Seattle, Washington

Dry conditions will continue across western Washington through Monday as an upper level ridge moves over the Pacific Northwest. The first half of the week will largely remain dry across the area, with chances of precipitation increasing the second half of the week as a series of systems approaches the Pacific Northwest. A brief break in the unsettled pattern is possible Friday night into Saturday as another ridge moves over the region.

Latest satellite imagery shows widespread fog development across the East Puget Sound Lowlands and Chehalis River Valley early this morning. Fog is also starting to develop along Hood Canal and expanding westward across the Southwest Interior as of 08Z. Observations show that fog has become dense in spots, especially along the I-5 corridor from Olympia southward to Chehalis, where widespread visibilities of a quarter of a mile are being reported. Fog will continue to expand across the area through the early morning hours and will linger a little longer today, before scattering between 18-21Z for some afternoon sun.

An upper level ridge will move into the region today and push inland on Monday, maintaining dry conditions across western Washington for the start of the week. Overnight lows will remain cool, mainly dipping down into the 30s, and will bring areas of additional frost development during the early morning hours. Ample moisture in the low levels will also promote another round of fog development across the western Washington on Monday morning. Afternoon highs will be seasonable, mainly in the low to mid 50s both days.

A splitting system approaching the region Monday night into Tuesday may bring some light precipitation to portions of the coast and the Olympic Peninsula. The majority of western Washington will remain dry, however, with temperatures warming a few degrees. Morning lows will be in the mid 30s to mid 40s across the area, with afternoon highs expected to be in the mid 50s to low 60s.

Chances for precipitation will increase the second half of the week as a series of systems looks to approach the Pacific Northwest. At this time, a weak system looks to move across the area on Wednesday, followed by a stronger system on Friday. The stronger system on Friday will likely bring gusty winds and more widespread lowland rain and mountain snow to the area. Discrepancy still exists with the pattern heading into next weekend, but ensemble clusters hint at a brief break in the parade of systems Friday night into early Saturday as a ridge of high pressure temporarily moves back over the region. The ridge looks to push inland rather quickly however, which would open the door for additional systems to move into the area by Saturday evening.

Temperatures will be near to just slightly above normal through the period, with morning lows expected to be in the upper 30s to upper 40s and afternoon highs expected to be in the mid to upper 50s.

14

High pressure will build over the terminals today into Monday. Low-end MVFR stratus has filled in from Everett, down through Puget Sound and into the south interior. The lowest visibilities have been around Olympia, Hoquiam, and Arlington with visibilities down to a quarter of a mile. The model guidance maintains ceilings lowering down to LIFR conditions (both ceilings and visibilities) for the previously mentioned areas covered by stratus by 14Z, and lasting through 18-21Z. Skies will clear this afternoon and evening. Another round of LIFR conditions is likely Monday for a majority of terminals in the Puget Sound/south interior. Winds are calm this morning/Monday morning, and will pick up to 3-5 kt this afternoon from the north, and southeast this evening.

KSEA...Stratus currently over the terminal this morning with ceilings just above 1,000 ft. Expectation remains that this will lower down to LIFR criteria during the morning (14-18Z is where the probabilities for fog and/or LIFR stratus peak). Skies will clear going into the afternoon, and redevelopment of LIFR conditions is likely again tonight/Monday morning. Northeast winds at around 5 kt will decrease this morning before increasing again this afternoon, switching to the southeast in the evening, and becoming calm again overnight.

HPR

High pressure rebuilds over the coastal waters today with dry conditions finishing the weekend over the waters. Couple patches of fog may affect portions of the Puget Sound waters this morning. A weak system will brush the coastal waters Monday into Tuesday with the chance of showers. While winds will pick up in the outer coastal waters (with winds gusting up to 20 kt), the main concern for the first part of the week will be seas, as swells of 17 seconds increase out of the southwest, and seas increasing to 8-11 ft going into tonight/Monday. A small craft advisory was issued to cover the threat, which will likely continue into Tuesday with seas returning to 6-8 ft Wednesday.

The second half of the week is more active with trough dropping out of Alaska, and a couple of systems likely to affect the waters finishing the week into next weekend. Best chance of winds greater than 20 kt is with a system Wednesday/Thursday, Friday, and this weekend, affecting the coastal and interior waters. Seas will increase going towards the end of the week, peaking Friday with heights up to 15 to 17 ft at 17 seconds.

HPR

WA

Dense Fog Advisory until 10 AM PST this morning for City of Seattle-Downtown Everett / Marysville Area-Eastern Kitsap County-Eastside-Lower Chehalis River Valley-Lowlands of Lewis and Southern Thurston Counties-Lowlands of Pierce and Southern King Counties-Middle Chehalis River Valley-Olympia and Southern Puget Sound-Shoreline / Lynnwood / South Everett Area.

PZ

Small Craft Advisory from 1 AM Monday to 1 AM PST 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-West Entrance U.S. Waters Strait Of Juan De Fuca.