textproduct: Seattle/Tacoma

SYNOPSIS

An upper level low will continue to weaken into Saturday, with drying and cooling conditions through the weekend. Upper level ridging will build through the first half of next week for continued dry conditions, before additional systems look to arrive by midweek.

SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/

Showers continue to taper off this evening, with a few lingering showers over western Washington. An upper level low will start to move southwards and weaken, taking away the showery influence over western Washington. We'll start a dry and cool trend heading into the weekend, with afternoon temps staying in the low 50s. Overnight lows, especially tonight into Saturday morning, will cool, with areas in the Southwest Interior seeing below freezing temperatures in the upper 20s and low 30s. Therefore, a Freeze Warning is in effect for those locations. A Frost Advisory has also been issued for the northern Olympic Peninsula and north of Seattle as temperatures are expected to range between 32 to 36 early Saturday. Take the proper precautions to protect vegetation if needed. Besides the cold temperatures, should be dry for any trick or treaters.

Dry and cool conditions through Sunday over the region. Overnight low temperatures will be flirting with freezing temperatures as well, in the low 30s.

Mazurkiewicz

LONG TERM /MONDAY THROUGH FRIDAY/

Ensemble guidance remains in reasonably good agreement for the first half of next week with an upper ridge remaining generally over the region for the start of next week. This will maintain mostly dry conditions, though a portion of ensemble members bring a weak disturbance into the ridge enough to bring some light precipitation chances (20-30%) west of Puget Sound. Another weak disturbance brings similar chances toward midweek. A more notable shift in the pattern becomes more likely late in the week with a stronger front approaching Western Washington, but it's worth noting that there's significantly increasing spread in the potential evolution of the pattern by that time. Cullen

AVIATION

South to southwest flow aloft continues into Saturday as upper level low offshore digs southward into the Oregon and northern California offshore waters. The low level flow will turn light overnight. Coupled with areas of clearing, this will be conducive to the formation of IFR or LIFR low clouds and surface visibility locally below 3 statute miles by early morning. Low clouds are expected to lift and scatter out for most areas 18Z-20Z Saturday.

KSEA...Last remaining showers will pass through this evening before some clearing takes place near or after 05Z. With surface moisture and light winds, this remains a favorable scenario for IFR low clouds to form. Low clouds should scatter out to VFR again around 20Z Saturday afternoon. Surface winds light and variable becoming E/NE under 7 knots toward morning.

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MARINE

Weak surface low pressure over the coastal waters will remain in place into Saturday before dissipating as high pressure builds across the interior of Western Washington early in the coming week. Southeasterly winds over the coastal waters this afternoon will reach 15 to 20 kts at times, but should remain under small craft advisory criteria. Winds look to remain generally benign and light across the area waters through the first half of next week.

Coastal seas 4 to 6 feet through the weekend. Seas will build to slowly build late Sunday into Monday, back around 10 to 11 feet as a larger swell train approaches.

Mazurkiewicz

SEW WATCHES/WARNINGS/ADVISORIES

WA...Frost Advisory from midnight tonight to 9 AM PDT Saturday for Downtown Everett / Marysville Area-Eastern Kitsap County- Eastern Strait of Juan de Fuca-Eastside-Foothills and Valleys of Central King County-Foothills and Valleys of Snohomish and Northern King Counties-Foothills and Valleys of the North Cascades-Lake Crescent Area Including US 101-Lowlands of Western Skagit and Northwestern Snohomish Counties-Lowlands of Western Whatcom County-Shoreline / Lynnwood / South Everett Area- Western Strait of Juan de Fuca.

Freeze Warning from midnight tonight to 9 AM PDT Saturday for Lowlands of Lewis and Southern Thurston Counties-Middle Chehalis River Valley.

PZ...None.