Pacific Northwest Storm, Including Remnant of Typhoon Songda, Will Bring Damaging Winds, Flooding, Huge Waves Saturday

Brian Donegan
Published: October 14,2016
A powerful Pacific Northwest storm, fueled by a remnant of a typhoon, will hammer parts of Washington, Oregon and northern California Saturday, with the potential for destructive winds, flooding rain, huge waves and coastal flooding.
This weekend storm will have its origins from the remnants of western Pacific Typhoon Songda.
(MORE: How a Remnant Typhoon Could Trigger a Pacific Northwest Windstorm)
High wind watches, warnings and advisories have been issued by the National Weather Service in parts of the West, as far south as the Sierra and east-facing front range.

Current NWS High Wind Alerts

A 103-mph wind gust was observed at Cape Meares in Oregon on Thursday evening, according to the National Weather Service, accompanying a separate Pacific storm. Power was knocked out to at least 25,000 customers in Oregon, and there was at least one rockslide reported in Tillamook County during this first Pacific storm.
(MORE: Tornado Reported, Thousands Without Power as Storm Slams Pacific Northwest)

Timing the Storm

Thursday's Pacific front has pushed inland, as can be clearly seen in infrared satellite imagery.

Current Satellite, Winds, Surface Pressure

The strongest frontal system, however, will intensify quickly and slam into the Northwest Saturday.

Current Radar, Warnings

Gusts over 60 mph are possible near the Washington and northwest Oregon coasts Saturday afternoon.
This system will be the remnants of Typhoon Songda, with a potentially dangerous threat of widespread damaging winds, flooding rain and coastal flooding.
(MAPS: 7-Day Forecast Highs and Weather)
This storm has gotten the attention of both the National Weather Service and prominent Pacific Northwest weather experts.
The National Weather Service in Seattle mentioned the track of Saturday's storm lines up with high-impact wind events in western Washington, potentially bringing the area its most significant windstorm in almost 10 years.

The National Weather Service in Portland, Oregon, is even calling this the "Ides of October storm", a nod to the infamous "Ides of March" in Roman history.
Here is the general timing of the strongest winds in the

• Saturday morning: Damaging winds develop along the Oregon and northwest California coasts; winds increase in Oregon's Willamette Valley.
• Saturday afternoon: Damaging winds spread to Washington coast, including the Olympic Peninsula and coastal ranges of Oregon; strong, possibly damaging wind gusts in parts of the I-5 corridor in Washington and Oregon.
• Saturday night: Lingering damaging winds gusts, especially early, near the coast of Washington and northwest Oregon; strong, possibly damaging wind gusts in the Portland - Seattle - Bellingham, Washington corridor.

City Wind Gust Forecasts

Detailing the Wind Threat

Of greatest concern is the threat for damaging winds with Saturday's storm, a remnant from Typhoon Songda, known to give rise to destructive Pacific Northwest windstorms in the past.

Potential surface setup for the Pacific Northwest storm.

In this scenario, low pressure deepens rapidly near the Pacifc Northwest coast. The uncertainty is in how widespread the damaging winds will ultimately become. This depends on the exact track and intensity of the rapidly-deepening low Saturday.

Two Possible Northwest Windstorm Scenarios

Scenario 1	Low stays much farther offshore, then heads to N. Vancouver Island	Some strong gusts in Seattle-Eugene corridor still possible, but most damaging winds mainly confined to coast
Scenario 2	Low moves either close or inland over Washington state or western Oregon	Stronger, more damaging winds inland, including the I-5 corridor, in addition to areas near the coast.

In either scenario, damaging winds are likely Saturday along the immediate coasts of Washington and Oregon, with power outages and downed trees.
The majority of forecast guidance suggests the second, more ominous scenario is more likely, but there is still some key track and intensity uncertainty, given the storm hasn't yet formed.
(FLASHBACK: Nov. 2015 Northwest Windstorm)
This would bring damaging wind gusts to the higher population centers of the I-5 corridor in the Pacific Northwest, including Seattle and Portland.
Residents in western Washington and western Oregon should be prepared for the potential of power outages and downed trees, perhaps even some structural damage Saturday and Saturday night.
Furthermore, deciduous trees yet to drop their leaves are more likely to be damaged by high winds given the greater surface area exposed to the wind.

Heavy Rain, Coastal Flood Threats

Winds aren't the only threat from this storm.
Additional heavy rain is expected to fall near the coast and below snow level in the coastal ranges, Olympics and Cascades through the weekend. Up to another 8-12 inches of rain may fall in these windward locations.

Rainfall Forecast

This will trigger flooding, especially in urban and poor-drainage areas, and along flood-prone rivers such as the Skokomish in western Washington.
Leaf-clogged drains could also worsen the situation since leaves are slowly beginning to fall from the trees; water will not be able to adequately flow into storm drains if leaves are clogging them.
(MORE: When Does Your City See Peak Fall Color?)
These strong winds from a parade of storms will also produce huge waves off the Northwest coast, in excess of 30, if not 40 feet. Pounding surf is likely to lead to coastal flooding, beach erosion and some damage, as well.

Forecast Wave Heights Saturday PM

Some snow could fall over the higher peaks of the Cascades and Sierra of California. Higher-elevation snow is also expected in the mountains of Idaho, southwest Montana and western Wyoming.

MORE: Pacific Northwest Storms