Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 141616

Area Forecast Discussion
National Weather Service Seattle WA
916 AM PDT Wed Mar 14 2018

Upper level low pressure off the Pacific Coast will drift slowly
southward through the end of the week. This will promote continued
near to below normal temperatures along with showery weather for
several days. No high impact weather events are expected through
early next week.


Radar shows showers moving north across the area and a more
isolated shower coverage pushing in from the southwest. Forecast
on track with high topping out mainly in the lower-mid 50s and a
few showers around the rest of the day. The main upper low will
drift south over the next few days. It should be primarily dry but
isolated showers still present. The main low will be quite a bit
south so rainfall should not be widespread or significant.
Temperatures will remain in low-mid 50s for several days along
with lows in the upper 30s to low 40s, so it will be very close to
normal for mid-March, if not maybe a degree or two below normal.
Besides some isolated or widely scattered showers on Saturday and
Sunday, the weekend weather looks relatively quiet. Johnson

A generally troughy pattern will remain over the area Sunday...allowing
precip chances to continue. Models in general agreement that the
start of next week looks to start off dry...with the ECMWF best
displaying the ridge at work behind this end result. They start to
deviate from each other after Tuesday...with the GFS keeping
things dry through Wed while the ECMWF looks to bring in an upper
level low from the south. Temps during this time look to hover
right in the mid-50s in the lowlands during this period. SMR


.AVIATION...The upper level trough over the offshore waters
will keep light southerly flow aloft over Western Washington today
with a moist and somewhat unstable air mass. At low levels weak
pressure gradients with light onshore flow. MVFR and local IFR
conditions lingering mainly north of King County this morning will
improve to VFR levels later this morning. Pockets of MVFR conditions
remain possible in and around scattered showers into the afternoon.
The air mass will dry and stabilize tonight as the trough offshore
shifts to the southwest of the region.

KSEA...Conditions have improved this morning to VFR levels. Showers
will remain over the area into the afternoon but will remain
isolated with little or no impact. Winds will remain S-SW 5-10 knots.


.MARINE...Weak onshore flow with westerly winds 10-20 kt in the
strait. Offshore flow will develop Thursday as a low moves south off
the coast. Some small craft advisory winds are forecast on the coast
as the low passes tonight through Thursday then become fairly light
Friday as the low moves shifts out of the region and gradients
become weaken. Onshore flow will return Saturday with gale west
winds possible in the strait.

PZ...Small Craft Advisory from 5 PM this afternoon to 5 PM PDT
     Thursday 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 for rough bar until 6 PM PDT this evening
     for Grays Harbor Bar.


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