FORECAST: Wet and windy weekend ahead

Tree damage and power outages possible Sunday-Monday

SYNOPSIS: Uncertainties continue with the very large Pacific storm that will be organizing over the weekend, particularly late Saturday through Sunday hundreds of miles off our coastline. Forecast models are in agreement this storm will reach its peak early Sunday morning about 300-400 miles off the northern Oregon coast. Yes, this storm will also undergo extreme “bombogenesis” which is rapid deepening (lowering) of atmospheric pressure in the low pressure center, but it is expected to weaken significantly before approaching the British Columbia coast, somewhere around Vancouver Island, on Monday. This is a similar scenario as we just saw with the last storm, though this storm will be a bit stronger and a bit closer, thus we can expect a bit greater overall impact to Western Washington

TONIGHT: Few showers and the chance of an isolated thunderstorm mainly south of Puget Sound. Mainly light rainfall accumulation.

SATURDAY: A rainy start. A little breezy with winds in the 15-25mph range, but typically fall-like. There will be some drier times as the day goes on. Highs will be in the 50s with rain showers tapering through the afternoon and mainly relegated to areas near the Cascades by late afternoon.

SUNDAY/MONDAY STORMINESS: The day will start with rain (heavy at times) moving into the area Sunday morning. It will then turn to showery rain with occasional downpours and possibly an isolated thunderstorm at the coast through the day. Pretty unsettled. The wind will increase Sunday morning, particularly at the coast where a High Wind Watch is in effect for the period starting Sunday morning. Winds at the coast will be out of the south and southeast from 25-40 mph through the late morning Sunday all the way into Monday with isolated gusts over 50 mph. In the interior of Western Washington, including Puget Sound, winds will be easterly or southeasterly from 15-25 mph with gusts over 35 mph starting late morning or early Sunday afternoon and continuing into Monday.

Isolated stronger wind gusts in the interior are more likely nearer water and also near the Cascades, as strong gap winds will blow well over 40 mph at times Sunday afternoon and Sunday evening. Monroe, North Bend, Enumclaw are just some of the communities that regularly see these gap winds, or “Cascadia winds” and will feel greater impacts Sunday through Monday.

We could see winds die down by Monday afternoon but there is a chance stiff breezes continue all the way into Monday night.

NOTE: If the low pressure center tracks significantly closer than forecast (unlikely but possible), winds will be significantly stronger. It will be a watch-and-wait forecast, at least into tomorrow.

BOTTOM LINE: Right now, this looks like a moderate wind event Sunday and Monday. when judged by expected wind gusts alone, mentioned above. However, it is early in the season and trees have lots of leaves which will dramatically increase wind load on branches and limbs. In addition, the duration of this wind event is especially concerning to me for two reasons: 1) the longer wind gusts of even moderate intensity continue (gusts 25-40 mph), the more and more branches, twigs, and potentially even whole trees could be weakened and topple. This period of strong winds will be unusually prolonged compared to usual fall storms and the impacts thus greater. 2) Power outages could be slower to be restored as strong winds persist along with rainfall. Power crews might not be able to access some areas for repair until winds calm down later on Monday.

TUESDAY and BEYOND: More rain will come through Tuesday through Thursday and we could have some minor flooding on the Skokomish River in Mason County. Snowfall looks to be limited to higher elevations throughout this whole period – mainly above Stevens Pass.