Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 292231
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
331 PM PDT Fri May 29 2020

.SYNOPSIS...Dry conditions expected this evening and overnight.
Wet conditions arrive Saturday morning and will linger through
Sunday. Dry conditions return early next week as weak high
pressure builds into the region. The unsettled pattern looks to
return by Wednesday/Thursday of next week.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...Conditions will remain dry
this evening as the ridge starts to give way to the system
arriving from the south. Rain will likely begin in the area early
Saturday morning. As of this afternoon`s forecast update, the
chances for thunder is not exactly zero, and will likely be
limited to the Cascades and the eastern slopes. Eastern Washington
will be the prime location for stronger storms. Rain could be
heavy at times in the area, as the QPF associated with this
system is more significant than recent systems that have moved
through.

Conditions will start to dry out from the south on Sunday, with
breezy conditions possible across the Sound. Monday will be dry as
weak ridging builds back into the area in the early part of next
week.


.LONG TERM /TUESDAY THROUGH FRIDAY/...Tuesday will continue to be
dry under the influence of the weak ridge. Highs will be in the
upper 60s and low 70s. Upper level flow turns more zonal by
Wednesday, opening the door once again to additional systems. The
next system will likely arrive by Wednesday evening, however, it
might only be enough to bring the temperatures down a few degrees
and cause a shower or two over the Cascades through Thursday.

The main wave to impact the area will be from a low that drops
down from the Gulf of Alaska on Friday. Details on the late week
system are messy at this point in time, and exact time of arrival
will be evaluated through the weekend and into next week. The
hints of a continuing, unsettled pattern are there in the long
term, and can be corroborated by the Climate Prediction Center`s
anticipation of a wetter than normal 6-10 day period.

Kristell

&&

.AVIATION...SCT-BKN VFR conditions continue this afternoon for all
TAF sites across western Washington, and this trend will persist
through the overnight hours. Through the morning hours on Saturday,
showers will begin to spread from the south, bringing with them
lowering ceilings, tho should largely remain VFR. By Saturday
afternoon, showers will become much more widespread while also
carrying the chance for thunder (especially TAF sites near Puget
Sound). Ceilings may flirt with higher end MVFR as this occurs or
may even temporarily drop lower. Winds will generally be from the
north near Puget Sound TAF sites, and more westerly at HQM, CLM, and
BLI. Wind speeds likely to range in the 8-12kt range, and may be
slightly higher at HQM and CLM.

KSEA...VFR conditions with mid and high level cloud cover continuing
to increase overnight. Showers are likely in the vicinity Sunday
morning before becoming widespread and accompanied by lower end
VFR/possibly MVFR cigs in the afternoon. An afternoon or evening
thunderstorm is not out of the question. Northerly winds generally
around 10 knots through this evening before decreasing and turning
northeasterly after sunset. Winds will increase again near 10kts
from the N/NE Saturday.

Kovacik

&&

.MARINE...A closed low off the coast of California will slowly push
inland, dampen, and move northward overnight tonight and through the
day on Saturday, while offshore of the WA/OR coasts exists another,
larger area of low pressure. Together, these systems are responsible
for increasing cloud cover across the area today, and this trend will
continue overnight as the systems move closer to the local area.
Enough of a gradient is currently in place for small craft advisory
winds to persist across the offshore waters and thru the central and
eastern Strait of Juan de Fuca into Saturday. In fact, the gradient
is expected to strengthen across the Strait this evening, which will
likely cause small craft winds to bleed into the Northern Inland
Waters and Admiralty Inlet. A small craft advisory was issued for
these waters to account for this.

As the coastal California system merges with a shortwave trough from
the larger Pacific trough, winds are expected to pick up across the
majority of the waters again on Saturday. Have expanded or extended
small craft advisories accordingly, with almost all western
Washington waters expected to see small craft level winds. Model
guidance also suggests strengthening gradients, particularly across
the eastern Strait to warrant a Gale Watch for Saturday evening and
portions of Saturday night.

By Sunday, winds will ease across all waters, with headlines
expected to expire for all waters except the central and eastern
Strait of Juan de Fuca, where diurnal westerly pushes will likely
persist into at least portions of the upcoming week.

Seas will generally remain benign for much of the next week, with
exception of this evening where waves will remain around 10ft across
the offshore waters before subsiding overnight. To account for this,
Small Craft for Rough Bar will continue at Grays Harbor through mid
evening.

Kovacik

&&

.HYDROLOGY...The daily hydrology discussion has ended until the
start of the next rainy season; it will only be updated as needed
until then.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 AM PDT Sunday 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
     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.

     Small Craft Advisory until 8 PM PDT this evening for Grays
     Harbor Bar.

     Gale Watch from Saturday afternoon through late Saturday night
     for East Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 5 PM PDT Saturday for East Entrance
     U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 5 AM to 11 AM PDT Sunday for East
     Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 5 AM PDT Saturday for Northern Inland
     Waters Including The San Juan Islands.

     Small Craft Advisory from 5 PM Saturday to 11 AM PDT Sunday for
     Northern Inland Waters Including The San Juan Islands.

     Small Craft Advisory from 2 PM Saturday to 11 AM PDT Sunday for
     West Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 11 AM PDT Sunday for Admiralty Inlet.

&&

$$

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