FXUS66 KSEW 122302

Area Forecast Discussion
National Weather Service Seattle WA
300 PM PST Mon Nov 12 2018

.SYNOPSIS...An upper ridge will keep the Western Washington dry
tonight and into Tuesday. A front will bring light rain to the coast
by Tuesday afternoon, spreading inland Tuesday night and Wednesday.
Another dry period with areas of overnight and morning fog is
expected Thursday through Saturday. A front may bring some light
rain to the area by late Sunday or early next week.


.SHORT TERM...Some high clouds...and that is about it...in place
over W WA this afternoon as the slowly eastward moving upper level
ridge keeps the weather fairly benign over the area. The inherited
wind advisory from this morning was allowed to expire. Gusts in the
east Puget Sound lowlands still kicking up to around 40 mph in some
locations...but with criteria being 45 mph...model pressure
gradients indicating some relaxation and a slow but steady downward
trend in wind speeds/gusts...felt pretty confident in allowing it to
expire and...thankfully...that reasoning still seems to be holding

The upper level ridge will push east enough to allow the next system
to make its way to the coast Tuesday afternoon with models in
general agreement on timing and precip amounts/coverage. Both models
show things starting to taper off at some point Wed night or early
Thursday morning...but 12Z runs agree that a secondary system mostly
to the north of the area will sag down into W WA allowing for
chances of precip to linger even into Friday before exiting the area
completely.  SMR

.LONG TERM...High pressure aloft begins to build offshore Thursday
but its influence does not look to be felt over the area until
Friday afternoon as the ridge axis draws closer to the coast. This
will make for a dry weekend and start to next week. Models are
hinting at the next system out in the day 7 or 8 time
frame...Tuesday or Wednesday depending which model you
consult...ECMWF or GFS respectively. No real surprises with the
disagreement. Neighboring office has bit on to the more aggressive
solution and have tweaked extended grids to remain within
collaboration guidelines...although hard to get excited about
anything that far out just yet.  SMR


.AVIATION...The air mass across Western WA will remain dry and
stable tonight with high pressure aloft and offshore flow. VFR
conditions expected, however, may see patchy fog in the south sound
early Tuesday morning. Otherwise, expect mainly SCT-BKN cirrus
clouds aloft. Rain will increase Tuesday night as the next frontal
system approaches and moves inland. 33

KSEA...Dry weather tonight with VFR conditions. E/NE winds to 10 kt,
becoming S by 18z Tues. 33


.MARINE...Offshore flow will persist through Tuesday with high
pressure east of the Cascades and low pressure over the NE Pacific.
Highest wind and waves will be over the Coastal Waters and western
Strait of Juan de Fuca - Small Craft Advisories are in effect. The
flow will turn onshore late Tuesday into Wednesday as a weak front
crosses the area. A second weak frontal system will clip the region
on Thursday. Offshore flow will return over the weekend. 33


.HYDROLOGY...River flooding is not expected the next 7 days.


PZ...Small Craft Advisory until 10 PM PST Tuesday 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-West Entrance U.S. Waters Strait Of
     Juan De Fuca.




NWS SEW Office Area Forecast Discussion

Discussion Script by Ken True at Saratoga Weather - WFO Script by SE Lincoln Weather