Saturday, April 3, 2010

Storm Review

The Friday Storm (I guess we can name it the Good Friday Storm of 2010) was one of the strongest late season windstorms in a while, with many locations experiencing gusts over 60 mph, and a few feeling true hurricane force winds. (Point of information: true hurricane winds require the sustained winds, averaged over two minutes, to exceed 74 mph). Such winds were achieved at Tatoosh Island yesterday. Here are some samples of max gusts (thanks to Scott Sistek of KOMO TV for collecting them)
  • Tattoosh Island: 94 mph
  • Lincoln City, Ore.: 78 mph
  • Destruction Island: 78 mph
  • Cape Disappointment: 74 mph
  • Oak Harbor: 62 mph
  • Bangor Sub Base: 62 mph
  • Kirkland (waterfront): 62 mph
  • Everett (Paine Field): 62 mph
  • Bellingham: 61 mph
  • Seattle (Alki Beach): 61 mph
Tens of thousands of homes lost power, including all of the San Juan Islands for a while.
Here is the hourly weather plot at Tatoosh Island. The the pressure dropped to 28.85 inches of mercury...around 976 mb as the low center moved NE in the close vicinity. And the maximum winds spiked after the lowest pressure. This is classic. Wind are not strong in the center of the low, but on its flanks where the pressure gradients (change in distance) are greatest.

The forecast the day before was close, but not perfect..here is the sea level pressure prediction made on Thursday. The low was displaced a small amount to the SE of the actual position and was not quite as deep as reality, but more than good enough to indicate a threat. National Weather Service warnings were highly accurate.


An interesting aspect of this event was the early snow. We had some moderately cool area over us and the evaporation and melting of precipitation forced the snow level down to the surface in some locations, particularly those over 500 ft and particularly over the SE side of the Olympics (Silverdale, Hood Canal Region). This location often experiences snow under strong SE flow--the air if forced to rise by the Olympics and evaporation and melting is favored there.

And snow is the big story now...1-1.5ft have fallen in the mountains from this event and another 1/2 feet will come today. Avalanche danger will be high in uncontrolled areas, but elsewhere this is a real opportunity for fine late season snow fun.

8 comments:

OregonGuy said...

Yesterday, we went off the first tee around 3pm. Time for some Iron Man Golf.

Had a few hail storms, but other than that, some slight, sporadic incidences of light rain fall. Getting a 50 or 60 mph gust when standing on the tee can be unsettling, but if given the chance of playing the "auld" course, you gotta admit, you'd play regardless of the conditions.

I always check here before going out on questionable days. The presence of hail was worrisome, as it is often associated with lightening, it seems. But, no thunderclaps, and some beautiful anvil formations. (You gotta love life at the beach.)

http://www.astoriagolf.com/

Josh said...

Updating map of Wind Event

Corie said...

Here in Oly the storm dumped 1.24 inches of rain in 24 hours..but the wind turned out to be a big nothin'...for which I am grateful. I dont like being without power.

We had one gust of 38mph but that's about it.

Crown City Rental said...

I've always loved storms and now I love reading about them on your blog!

Thank you.

scotts said...

Thanks Cliff! I think since I published, I saw Tatoosh hit 94 mph. I'll edit my blog too. -Scott

heddie said...

The snow is excellent! Waist deep in the Crystal backcountry yesterday and stability wasn't bad at all. Moderate winds, combined with some sunshine. Unbelievable day for April, to say the least.

tipo158 said...

A friend and I was out confirming driving distances for a road rally in Grays Harbor and Pacific counties during the storm.

We encountered wet snow driving on Hwy 109 along the shore south of Taholah.

We got the car stuck in the snow at around 2200 ft, NW of Lake Quinault. We were in a brief whiteout there and we were getting the car unstuck.

We found a huge tree had been blown down and drove itself into the road like a nail between our trips up and down the hill.

We were held up by downed trees in three places.

We saw heavy, heavy rain and hail south of Cosmopolis. We saw even more in Raymond.

It was an impressive weather show.

Terri said...

We were on the ferry from Anacortes to Lopez around 1:30 Friday. I had no idea a ferry could tip like that. We were not looking at land, only sky. A crew memebr came down from the bridge to let us know we had winds at 80 knots. Impressive.