Sunrise 5:26 AM   Sunset 8:53 PM Moonrise 2:57 PM   Moonset 2:33 AM

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PZZ133 Northern Inland Waters Including The San Juan Islands- 221 Pm Pdt Sat May 18 2024
Tonight - SW wind 5 to 15 kt. Wind waves 2 ft or less. Sun - W wind to 10 kt in the morning becoming light. Wind waves 1 ft or less in the morning becoming less than 1 ft. Sun night - SW wind to 10 kt. Wind waves 1 ft or less. Mon - Light wind. Wind waves less than 1 ft. Mon night - SW wind to 10 kt becoming 5 to 15 kt after midnight. Wind waves 2 ft or less. Tue - S wind to 10 kt becoming 5 to 15 kt in the afternoon. Wind waves 2 ft or less. Tue night - SW wind to 10 kt. Wind waves 1 ft or less. Wed - W wind to 10 kt becoming sw. Wind waves 1 ft or less. Thu - S wind to 10 kt. Wind waves 1 ft or less.

PZZ100 221 Pm Pdt Sat May 18 2024
Synopsis for the northern and central washington coastal and inland waters - Broad surface ridging will remain centered well offshore with low pressure inland and will result in onshore flow for much of this weekend into early next week. A frontal system looks to traverse the area waters on Tuesday.

FXUS66 KSEW 181612 AFDSEW

Area Forecast Discussion National Weather Service Seattle WA 912 AM PDT Sat May 18 2024

SYNOPSIS
An upper level trough will produce cool and occasionally showery conditions across Western Washington today into early Sunday. The trough will move east of the region by Sunday afternoon and a weak upper level ridge will give drier and somewhat warmer conditions on Monday. Another trough will arrive on Tuesday for a return to cool and unsettled conditions for much of next week.

SHORT TERM /TODAY THROUGH MONDAY/
Radar shows scattered shower activity across the region this morning. Expect shower coverage to increase over the next few hours and for conditions to remain rather showery and cool today. The forecast remains on track. The previous discussion follows below, with updates made to the aviation and marine sections. 14

Early morning satellite imagery shows the next in a series of upper level troughs slipping down the British Columbia coast toward the region. Onshore flow will increase through the day as this system digs southward through the area. Shower coverage will increase later this morning...especially across the northern half of the CWA A convergence zone is likely to form by late morning then gradually drag southward across Puget Sound through the afternoon before dissipating in the Cascades late this evening.
High temperatures will be a good 5 to 10 degrees below normal.

The upper trough axis will shift east of the Cascades tonight and only a few remnant showers in the Cascades are expected by Sunday morning. Drier northerly flow aloft takes over Sunday afternoon and most lowland locations should see some afternoon sunshine...allowing high temperatures to nudge upward a few degrees. Weak upper ridging will move across the area on Monday and low level onshore flow will weaken. That spells drier and marginally warmer conditions...if only briefly.

LONG TERM /TUESDAY THROUGH FRIDAY/
By early Tuesday, the ridge gives way to yet another upper trough digging southward over British Columbia. We'll see a return to cool and wetter conditions on Tuesday. The QPF totals with this system look fairly robust by late May standards. Cool and showery conditions look to continue into Wednesday as the upper trough continues to progress southeastward across the Pacific Northwest. The forecast details become more uncertain late next week. In general, ensembles maintain negative height anomalies over the western third of the lower 48 with strong ridging centered over the Gulf of Alaska.
But there are considerable differences amongst ensemble members with the placement and depth of the trough over the Western US.
Current forecast from the NBM have mostly chance PoPs and temps a little below average late next week. This seems like a reasonable forecast until the overall picture becomes clearer. 27

AVIATION
West/northwesterly flow aloft today as an upper level trough moves through the region. Ceilings between VFR and MVFR this morning with a broken low-level cloud deck. Ceilings look to rise for most to low-end VFR as cloud cover remains broken with scattered showers developing this afternoon. Ceilings will be locally lower at times, especially around the convergence zone. A lightning strike or two cannot be ruled out this afternoon. Showers will then taper off this evening. MVFR ceilings look to redevelop overnight tonight as the low-level airmass remains moist and light onshore flow persists.

KSEA...MVFR conditions this morning with light showers in the vicinity. Breaks to low-end VFR possible this afternoon and tonight, however locally lower under scattered showers. Better chance at redeveloping MVFR CIGs after 12Z Sunday. S winds shifting to light N/ around 21z then back to S by 06z tonight.

LH

MARINE
High pressure over the NE Pacific will maintain onshore flow across western WA through the weekend. Strongest winds will be over the Strait of Juan de Fuca with Small Craft Advisory winds extending through late tonight. The next frontal system will reach the region early next week.

Seas around 6 ft through most of the forecast period, through the frontal system on Tuesday may raise seas and be steeper.

33/LH

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

SEW WATCHES/WARNINGS/ADVISORIES
WA...None.
PZ...Small Craft Advisory until 5 AM PDT Sunday for Central U.S.
Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.

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Roche Harbor
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Sat -- 02:12 AM PDT     7.11 feet High Tide
Sat -- 03:33 AM PDT     Moonset
Sat -- 05:27 AM PDT     Sunrise
Sat -- 09:20 AM PDT     2.07 feet Low Tide
Sat -- 03:18 PM PDT     4.77 feet High Tide
Sat -- 03:56 PM PDT     Moonrise
Sat -- 08:13 PM PDT     3.21 feet Low Tide
Sat -- 08:51 PM PDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION

Roche Harbor, San Juan Island, Washington, Tide feet

Limestone Point
Click for MapFlood direction 85° true
Ebb direction 283° true

Sat -- 01:09 AM PDT     -0.00 knots Slack
Sat -- 03:33 AM PDT     Moonset
Sat -- 05:26 AM PDT     Sunrise
Sat -- 05:57 AM PDT     -3.25 knots Max Ebb
Sat -- 09:31 AM PDT     0.00 knots Slack
Sat -- 11:51 AM PDT     1.44 knots Max Flood
Sat -- 02:12 PM PDT     -0.00 knots Slack
Sat -- 03:56 PM PDT     Moonrise
Sat -- 06:14 PM PDT     -1.75 knots Max Ebb
Sat -- 08:51 PM PDT     Sunset
Sat -- 09:04 PM PDT     0.00 knots Slack
Sat -- 11:27 PM PDT     1.46 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION

Limestone Point, Spieden Channel, Washington Current, knots

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