Marine Weather and Tide Forecast for Medina, WA

SYNOPSIS
A trio of frontal boundaries will continue to produce widespread precipitation this weekend across Western Washington. Rain with high snow levels will transition to snow in the Cascades above 3,000 feet later today as cool air sinks in behind one of the cold fronts moving through. Breezy conditions are also expected at times Saturday, primarily in the morning. Once the last front sweeps through Saturday into Sunday, conditions will dry out Monday and Tuesday before additional systems return middle of next week.

SHORT TERM /TODAY THROUGH MONDAY/
Plenty of precipitation is already on radar this morning (primarily along the coast and up to the Northwest Interior). Most of the precipitation bands have been light, but a couple heavier pockets have been observed. Gusty winds have also been observed in pockets of the region with the initial warm front scooting by to the north. Expectation is that the southerly wind gusts will have already peaked early this morning (widespread 35-40 mph gusts and a couple isolated higher gusts), and begin coming down to around 20 to 30 mph late this morning into Sunday morning.

Precipitation coverage will increase more throughout the morning and afternoon. This will primarily be stratiform in nature, with some convective pockets able to produce moderate to heavier rates of precipitation. Coverage will drop off to just the Cascades (convergence zone) going into late this afternoon and evening, with another round of scattered showers coming in with the third front later Saturday evening/Sunday morning, covering the whole region. The precipitation with this system will wrap up Sunday afternoon and evening (Cascades will be the last region to clear out).

In terms of precipitation totals, most of the QPF will fall on Saturday. Lowland areas will see around three quarters to just over an inch of rain. The Olympics and Pacific Coast will see 1 to 2 and half inches of QPF (heaviest over the Olympic Mountains), and the Cascades will be hit with generally 2 to 3 inches of QPF (locally higher amounts of 4 to 5 inches are possible at the highest peaks). For Sunday, lowlands and Pacific Coast will only see around a tenth to a quarter more inch of QPF, with the Olympics seeing half an inch to an inch, and the Cascades seeing an additional 1-2 more inches through the day.

Cold air will bring snow levels down later Saturday afternoon to around 3,000 feet. This will transition the rain in the Cascades and Olympics to snow, with the majority of the snow falling in the Cascades. There is a very low chance that freezing rain mixes in during the precipitation transition period late this morning (this would primarily concern areas east of Snoqualmie and Stevens Pass with trace amounts). Otherwise the main threat will be snow, with the heaviest of accumulations expected to be in the northern Cascades (9 to 15 inches total Saturday through Sunday). The South Central Cascades will still see around 6 to 10 inches of snow over the same time period. There will be the potential for convective snow bands able to produce heavier snowfall rates. This may also impact trips through the passes, so be sure to check road conditions before traveling.

With precipitation wrapping up Sunday, the concern will shift more to high surf along the Pacific Coast Sunday morning, due to seas building to 20 feet. resulting in breaker waves to the shoreline, and possible localized coastal shoreline erosion.

The low will depart the region late Sunday, with ridging to follow on Monday behind the low. This will dry out the entire region, with some nice weather to follow Monday and into Tuesday. Patchy fog will be possible (in the morning), and temperatures will cool back down into the low 30s for overnight temperatures (with highs in the 40s).

LONG TERM /TUESDAY THROUGH FRIDAY/
The upper level ridge pattern will continue with dry weather on Tuesday. Behind the ridge, there's disagreements in the operational and ensemble models on what will follow, but a majority of members agree on troughing returning in the second half of the week. This has resulted in increased precipitation chances going into this timeframe. Check back for more details as more is known getting closer to the middle of the week next week.

HPR

AVIATION
A pair of fronts will move through today and tonight.
Southwesterly flow aloft today will become northwesterly tonight.
Low level onshore flow will increase tonight behind second front.
MVFR ceilings with pockets of IFR will persist into Sunday morning.
Ceilings could briefly lift to VFR late this afternoon across central/south Puget Sound as a convergence zone develops near KPAE.

KSEA.. MVFR and tempo IFR ceilings with visibility 3-5sm in rain at times into this afternoon. Low end VFR is possible for a few hours late afternoon into the evening hours with convergence zone well north of the terminal. Ceilings lowering back down to MVFR overnight into Sunday morning as next front arrives. South wind 4 to 8 knots increasing to 10 to 15 knots this afternoon into Sunday morning.

Felton/27

MARINE
A pair of frontal systems will cross the waters in quick succession this morning and again tonight. Surface high pressure will rebuild across the waters Sunday afternoon and move inland Sunday night. The ridge will remain over the waters into Tuesday. Another front will reach the area Wednesday night.

Small craft advisory winds Central and Eastern Strait later today into tonight. Small craft advisory winds over portions of the coastal waters tonight and Sunday.

Seas around 10 feet today building to 14 to 19 feet tonight.
Seas subsiding to 12 to 14 feet Sunday night and to below 10 feet Monday.

Another round of small craft advisory winds possible with frontal system in the middle of next week along with seas in the coastal waters in the 10 to 14 foot range.

Felton

HYDROLOGY
Systems moving through the area today will bring significant precipitation to the area especially the mountains.
Snow levels climbing to 7000 to 9000 feet during the bulk of the heavier rain today. This combined with the heavier rainfall, will result in rises on rivers across the region. While the precipitation forecast continues to fluctuate a bit run to run, 2 to 3 inches of rainfall appears most likely result. However, high end potential amounts would reach into the 4 to 5 inch range across portions of the Olympics and the northern and central Cascades. As a result, a flood potential outlook (ESF) remains in effect for Whatcom, Skagit, and Snohomish counties. A Flood Watch remains in effect for Mason County for the Skokomish River.
Current forecast for the Skokomish has it cresting barely below flood stage Sunday morning. A brief period of drier conditions will allow for rivers to recede early next week, but another round of hydrologically significant precipitation may follow later next week.

Bower/Felton

CLIMATE
The rain held off at Seattle-Tacoma airport with just a trace of rain right before midnight last night. This means the first 6 days of December had no measurable rain in Seattle. How rare is this event? Very rare. In 80 years of records at Seattle- Tacoma airport this is only the 3rd time there has been no measurable precipitation in the first 6 days of December at the airport ( other years 1997 and 1984 ). The longest dry streak in December in Seattle is 21 days during the infamous fog ridge of December 1985 that made a mess of holiday travel. In December 1985 there was no measurable rain at Seattle-Tacoma airport December 8th through the 28th. For 13 days in a row, December 16th through the 28th, Seattle-Tacoma airport reported visibility of a 1/4 of a mile or less at some point during the day.

Felton

SEW WATCHES/WARNINGS/ADVISORIES
WA...Flood Watch from 4 PM PST this afternoon through Sunday evening for Hood Canal Area-Lower Chehalis Valley Area-Olympics.

Winter Storm Warning from 4 PM this afternoon to 4 PM PST Sunday for West Slopes North Cascades and Passes-West Slopes North Central Cascades and Passes.

Winter Weather Advisory from 4 PM this afternoon to 4 PM PST Sunday for West Slopes South Central Cascades and Passes.

PZ...Small Craft Advisory until 6 PM PST Sunday for Grays Harbor Bar- West Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until midnight PST tonight for Central U.S.
Waters Strait Of Juan De Fuca.

Small Craft Advisory from noon today to midnight PST tonight for East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 6 AM PST 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.