Oregon Tornado and Impactful Storm Moving In

A very active period of weather will occur from tonight into tomorrow. But before I dive into that, I want to talk about the tornado that occurred near Rockaway beach in Oregon yesterday evening. 

Tornado
Yesterday, at approximately 9:24 PM, an EF-0 tornado with winds up to 85 mph occurred in Rockaway Beach, Oregon. It was likely a waterspout that made landfall on the beach. The tornado damaged fences and broke roof shingles off houses. It went through a school parking lot, picking up various items including a porta-potty and several dumpsters. It ripped a roof off of one of the garages in the vicinity. This tornado caused one minor injury. It had a maximum width of 150 yards and an approximate path of 0.25 miles. This is all based on the damage assessment performed by NWS of Portland, OR. The official report can be viewed here.

Another interesting thing is there was only one storm report in the country yesterday and that was from this storm in Oregon.
Not often is there only one storm report in the country, and this time, that one storm report comes from one of the least severe weather prone parts of the country!

There will be more severe weather in the PNW tomorrow and that will be talked about later in this post.






Storm
We're in for a stormy night here in western Washington as a big, ominous looking storm approaches our coast this evening. This storm looks to be the most impactful of a fairly tame fall so far here in the Northwest. It will pack quite the punch, with heavy rain, flooding, a region-wide wind event, and even some severe weather.


Winds
A regional windstorm looks likely tonight. Wind advisories are out for all of the Puget Sound and there are high wind warnings in place on the coast and in western Whatcom county. At about 7 PM, southerlies should start up and areas near the coast will begin to feel the winds. By 9-10 PM, most of Puget Sound, including areas that were sheltered by the mountains last time (Seattle, Bellevue, Kirkland, etc) should begin feeling the winds. The wind will peak around midnight before slowly winding down through tomorrow morning.

The HRRR and the NAM 3KM are two high resolution models that are often used in short term forecasting. They seem quite bullish for this event with gusts up to 80 MPH in parts of the coast and 50-60 MPH gusts in the sound. I do think that these are slightly higher than what will occur tonight. The NWS also seems to agree in their latest forecast. Keep those phones charged and prepare for power outages, particularly on the coast!


Rain, Snow and Flooding 

Most of the area will receive a good amount of rain from this system. For the main event from tonight into tomorrow night, rain amounts look to be around 2-4 inches for areas in the coast and around an inch of rain for most of the Puget sound. After the main event, there will be plenty of showers around so an additional half an inch of rain for some areas seems possible. Of course this is coming after yesterday's respectable rainfall of more than an inch in places so minor river flooding seems very possible. The WPC has encompassed western Washington in a marginal risk for excessive rainfall accordingly. One beneficial outcome of this storm will be more mountain snow. Snoqualmie pass will receive 4-6 inches of snow and Stevens could receive up to 10 inches of new snow. Higher amounts will be possible in parts of the north cascades like Mt. Baker where multiple feet of new snow will be possible. Certainly positive for ski areas!!


Severe Weather


Lastly, there is a threat of severe weather tomorrow. The SPC has placed the Washington and Oregon coastlines under a marginal risk of severe weather. Currently this is a wind driven threat, but I am also concerned for the potential of waterspouts/tornadoes. It is rare to see any part of the PNW have a risk of severe weather in the SPC outlook so I do hope it is taken seriously.


Getting into the details, once the front passes through early tomorrow morning, the atmosphere will begin destabilize with all the unstable energy behind the front. Up to 500 joules of convective potential energy(CAPE) will be present on the coastline. This energy coupled with a decent amount of shear will lead to the threat of severe weather. As convective showers and thunderstorms form off the coast and move inland, they will pose a threat for heavy rain, small hail, gusty winds, lightning and a weak tornado/waterspout. Further inland, instability will be much more meager but still enough for the potential of a lightning strike or two within stronger showers.

Phew, that was a lot to cover!! We will get a respite from the rain on Friday before another interesting trough digs in the Northwest on the weekend. That will be covered in a later blog!!

Have a good, stormy night!!

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