textproduct: Seattle/Tacoma

SYNOPSIS

Warm and dry conditions will continue today. Wet and cooler conditions expected this weekend. A weak ridge will build over the region on Monday. A stronger frontal system midweek will bring lowland rain, mountain snow, and breezy winds.

SHORT TERM /TODAY THROUGH SUNDAY/

A weak upper level ridge will remain in place through today. Cloud cover will increase throughout the day as moisture from an upper level low moving through California moves northward into Western Washington. Dry and warm conditions today; however, light isolated showers may lift northwards across the region today. Temperatures today will peak in the low 60s along the coast and upper 60s/low 70s in the interior.

An upper level low will move southwards from the Gulf of Alaska today and impact California this weekend. As this system slowly pushes across the Golden State, rain will lift north and bring unsettled conditions back to Western Washington. Precipitation amounts with this system are expected to be light, with most places seeing 0.10-0.25 inches across the lowlands and up to 0.50 inches in the mountains. In addition, this system will bring slightly cooler daytime temperatures. High temperatures will peak in the 50s this weekend.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

A weak transient upper level ridge will be in place on Monday. The ridge will quickly weaken as an upper level trough approaches Western Washington on Tuesday. The stronger system will move over the region on Wednesday, which will be accompanied by wet and cooler conditions. Lower snow levels will bring light to moderate snowfall to the mountains and passes. Guidance hints at below normal temperatures late next week, which may result in frost.

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AVIATION

Southerly flow aloft continues through today with an upper low located offshore of California. High clouds will increase through this afternoon with south flow aloft, but VFR conditions will prevail into this evening. Cigs will slowly lower tonight into Saturday morning into MVFR as showers begin to arrive after 06 Saturday. Winds will remain light, mainly under 5 kts, for most sites through today, before increasing from the south early Saturday.

KSEA...VFR conditions into tonight. High clouds will increase through today. Cigs are expected to lower into MVFR Saturday morning, with a 50-60% probability of MVFR cigs by 18z Saturday. Showers will also begin to arrive after 06z tonight. North winds around 4 to 7 kts are expected to transition more W/NW this afternoon, mainly under 6 kts. Winds will become more S/SW late tonight into Saturday. JD

MARINE

Northerly flow will continue over the waters today. High pressure over the area will continue to weaken today as a low pressure system swings south from the Gulf of Alaska to the west of the coastal waters. No significant impacts expected from this system.

High pressure will rebuild over the NE Pacific this weekend, while lower pressure remains situated inland, resulting in onshore flow. Periods of diurnal westerly pushes are expected through the Strait of Juan de Fuca this weekend through into early next week. Guidance is hinting that the strongest push through the Strait of Juan de Fuca will be Monday night into Tuesday. Confidence continues to increase for small craft winds through the central portion of the Strait. Current probabilities are around 50-80%. A frontal system will traverse area waters late Tuesday into Wednesday. Guidance continues to highlight increased winds for the coastal waters and portions of the Strait of Juan de Fuca. Current probabilities of small craft winds for the coastal waters are 50-70% and 50-90% for the Strait of Juan de Fuca. There is a small chance (20-30%) for gales through the central portion of the Strait of Juan de Fuca Tuesd.ay evening.

Seas will remain below 10 ft through the weekend and into early next week, hovering between 4-7 ft. Seas will build on Wednesday towards 10 ft.

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HYDROLOGY

No river flooding is expected in the next seven days.

SEW WATCHES/WARNINGS/ADVISORIES

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