I Am Actually Looking At Weather Models

Thursday, October 11, 2012
2:52 P.M.

I'm a weather fanatic, and most of you know that. But during the last 80 days, I've been out of touch with my meteorological side. Back in September, if you asked me what the weather was going to be a week from now, I would have no clue. All I knew is that it would probably be boring. I honestly didn't care about the weather, and I did not look at the weather models, because it would be depressing and pointless. Looking at the weather models this past summer would be like watching the UW - LSU football game this past season in the 4th quarter. There's nothing to see. You could be doing so many other productive things with your time, like calling a friend, taking a nap, or watching funny Youtube videos. Summer is great, but let me tell you, this past summer's weather is more boring than watching my roommate play ten hours of League of Legends each day (ok, I admit, it's actually pretty entertaining).

So, I heard through the grapevine that we could see some rain in the coming days, and I looked at the weather models. Since then, I've been looking at them constantly. I've also been reading the forecast discussions put out by the National Weather Service, the hydrology forecasts, and the direct model output for certain places using a program made by a weather/computer genius out of Portland named Brian Schmit that extracts the model output and gives various quantifiable information for certain locations about the forecast. Go to http://www.directpaintsaleswa.com/brianschmit/weather/index.htm and click on "downloads" on the lower left hand corner, and then click the first download, which is the "16-Day GFS Extraction." He also has a bunch of other free downloads that are very cool and useful.

After a couple days of getting re-involved with the weather scene, I had a revelation; I was actually looking at weather models. Of course, this sounds obvious, but it really hit me to my core. I, Charlie Phillips, was, for the first time in months, actually looking at weather models. I dunno... it's kind of stupid... it kind of sounds like something a person would say while smoking weed. No weed here though... it was really that fascinating for me.

ANYWAY, let's get down to business. The weather models have been consistent in their main idea, but inconsistent in the details. The main idea is that we will end our incredibly long dry spell (0.03 inches of rain at SeaTac since July 23) on Friday, as a moderate front swings through our area. It won't be very strong... Seattle will probably not get more than 0.30 inches of rain from this storm, but seeing as 0.30 inches of rain is ten times the amount of rain we have seen in the last 80 days, it will probably feel like a Biblical flood.

Valid 05:00 am PDT Sat, 13 Oct 2012 - 48hr Fcst - UW 4km 12z WRF-GFS 24-hour precip ending 05:00 am PDT Saturday

This rain will make the roads quite slippery, because there is a lot of oil and dust on them that has accumulated and not been washed away for a very long time. The rain mixes with the oil and dust to create a very slippery lubricant. Also, there are likely people who have forgotten how to drive in even the slightest amount of rain. I remember when I was taking a calculus class last year that I had placed into because of AP testing at Garfield, but I couldn't even remember what the chain rule was, so I had to do a bit of catching up. That was a pretty long quarter for me.

But the great thing about this front is that it will open the door to a much stronger and wetter series of storms that will reach our area Saturday night and persist until Monday morning. These storms have tapped into some tropical moisture, and they will be centered right over our area in an "atmospheric river" type pattern, where the atmosphere flows in such a way that a moist air mass from the subtropics makes its way into the mid-latitudes in a "river-like" fashion and tends to flow over an area without moving too far away from it. Take a look at the picture below, which shows the "river" of moisture over our area.

Valid 11:00 pm PDT Sun, 14 Oct 2012 - 90hr Fcst - UW 36km 12z WRF-GFS Column Integrated Water Vapor

Most of our big flooding events come from atmospheric river events. Since the air has subtropical origins, snow levels are high, so the precipitation that does fall falls as rain. As I stated previously, they tend to stall over a region, leading to prolonged periods of heavy precipitation. And since the air is very moist, there are high rainfall rates associated with them. The good thing is that we will not see flooding from this atmospheric river event. The river levels are pretty darn low because of the lack of rain, so the rivers will have plenty of space to rise without reaching bankfull. The only exception is the Skokomish, which floods very easily, but even if it does flood, the flooding will be minor. 

So how much rain are we talking here? Take a look at the picture below.

Valid 05:00 am PDT Mon, 15 Oct 2012 - 96hr Fcst - UW 12km 12z WRF-GFS 24-hour precip ending 05:00 am PDT Monday

We are generally looking at 0.5-2.5 inches in the lowlands, 2-6 inches in the Cascades, and 4-8 inches in the Olympics, with the differences being due to different amounts of adiabatic forcing. Areas north of Seattle, particularly around Sequim, will see 0.1 to 0.5 inches of rain, and the areas marked in red on the Olympics and parts of the Cascades could see 8 inches of rain from this single storm. Folks, that's a lot of rain.

But it's not just rain that we will have to contend with. Some models, most notably the GFS (which is one of the ones the UW uses for their high-resolution forecasts), bring a strong low pressure center into Vancouver Island Monday morning. With lower pressure to our north and higher pressure to our south, we can expect some pretty breezy conditions in our area. As is usual, the highest winds will be over the coast and north interior.

Valid 05:00 am PDT Mon, 15 Oct 2012 - 96hr Fcst - UW 12km 12z WRF-GFS 10m Wind Speed

The model above shows a 977 mb low pressure center headed towards North Vancouver Island. The models differ on the timing and track of this storm, but a storm like this could give Seattle gusts of 40 miles per hour. Yeehaw!!! 

Tomorrow is the 50th anniversary of the famous (or infamous) Columbus Day Storm of October 12, 1962. I'm going to a presentation Cliff Mass is giving for free at 7:30 tonight at the UW's Kane Hall, so I'll have plenty of fresh information to relay back to you guys tomorrow. If you read this blog in time, you should try to make it, it should be an interesting lecture.

Chuck

La Nada?

Monday, October 8, 2012
11:03 A.M.

Most people know what El Nino is, and most people also know what La Nina is. But if you throw around the highly scientific term "La Nada," most people will raise their eyebrows, cock their head, and ask you to repeat yourself. "La Nada" is the term affectionately given to neutral winters, in which there is neither El Nino or La Nina.

Take a look at the picture above. It shows the SST anomalies over the past week in the tropical Pacific. The temps are just about normal in the equatorial Eastern Pacific! And take a look at this diagram below. There were weak El Nino conditions over the summer, but they are dying out. NOAA's Climate Prediction Center (CPC) has noticed this, and on October 4, they dropped their previous estimate of a 69% chance of an El Nino occurring to 55%.

Here's NOAA's latest take on the matter.

Due to the recent slowdown in the development of El Niño, it is not clear whether a fully coupled El Niño will emerge. The majority of models indicate that borderline ENSO-neutral/ weak El Niño conditions will continue, and about half suggest that El Niño could develop, but remain weak. The official forecast therefore favors the continuation of borderline ENSO-neutral/ weak El Niño conditions into Northern Hemisphere winter 2012-13, with the possibility of strengthening during the next few months.

I personally believe that we will see a neutral winter. And let me tell you, I am more excited about the weather than I have been in a very long time.

It's been a while since we've seen a La Nada winter. Take a look at the picture below. Every year since 2005 has either been an El Nino year or a La Nina year, and the variations in the past five years have been huge. 2012 is not shown, but it was a La Nina as well.

Forecast models were predicting this year to be an El Nino year. I dislike... no... I feel contempt for El Nino years. They infuriate me. For us, El Nino winters = boring winters. La Nina winters are generally more exciting, and they are a lot snowier for the mountains.

But nobody really talks about neutral winters, and neutral winters could perhaps be the most interesting of all the winters. If you take a look at the major windstorms of the Pacific Northwest, all of them occurred on La Nada winters. All of them! What's more? Many times, our most dramatic floods come on neutral winters, and even though La Nina winters are snowier on average in the Western Washington lowlands, some of our biggest snowstorms come during neutral years as well! Remember the huge snowstorm of December 2008? That was actually during a weak El Nino year. Go figure!

This is fantastic news. Absolutely stellar. And we are still on track for our first big rainstorm of the year on Monday.

See if you can find the movie that wonderful quote is from. :)

Charlie

So Long, Treadmill

Saturday, October 6, 2012

4:02 P.M.

It's been a pretty boring run, but we are approaching the end

I love running, but I absolutely hate treadmills. With a treadmill, you don't get the relaxing breeze in your face, you don't get to explore new places around the city, and you are in constant danger of slowing down a wee bit too much, falling off the treadmill, and becoming the laughing stock of all the other sad souls who are running on treadmills. Treadmills are atrocious for so many reasons. The only positive thing associated with treadmills is the 'Ok Go' "treadmill" music video, and even that is pretty boring to watch.

This weather has reminded me of a treadmill. It's the same stuff every day. We are experiencing the same lack of precipitation, the same degraded air quality because of forest fires... everything. It would be one thing if we were seeing the same cool stuff every day... that would be like swimming up-current in a beautiful, pristine river; sure you wouldn't be going anywhere, but it would still be intellectually stimulating and spiritually fulfilling. But the same boring stuff every day, hence the treadmill analogy. I will never degrade myself to buying a treadmill.

However, this metaphorical treadmill is just about dead, and when it dies, we will start to see interesting weather once again.

Let's take a look at the ole' trusty GFS Superensemble (aka: the really far range model I use when I am desperate for interesting weather to occur).

Valid 05:00 pm PDT Sat, 06 Oct 2012 - 6hr Fcst - 18z North Pacific GFS Superensemble  1000-500mb thickness, 6-hour precip

As you can see, there is still that huge fat ridge of high pressure over our area. It's massive! You can also see a very weak area of lower pressure off the coast of California. This setup is called a Rex Block, because apparently there was some guy named "Rex" who discovered it and decided to put his name on it. It's kinda hard to see in this bigger model chart, so let me show you a UW chart where it is easier to see.

Valid 05:00 pm PDT Sat, 06 Oct 2012 - 12hr Fcst - UW 12z GFS 500mb absolute vorticity, heights

It's very easy to see the Rex Block in the above chart. Here's an idealized diagram of one, just for good measure.

 This thing has been here for such an infuriatingly long time, and I am ready to see it go. Will it?

The answer? YES!!! Also, no clue why, but blogger decided to highlight the back of my text white after the next sentence, and I don't know how to get rid of it.

You have to go to the very end of the latest Seattle NWS forecast discussion to get to the good part, but at the very end, they say:

 A MORE SIGNIFICANT CHANGE TO A WET WEATHER PATTERN APPEARS  
  INCREASINGLY LIKELY BY LATER NEXT WEEKEND AS THE WEST COAST  
  RIDGE BREAKS DOWN AND TROPICAL MOISTURE ORIGINATING IN THE WESTERN  
  PACIFIC GETS ENTRAINED INTO THE WESTERLIES. ALBRECHT

I've been waiting for a sentence like this for months on end. The boredom is coming to an end. Folks, we are  finally getting off the treadmill.

Valid 05:00 pm PDT Sat, 13 Oct 2012 - 180hr Fcst - UW 12z GFS 500mb absolute vorticity, heights

No more Rex Block! Surface-wise, we have a bit of precipitation coming through our area. But we gotta go to the superensemble to see any real storms affecting our area.

Valid 05:00 am PDT Sat, 13 Oct 2012 - 186hr Fcst - 18z GFS North Pacific Superensemble 1000-500mb thickness, 12-hour precip


Would'ya look at that. A nice, fat, juicy front poised to strike our area. It's about time.
Charlie

A Record Low for Arctic Sea Ice

Monday, September 24, 2012
10:43 A.M.

Retrieved from National Snow and Ice Data Center (NSIDC)

On September 16, 2012, the arctic reached a record low for sea ice cover. Now, it is finally expanding as autumn arrives, but it is still well below average.

The sea ice cover this year fell to 3.41 million kilometers, which is 18% less than the previous record for lowest ice extent, which was set in 2007. It is also 49% less than the median for 1979-2000, which is outlined in the orange. This is the fifth consecutive year, and the fifth time in recorded history, that ice-free navigation was possible from the north coast of Canada to the north coast of Siberia, and, as you can see, this navigation window was massive. 

Retrieved from Chapman & Walsh (2001), and updated by the University of Illinois Cryosphere Today. In addition, Wunderblog blogger Jeff Masters updated the graph to include 2011 and the first nine months of 2012.

As the above graph shows, this event, while record-setting, is by no means an outlier. The loss of sea ice has been accelerating since the 50s, and the sea ice has drastically declined in the past five years or so. An important measurement to point out is that the winter sea ice cover has changed relatively little - from ~15.5 million square kilometers to 14.5 square kilometers. However, the summer ice extent has dropped drastically - from ~11 million square kilometers to ~ 6 million square kilometers.

This graph begs the question: why has the change in summer ice been so much more drastic than winter ice? Well, this graph measures ice extent, and not the thickness of ice. As the Earth becomes warmer due to global warming (which is very real and very serious - see my post here), the ice thins, so it takes less heat to expose a certain amount of water. Add this with the positive feedback of the albedo of water being much lower than the albedo of sea ice, and you have a recipe for disaster... a polar ice cap that is dying before our very eyes. In the mid 2000s, the scientific consensus was that the arctic would be ice-free in the summer by 2040 or 2050. But as there has been a drastic decline in sea ice in the past five years, most scientists predict that arctic summer sea ice will be completely gone by 2030, and some radical estimates show it being completely gone by as soon as 2016.

 This general sequence of editing previous estimates to become more dire is pretty common, especially when it comes to ice caps and sheets, both on land and on the ocean. The summer sea ice extent has declined at ~12% per decade, which is far more than the 2007 IPCC's "worst case scenario."

Retrieved from Kinnard et al.'s 2011 paper: Reconstructed changes in Arctic Sea Ice over the past 1,450 years.

Here's a longer term graph of average sea ice extent. Needless to say, this type of warming is unprecedented in this graph, and according to climate proxies such as ocean sediments and ice cores, perhaps much longer.

Interestingly enough, in the article I got this information from showed that the Antarctic sea ice extent was actually growing instead of shrinking, even as the air temperature by the southern oceans has begun to rise.

Why is this? Bear with me here, because the reasons are complex. First off, the water at the surface of the Antarctic Ocean (specifically the Weddell Sea) is actually colder than the deeper water because of the cold air temperatures at the surface. This warm water upwells and melts sea ice. However, there has been an increase in precipitation in recent years as the air temperatures have warmed. This does two things: 1.) the snow acts to expand ice caps, and 2.) the surface water freshens because of the increased precipitation, which leads to a more stratified ocean where the water mixes less easily, and since the decreased salinity in the surface ocean decreases the density, the water from the surface ocean does not sink as easily, and the warmer water from the ocean bottom, which acts to melt the ice, rises more slowly, so less ice is melted.

It is very important to look at everything that is changing in our climate, whether there is a decrease or increase in temperature and/or ice caps. This can go both ways... global warming deniers will specifically point out places where ice is expanding (like the Antarctic) and say that global warming is nonsense, and some global warming activists only point out places where the Earth is warming and ice cover is decreasing. Both of these methods are flawed. The only way we can definitively prove that the Earth, as a whole, as warming, is by looking at everything that is happening to our climate and taking an unbiased, scientific approach to an environmental change unlike anything the Earth has experienced for a very long time.

We have to go back 55 million years ago to the Paleoeocene - Eocene Thermal Maximum (PETM) to find an analog for the climate change the Earth will undergo in the future. But we have to be logical and scientific in our analysis of the problem, and we cannot specifically pick out data that supports global cooling or global warming. We have to look at all the data.

Charlie

Making Something Out of Nothing

Sunday, September 23, 2012

3:10 P.M.

It's been bad. Interesting weather is my drug of choice, and unlike most recreational drugs, it has good long term effects which include but are not limited to career opportunities, meeting new people, and the knowledge to impress and win the hearts of millions in the Seattle metropolitan area.

But like most drugs, weather has a dark side. It is addictive, and therefore, when there is no interesting weather to be found, withdrawal symptoms occur. The main symptom is my constant staring at models, hoping for something to magically change in them, but alas, no change is to be found at this time. Of course, there are ways to cope, such as looking at weather happening in other parts of the world, or reminiscing on past weather events, such as the Hanukkah Eve Storm of 2006, the Great Coastal Gale of 2007, and the Awesome Phillips' Snow Forecast of January 17, 2012.

So what do we do now?

Well, first, let's look at the weather models to see if anything has changed. I'll take some snapshots from different times in the 12z GFS model run.

Valid 11:00 am PDT Sun, 23 Sep 2012 - 6hr Fcst - 12z GFS 1000-500mb thickness, 6 hour precip, SLP

There is a huge ridge over our area, with storms being directed north into Alaska. Super boring.

Valid 05:00 am PDT Wed, 26 Sep 2012 - 72hr Fcst - 12z GFS 1000-500mb thickness, 6 hour precip, SLP

Almost the exact same setup. Storms over Alaska, but nothing here.

Valid 05:00 pm PDT Sun, 30 Sep 2012 - 180hr Fcst - 12z GFS 1000-500mb thickness, 6 hour precip, SLP

Same darn thing! Alaskan storms, but a huge ridge over us.

Ok, let's go out to 384 hours, which is the furthest the GFS goes out.

Valid  05:00 am PDT Tue, 9 Oct 2012 - 384 hours Fcst - 12z GFS 1000-500mb thickness, 6 hour precip, SLP

It looks like a weak front MIGHT hit the area. And sadly, that's the most interesting thing in the extended.

Most of you who read this blog know that a 384 hour forecast is useless. In fact, on October 9th, I'll post the same model run, and we'll see how similar the two model charts are.

But, by writing a weather blog, I made something out of nothing.

To my UW com-padres, enjoy the beginning of the school year (school starts tomorrow).

Charlie