textproduct: Seattle/Tacoma

SYNOPSIS

Cold and cloudy conditions will continue into Tuesday under westerly flow aloft. A frontal system will cross the reigon on Wednesday, bringing breezy winds alongside lowland rain and mountain snow. Showers will linger over the mountains Thursday before drier and warmer conditions settle into western Washington over the weekend.

SHORT TERM /TODAY THROUGH WEDNESDAY NIGHT/

The morning fog and low stratus that blanketed the region has mostly burned off this afternoon, revealing mostly clear skies across western Washington. Zonal flow will develop by tonight as upper level flow turns more westerly, bringing in high clouds that will likely limit the extent of fog and low stratus early Tuesday morning. However, patchy fog is still possible, especially where cloud cover is thin, and confidence is low over the extent of fog in the morning. Upper level flow will turn southwesterly by Tuesday afternoon, with warmer air aloft allowing for high temperatures to warm a degree or two. Cloud cover will increase throughout the day as a trough approaches the coast.

A frontal system will cross western Washington on Wednesday, bringing in widespread lowland rain, mountain snow, and breezy winds. Winds will increase along the Pacific Coast and through the Strait of Juan de Fuca to Whidbey Island Wednesday morning, with max wind gusts in the ballpark of 35 to 45 mph. The lowlands will see steady rain, measuring up to a half inch, throughout the day Wedndesday, with lingering snow showers continuing over higher terrain Wednesday night. With snow levels around 3000-3500 feet, the mountains will see snow accumulations of around 3 to 6 inches.

LONG TERM /THURSDAY THROUGH SUNDAY/

The low pressure system will shift inland over Oregon on Thursday, with potential for wrap around moisture to continue light snow showers over the Cascades. Elsewhere, conditions are favored to dry out with some sun breaks in the afternoon.

An upper level ridge is then favored to build over the western US over the weekend, bringing warmer and drier conditions to western Washington. While a weather system may try to overrun the ridge, any precipitation is expected to remain north of the Canadian border. Mild conditions will prevail, with highs near 60 degrees across much of the lowlands on Saturday and Sunday.

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AVIATION

Westerly/northwesterly flow aloft this afternoon as a surface high pressure remains over western Washington. VFR conditions this afternoon as most of the fog has dissipated over the area. High clouds will stream in overhead this evening, into Tuesday, which will help limit fog development Tuesday morning. Most of the area likely staying VFR except fog prone spots such as OLM and PWT, where we could see a 15-20% of LIFR/IFR conditions Tuesday morning.

Northerly winds will increase this afternoon around 8 to 12 knots, easing tonight and into Tuesday.

KSEA...VFR conditions this afternoon. Northerly winds increasing around 8 to 12 knots and remaining throughout the evening. Winds slightly shifting to the NE and decreasing to 3 to 6 knots overnight and into Tuesday morning. VFR conditions throughout Tuesday morning.

Mazurkiewicz

MARINE

Surface high pressure over the coastal waters this afternoon for northerly winds. Light winds will continue over the area waters through Tuesday. A low pressure system will start to approach the waters Wednesday morning with increasing southerlies over much of the waters, with headlines likely needed in the next day for winds trending near small craft advisory strength. Winds will peak mid Wednesday afternoon for most of the waters, decreasing into Thursday.

Broad high pressure will redevelop on Thursday and into the end of the week, bringing generally benign marine conditions to the waters.

Coastal seas remaining 3 to 5 feet throughout Tuesday. Seas will then build up to 9 to 11 feet Wednesday morning. Seas will remain elevated into Thursday before decreasing on Friday and into the weekend, back down to 3 to 5 feet.

Mazurkiewicz

HYDROLOGY

No river flooding is expected over the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...None.