Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Seattle Washington
933 PM PDT sun Jul 24 2016

Synopsis...high pressure will bring dry and mild weather tonight
and Monday. A weak system will move by Monday night bringing some
marine air into the interior for Tuesday. The ridge will
strengthen Wednesday into the end of the work week with the
warmest temperatures of the month expected Thursday and Friday.


Short term...westerly flow aloft with relatively high heights
will prevail for dry weather through Wednesday. Onshore flow will
strengthen a bit tonight and Monday but this will not have much
impact on the weather. Stratus will likely form at the coast
tonight and push partially inland Monday morning through the
Chehalis gap and down the Strait of Juan de Fuca but most of the
interior will remain cloud free. Highs Monday will be about the
same or maybe a couple degrees cooler compared to today.

A weak passing upper short wave will further strengthen the
onshore flow Monday night and Tuesday morning. Stratus should push
further inland Tuesday morning but then burn back to the beaches
in the afternoon. In other words, a fairly typical Summer day with
morning clouds and afternoon sunshine and highs cooling to near

Wednesday should be a bit sunnier with low clouds burning off a
little earlier as upper heights rise again over the area again.
This should also translate into a few degrees of warming for most
spots. Schneider

Long term...previous discussion...a strong upper level ridge
over the west will bring warm temperatures to much of the area
Thursday and Friday. High temperatures in the interior will be in
the 80s with a few low 90s possible. The low level flow will
remain onshore with cooler conditions by the water - highs mainly
in the 70s.

An upper level trough will track down from Alaska next weekend,
while kicking the ridge east and out. This will end our warm spell
with temperatures trending back toward normal. 33


Aviation...light westerly flow aloft for the next 24 hours with
slowly falling upper heights. An upper level shortwave will
approach the coast late Monday, strengthening low-level onshore
flow. Expecting similar coverage of marine stratus on Monday
morning as Sunday morning, meaning IFR marine stratus will reach
inland to near kshn and down the Strait to Whidbey Island. Marine
clouds will burn back to the coast on Monday afternoon. Above
low-level marine layer, the air mass above will be dry and stable
through Monday night.

Ksea...clear skies and a northerly breeze will continue through
Monday evening. Haner


Marine...high pressure offshore with lower pressure east of the
Cascades will result in continued onshore flow through Friday. The
flow will become strong on Monday for possible gales in the
central and eastern Strait on Monday night. Moderate onshore flow
will resume from Tuesday through Thursday, becoming strong again
on Friday. Haner


Sew watches/warnings/advisories...
Pz...Small Craft Advisory until 11 PM PDT this evening for 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 midnight PDT Monday night 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.

Gale watch from Monday evening through late Monday night for
central U.S. Waters Strait of Juan de Fuca-East Entrance
U.S. Waters Strait of Juan de Fuca.

Small Craft Advisory until 5 am PDT Monday for central U.S.
Waters Strait of Juan de Fuca-East Entrance U.S. Waters
Strait of Juan de Fuca.




You can see an illustrated version of this discussion at

National Weather Service Glossary of Abbreviations