Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
219
FXUS66 KSEW 021034
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
334 AM PDT Sun Aug 2 2026
.SYNOPSIS...
Upper level trough moving through Western Washington today.
Upper level ridge building offshore tonight and Monday moving
inland Tuesday and Wednesday. The ridge will shift east Thursday
and Friday with increasing low level onshore flow at the end of
the week.
&&
.SHORT TERM /TODAY THROUGH TUESDAY/...
Satellite imagery shows mostly cloudy skies over most of the
area this morning. Mostly clear skies only over the Central and
Southern Puget Sound. Convergence zone over Snohomish and
Southern Skagit county not producing much shower activity at 3
am/10Z. Temperatures were in the upper 40s to near 60.
Convergence zone this morning will continue to not produce many
showers. The zone will dissipate this afternoon. Upper level
trough swinging down from the north with the trough axis right
over Western Washington at 00Z Monday. Not much moisture
associated with the trough. Best chances for showers will be in
the North Cascades. Slight chance ( 10-15 percent ) of an
afternoon thunderstorm in the North Cascades as well. Highs
will remain below normal, in the 60s and lower 70s.
Trough axis moving east of the area tonight with an upper level
ridge building offshore. The combination of light northerly flow
in the lower levels and dry north northwesterly flow aloft
behind the trough will help clear skies out across the area.
While the clouds will decrease the chances for smoke, especially
aloft, will increase with the northerly flow. It will be a
chilly morning for the first week of August. Lows in the mid 40s
to mid 50s.
Upper level ridge continuing to build offshore with the ridge
axis approaching 130W late in the afternoon. No cloud cover but
the north northwesterly flow aloft and light northerly flow at
the surface will bring smoke at all levels into the area
especially over the interior. Highs warming into the 70s.
Upper level ridge axis continuing to drift eastward towards
Western Washington Monday night and Tuesday. 500 mb heights
rising into the mid 580 dms by Tuesday afternoon. Upper level
flow becoming west northwesterly which will help reduce the
amount of smoke aloft. Low level flow remaining light northerly
keeping the threat of low level smoke in the area. Warming trend
continuing with highs in the 80s and lower 90s inland and near
80 on the coast. Lows in the 50s. HeatRisk increasing into the
moderate category for most of the area Tuesday afternoon. Felton
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Upper level ridge axis moving over Western Washington Tuesday
night will remain over the area through Wednesday night. Low
level flow north northeasterly. Highs Wednesday in the 80s to
mid 90s inland and near 80 on the coast. If the low level smoke
is thick enough these temperatures will be too warm. Lows in the
mid 50s to mid 60s. Moderate HeatRisk for most of the area with
a 20-40 percent chance of major HeatRisk over the Southern
Puget Sound.
Thursday a transition day with the upper level ridge axis
shifting east and the low level flow turning onshore later in
the day. Highs along the coast cooling into the lower to mid
70s. The transition to onshore flow looks to not happen in time
for any cooling over the interior. Highs again in the 80s to mid
90s. Like Wednesday moderate HeatRisk for most of the area with
a 20-40 percent chance of major HeatRisk over the Southern
Puget Sound.
Upper level ridge axis well to the east Thursday night and
Friday with increasing low level onshore flow. This will push
any low level smoke out of the area. Highs cooling into the mid
70s to mid 80s inland with highs near 70 on the coast. Lows
in the 50s and lower 60s.
Westerly flow aloft with low level onshore flow Friday night
and Saturday producing a "normal" first half of August day with
some morning clouds and afternoon sunshine. Highs in the 70s and
lower 80s inland and mid to upper 60s on the coast. HeatRisk
returning to the minor category. Felton
&&
.AVIATION...Westerly flow aloft becoming more northerly
tonight. Areas of MVFR ceilings are expected to develop as the
morning progress. However, it won`t be long lasting as VFR
conditions will then return across the region by midday today.
Lesser low stratus coverage Sunday night into Monday as low-
level moisture becomes drier - mostly clear VFR for much of
Monday. Surface winds post- frontal out of the south-southwest
this morning 4 to 8 kt, becoming west-northwesterly into the
afternoon 5-10 kt.
KSEA...VFR conditions currently but LAMP guidance suggests a 45-55%
chance of MVFR ceilings between 12-16z this morning - VFR
thereafter. S surface winds 4-8 kt veering to the N/NW after 21Z
Sunday between 5-10 kt with gusts up to 20 kt. Less than 10% chance
of MVFR ceilings developing Sunday night into Monday morning
per current guidance.
41
&&
.MARINE...A shortwave trough will traverse across area waters today
as a thermal surface trough snakes northward along the US West
Coast. It doesn`t appear strong but as a result we`ve issued SCAs
for the central/eastern Strait and coastal waters. REFS
probabilities of SCA gusts being met (21 kt) range between 80-100%
for these aforementioned areas this afternoon-evening. High pressure
will rebuild over the coastal waters today and remain in place into
early next week as thermally induced low pressure continues to
expand northward across the interior for relatively quieter
conditions across area waters.
41
&&
.FIRE WEATHER...Continued onshore flow today will keep fire
weather concerns at a minimum. Warming trend beginning Monday,
with elevated fire weather concerns Tuesday through at least
Friday. Minimum relative humidity values dropping into the 20s
Tuesday and as low as the upper teens Wednesday and Thursday for
the Cascade Valleys and South Puget Sound with high
temperatures in the 90s. Fire weather concerns easing next
weekend with the return of low level onshore flow and cooler
daytime high temperatures. Felton
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 4 PM this afternoon to 2 AM PDT
Monday for Central U.S. Waters Strait Of Juan De Fuca-
East Entrance U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory from 4 PM this afternoon to 3 AM PDT
Monday 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.
&&
$$
NWS SEW Office Area Forecast Discussion