Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
FXUS66 KSEW 292148
Area Forecast Discussion
National Weather Service Seattle WA
300 PM PDT SUN MAY 29 2016
.SYNOPSIS...Skies will clear tonight as a strong upper level ridge
builds offshore. The upper ridge will move slowly east Monday and
Tuesday bringing sunny skies and a warming trend. A weak weather
system will bring increasing clouds Wednesday and a chance of
showers Thursday and Friday. Dry and warmer conditions will return
.SHORT TERM...Showers have mostly ended though radar shows a few
in the Cascades and around central Puget Sound. These remaining
showers will end this evening under the influence of a strong upper
ridge building offshore. Clearing in western areas is apparent in
satellite imagery. Once the cumulus diminishes toward sunset,
clearing will increase giving mostly sunny skies on Monday.
Temperatures will rise above normal with highs mostly in the 70s.
The upper ridge axis will be right over western Washington Tuesday.
At the surface the flow will turn northerly and offshore as low
pressure develops along the coast. Temperatures will rise further,
reaching the 70s to low 80s Tuesday.
Surface flow turns solidly onshore Wednesday, and there may be
increasing clouds from an approaching weak system. Highs will
probably still approach 80 over inland areas. Burke
.LONG TERM...The EURO and GEM are remarkably wet with a weak weather
system that drags through the area on Thursday. The GFS is drier. As
a compromise will bring a chance of showers to most areas Wednesday
night through Friday morning. Clouds will cause a slight dip in high
temperatures on Thursday. Then models rebuild heights over the
weekend for a return to 80 degree temperatures. Burke
An upper level trough over eastern British Columbia extending
south across eastern Washington will move east and away from the
area tonight. High pressure at the surface and aloft will build
over the northeast Pacific tonight and Monday. The upper ridge
will move into Western Washington Monday night while the surface
high bridges across British Columbia. Light northwesterly flow
aloft will become westerly Monday night. The air mass is moist and
stable this afternoon. The air mass will dry tonight and become
dry Monday through Monday night.
Convergent flow around the Olympics continues to produce light
showers from the northeastern Olympic Peninsula eastward into
mainly King and Snohomish counties. The leading edge of the low
level northerlies have shifted down to between southern Hood
Canal and Tacoma. Showers are also seen over the Cascades. Some
MVFR conditions linger in the central Puget Sound area but
elsewhere skies are clearing as drier air filters in from the
northwest. Clouds and showers associated with the convergence zone
are expected to dry and weaken this evening as high pressure
builds into the area from the west. By Monday expect good VFR
conditions throughout the forecast area. Albrecht
KSEA...North winds 9-13 kt will ease to 6 to 8 kt this evening
then become NE 4-6 kt after 06Z. Winds will shift to more
northerly about 19Z Monday. Clouds and showers associated with the
left over convergence zone over or just south of the terminal will
slowly dissipate this evening and improving VFR conditions are
expected from here on out. Albrecht
Post-frontal onshore flow will prevail through tonight but
gradually ease. Small Craft Advisory westerly winds have developed
over the central Strait of Juan de Fuca and will spread into the
east entrance by later this afternoon. Winds in the Strait will
diminish about 4 AM Monday. Winds over the other waters will
likely stay below 20 KT tonight through midday Monday.
High pressure will build over the offshore waters on Memorial
Day. This will give the potential for northwesterly winds up to 25
KT over portions of the coastal waters Monday afternoon and
evening. Winds will become northerly inland and northerlies will dominate
on Tuesday as a thermally induced trough of low pressure develops
northward along the Oregon and south Washington coasts.
Forecast models are now about a day quicker in shifting the
thermal trough eastward across the Cascades. Onshore flow is
now expected to develop Tuesday night and continue through
Wednesday night or Thursday. Winds are likely to reach Small Craft
Advisory criteria in the central and east portions of the Strait
of Juan de Fuca during the late afternoon and overnight hours
Tuesday and Wednesday.
High pressure over the offshore waters early Thursday will shift
east into the coastal waters later Thursday then inland on Friday.
PZ...Small Craft Advisory until 4 AM PDT Monday for Central U.S.
Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
Strait Of Juan De Fuca.
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