792 
FXUS66 KSEW 091951
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
930 AM PDT Tue Oct 9 2018

.SYNOPSIS...Showers will taper today as a weather system exits.
The rest of the next week looks dry with high pressure aloft in
control. Lingering low level moisture and light winds will 
produce some night and morning fog through Friday. Increasing 
offshore flow for the weekend will likely limit the fog coverage. 

&&

.SHORT TERM...The remnants of a weather system will shift 
southeast this morning with showers and drizzle tapering and 
eventually ending. It should be generally dry by afternoon other 
than a few lingering showers over the mountains. The air mass is 
moist and soupy this morning. Clouds will slowly lift and break 
up today but clearing will hold off until mid afternoon or even 
early evening some locations with light winds and lingering low 
level moisture. Highs will be a few degrees below normal today. 

High pressure aloft will be in control Wednesday and Thursday for
dry weather. Mostly clear skies, longer nights, and light 
northerly winds should allow for areas of night and morning fog. 
Highs will inch back up to near normal. Schneider

.LONG TERM...An upper ridge will remain over the area Friday
through Monday with northerly low level offshore flow for dry 
weather and seasonable temperatures. Models show a weak weather 
system brushing the area to the north Thursday night and Friday. 
This might bring some sprinkles to the north part of the area but 
for now the forecast is dry. Schneider

&&

.AVIATION...Northwest flow aloft continues early this morning as 
a cold front that moved through the central Puget Sound around 07Z 
shifts south and east of the region. Moderate to strong north-
northwest flow aloft will continue today as an upper trough over 
central Washington digs southeastward into southern Idaho this 
evening. A few gaps in the low cloud cover have materialized behind 
the front this morning, but IFR ceilings remain prevalent across the 
area this morning in a very moist air mass. 

The air mass will gradually dry from the north later today, but the 
keyword is gradually. IFR or low MVFR ceilings are likely to linger 
across much of the region through 18Z then lift somewhat in the 
afternoon. Ceilings will scatter out to VFR across the north 
interior 18Z-20Z then over the Puget Sound terminals 22Z-00Z. Low 
level northerly flow will increase somewhat during the afternoon 
hours, but light surface gradients, recent rainfall, and a longer 
night spells the return of widespread IFR or LIFR conditions in fog 
for much of the region from 09Z-18Z Wednesday morning.

KSEA...Above discussion applies. IFR expected to be the predominant 
condition through the morning. Ceilings gradually lifting through 
MVFR this afternoon before scattering out 22Z or later. Fog and low 
clouds with surface visibilities under 3SM a very good bet after 09Z 
tonight. Surface winds northerly rising to 5 to 10 knots later this 
morning, then light and variable after sunset. 27

&&

.MARINE...Strong northwesterly winds remain in place over the 
coastal waters this early morning in the wake of a passing cold 
front...as such a small craft advisory remains in effect there. Race 
Rocks also came in with a bit of a surprise with a couple of hours 
worth of obs showing SCA speeds there as well. As no other 
surrounding waters show speeds close to this...will confine new SCA 
to the central strait through 6 AM. Winds over the remaining inland 
waters remain fairly benign.

High pressure will gradually build into the waters by late this 
afternoon and continue through Thursday. This will result in light 
winds persisting and areas of fog. Fog is expected to become less 
likely on Friday as drier air filters into the area and northerly 
flow increases somewhat...but winds are expected to remain 20 kt or 
less. SMR

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until midnight PDT tonight 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 until noon PDT today 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 6 AM PDT early this morning for 
     Central U.S. Waters Strait Of Juan De Fuca.

&&

$$

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