Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 250331

Area Forecast Discussion
National Weather Service Seattle WA
831 PM PDT TUE MAY 24 2016

.SYNOPSIS...Mostly cloudy skies will continue through Wednesday
with onshore flow. An upper low will bring an increasing chance of
showers Thursday through Saturday. Another upper level trough will
reach the area Sunday night or Monday.


.SHORT TERM...Weak high pressure aloft and low level onshore flow
will produce mostly cloudy and generally dry weather tonight and
Wednesday. An upper low will drop down from the northwest
Thursday and bring some showers...mainly from Thursday afternoon
through Friday. A Puget Sound convergence zone seems likely at
times during this period. The onshore flow pattern will maintain
mostly cloudy skies and highs will be a few degrees below normal.

.LONG TERM...Previous discussion...By Saturday morning the low is
opening up to more of a trough and is near the Idaho Panhandle--
but some PSCZ precip could still be going over Western WA. The 12z
GFS has a second trough arriving around daybreak Monday for
another round of shower activity. Camping this holiday weekend may
require blue tarps in the mountains and in the PSCZ, but might not
be too bad overall in the lowlands.


.AVIATION...A long wave trough continues to linger over the West
as the associated upper level low spins over the MT/Saskatchewan
border. The air mass over western WA is stable. The flow aloft is
northerly with low level onshore flow at the surface. Low level
stratus clouds increasing over the area although cigs remain
VFR...except HQM at the time of this writing. Could see some
locations with cigs dropping down into MVFR very late tonight or Wed
morning. As has been the pattern...should see cigs lift and cloud
cover break up some by Wed afternoon. 33/SMR

KSEA...VFR conditions through this evening. Light N winds expected
to shift back to S between 09-12Z tonight. Ceilings near 2000 ft
early Wednesday morning. 33/SMR


.MARINE...Onshore flow will prevail this week with high pressure
over the NE Pacific. Inherited Small Craft Advisory looks to be on
track. Given the weather pattern...can expect to see Small Craft
Advisory winds in the Central and East Strait of Juan de Fuca during
the afternoon and evening hours each day. 33/SMR


.SEW Watches/Warnings/Advisories...
PZ...Small Craft Advisory until 5 AM PDT Wednesday for Central U.S.
     Waters Strait Of Juan De Fuca-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-East
     Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland
     Waters Including The San Juan Islands.



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