue to develop and
spread inland tonight as marine layer deepens. Front will then
approach the coast tomorrow afternoon with rain spreading inland
during the afternoon to overnight hours. Amounts will be fairly
light with high snow levels so relatively little impact expected.
Trough will hang around on Saturday with more hit-or-miss showers
throughout the day. System then exits on Sunday for a mostly dry
day. Daytime highs generally in the 50s Saturday, warming several
degrees on Sunday. CEO

.LONG TERM /MONDAY THROUGH THURSDAY/...Unsettled pattern will
continue next week with several systems rotating through the area.
Models continue to differ on timing, strength, and moisture
associated with each system. Though current forecast suggests
chances for precipitation across most periods, there will likely
be some breaks in there. Until differences can be resolved, no
major changes made in the extended forecast. Temperatures will be
near normal. CEO

&&

.AVIATION...High clouds across the area with mid level clouds
mainly over coastal areas. Expect VFR conditions for most TAFs
north of KSEA with periods of MVFR across the south Sound and
coast into tonight. Additional cloud cover expected into tomorrow
morning with MVFR/VFR at most sites. Chance for showers return
Friday afternoon into Friday evening with VFR/MVFR conditions.
Winds generally southerly through the period from 5 to 15 kts.

KSEA...VFR conditions with high clouds to continue. Cigs generally
VFR through tonight with MVFR possible during the morning hours.
Dry tomorrow morning with chance of showers by later afternoon.
Winds generally between SE and SW at 5 to 12 knots. JD

&&

.MARINE...Small Craft Advisory conditions through this evening
along the central Strait with onshore flow. Winds and seas will
ease this into tonight ahead of the next frontal system.
Increasing southerlies are expected into Friday. Small Craft
Advisory issued for coastal areas for Friday into Friday evening.
Significant westerly swell - 10 to 12 feet - over coastal waters
and west entrance Friday night rising to 14 feet at 16 seconds on
Saturday for coastal areas.

&&

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

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 5 AM to 7 PM PDT Friday 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-Coastal Waters From Point Grenville To Cape
     Shoalwater 10 To 60 Nm.

     Small Craft Advisory from 1 PM to 11 PM PDT Friday for Coastal
     Waters From Cape Flattery To James Island Out 10 Nm-Coastal
     Waters From James Island To Point Grenville Out 10 Nm-
     Coastal Waters From Point Grenville To Cape Shoalwater Out
     10 Nm.

     Small Craft Advisory until 8 PM PDT this evening for Central
     U.S. Waters Strait Of Juan De Fuca.

&&

$$

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NWS SEW Office Area Forecast Discussion