Wednesday, December 17, 2014

A Review Of The Windstorm

Wednesday, December 17, 2014
1:46 pm

Last Thursday night, right after I had finished my final, my mom and I decided to trek up to Sandy Hook, which is a little coastal community situated on Cultus Bay on the southern tip of Whidbey Island, to catch what ended up being the biggest windstorm of the year thus far for the Pacific Northwest as a whole, and some of the strongest winds I have experienced in my entire life. Here, I'll just give a general overview of the storm, and I'll show you some pictures and videos that I took up at Sandy Hook Thursday night and Friday morning.

First off, let's take a look at an animation of the windstorm. The loop below shows water vapor satellite imagery from November 29th to December 14th. Our windstorm begins forming to our southwest at about 0:21 and passes over our area at around 0:24.

Here's a more in-depth picture when it was near peak strength. Look at the beautiful, symmetrical form of the cyclone, and how tightly the bent-back-occlusion wraps around the center of circulation. It almost looks like a hurricane. Pretty extraordinary.

8 pm December 10, 2014 (PST). Retrieved from NOAA WRH Satellite Loop.

As I explained in my previous post, this cyclone was a "Sou'wester." Most of our major regionwide windstorms have been of the "Sou'wester" type. The Hanukkah Eve Storm was the most destructive storm for Puget Sound since the great Columbus Day Storm of 1962, but it was not a truly region-wide storm. This storm affected everywhere from San Francisco (they actually closed schools due to the wind and rain from this storm... wimps) to Vancouver Island and Southern British Columbia. Seattle did not experience anywhere near the amount of damage it experienced with the Hanukkah Eve Storm, but if this storm had kept its strength as it tracked northward and if it had tracked a bit further east through the Chehalis Gap, the winds could have approached Hanukkah Eve levels.

One of the most striking things about this storm is how closely its track mirrored that of the Columbus Day Storm. Take a look at this picture below comparing it to other famous Sou'westers to strike the Pacific Northwest. You can see that its central pressure is much higher, hence the lower winds over much of the area. However, it tracked much more closely to the coast, and if it had deepened to 960 millibars or lower, there is a distinct possibility that it could have caused the tremendous winds witnessed in 1962.

Credit: NOAA

I wasn't able to find a definitive list of the highest gusts throughout the entire Pacific Northwest region, but I was able to find some gust information for some individual areas. I put a small list together of gusts that I thought that were particularly notable. Values given are in mph. I have a more complete list of gusts below from the Seattle, Portland, and Pendleton NWS forecast offices. I looked but I could not find any reports from California NWS offices

NWS Portland gusts
NWS Seattle gusts
NWS Pendleton gusts


White Mountain: 139
Mount Lincoln: 135
Slide Mountain: 112
Mammoth Summit (yes, the ski area): 111
Alpine Meadows: 109

San Francisco: 50
Oakland: 46


Mt. Hebo (3160 ft): 90
Sea Lion Caves: 89
Marys Peak (4137 ft): 88
Newport (120 ft): 72
Portland (30 ft): 67
Garibaldi: 64
Salem: 53


Crystal Mountain (6870): 97
Mission Ridge: 78
Mt. Baker (5000 ft): 78
Naselle Ridge (2008 ft): 77
Port Townsend (28 ft): 70
Whidbey Island Naval Air Station (47 ft): 69
Hood Canal Bridge : 63
Cape Disappointment: 63
Paine Field (Everett): 62
Useless Bay: 59 (this is the closest location to where I was)
Hoquiam (12 ft): 56
520 Floating Bridge: 51
Boeing Field: 49
Sea-Tac (370 ft): 49
Tacoma Narrows Airport: 48

As you can see, the highest winds generally occurred on mountain ridgetops. I heard rumors of Mt. Hebo having a 130 mph gust, but this figure did not show up in the official NWS list. Portland's gust of 67 mph was actually the strongest gust since the great Sou'wester of December 12, 1995, so this storm was no slouch.

Also, just for funsies, let's take a look at all the rain that fell in California. While Seattle and Oregon weren't extraordinarily wet, California, particularly San Francisco and areas north, got absolutely soaked. This storm was fantastic for drought relief, but it would take 4-5 more of these to end what is the worst drought for California in at least 1,200 years.

Going back to our region, some of the highest winds in all of Western Washington were located right where I was. Useless Bay is that larger Bay that is to the west of Scatchet Head on the southern tip of Whidbey Island. This lines up well with what the UW's WRF-GFS model was predicting at the time; note how the highest winds are there and regions to the south over the water.

Valid 10:00 pm PST, Thu 11 Dec 2014 - 18hr Fcst

Anyway, let's take a somber look at some of the catastrophic damage inflicted upon the residents of Sandy Hook.

Play structures were ripped to shreds...

Furniture across our backyard was slaughtered...

And I would have loved to witness the gust that put this chair in this precarious position.

But all dishevelment of lawn furniture and children's play structures aside, there was some moderate property damage as well. Our "crab shack" got slightly de-roofed, which may end up being a blessing in disguise, as we now have an excuse to give it a new one. I didn't take a picture of it, but our 18-20 foot aluminum canoe got blown right off our dock and drifted a good quarter-of-a-mile down the man-made canal that our dock lies on. We are very lucky to have found it!

A big wooden fence that surrounded the community swimming pool toppled over under the storm's strong gusts.

Also, some similar fences right off the bay slightly leaned over due to the strong winds coming off the Sound. All in all, the structural damage doesn't look like much, but after witnessing how strong the winds were and how they hardly caused any damage, I've really gained an appreciation for the extreme strength of winds when significant structural damage is evident.

When we drove out to go back to Seattle, there were tons of branches all over the road and many downed trees that had taken out power lines. Our power was out for two days.

Lastly, here's something that's unrelated to the winds but is related to the low pressure system itself. With such low pressure over us in tandem with astronomically high tides, the observed tide was as high as I had ever seen it and almost passed over our dock. Pretty incredible.

On a final note, I'll leave you with some videos that I took. Here's one that shows how noisy our house was on that night, with some tasteful lighting to boot.

And here's the piece de resistance... an on-site video of the storm itself. I was recording right above a breakwall on the coast that was actually very close to the children's play structure that got thrown around. I'd estimate that winds were a good 50-55 on the water at that time, but as they went over the breakwall they accelerated as the wind was noticeably stronger there than right on the water.

I'll have more blogs coming soon, including ones regarding the potential for cold in the extended future. However, the short term forecast holds flooding, primarily for Oregon, where over 15 inches of rain may fall in select locations over the weekend.


Wednesday, December 10, 2014

Major Windstorm Tomorrow?

Wednesday, December 10, 2014
12:30 pm

I've got one more final tomorrow at 11:30 am, but here I am, blogging away my anxiety. Why on Earth would I put 40% of my grade on the line to write a stupid weather blog (and yes, I'm going to need all the time I have to study for this test. Kids, beware of atmospheric motions 441.)?

Because we might see a major windstorm tomorrow. 

Now, this isn't going to be a catastrophic windstorm for the Puget Sound lowlands, at least not at this point. Believe it or not, there were a couple models that were advertising that it could be. I define a "catastrophic windstorm" to be a storm with widespread gusts to 60-70 mph in our region. While that may not be a lot for the coast, it's a pretty big deal for the inland areas west of the Cascades. And with our saturated soils and excess of giant evergreens, you can bet that 60-70 mile per hour winds here are going to cause a lot more damage than equivalent winds in the Great Plains or even New York City. I would say our last catastrophic storm was the Hanukkah Eve Storm of 2006. This storm doesn't look to equal that one in magnitude for our region, but it could be one of the strongest since then. It could be. 

Why all the uncertainty? The storm is 24 hours out, so shouldn't we be smart enough to know if we're all going to die a grisly death? Well, the answer is yes, but the reality is no. The models have been inconsistent with the storm, but honestly, that's not the biggest problem. It's the very nature of the storm that were dealing with.

You know those Nor'easters they get on the East Coast? Well, this is its Northwestern cousin, the "Sou'wester." These are the storms that are historically the most damaging storms to our area, and they tend to impact the entire west coast. The last really big one was in December 1995, creating gusts of 72 mph from Cape Mendocino, CA to 76 mph up in Bellingham, WA. Portland hit 74, Sea-Tac hit 60, and Mukilteo, just to the north of Seattle, hit 86. And Cannon Beach, Newport, and Sea Lion Caves on the Oregon Coast all hit well above 100 mph.

The Columbus Day Storm of 1962 was also a Sou'wester, and any Pacific Northwest weather aficionado is familiar with "The Big Blow." With 179 mph winds at Cape Blanco, 116 mph winds in Portland, 127 in Corvallis, 100 in Redmond... you get the point. The Columbus Day Storm was the David Banner of Pacific Northwest windstorms, and we likely will not see one like it for hundreds of years. All these diagrams were taken from Wolf Read's The Storm King website.

I'd love to go on and on about massive Sou'westers, but you get the point. These are the big storms. They typically form south of Eureka around 135 West, and from there, they rapidly intensify and curl northward. Depending on how close they get to the coast, they can bring strong winds to an extremely large area. The Columbus Day Storm nearly paralleled the coast from California to Vancouver Island and remained just offshore, giving all areas a tremendous blow. Conversely, the Hanukka Eve storm came from the WSW and crossed Vancouver Island, only delivering its main blow to Washington as it never got close enough to the California and Oregon coasts for them to feel the full effect. Take a look at the pics below and notice the difference in tracks.

You can see how the Columbus Day Storm would have impacted a much wider area. Additionally, it was much deeper, so that contributed to the breadth and magnitude of destruction. AND, it occurred, on, well, Columbus Day, when many trees still had their leaves. Truly a worst-case scenario for destruction, yet a fascinating one from a meteorological point of view.

Now that you have a little background on Sou'westers, let's get back to talking about our forecast. As the track from the Columbus Day Storm shows, even a slight displacement to the west would have weakened the winds significantly across the region. Storms like the Hanukkah Eve Storm shown above that smash into southern Vancouver Island from the SW are not nearly as sensitive to changes in track. That's what makes this forecast so hard. Tiny changes in track with these types of storms mean major changes in effects. Remind you of another type of forecast here? (hint: it starts with an 's'). The National Weather Service sums this up well with their latest "weather story."

This specific storm has changed wobbled from making a direct pass right over Seattle to passing right off our coast, sparing us major winds. It will not even approach the Columbus Day Storm, and it will not be as strong as the Hanukkah Eve Storm even in a worst case scenario. The storm itself has a much higher pressure than the CDS; it bottoms out at around 970 off of the Californian Coast, and then it slowly weakens as it travels northward. Let's compare some previous model runs just so ya'll know what I'm talking about.

Here are the two most recent model runs from the UW. Last night's is below, and this morning's is below that.

Valid 01:00 pm PST, Thu 11 Dec 2014 - 45hr Fcst - Retrieved from UW mm5rt

Valid 01:00 pm PST, Thu 11 Dec 2014 - 33hr Fcst - Retrieved from UW mm5rt

You can see that the low this morning is further south (it is arriving later), weaker, and further offshore (this becomes even more apparent during later slides). However, I just checked the European model, and it is slightly closer with the low.

Credit: Weather Underground

Additionally, I just checked the latest 18z GFS, and it is ever so slightly closer with the low, although still offshore.

The bottom line:

I don't think this will be a major event for the Puget Sound lowlands. It will get windy, and there will be power outages. But I don't expect this to be a widespread, damaging event. The main reason is that regardless of the track, the low looks to be weakening too quickly as it heads up north.

However, as I said before, tiny changes will have big effects. We have a high wind watch over our area.

OK, NOW it's time to study. I might make a webcast tonight if I get some stuff done. Maybe.


Sunday, November 23, 2014

Crazy Snow in Buffalo

Friday, November 21, 2014
9:58 pm

We have a bad habit of making a big deal out of the white stuff in Seattle, and it seems to get worse with each passing 'blizzard.' It's all too predictable; the chains on buses strike sparks with the ground as the snow that was seemingly 'promised' by the forecasters never came, schools close due to uncertain snow forecasts (this actually happened in 2008; Seattle Public Schools had a snow day when not a flake of snow fell), and suddenly, snow is the only thing in the world that matters. The last thing is actually nice for a change, but the hysteria that commences in the city is downright laughable.

But my favorite part of the Seattle snow rush is how it gets hyped up by the media. I don't know if it's because the writing staff have decided that their ratings will go up if they are in 'winter storm coverage' days leading up to the event, or if the newscasters just have a competition to see who can more effectively convince the populace that a winter storm of cataclysmic proportions is heading our way. Here's how things usually go down in the newsroom.


Anchorman: "People are scared, and they should be. Snowstorms in Seattle are not only deadly, but dangerous too. The upcoming storm could be the worst we've seen in many, many years."

Anchorwoman: "Flakes were spotted up earlier at Capitol Hill, and although it looks sunny right now, experts say that millions, nay, trillions of additional flakes are on their way."

Anchorman: "People all over Twitter have been talking about the impending storm. iLikeClams says "my pulse is quickening, I hope my increased metabolism doesn't create extra heat to melt any snow coming our way," while No_Umbrellas says "I hate snow, I hope it ends up being rain so I can run in it naked." Lastly, SubaruGurl4Lyfe tweets "I can't wait for the snow! With my Subaru, I'm more prepared than anybody else in Western Washington who doesn't own a Subaru!" Clearly a variety of opinions out there with regards to the snow."

Anchorwoman: "There certainly are! But while opinions are great, we want the facts. With that, let's take it back to our weather center, where our weatherman, Voice Reason, is standing by. So, tell us Voice, how much extra firewood do we need to buy?"

Voice Reason (shaking nervously): "Well, the truth is, there could be snow, or there could not be snow. Most models haven't been showing snow at all, but there is one that has been consistently showing three to six inches of snow over our area sometime tomorrow. It's really hard to know."

Anchorman: "Thank you for that, Mr. Reason. It truly sounds like we are in for a catastrophic event. Hang in there folks, and button down the hatches. And don't die."


In Buffalo, that last sentence would actually hold true.

Buffalo and suburbs to the south are now recovering from the most severe lake-effect snowstorm in memory. 13 people have died. Dozens of roofs have caved in. Parts of the region picked up over 80 inches this week, and even more incredibly, most of that snow fell in one day. A suburb to the south of Buffalo picked up 66 inches (5 1/2 feet) of snow on Tuesday. If you average that over 24 hours, you get an average rate of 2.75 inches per hour, which is hard for me to fathom. There were reportedly times where thundersnow occurred with rates exceeding 5 inches per hour, which is absolutely shocking. For those of you who prefer the metric system, that's slightly over a centimeter of snow every 5 minutes.

Any unprecedented event begs the question: "how on earth did this happen?" Well, as I mentioned before, this snowstorm was of the "lake-effect" variety. But what is lake-effect snow? And how did we get a pattern so conducive to it in the first place?

Bering Sea cyclone on November 8 at its peak intensity. Credit: NASA
Well, do you remember that Bering Sea superstorm that formed out of the remnants of supertyphoon Nuri? That was also a storm of unprecedented strength; it was the strongest extratropical cyclone on record in the Pacific. But this storm did more than cause hurricane-force winds and 50-foot waves, it actually was responsible for pushing a tongue of cold, arctic air into the lower 48, giving the contiguous U.S. its first "polar vortex" of the 2014 winter season. In fact, take a look at what I said from this blog post two weeks ago.

"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.

Excellent weather forecaster, or supernatural meteorological prophet? I'll let the reader decide.

I actually explained how polar vortices work in my previous blog post, so if you are interested on the physics of those, just read that blog. But now that we've got all that straightened out, let's define lake-effect snow.

Lake-effect snow is snow formed when cold, dry air flows over a relatively warm body of water, picking up moisture and creating clouds and snow downwind as a result. These bodies of water are generally lakes, but lake effect snow has been known to occur over inland seas such as the Caspian Sea, and sometimes it can even occur over the ocean if the winds are aligned correctly. In fact, sometimes Sequim will actually get "Strait-effect snow" when we get especially strong arctic outbreaks as air picks up moisture as it crosses the Strait of Juan de Fuca and runs into the northeast side of the Olympics, rising and creating snowfall as a a result. The bodies of water have to be quite large; your standard holding pond isn't big enough to create any sort of snow. If it were, you can bet that kids all over the midwest would collaborate to build ponds upwind of the superintendent's house.

Lake-effect snow formation. Credit: NOAA Earth Sciences Laboratory.

The air flowing over the lake obtains heat via two methods: sensible and latent heating. Sensible heating is the heating we are all familiar with; if you have a stove top above a column of air, it will warm the air above it. Latent heat, on the other hand, is a function of water. It takes energy to evaporate water from the lake, so when this water vapor turns back into its liquid phase (i.e. where the clouds form), the energy inherent in the water vapor is then re-released, warming the atmosphere.

These two processes combine to make strikingly beautiful "cloud streets" such as the ones shown in the satellite picture below, which was taken on Tuesday the 18th at the height of the lake-effect snow-storm. Notice how it is clear upwind of the lakes, yet clouds form as soon as the air flows over them. Additionally, the flow is nearly parallel to lakes Erie and Ontario, meaning that a ton of moisture was able to have been suctioned up by this cold air. This, combined with relatively warm temperatures due to the early-season nature of this event and an extremely persistent, stationary flow, was responsible for the historic snow amounts witnessed in Buffalo.

Cloud streets over the Great Lakes on November 18, 2014. Source: NOAA

Buffalo is forecast to experience springtime warmth over the next week. While this may seem welcome after such snowfall amounts, it's actually the last thing they need, as the warm temperatures will quickly melt snow. Roofs have already collapsed due to the immense weight of the snow on top, and this melting make the snow more dense and compound the problem. With five feet of snow turning to water, you can definitely expect a lot of ponding and flooding in regions that were particularly hard hit.

I'll leave you guys with some pictures of the snowmageddon to gawk at. Brace yourselves.

I think it's going to be a long day. Credit: Empire State College

And the Buffalo Bills actually thought they were going to play here this Sunday. Credit: Buffalo Bills

I don't even know what these things are. The Spectrum - University of Buffalo's Student Newspaper

And of course...

If you've ever wanted to build one of these guys, now's the time.


Monday, November 10, 2014

The Polar Vortex - Winter is Coming

Monday, November 10, 2014
12:39 pm

I think the above meme explains all you really need to know about the weather this coming week. But since I am a kind and merciful weatherman, I shall oblige your curiosity and explain the meteorological situation that has led us to our first real chill of the winter.

But first let me explain what a "polar vortex" is. This catchphrase became quite the buzzword last year as all sorts of media dished it out like free miniature Bibles. Professor Rush Limbaugh took it upon himself to define the polar vortex, seemingly settling the hysteria once and and for all.

"So, ladies and gentlemen, we are having a record-breaking cold snap in many parts of the country. And right on schedule the media have to come up with a way to make it sound like it's completely unprecedented. Because they've got to find a way to attach this to the global warming agenda, and they have. It's called the 'polar vortex.' The dreaded polar vortex."

"Do you know what the polar vortex is? Have you ever heard of it? Well, they just created it for this week."

"Now, in their attempt, the left, the media, everybody, to come up with a way to make this sound like it's something new and completely unprecedented, they've come up with this phrase called the 'polar vortex.'"

And here's my favorite part.

"Whatever it is that keeps the polar vortex vortexed in the Arctic Circle is vanishing, and that cold air is coming to us. Normally it stays up there. But now it's down here. How did it get here? That's the deepening mystery. That is the crisis. That is what is man-made. Man is destroying the invisible boundaries that keeps that air up there.

"Polar vortex vortexed." Good one Rush. The fact is, the polar vortex was not just created in the last week. In fact, the term has been alive and well for over 50 years. 

The polar vortex is a persistent cyclone that encircles either one of Earth's geographical poles in a cyclonic fashion (in the same direction as low pressure systems; counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere). They are usually less than 1,000 km in diameter, and their strength depends on the temperature gradient between the poles and midlatitudes. As such, the vortices are stronger during the winter than the summer, as the temperature gradient between the poles and midlatitudes is greatest at this time. 

It can be a little bit tricky to explain just in terms of words, so hopefully the picture below help you understand.

Northern Hemisphere Polar Vortices. Source: NASA Earth Observatory

Vorticity is an advanced concept, but it can be thought of as the tendency for a an air parcel to spin, with higher values responding to higher tendencies. Therefore, the higher the the vorticity, the stronger the polar vortex. The diagram above shows how a singular polar vortex over the North Pole weakens and breaks down into two separate vortices. When this happens, one of these vortices can slide south and bring a whole bunch of cold air that had been previously been stored up near the poles with it. 

The below diagram gives a general idea to how a part of the polar vortex gets cut off from the main circulation by the pole, bringing frigid air southward with it.

Schematic of the formation of an arctic outbreak in the Northern Hemisphere. Source: Wikipedia.

So, now, we've got a general idea of what the polar vortex is, and how it works. So what's gonna happen this week?

It turns out we are actually going to see an event like the one illustrated in pictures a, b, and c above. Take a look at the model chart below, and you'll see what I mean.

Retrieved from Supercell Weather

The colors represent the "thickness" in decameters of the atmosphere, which is a function of the overall density of the atmosphere and therefore the temperature via the ideal gas law. Take a look at how much lower the thicknesses are over much of the United States than areas much further north, with Southern Canada having particularly low thicknesses. This, right here, is the "polar vortex" that has been cut off from its 'parent' circulation up by the pole. Some of this cold air is actually infiltrating into Washington and even Seattle, and we will see our first freeze of the region Tuesday night. Models had been flirting with snow in the Portland region, but for now, it looks like any snow will be confine at and east of the Cascades, particularly near the Columbia Gorge. 

In the extended, we'll have a ridge of high pressure off our coast that will close the door to the the Pacific storm train that has been open for so long. We look to be relatively dry for the foreseeable future. Enjoy the break!


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!

Tuesday, November 4, 2014

My Winter Weather Outlook

Tuesday, November 4, 2014
6:02 pm

Hey everybody, I actually just produced a winter weather outlook for WeatherOn, and you can find it here. Long story short, our weak El Nino played a major role in my forecast, and the previous existence of the "Blob" did to a lesser extent.

Snow in Eugene


Saturday, October 25, 2014

Windstorm on the Way

Saturday, October 25, 2014
1:12 p.m.

First off, sorry for not being the most punctual poster as of late. I was actually recently contacted by the University of North Carolina of all places to write a weather blog using some of their graphics for WeatherOn. I really hope it will put uss "On" the map. Get it? :D

Anyway, you can check out the blog I wrote here.

But that post can be read anytime. We've got some action coming in right as I type this sentence, and things are starting to look pretty hairy around the Pacific Northwest.

Earlier this week, there was some talk about a windstorm impacting Oregon and Washington. This windstorm had the classic track of a "Sou'wester," (compare to Nor'easter) which is the slang term for the biggest region-wide windstorms we get in the Pacific Northwest, as they often come out of the southwest.

Image Credit: OWSC: Wolf Read's Storm King Website

We haven't had too many of these big Sou'westers lately. Our last one of note was January 16, 2000, but our last really big one was December 12, 1995. We had another big one back on November 13, 1981 as well. Still, none of these can compare to the granddaddy off all sou'westers, and in fact, the strongest extratropical storm to ever hit the United States: the Columbus Day storm of October 12, 1962. Some call it the CDS, some call it simply "The Big Blow," and others, like myself, prefer the unnecessarily verbose "Terrible Tempest the Twelveth." Either way, the Columbus Day Storm was a sou'wester on a whole other level, and a storm a likes of which we will not see for centuries, even millennium. It truly was a singularity, and it still casts a dark shadow over every other single storm to hit the Pacific Northwest. Many of them have been very memorable, but none of them have caused such widespread destruction over such a wide area. I would give an arm and a leg to see what that beast looked like on satellite, but alas, there were no satellite shots taken of it. The sad thing is that I'm not necessarily joking when I say I'd give an arm and a leg... I'd just be taking one for the team. I'd have to ponder over it.

You'll notice that two of Seattle's largest windstorms - the Inaugural Day Windstorm of 1993, and the Hanukkah Eve Storm of 2006, are not listed. The reason for this is that they are not sou'westers in the first place. They approached the coast from a more western track instead of paralleling the coastline. If they did parallel the coastline, they would have impacted a much larger amount of inhabited land, and the damage totals would have been much higher.

The three major cyclones I just mentioned - 1962, 1981, and 1995, were all below 960 mb, which is about equivalent to the pressure of a category 3 hurricane. This cyclone is predicted to drop to around 985 mb. Accordingly, the winds will be much less, but it has already taken a track of a region-wide windstorm and affected a large area, and it is on a course to provide particularly high winds to the Seattle metro area as it passes just to the north of it. Winds are already picking up here right now.

Take a look at the rooftop data from the UW atmospheric sciences building. In particular, take note of now the winds have strongly increased just in the past hour. And folks, they are only going to get stronger.

Atmospheric Sciences Building 24-hour rooftop summary

Taking a look at our current satellite, you can see that the low pressure is just starting to make landfall into Western Washington. Oregon is still seeing strong winds, but the strongest ones are likely over. Winds will hang on a little longer in northern Oregon.

5pm UW Infrared Satellite

Additionally, here are the warnings and watches in effect for Western Washington and Western Oregon. It's not often that you see tan in the Puget Sound area, especially in October.

NWS Seattle

NWS Portland

The effects of this windstorm could be exaggerated by the fact that the deciduous trees still have the majority of their leaves on them (at least they do right now!). More leaves = more surface area, and a higher surface area will catch more of the force of the wind gusts and transfer that force to the tree, making it more likely to snap or topple. In addition, our soil is relatively saturated due to that massive rainstorm we saw earlier this week, and since saturated soil loses its cohesion, it is easier for complete tree failures to occur in the presence of it. As if all this wasn't enough, there have been weak and dead branches that have stayed in the trees all summer long, and being the first windstorm of the season, this one is the one that is most likely to blow them all off. Don't be startled if you lose your power tonight.

Thank you! Stay safe!

Friday, October 10, 2014

Is El Nino Making A Comeback?

Friday, October 10, 2014
5:08 pm

After a return to neutral conditions over the summer, we will likely see weak El Nino conditions for the 2014-2015 winter.

At least that's my prediction. And I will tell you why.

There's a wonderful, wonderful website hosted by the National Weather Service's Climate Prediction Center that you can access right here, and it is an animation of the current sea-surface-temperatures in the tropical Pacific. As I'm sure many of you know, the tropical Pacific is where the single most influential short-term atmospheric/oceanic oscillation occurs. El Nino, and its sister phase, La Nina, influence weather throughout the world. And it looks as though after teetering on the edge of an El Nino, we may finally enter one in the near future.

Before we take a look at how the SST have evolved over the past few months, lets review our El Nino "regions."

Retrieved from the National Climatic Data Center

Atmospheric scientists and oceanographers refer to certain regions when talking about SST in the tropical Pacific. For example, they might say "temperatures were 1 degree Celsius above average in Nino 1+2, and 0.7 degrees Celsius above average in Nino 3.4."  Nino 3.4 is the most commonly cited region, and El Nino conditions are often classified as anomalies of 0.5 degrees C or above in Nino 3.4. 

Now, we can take a look at the SST traces.

ENSO Discussion

You can see that we had neutral conditions until May in most locations, after which we turned slightly El Nino. By August though, things were on the decline, and we have been in borderline El Nino conditions ever since. However, if you will recall that SST animation link I gave you above, the most recent charts show an increase in warm water in the eastern Pacific, particularly in Nino 1+2. The water that upwells off Peru propagates westward, meaning it won't be long before this newly-formed poll of warm water ends up in Nino 3.4. The big "blob" of warm water in the Northern Hemisphere north of Hawaii is related to the Northeast Pacific Mode (NEPM), and I shall talk about it in a different blog.

ENSO Discussion

In addition, the CPC and IRI (International Research Institute for Climate and Society) have climate models that predict whether ENSO will occur or not. These models are far from perfect... they originally predicted that this year would feature a very strong El Nino rivaling the 1997-1998 El Nino event, which was the strongest on record, though an El Nino from 1982-1983 was very strong as well. Instead, now models are leaning towards a weak El Nino, with some not even developing an El Nino. The CPC lists a 2/3 chance of an El Nino developing within the next 4-8 weeks and continuing into next spring. As I said before, based on the latest SST profiles from the tropical Pacific, I believe that we will see a weak El Nino this winter.

ENSO Discussion

Alright, enough of this tropical Pacific stuff. What's in it for us, here in the Pacific Northwest?

Below are some diagrams of patterns associated with El Nino and La Nina (which, by the way, describes cooler than average SST in the tropical Pacific). With El Nino, the Pacific Northwest is often warm and dry, while California gets clobbered with big storms. Los Angeles had F2 tornados in 1983 and 1998, both strong El Ninos. Coincidence? I think NOT!

Climate Prediction Center

Many people may welcome a warm and dry winter, but I certainly do not. I like my winters to be dark, rainy, stormy, and above all, snowy. However, even El Nino winters can feature snow, particularly weak ones. In fact, our snowiest winter ever occurred during an El Nino winter. December 1968 and January 1969 combined for an astonishing 67.5 inches of snow (thank you Scott Sistek for that statistic). Scott wrote an excellent blog on this; you can read it here.

We don't have any snow data for the 1997-1998 winter, but the snowfall accumulation for 1982-1983? "Trace." If we had a strong El Nino, I'd abandon all hope now, but history tells us that we aren't completely out of the snow game yet. Not by a long shot.

Long range forecasts keep us warm and dry. The thing is, long range forecasts have always been keeping us warm and dry since El Nino started to appear, yet July, August, and September were all wetter than normal, primarily due to heavy precipitation events. As we all know, they were all much hotter than normal, making for a spectacular summer. I personally hope that we go the way of 1968-1969, and even if we can't get 6 1/2 feet of snow in the lowlands, we can try and get a significant amount in the mountains for winter recreational activities and water storage purposes.

With a weak El Nino, you never know what can happen. ;)