Synopsis
Generally dry and mild conditions are expected through the end of the week, with light precipitation possible over the weekend as low pressure moves south from the British Columbia coast. Weak ridging and drier conditions are forecast through the last week of the month, but a return to a more active weather regime is possible as of the first week of November.
Short Term /Tonight Through Saturday Night/
The dissipating front has left mostly cloudy skies across western Washington this afternoon, with highs in the mid 50s and low 60s. Skies will be clearer on Friday and with slightly cooler temperatures. A low pressure system will be moving into Washington waters Saturday for a chance of showers throughout the day. Morning lows on Saturday will be in the upper 30s to low 40s. Mountain valley locations could be in the low 30s for possible frost and freezes. More of the precipitation will be focused along the Olympic Peninsula with amounts of only a few hundredths of an inch inland through Puget Sound.
Long Term /Sunday Through Thursday/
Some shower activity will linger into Sunday but will remain mostly cloudy. Only a few hundredths of an inch are in the forecast for Sunday but generally conditions look to become drier trending into Sunday afternoon. Some of the ensemble guidance takes the aforementioned low pressure system inland into Oregon early in the week, which would keep conditions on the cooler and cloudier side, other solutions bring in weak high pressure. The majority of the week will be dry. However, there are extended range solutions indicating that the end of the month and into the first week of November may signal a switch to a more active pattern. The probabilistic week two hazards have portions of the CWA highlighted for slight risks of heavy rain, possible mountain snow and some breezier conditions for the immediate coast. Stay tuned to the forecast as details evolve.
21
Aviation
Generally VFR this afternoon with pockets of MVFR ceilings affecting terminals near the Canada border. Low end VFR clouds are expected to continue to fill in across western Washington this evening, continuing to lower to MVFR/IFR overnight. Calm conditions overnight will result in another round of MVFR to IFR/localized LIFR conditions as low stratus and fog expand over the region early Friday morning, particularly south of the Puget Sound and over the Kitsap Peninsula. Flight conditions are expected to improve to VFR across western Washington Friday afternoon under clear skies.
Surface winds this afternoon generally northerly around 5-12 kt will ease this evening and shift southeasterly early Friday morning, switching back to northerly Friday afternoon.
KSEA...VFR with occasionally breezy NW winds 10-15 kt with gusts to 20 kt. Winds will ease later this evening, gradually veering easterly to southerly to westerly overnight, and back to northerly flow Friday afternoon. Confidence is increasing over MVFR ceilings developing over the terminal overnight, with a 35-40% chance of cigs below 3000 feet and a 30% chance of cigs below 2000 feet between 12z- 18z Friday morning. VFR conditions expected to return by the afternoon under clear skies.
15
Marine
Northwesterly winds will continue to pick up through the evening and into early Friday in the wake of a weak frontal system. Along with winds, seas will build to 9 to 14 feet over the inner coastal waters, and up to 11 to 17 feet across the outer coastal waters through Friday morning. As a result, a Small Craft Advisory remains across the coastal waters through Friday. While seas will gradually ease along the coast Friday afternoon, seas will come down a little slower further from shore, and the Small Craft goes through Friday afternoon across the outer coastal waters.
In addition, winds this evening will pick up in the Strait of Georgia west of Whatcom County, and while winds are expected to remain below SCA, will keep an eye on how things evolve this evening. Seas at Grays Harbor Bar will also continue to build into the evening, and while they are expected to stay just under 10 feet, rough seas are not out of the realm of possibility and that will be watched as well.
Winds and seas will ease and subside by late Friday, 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. While winds are expected to remain low, seas may build over the outer coastal waters to around 10 feet Sunday morning with this incoming system, then ease into next week where they will remain around 4 to 5 feet.
15
Sew Watches/Warnings/Advisories
WA...None. PZ...Small Craft Advisory until 11 AM PDT Friday 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.
Small Craft Advisory until 5 PM PDT Friday 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.