Marine Weather Net

Cape Flattery to James Island WA out 10 NM Marine Forecast


TODAY

W
WINDS
15 - 25
KNOTS

TONIGHT

W
WINDS
5 - 15
KNOTS

TUE

S
WINDS
TO 10
KNOTS

TUE NIGHT

SW
WINDS
TO 10
KNOTS

The Marine Weather Forecast In Detail:
PZZ150 Forecast Issued: 232 AM PDT Mon May 16 2022

SMALL CRAFT ADVISORY IN EFFECT UNTIL 11 AM PDT THIS MORNING
Today...W Wind 15 To 25 Kt Easing To 10 To 20 Kt In The Afternoon. Wind Waves 2 To 4 Ft. Sw Swell 5 Ft At 8 Seconds. A Chance Of Showers.
Tonight...W Wind 5 To 15 Kt Becoming To 10 Kt After Midnight. Wind Waves 2 Ft Or Less. Sw Swell 5 Ft At 9 Seconds.
Tue...S Wind To 10 Kt. Wind Waves 1 Ft Or Less. W Swell 4 Ft At 9 Seconds Building To 6 Ft At 9 Seconds In The Afternoon.
Tue Night...Sw Wind To 10 Kt Becoming S 20 To 30 Kt After Midnight. Wind Waves 1 Ft Or Less Building To 4 To 6 Ft After Midnight. W Swell 5 Ft At 9 Seconds.
Wed...S Wind 30 To 40 Kt Becoming Sw 25 To 35 Kt In The Afternoon. Combined Seas 9 To 12 Ft With A Dominant Period Of 13 Seconds.
Wed Night...W Wind 20 To 30 Kt Easing To 15 To 25 Kt After Midnight. Wind Waves 3 To 6 Ft. W Swell 9 Ft At 11 Seconds.
Thu...W Wind 15 To 25 Kt Easing To 5 To 15 Kt. Wind Waves 2 To 4 Ft Subsiding To 2 Ft Or Less. W Swell 8 Ft Subsiding To 6 Ft.
Fri...Light Wind Becoming Nw To 10 Kt. Wind Waves 1 Ft Or Less. W Swell 6 Ft Subsiding To 4 Ft.
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Area Forecast Discussion
National Weather Service Seattle WA
348am PDT Monday May 16 2022

Synopsis
Upper level trough offshore today weakening tonight and Tuesday. Potential strong for May front moving through Wednesday with locally windy conditions and heavy snow above 4000 feet in the mountains. Cool upper level trough Thursday followed by a weak upper level ridge Friday. Next system arriving over the weekend.

Short Term - Today through Wednesday
Satellite imagery shows broad upper level trough offshore with cloudy skies over Western Washington at 3 pm/10z. Doppler radar picking up widely scattered showers with most of the activity along the coast and over the mountains. Temperatures were in the lower to mid 50s.

Upper level trough remaining offshore today. Nothing organized spinning out of the trough over Western Washington but the combination of low level onshore flow and southwesterly flow aloft will keep the slightly unstable air mass moist enough to produce some showers. Shower activity mostly over the mountains and in a convergence zone over Snohomish and Skagit county by later this afternoon. Cloudy skies for the most part keeping highs only a few degrees warmer than the current temperatures, in the mid 50s to lower 60s.

Trough weakening tonight into Tuesday with shower activity ending early this evening. Weak low level onshore flow and moist west southwesterly flow aloft will keep skies partly to mostly cloudy overnight into Tuesday. With some breaks in the cloud cover lows over the Southwest Interior getting down to the mid to upper 30s. Most of the remainder of the area in the lower to mid 40s. Highs Tuesday once again in the mid 50s to lower 60s.

Models a little faster with the next system with rain out ahead of the front reaching the coast by early Wednesday morning with a chance of rain inland. Lows in the mid 40s.

Rain spreading over the entire area Wednesday morning. Models still having trouble with the intensity of the front Wednesday. ECMWF (European Centre for Medium-Range Weather Forecasts) still stronger than the GFS taking a weakening 1000 mb low over the north end of Vancouver Island midday. The GFS has the surface low near Haida Gwaii at the same time. Ensemble solutions off the ECMWF have the mean max gusts near 40 mph in Seattle, mid 40s in Bellingham and lower 50s mph at Forks. Not very May like. The GFS ensemble means are in the 20 to 30 mph range. Operational MM5 a little stronger than the GFS ensemble mean. Forecast right now leaning toward the stronger solutions. It's certainly possible we will need wind advisories for the North Coast and the Northwest Interior Wednesday. In addition to the surface winds good orographics will produce significant precipitation in the mountains. Snow levels at this time look to be in the 4000-4500 foot range. 12 to 18 inches of new snow possible at Mount Baker and at Paradise on Mount Rainier by the end of the day Wednesday. Strong convergence zone over Snohomish county Wednesday night behind the front. Highs in the lower to mid 50s.

Long Term - Thursday Through Sunday
Models in good agreement Thursday with cool upper level trough moving through the area keeping showers in the forecast. Weak upper level ridge building offshore Friday for a dry day. Model solutions start to differ over the weekend with the ECMWF bringing a warm front into the area Saturday while the GFS holds this feature off into Sunday. Model ensemble solutions support the operational runs. Will go with a broadbrush chance of rain for the weekend. High

Marine
Onshore flow today will ease on Tuesday with small craft advisory strength westerly winds ending later today or tonight. A vigorous frontal system will move through the area Tuesday night and Wednesday. Gales are likely for the Coastal Waters, entrances to the Strait, and Northern Inland Waters. Seas over the Coastal Waters could build to around 10 feet Wednesday and Thursday. Moderate to strong onshore flow behind this frontal system will gradually ease Thursday and Friday. 16

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

.CLIMATE...Seattle monthly May rain total through the 15th at 2.94 inches. With over half the month to go this is already the 13th wettest May in 78 years of records at Sea-Tac. After Wednesday should be in the top 10 ( current 10th wettest 3.07 inches in 1961, 5th wettest 3.32 inches in 2005 ). The record wettest May 4.76 inches in 1948. The second wettest 3.70 inches in 1977. The yearly rain total for Seattle is up to 21.35 inches, 3.48 inches above normal. The normal yearly rainfall total on August 19th is

NOAA Seattle WA Office: Watches - Warnings - Advisories
WA...None. PZ...Small Craft Advisory until 11am PDT this morning 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.

Small Craft Advisory until 5am PDT Tuesday for
Central U.S. Waters Strait Of Juan De Fuca-
East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 11pm PDT this evening for
Northern Inland Waters Including The San Juan Islands.

Small Craft Advisory until 5pm PDT this afternoon for
Puget Sound and Hood Canal