textproduct: Seattle/Tacoma

SYNOPSIS

An upper ridge will remain over Western Washington through the weekend. Cold temperatures are expected during the overnight periods. A weak system will brush the coast on Monday. The ridge will rebuild Tuesday before moving inland on Wednesday as another weak system may reach the area.

SHORT TERM /TODAY THROUGH SUNDAY/

Clear skies across the area this afternoon with an upper level ridge positioned offshore. Fraser Outflow continues this afternoon across western Whatcom County before weakening tonight. The upper ridge will promote dry conditions through the weekend. The main weather concern will be cold overnight temperatures Saturday and Sunday morning. Widespread overnight lows in the 20s are expected both mornings, with upper teens possible in localized locations. Temperatures in the metro areas will drop towards 25 degrees tonight into early Saturday, especially away from the water. For this reason, have issued a Cold Weather Advisory from Everett to Tacoma, including portions of the Kitsap Peninsula. The coldest temperatures will be away from the water, with temps near 30 along the Puget Sound coast. Make sure to wear appropriate clothing if you're heading out this weekend. Additional Cold Weather Advisory headlines may be needed on Sunday. Otherwise, patchy freezing fog may develop each morning, mainly from Olympia southwards.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

The aforementioned upper ridge will flatten late Sunday through Monday as a weak weather system brushes Western Washington. At this time, any QPF amounts are expected to remain nominal, if any. The upper ridge then rebounds on Tuesday for dry weather and warming temperatures. The ridge axis shifts east Wednesday into Thursday as a system may approach from offshore. However, uncertainty continues in the ensembles in regards to the extent of precipitation over Western Washington, with approximately 40% of the multi-model ensemble (GEFS, EPS, GEPS) remaining dry solutions. Either way, little in the way of impacts are expected for any midweek precipitation. Temperatures will moderate on Tuesday and remain near to slightly above normal into late week. JD

AVIATION

A high-amplitude ridge offshore is maintaining northwesterly flow aloft across western Washington today. VFR conditions prevail across the region with clear skies. These conditions will continue through much of tonight. There's a chance (20-25%) that IFR or lower ceilings may develop early Saturday morning. Mostly clear skies will continue once again during the day on Saturday with increasing high clouds late. Northeasterly winds this afternoon around 5 to 10 kt (except gusts up to 25 kt at BLI) will slowly ease tonight, becoming light and variable overnight into Saturday morning. Mostly light N/NE winds expected throughout the day Saturday.

KSEA...VFR conditions with clear skies. These conditions will continue through tonight, with 20-25% chance of IFR or lower ceilings between around 14-19Z Saturday. Winds NE 8-15 kt this afternoon will decrease to around 5 kt tonight, and remain around there through Saturday morning.

62

MARINE

Broad high pressure across the northeast Pacific will remain in place through the first part of next week. A weak thermal trough along the coast will keep offshore flow continuing through the rest of today, but winds will start to weaken tonight and through the weekend. The breeziest winds will continue through this afternoon in the entrance to the west Strait of Juan de Fuca, as well as through portions of the Northern Inland Waters. Gusts up to 20 to 25 kt will continue this afternoon in these localized spots.

The next period of impactful marine weather doesn't look to arrive until later Monday into Tuesday as a frontal system approaches the west coast and brings back increasing southerly winds.

Seas 3 to 5 ft will continue this weekend, increasing to the 8-12 ft range Tuesday and into the middle of next week as systems move back into the area.

62

HYDROLOGY

No river flooding in the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...Cold Weather Advisory from midnight tonight to 9 AM PST Saturday for City of Seattle-Downtown Everett / Marysville Area-Eastern Kitsap County-Eastside-Lowlands of Pierce and Southern King Counties-Shoreline / Lynnwood / South Everett Area.

PZ...None.