textproduct: Seattle/Tacoma

SYNOPSIS

High pressure aloft will provide another day of dry conditions for Western Washington today. An area of low pressure moving southward from the British Columbia coast will bring some rain to the region later Saturday into the early portion of next week. Drier conditions are expected to return by the middle of next week as the low pressure system moves eastward.

SHORT TERM /TODAY THROUGH SUNDAY/

High pressure aloft will briefly rebuild into Western Washington today for a dry day ahead and near seasonal temperatures. An area of low pressure sliding south from the British Columbia coast is still slated to begin to affect the area later Saturday into Sunday. Models still remain at odds with respect to its track, but there's enough consensus to warrant likely to categorical PoPs for the coast and Olympic Peninsula Saturday night into Sunday. Some QPF is expected to make it into Puget Sound on Sunday, but present thinking is that it will remain rather light. Temperatures through the short term period will hover within a couple degrees of normal for the final week of October.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

Upper troughing remains over the Pacific Northwest Sunday night into Monday for a lingering chance of precip...mostly focused on the southern half of the CWA. The upper trough is expected to shift eastward on Tuesday, but confidence in the forecast trails off by the middle of the coming week as ensembles begin to diverge somewhat from what they featured just a day ago. The GFS suite of solutions have a stronger influence of upper troughing over the region while the ECMWF height anomalies would keep broad upper troughing just offshore of California. To be clear, neither of these is a particularly wet scenario for Western Washington, but it lends enough uncertainty to retain some generic low chance PoPs for much of the CWA...and that's exactly what the NBM is using in the forecast. Temperatures are expected to remain generally seasonal, but chances for some sub-freezing overnight lows in the Southwest Interior and outlying areas increase toward the middle/later portion of next week.

27

AVIATION

Northwesterly flow aloft in the wake of an exiting trough expected to remain that way throughout the day and into Saturday. Surface winds at all terminals light and variable this early morning with northerly winds expected to develop by this afternoon with speeds ranging 4-8 kts. Light and variable winds expected again tonight.

Much like the past few days, most of W WA remains VFR with ridging building in. The clear skies that come with that are also responsible for the islands of MVFR/IFR/LIFR thanks to low cigs and fog. Some mid-level clouds helping to prevent fog at some of the terminals, however the terminals that have been the most problematic this past week...OLM and BLI...showing enough hints that while IFR/LIFR may not be the dominant conditions, confidence is not there to remove fog entirely. Thus, will opt for TEMPO groups to cover worst case scenario. Any low cigs that develop should be gone by 18Z, with widespread VFR conditions returning.

KSEA...Cigs expected to sink a little further, but generally will remain between 4000-5000 ft. Forecast confidence on cigs any lower than this still hovers around 30 pct, so will leave that out of the forecast for the time being. Clearing skies expected around 18Z with VFR persisting into overnight tonight.

18

MARINE

Northwesterly winds will ease throughout the day, although SCA level winds still expected throughout this morning. Seas expected to behave similarly. That said, SCA looks on track with no alterations to end time needed. Nearshore seas will take a little longer to ease, so rough bar SCA for Grays Harbor also on track.

Winds and seas will ease and subside by this evening/tonight, with a more benign pattern settling in over area waters into Saturday. By Sunday, a low pressure system will move southward over the region, though some uncertainty remains over the storm track. Winds and seas look to potentially ramp up again with waves once again encroaching on 10 ft or a little higher Sunday. Will wait for current headlines to expire before contemplating next round, if needed. Seas expected to ease next week where they will remain around 4 to 5 feet.

18/15

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory until 11 AM PDT this morning for Coastal Waters From Cape Flattery To James Island Out 10 Nm- Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm-Grays Harbor Bar.

Small Craft Advisory until 5 PM PDT this afternoon for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm- Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.