textproduct: Seattle/Tacoma

SYNOPSIS

Dry conditions will continue the remainder of the evening. A weak system will brush the region tonight, bringing chances of light rain to the area early Tuesday. The pattern introduces more active weather mid to late week as a series of systems brings lowland rain, mountain snow, gusty winds, and the potential for high surf to western Washington. A brief break in the unsettled weather is possible Friday night into Saturday, before the next round of active weather moves in late in the weekend into the first half of next week.

SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/

An upper level ridge will continue to push inland western Washington this afternoon with dry conditions expected the remainder of the day. A cloudy day with high temperatures in the low to mid 50s across much of the area. A weak system will brush over the region tonight into Tuesday, bringing a small chance of showers. The areas that may receive showers would be locations along the coast, the Olympics, and perhaps the Northwest Interior. Elsewhere, conditions should remain dry throughout the day on Tuesday. High temperatures will be a touch warmer in the upper 50s, maybe low 60s for areas in the Southwest Interior.

The weather pattern will shift to more active, with a series of weather systems starting to approach the area starting on Wednesday. A frontal system looks to move over the area Wednesday afternoon, bringing widespread rain and high elevation snow. Most of the rain activity will be focused in along the coast, Olympics, and the North Cascades with these areas seeing perhaps a half of inch of rain. Locations in the interior will likely get rain shadowed and may see a shower or two, especially areas like the Puget Sound. Snow levels will be generally around 5000 to 5500, with moisture bringing a few inches of snow in the higher peaks of the Olympics and Cascades. Heading into Wednesday evening, we will also see an uptick in southerly winds, primarily along the Pacific coast, with gusts around 25 to 35 mph. Locations in the interior could see gust up to 25 mph at times through the evening. Wind and precipitation will begin to slowly decrease heading into Thursday morning. Temps on Wednesday staying in the mid to upper 50s.

Mazurkiewicz

LONG TERM /THURSDAY THROUGH MONDAY/

Ensemble guidance continues to favor a brief lull on Thursday before the more active pattern takes hold over the region late Thursday into Friday. This is shaping up to potentially bring a strong frontal system with multiple hazards including gusty winds, lowland rain, and high elevation snow, as well as high surf for the Pacific coastline. Snow levels around 5000 ft will support heavy snow across the higher mountain elevations, with 1-2 inches of rain in the lower mountain elevations. In addition, probabilistic guidance continues to indicate around a 50% chance of 40 mph or stronger wind gusts along the coast and areas from Whidbey Island northward. High surf potential also increases as a large, long period swell moves through the waters to the coastline, bringing risks for beach erosion and hazardous conditions along beaches and jetties.

Guidance begins to depict a wider range of potential outcomes toward the weekend, but these are largely centered around differences in timing of subsequent systems. If the upper ridge builds a bit more, this would direct more of the moisture into the B.C. coast. However, any ridge looks to be rather transient, allowing the next surge of moisture to return to the region by the end of the weekend. In any event, it's clear that we're entering into a more active period of weather late this week through the start of next week. Cullen

AVIATION

VFR conditions at all terminals this afternoon as a weak front spreads high clouds across most of the region. As high clouds continue to filter in, this will help limit any fog development tonight into Tuesday morning, with most area terminals remaining VFR throughout the period. The only exception being KOLM, KPWT, and KBLI where localized MVFR low clouds/fog could form at the lower prone terminal. Light winds this afternoon with some areas seeing a N/NE direction. Winds will tilt more NE overnight with speeds around 3 to 6 knots.

KSEA...VFR conditions this afternoon with high OVC clouds over the terminal. Expect this trend to continue overnight, with cloud cover limiting any fog development. VFR will continue through Tuesday morning. Variable winds turning more NE overnight, with speeds remaining light.

Mazurkiewicz

MARINE

The primary marine issue remains the larger seas associated with the long period swell working through the coastal waters. Seas will remain around 10 feet, largest over the outer zones through tonight. Otherwise, attention turns to a shift to a much more active pattern around midweek and especially into the late portions of the week. Expect widespread advisory winds across the coastal waters with probabilities greater than 75% at this point. Seas will also build late Wednesday into Thursday over the coastal waters, reaching around 12 to 14 ft. A stronger frontal system Friday will bring widespread advisory winds and around a 35% chance of gales to the coastal waters and the eastern Strait of Juan de Fuca. Expect seas to build more significantly with this system, bringing around a 20- 30% chance of 20 ft seas over the coastal waters. Additional frontal systems may follow this weekend, maintaining an active pattern into the start of next week. Cullen

HYDROLOGY

River flooding is not expected through the next seven days. However, a series of increasingly moist weather systems will begin to bring rain (and high mountain snow) to the region this week, especially Friday onward. While current forecasts are not expected to cause flooding, this will begin to saturate soils and raise base flows that could bring a concern with subsequent storms systems.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory until 1 AM PST Tuesday 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-West Entrance U.S. Waters Strait Of Juan De Fuca.