textproduct: Seattle/Tacoma

SYNOPSIS

Dry conditions will persist through at least the first half of Tuesday. Chances for low elevation rain and mountain snow will increase through the day Tuesday, then moderate precipitation is expected to persist Wednesday through Friday. Isolated flooding cannot be ruled out, mainly for rivers of the Olympic Peninsula. Precipitation will slowly diminish this weekend and drier conditions are favored again by early next week.

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/

Quiet conditions with mostly cloudy skies remain in place this afternoon across the region. The ridge axis will finally move east of the area on Tuesday, opening the door for precipitation to move into the area.

Initially, this will come in the form of light lowland rain and mountain snow Tuesday and Tuesday night. With cold air near the Cascade crest, a brief period of freezing rain cannot be ruled out across the mountain passes. REFS guidance indicates between a 20-40 percent chance. However, by mid-day Wednesday, it's expected that conditions will warm up enough to bring an end to that threat.

More widespread precipitation is expected Wednesday through Friday. Snow levels will be rising from 3500-4000 feet initially on up to around 5000-6000 feet by Wednesday night and eventually to between 6000-7000 feet Friday. The bulk of the precipitation will be focused along the Olympic Peninsula, but wet conditions are expected area-wide. See the HYDROLOGY section for more details on the flood potential.

This active weather will also result in breezy to locally windy conditions, mainly for the coast and the areas from Island County northward. Winds over the Pacific and a storm system well off the coast will also generate waves that could approach 20 feet late Wednesday into Thursday which could bring waves flirting with high surf advisory levels.

LONG TERM /SATURDAY THROUGH MONDAY/

By the weekend, things will begin to wind down a bit. Chances for precipitation will persist but the overall intensity will decrease. The main item of note this weekend will be rising astronomical tides, which may flirt with minor flood thresholds for the Puget Sound and Salish Sea on at least Saturday and Sunday. That said, MSLP will remain fairly high and winds will be lower, decreasing the risk of a significant flood event.

As we move into next week, the overall pattern begins to favor ridging again, likely resulting in drier conditions once again. -Wolcott-

AVIATION

An upper level ridge will build back into Western Washington briefly into Tuesday morning for west flow aloft before transitioning more southwesterly on Tuesday. VFR mid and high clouds will continue at times through Tuesday. MVFR stratus along the coast into tonight will improve to VFR Tuesday AM before a return of lower stratus Tuesday afternoon. Fog development tonight will be limited due to high cloud cover, but localized fog may develop, mainly OLM southwards. E/SE surface winds through Tuesday will increase along the coast Tuesday afternoon.

KSEA...VFR through the TAF period with continued mid and high clouds. Light S/SE surface winds into Tuesday, mainly under 6 kts. JD

MARINE

Southeast winds will increase, especially along the Coastal Waters tonight, and remain elevated through Wednesday morning, due to a front moving across the area. A Gale Warning has been issued for the outer Coastal Waters on Tuesday due to higher confidence in gale force wind gusts. Small Craft Advisories are in effect for the inner Coastal Waters and western Strait of Juan de Fuca. Winds will increase for the interior waters Tuesday night, and a Gale Watch is in effect for the eastern Strait of Juan de Fuca. A stronger system will move through the waters again Wednesday into early Thursday, resulting in additional headlines likely necessary, including gales for portions of the waters. The active pattern continues with a front again late in the week.

Seas of 4 to 7 feet tonight will build to 10 to 15 feet Tuesday night. Seas will then continue to build towards 15 to 20 feet late Wednesday through Thursday, with seas near 15 ft continuing into late week with the active pattern. JD

HYDROLOGY

Moderate precipitation is expected to impact the region Wednesday through Friday with snow levels rising to 6000-7000 feet. The bulk of the precipitation is expected to impact the Olympic Peninsula. The Skokomish River in Mason County is expected to reach minor flood stage by Thursday morning and will remain elevated there through late this week and perhaps into the weekend. Other rivers originating from the Olympics will need to be monitored, including the Bogachiel. For rivers coming from the Cascades, the flood threat is relatively low. It would generally take precipitation near the 90th percentile range to generate flooding in these areas. In other words, it cannot yet be ruled out completely.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory from 4 PM this afternoon to 10 PM PST Tuesday for Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm.

Small Craft Advisory from 4 PM this afternoon to 4 AM PST Tuesday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.

Gale Watch from late tonight through Tuesday evening for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.