Marine Weather Net

West Entrance U.S. Waters Strait of Juan de Fuca Marine Forecast


TONIGHT

S
WINDS
15 - 25
KNOTS

WED

SW
WINDS
20 - 30
KNOTS

WED NIGHT

SW
WINDS
5 - 15
KNOTS

THU

SW
WINDS
5 - 15
KNOTS

The Marine Weather Forecast In Detail:
PZZ130 Forecast Issued: 333 PM PST Tue Feb 27 2024

SMALL CRAFT ADVISORY IN EFFECT THROUGH WEDNESDAY AFTERNOON
Tonight...S Wind 15 To 25 Kt. Wind Waves 2 To 4 Ft. W Swell 5 Ft At 10 Seconds.
Wed...Sw Wind 20 To 30 Kt. Wind Waves 3 To 5 Ft. W Swell 6 Ft At 10 Seconds.
Wed Night...Sw Wind 5 To 15 Kt. Wind Waves 2 Ft Or Less. W Swell 7 Ft At 10 Seconds.
Thu...Sw Wind 5 To 15 Kt Becoming S 10 To 20 Kt In The Afternoon. Wind Waves 1 To 3 Ft. W Swell 8 Ft At 13 Seconds.
Thu Night...S Wind 15 To 20 Kt Becoming Se 15 To 25 Kt After Midnight. Wind Waves 2 To 4 Ft. W Swell 8 Ft At 13 Seconds.
Fri...S Wind 15 To 25 Kt. Wind Waves 2 To 4 Ft. W Swell 9 Ft At 15 Seconds.
Fri Night...E Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 10 Ft At 14 Seconds.
Sat...Se Wind To 10 Kt. Wind Waves 1 Ft Or Less. W Swell 7 To 8 Ft Subsiding To 5 To 6 Ft.
Sun...Se Wind To 10 Kt. Wind Waves 1 Ft Or Less. W Swell 4 To 5 Ft Building To 6 Ft.
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Area Forecast Discussion
National Weather Service Seattle WA
955am PST Tuesday Feb 27 2024

Synopsis
Much colder air will continue to push eastward into the region this morning as conditions dry out. An atmospheric river pattern will develop later on Tuesday as a trough deepens offshore, bringing in heavy mountain snow, heavy lowland rain, and strong winds. Active and wet conditions will continue through the end of the week as a series of fronts cross the region.

* HEAVY SNOW: High confidence that another storm system will bring in significant snowfall to the mountains Tuesday afternoon through Thursday morning, with preliminary snowfall totals of 1 to 3 feet over the Olympics and 2 to 4 ft, with locally higher amounts possible over the Cascades.

* WIND: Strong winds will develop on Wednesday, with gusts reaching 40 to 45 mph across the lowlands and up to 50 mph through the mountain passes.

Short Term - Today through Thursday
Convergence zone snowfall has largely tapered off over Snohomish and Island counties, allowing the Winter Weather Advisory for those regions to expire. As of 900 AM, radar and surface analysis show the warm front approaching the region from the west, with light rain being reported along the coast as it makes its way inland.

An atmospheric river pattern will is beginning to develop over the Pacific Northwest now and will continue throughout the day today as a low centered over the Gulf of Alaska deepens southward. A surface front will lift northeastward across the region this afternoon as precipitation spreads inland. Strong southerly flow at the surface will develop and allow temperatures to increase, with snow levels rising above 2000-3000 ft by Tuesday evening for most areas. Strong westerly flow aloft may initially cause rain shadowing across the Puget Sound lowlands, but moderate rainfall will fill in across the lowlands by the evening.

Snow chances this afternoon into early tonight:

There is a chance for some light accumulations along the eastern slopes of the Olympics up against the west side of Hood Canal for some light snow accumulations, with a 20-30% chance of up to an inch of snow this afternoon into early tonight. Temperatures are still below freezing in Bremerton and cold air could remain trapped in this region which may promote some light snow accumulations as the warm front works its way northward before switching to all rain.

Areas along the North Interior will be the last to see the incoming warm front this evening. Colder conditions at the surface paired with incoming warmer air aloft may generate conditions conducive to light snow, with 50-70% probabilities of up to an inch of snow, with accumulations highest along the Canadian border. There is a low (20-30%) chance for some light freezing rain if the cold air hangs on longer than expected.

The storm system will stall along the Washington Coast and amplify southward on Wednesday, spreading a series of fronts across the Pacific Northwest. Widespread precipitation will continue and intensify as the system pulls in deep moisture from the Pacific, with periods of heavy lowland rain and heavy mountain snow. Rising snow levels up to 4500 ft on Wednesday may create some hydrologic impacts to rivers in the Southwest Interior. South to southwest winds will also pick up across western Washington, gusting up to 40 mph across most lowland locations and up to 50 mph across the mountain passes Wednesday afternoon and evening. These conditions may make for some periods of hazardous travel and reduced visibilities over the passes. However, sustained winds will likely be too low on Wednesday to fully reach blizzard criteria.

The storm system will continue to slowly deepen southward along the Pacific Coast into Thursday morning, sliding a cold front across western Washington and pushing the axis of heaviest precipitation southward. The low pressure center will station west of Vancouver Island, maintaining wet conditions across the Pacific Northwest, but precipitation and winds will begin to ease up on Thursday as conditions destabilize and become more convectively driven. Models indicate 200-300 J/kg over the coast Thursday. A few thunderstorms cannot be ruled out on Thursday, in particular over the coastal waters and along the immediate coast.

In total, preliminary precipitation totals between Tuesday and Thursday remain steady compared to this morning's forecast, with 2 to 4 feet of snowfall over the Cascades and 1 to 3 ft in the Olympics. The lowlands are on track to see between 1 and 3 inches of rain during this period, with the heaviest rainfall along the coast and through the Southwest Interior.

Lindeman/LH

Long Term - Friday Through Monday
A deep trough over the West will keep us cool and showery moving into Friday and the weekend. Temperatures will continue to track below average with highs in the 40s and lows in the 30s. We'll see additional threats for lowland rain/snow mix during the late overnight and early morning hours although significant/widespread snow accumulations are not expected with mainly light/spotty precipitation.

Marine
Latest observations continue to indicate seas over the coastal waters hovering near 10 feet, so have issued a Small Craft Advisory for Grays Harbor Bar through this afternoon. Seas may then subside to 7 to 9 feet by this evening, before increasing again ahead of the next system. The remainder of the previous marine discussion follows below.

Brief break in the action over area waters this morning, however winds associated with next incoming frontal system will ramp up late this morning/early this afternoon. As such, SCAs (Small Craft Advisories) posted for all waters except Puget Sound late this morning and throughout the afternoon. The Sound joins in on the action this evening. Evening and into Wednesday may see occasional gale-level winds in the Strait as well as the adjacent waters...however, confidence not quite there for any gale watch/warning. As the situation progresses, in-situ obs will likely inform any decision to upgrade if needs be. However, confidence is there for gales in the coastal waters throughout the day Wednesday. That will be a new headline for the morning forecast issuance.

Seas generally hovering at 10 feet this morning and may diminish a little bit more throughout the day before rising again in anticipation of next incoming system. Seas may remain elevated to 15 feet or higher by late week in the wake of the active weather.

18/14

Hydrology
A strong frontal system will translate over south- central British Columbia Tuesday night through Wednesday night bringing a wide swath of moderate to heavy rainfall across western Washington. Snow levels will quickly rise from below 1000 feet Tuesday to near 4500 feet Wednesday as a warm front lifts northward across southwestern Washington, leading to a transition to primarily rainfall over the Olympics and the central and southern Washington Cascades on Wednesday. Rainfall totals of 3 to 5 inches are possible across these areas with 1 to 3 inches across the lowlands. There will likely be low to mid elevation snow melt but since there are few observations, tracking that is difficult. With wet antecedent conditions, this will lead to rapid rises on area streams and rivers Wednesday into Wednesday night. How fast the snow level rises in relation to the heavy precipitation will have a major effect on the degree of runoff and any flooding. At this time, the Skokomish River at Potlatch is the only river forecast to enter Flood Stage Wednesday afternoon, though many other rivers across southwestern Washington have the potential for flooding given the right combination of factors.

Davis/JBB

NOAA Seattle WA Office: Watches - Warnings - Advisories
WA...Winter Storm Warning from 4pm this afternoon to 4pm PST Thursday for Olympics-West Slopes North Cascades and Passes- West Slopes North Central Cascades and Passes-West Slopes South Central Cascades and Passes.

PZ...Small Craft Advisory until 7pm PST this evening for
Grays Harbor Bar

Small Craft Advisory until 4pm PST Wednesday for
Central U.S. Waters Strait Of Juan De Fuca-
East Entrance U.S. Waters Strait Of Juan De Fuca-
West Entrance USA Waters Strait Of Juan De Fuca.

Small Craft Advisory until 10pm PST Wednesday for
Admiralty Inlet
Northern Inland Waters Including The San Juan Islands.

Small Craft Advisory from 4pm this afternoon to 10pm PST Wednesday for
Puget Sound and Hood Canal

Small Craft Advisory until 4am PST Wednesday 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.

Gale Watch from late tonight through Wednesday 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.