Marine Weather Net

James Island to Point Grenville WA out 10 to 60 NM Marine Forecast


TODAY

NW
WINDS
15 - 20
KNOTS

TONIGHT

NW
WINDS
15 - 20
KNOTS

WED

N
WINDS
TO 10
KNOTS

WED NIGHT

N
WINDS
5 - 15
KNOTS

The Marine Weather Forecast In Detail:
PZZ173 Forecast Issued: 810 AM PDT Tue Apr 16 2024

SMALL CRAFT ADVISORY IN EFFECT UNTIL 5 PM PDT THIS AFTERNOON
Today...Nw Wind 15 To 20 Kt. Wind Waves 2 To 3 Ft. Nw Swell 7 To 9 Ft At 8 Seconds Subsiding To 6 To 7 Ft At 8 Seconds In The Afternoon.
Tonight...Nw Wind 15 To 20 Kt Easing To 5 To 15 Kt After Midnight. Wind Waves 1 To 3 Ft. Nw Swell 7 Ft At 8 Seconds.
Wed...N Wind To 10 Kt. Wind Waves 1 To 2 Ft. Nw Swell 5 Ft At 8 Seconds.
Wed Night...N Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. Nw Swell 5 Ft At 9 Seconds.
Thu...Ne Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 3 Ft At 10 Seconds.
Thu Night...Ne Wind 5 To 15 Kt. Wind Waves 1 To 3 Ft. W Swell 3 Ft At 17 Seconds.
Fri...E Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 3 Ft.
Sat...Se Wind 5 To 15 Kt Becoming W. Wind Waves 2 To 3 Ft. S Swell 2 To 3 Ft Building To W 7 To 8 Ft.
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Area Forecast Discussion
National Weather Service Seattle WA
902am PDT Tuesday April 16 2024

No changes to the overall forecast this morning. Please see the aviation and marine sections below for updates to those forecasts.

/issued 401am PDT Tuesday April 16 2024/

Synopsis
Cool upper level trough over the area today will move east tonight. High amplitude upper level ridge building offshore extending into Northern British Columbia tonight and Wednesday. Weak upper level trough swinging down the backside of the ridge moving through Thursday. Upper level ridge building over Western Washington Friday will move east Saturday as a weakening front moves through the area. Another ridge will build into the Pacific Northwest Sunday into the first part of next week.

Short Term - Today through Thursday
Satellite imagery shows cool upper level trough over the area this morning. Doppler radar indicating a convergence zone over Northern King county with isolated showers over the remainder of the area. Temperatures at 4 am/11z were in the upper 30s to mid 40s.

Trough weakening as it remains over Western Washington today. Convergence zone staying intact this morning before dissipating this afternoon. The zone will wobble around between the northern half of King county and the southern half of Snohomish county. Scattered showers with the convergence zone with just isolated shower activity outside of the zone. With the trough overhead temperatures will remain cool with highs mostly in the lower to mid 50s.

Trough moving east tonight with little shower activity there is left with the trough wrapping up in the evening hours. Skies clearing a bit with an upper level ridge building offshore. Air mass aloft still cool and with little wind in the lower levels good chance we will see freezing low temperatures in the Southwest Interior, southern end of the Hood Canal and into the Lower Chehalis Valley. Have issued a frost advisory for Wednesday morning between 2 and 9 am. Lows in the 30s.

Upper level ridge continuing to build offshore into Northern British Columbia with dry north northwesterly flow aloft over the area. Temperatures warming after a cool start with highs a couple of degrees either side of 60.

Ridge remaining in place Wednesday night. Weak and fairly dry upper level trough moving down the backside of the ridge into Western Washington Thursday. Low level flow turning weakly offshore Thursday pushing high temperatures mostly into the 60s. Lows Thursday morning in the 30s and lower 40s.

Long Term - Friday Through Monday
Extended models in good agreement with upper level ridge rebuilding over Western Washington Friday. Low level flow still weak offshore. Friday looks to be the warmest day of the forecast period with highs in the 60s and the warmer locations near 70. Ridge shifts east Friday night into Saturday allowing a weakening front to move through by Saturday night. Not much left of this system by the time it reaches Western Washington so will just have chance probability of precipitation Saturday afternoon and Saturday night. Surface and upper level ridge building behind the front Sunday. Low level flow switching to onshore behind the front will result in cooler high temperatures Sunday, near 60. A little warmer Monday as the ridge continues to build and the low level flow turns offshore with highs in the

Marine
Northwesterly winds and onshore flow will continue today and into Wednesday as a surface high pressure ridge continues to work its way towards the coastal waters. Winds will turn offshore on Friday as a thermal trough develops along the coast. Relatively calm winds expected through the rest of the week. The next frontal system will traverse the region on Saturday.

Steep seas will continue through today with seas 6 to 8 ft at around 8 seconds, for which there is a Small Craft Advisory for the coastal waters and the West Entrance to the Strait of Juan de Fuca. Seas will ease tomorrow to 4 to 6 ft early tomorrow and will continue through the end of the week.

LH

Hydrology
No river flooding expected in the next 7 days.

NOAA Seattle WA Office: Watches - Warnings - Advisories
WA...Frost Advisory from 2am to 9am PDT Wednesday for Hood Canal Area-Lower Chehalis Valley Area-Southwest Interior.

PZ...Small Craft Advisory until 5pm PDT this afternoon 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-
West Entrance USA Waters Strait Of Juan De Fuca.