Sunday, November 9, 2014

A Historic Storm

Sunday, November 9, 2014
5:04 pm

Every once in a while, a storm so unbelievably massive, so breathtakingly powerful, and so horrendously destructive appears in the models that you literally go into cardiac arrest.

This is one of those storms.

I've seen many crazy, crazy storms in the models. I've seen gigantic 930 hPa "bombs" in the Gulf of Alaska, over a foot of snow in Seattle in 24 hours, sustained winds of over 50 knots in the foothills of the Cascades... you get the idea. None of these scenarios came true. The 930 hPa lows nearly always appear in the far extended and never develop, and the snow is notoriously hard to predict. The only time I can remember the foothill winds being forecast to be this strong was on December 20, 2008, with one of our legendary winter storms then. North Bend hit 57 mph, Enumclaw hit 70 mph, and the foothill town of Cumberland hit 100 mph, but this was nowhere near as bad as the forecast widespread, 50+ knot sustained winds (credit to Scott Sistek for these statistics, you can find his article on the storm here).

On Friday, one of the strongest storms in recent memory hit the Aleutians. This low was fed by the remnants of supertyphoon Nuri, which, at its most intense point, had a minimum low pressure of 910 millibars and sustained winds of 185 miles per hour. For comparison, Hurricane Katrina had a low pressure of 920 millibars and sustained winds of 125 miles per hour when it made landfall on the Louisiana Coast.

Supertyphoon Nuri at maximum strength

The Western Pacific is the the most active tropical cyclone basin in the world, and storms like these occur with almost disturbing regularity. However, what they generally do not do is travel northward to become super-ultra-mega storms in the Bering Sea, and that's exactly what this one did.

Track of Nuri.

Thankfully, when Nuri was at category 5 strength, it was far out in the Pacific and did not cause any injuries or deaths. As it began to head northward and dissipate, it was absorbed by an extremely strong jet stream off the Siberian coast. This jet stream had winds in excess of 210 knots, which is simply extraordinary. It was the strongest jet I've ever seen, regardless of location.

This jet stream provided the storm with the large horizontal temperature gradient needed for serious development, and with a ton of tropical moisture already in place from the remnants of a supertyphoon, a storm of the likes the Bering Sea had never witnessed before was formed.

Surface Analysis over the North Pacific on Saturday morning. Credit: NWS.

The analysis above of the storm at peak strength gives an idea of the the depth and breadth of the storm, but it's so far beyond anything that I have seen before that it is seemingly beyond my comprehension in many ways. It bottomed out at 924 millibars, which is deeper than any extratropical low ever for the Northern Pacific. It spanned over 2,000 miles (just look at how long that cold front extends outwards), and it created waves over 50 feet high in the Bering Sea. Our Hanukkah Eve Storm was around 976 millibars when it made landfall on the night of December 14, 2006, and cut power to millions while giving Sea-Tac its all-time highest gust of 69 mph. The thought of a 924 millibar storm hitting our region is, while impossible in our current oceanographic, geographic, and atmospheric setup, is truly frightening.

The infrared satellite picture above taken Saturday morning gives you an idea of the scope of the storm. The storm covers much more latitude than the United States. A snapshot of the wind field of the atmosphere at the same time reveals that the highest winds are just to the north and just to the south of the low, with an "eye" of calm winds right where the low is located, not unlike Supertyphoon Nuri itself.

Because this storm his such a remote region and caused very little damage as a result, it was not widely covered in the media. I feel as though it definitely should be though, as it is one of the most fascinating occurrences we have seen in the atmospheric sciences for quite some time. Instead of learning about violence in the Middle East, it sure would be nice to learn about the power that Mother Nature has manifested in this storm.

Oh yeah, one more thing. This storm is so big that it will actually force a pool of arctic air down into the states this week. Yup, that's right. An early-November polar vortex. And you can bet that will be covered, both in the media and on this blog.

Thanks for reading!

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