textproduct: Seattle/Tacoma

SYNOPSIS

A frontal system has arrived this afternoon which will continue to bring rain, breezy winds, heightened marine activity, and a slight chance of thunderstorms. Unsettled and showery conditions will continue into Tuesday and Wednesday, before high pressure rebuilds later in the week for dry and warm conditions.

SHORT TERM /TONIGHT THROUGH WEDNESDAY/

Recent radar imagery shows a front moving through the Southwest Interior through Puget Sound this afternoon with mostly light rain falling in these locations, with some convective showers along the coast. Expect this front to move eastward with post frontal showers in its wake for the remainder of the Memorial Day evening. Winds will remain breezy for most of the day for interior locations, with the strongest winds along the coast seeing anywhere with gusts up to 35 to 40 mph. High temperatures have cooled significantly than previous days, with highs in the upper 50s to lower 60s.

Unseasonably large wave are on track to arrive along the coast later today, which will continue into Tuesday with waves between 14 to 16 feet. A High Surf Advisory remains in effect for these conditions

Conditions will remain unsettled into Tuesday with an unstable airmass. Can expect scattered showers throughout most of the region with a slight chance for thunderstorms once again, but locations have been trimmed back, so the most likely locations to see any sort of isolated thunder is areas south of the Sound (mainly Lewis county) during the afternoon and evening hours. Conditions remain the same into Wednesday, with isolated chances of thunder possible for all areas of western Washington. High temps will warm into the low 70s on Wednesday.

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/

Ensemble guidance shows split flow regime which slowly transitions into weak high pressure building back into the region midweek. Temperatures will warm on Thursday into the upper 70s. Guidance then suggests weak troughing over the area later into the week and into the weekend which will cool temperatures down into the low 60s and may bring some showers into the mountains.

Long period swell looks to also arrive to the coast on Thursday, which will pose a bigger threat for significant wave runup on coastal beaches as well as the potential for minor erosion.

Mazurkiewicz

AVIATION

Southwesterly flow aloft this afternoon will gradually transition to more northerly by Tuesday morning as an upper level low drops southward across the region. A frontal system continues to push across the interior this afternoon, with latest radar showing the more widespread rain currently moving across the Sound. Cigs have been slow to come down across the interior, with most Puget Sound terminals still reporting VFR conditions this afternoon. Expect cigs to gradually continue to lower, but remain VFR through the evening hours. Cigs and visibilities may temporarily drop to MVFR at times through this evening in any steadier rain, but expect more widespread MVFR ceilings to develop across the area overnight into Tuesday morning. Southerly winds generally persist at 8-12 kt this afternoon and have been gusty to 25-30 kt for terminals from KPAE northward. Gusts to 20-25 kt will still be possible for central and south Sound terminals as the front moves through. Expect winds to subside again tonight into early Tuesday. Winds will then switch to the north between 16-18Z Tuesday and persist between 4-7 kt.

KSEA...VFR cigs continue for the terminal this afternoon in rain. Cigs and visibilities could briefly drop to MVFR this afternoon and evening as the steadier rain associated with the front moves through. Otherwise, expect predominantly VFR cigs to persist through tonight, with a lowering towards MVFR expected into Tuesday morning. Southwest winds persist at 8-12 kt this afternoon and could be gusty to 20-25 kt at times into this evening. Southwesterly winds will ease tonight into the overnight period and transition to the north at 3-7 kt between 16-18Z.

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MARINE

A low pressure system will move across the waters today as a cold front continues to push inland across the area. Southerly winds have become gusty across the interior waters this afternoon as the front makes its way through, while winds across the coastal waters have eased back to 10-20 kt. Widespread Small Craft Advisory southerly winds have been observed across the majority of the interior waters, with some brief gale force wind gusts over portions of the eastern Strait of Juan de Fuca and Northern Inland Waters. Winds will ease in the wake of the front this evening into early Tuesday.

High pressure will then quickly rebuild into the coastal waters on Tuesday, allowing for winds to transition to more north/northwesterly by Tuesday afternoon. SCA northwesterly wind gusts are expected at times through much of the week for the outer Coastal Waters. Additional systems may move across the waters late in the week, bringing additional rounds of building seas and increasing onshore flow. Onshore flow looks to gradually increase Thursday through late week, with SCA winds (to gale gusts) expected along the Strait late Thursday into Friday. An even stronger push on Friday then looks to bring more widespread gales to the central and east Strait.

Seas over the coastal waters around 10-12 ft this afternoon will continue to build towards 12-16 feet late today into early Tuesday. Seas will slowly subside again through the day on Tuesday, but look to remain elevated to around 10 ft through much of the week. With the transition back to northwesterly winds, steep seas will also return to the coastal waters late Tuesday into Wednesday as the predominant wave group's period becomes 10 seconds. The arrival of a 7-10 ft long period swell with a period of 15-18 seconds on Thursday will help build significant wave heights back up to 10-13 ft. Seas will then slowly subside again towards 10 ft Friday into the weekend.

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HYDROLOGY

The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated during this time as needed.

SEW WATCHES/WARNINGS/ADVISORIES

WA...High Surf Advisory from 5 PM this afternoon to noon PDT Tuesday for Grays Harbor County Coast-Northern Washington Coast.

PZ...Small Craft Advisory until 11 AM PDT 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-Grays Harbor Bar.

Small Craft Advisory until 5 AM PDT Tuesday for West Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 5 PM PDT this afternoon for Admiralty Inlet-East Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters Including The San Juan Islands-Puget Sound and Hood Canal.