Tuesday, August 26, 2014

Here Comes The Rain

Tuesday, August 26, 2014
7:30 p.m.

Here comes the sun... not. 

Although you wouldn't know it, we are actually well above average for rainfall this month (and, come to think of it last month was above average in the rainfall department as well). This is due to Sea-Tac accumulating 0.50 inches of rain on the 12th and 0.85 inches on the 13th. We've tallied up a grand total of 1.43 inches of rain at Sea-Tac the entire month, but seeing as 1.35 inches fell in two days, you wouldn't know that we are so much above average. Average for this time of month is 0.67 inches.

At the end of this week and into next week, we actually will have a pattern change which will bring us more rain. However, this rain will come to us in a more familiar fashion with periods of light rain as opposed to heavy downpours from convective activity. Before that though, we've got some warm weather to go through.

Tuesday got up to 88 at Sea-Tac, and Wednesday, while cooler, should still be pretty darn hot.

Valid 08:00 pm PDT, Tue 26 Aug 2014 - 3hr Fcst: Taken from the UW mm5rt website.

As you can see, there is a ridge of high pressure over us, but it is moving east and will continue to do so. As it does so, the door will be opened to a cooler, moister Pacific flow. I'd expect temperatures to climb into the mid 80s across much of Western Washington Wednesday with high 70s directly by the Sound, but Thursday and Friday will feature increasingly cloudy conditions with highs in the mid 70s, particularly in the mornings as a marine layer off the ocean settles in overnight and thins throughout the day. Don't be surprised if you feel some drizzle in the mornings these days if there is a particularly strong marine push, particularly on Friday.

As for the rain, a small amount might stick around the Seattle area Thursday night as a very weak feature comes through, but most of it looks to roll through Saturday afternoon.

Valid 02:00 pm PDT, Sat 30 Aug 2014 - 93hr Fcst: Taken from the UW mm5rt website.

As you can see, the rain shown above is pretty negligible. The GFS shows a stronger system coming in Monday night though, and it could bring heavier amounts of rainfall. That being said, the European model, which is generally more accurate, predicts a drying trend after the weekend.

Valid 05:00 am PDT, Mon 01 Sep 2014 - 132hr Fcst: Taken from the UW mm5rt website.

Will we follow the GFS' predictions, or will we tailor more closely to the Euro? It's too far away to tell at this point, and the models have not been very consistent run-to-run. For example, the Saturday system was much stronger on Tuesday morning's GFS than the run Tuesday night.

Either way, I don't think we'll be seeing much in the way of wildfires for a while. :)


Saturday, August 23, 2014

Bárðarbunga - Is a Major Volcanic Eruption In The Cards?

Thursday, August 22, 201411:05 p.m.

Bárðarbunga releasing steam from beneath the Vatnajökull Glacier. Photo Credit: Oddur Sigurdsson, Iceland Geological Survey. 

It's safe to say that Iceland's remote Bárðarbunga volcano doesn't look like a typical volcano. Even though it is 6,591 feet tall, it has all but been completely consumed by the massive Vatnajökull glacier, with the only evidence of a volcano being a snow-covered caldera with a tiny hole in the center formed by warm gases melting snow as they travel from the volcano into the atmosphere.

Isn't it cute? Photo link: http://www.geo.mtu.edu/volcanoes/iceland/vatnajokull/

But the above dimple is far from docile. Bárðarbunga has had major eruptions in the past, and it looks as though another one may be in the cards. We have many things to talk about, but before I go any further, let me explain what's been happening recently with the daintily cute aforementioned volcano.

Bárðarbunga has been the site of a vast swarm of earthquakes recently, with the strongest one (magnitude 4.7)  occurring around 18 hours ago at midnight 8/22/2014 Iceland time. Swarms of earthquakes are often a precursor to volcanic activity... Mt. St. Helens was having hundreds of small earthquakes a day before it finally blew its top on 8:32 a.m., May 18, 1980. Between last Saturday morning and Monday evening, the Iceland Meteorological Society measured 2,600 earthquakes, with that 4.7 earthquake being the biggest one measured since 1996.

So far, no magma has made it to the surface, but scientists are concerned that these earthquakes may signal an impending eruption. Even though it has been found that earthquake swarms lead to eruptions less than 10% of the time, a Bárðarbunga eruption could paralyze not only Iceland but all of Europe.

First, let's talk about the anatomy of this volcano.

It lies under the northwestern edge of the Vatnajökull glacier, and, as I said before, is completely encased in ice. You are not able to see the structure of the mountain. At the rate we are warming up, several generations south of us will surely be able to see parts of the mountain, but we don't live in a world that has truly felt the effects of anthropogenic greenhouse gas emissions.

Some of you may remember the eruption of the volcano Eyjafjallajökull (aka: "that Iceland volcano") back in 2010. While Bárðarbunga is easier to pronounce (the anglophone spelling is "Bardarbunga"), they share many similarities, as they have comparable geological properties and are both covered in ice. The difference is that  Bárðarbunga is much bigger, and if it does erupt, it will release far more magma.

8,500 years BP,  Bárðarbunga released 21-30 cubic kilometers of lava and covered 950 square miles with it. This is speculated to have been the largest lava flow of the Holocene Era, which began at 11,700 years BP (right after the last ice age) and continues today. The Vatnaöldur eruption of 870 was very large, as was the Veiðivötn eruption in 1480. Bárðarbunga hasn't witnessed an actual eruption since 1862, though it did have some activity in 1996.

So what are the consequences of a possible eruption?

Well, the biggest local consequences will be the threat of massive flooding. A large eruption would melt an incredible amount of water, and this water could sweep villages away. These "volcanic floods" are not unique to Icelandic volcanoes; they occurred as Mt. St. Helens melted snow in 1980 and are actually one of the biggest threats to nearby towns in the event of a Mt. Rainier eruption.

Something with a far broader geographic scope would be the ejection of ash into the atmosphere. Remember the Eyjafjallajökull volcano I was talking about earlier? The 2010 eruptions of it led to the highest travel disruption in Western Europe since World War II. The eruption truly was small... the ash cloud only reached 10 kilometers high, and only 270 million cubic meters of ash was ejected into the atmosphere. Mt. Pinatubo, for instance, ejected 10 billion cubic meters of ash 34 kilometers high. What made Eyjafjallajökull so much more destructive?

Eyjafjallajökull erupting on April 18, 2010.  http://en.wikipedia.org/wiki/2010_eruptions_of_Eyjafjallajökull

First off, it's important to remember that Iceland is right between the U.S. and Europe, so it is important as a hub for air travel. But there are other geological factors at work. When the magma at Eyjafjallajökull's vent reacted with the nearby glaciers and rapidly cooled, it contracted into much smaller and more jagged/porous ash particles than are usually seen. Moreover, more fine ash was created when small gas bubbles in the molten rock expanded as the magma rose and approached the surface. The median width of all the ash grains was found to be less than 1 millimeter wide, and further away from the vent, 20% of the ash particles were smaller than 16 microns, which is approximately six times thinner than a human hair. In the process of cooling rapidly as it rose, the  Because this ash was so light and, due to its rough and porous texture, was aerodynamically favored to stay high in the atmosphere for a long time, massive air travel disruptions resulted. There was also a fairly stagnant weather pattern over Western Europe at the time, so these particles were not carried laterally either. They just sat there and wreaked 1.7 billion dollars worth of havoc on the airline industry.

Canceled flights at Leeds Bradford Int'l Airport. http://en.wikipedia.org/wiki/Air_travel_disruption_after_the_2010_Eyjafjallajökull_eruption

If Bárðarbunga were to erupt, it would be in that same jet path, and the ash particles would probably have similar characteristics and be FAR more numerous. The weather would be the wild card.

By the way, Bárðarbunga was recently just updated to a "orange" risk level, which is apparently the highest there is without a volcano already erupting. They updated it after they found out that, in addition to all these earthquakes continuing to happen, the magma is moving closer to the surface.

When I was little, I loved volcanoes more than anything else. I've now given my heart to weather, but my love for volcanoes is still very alive.

Update: 8/23/2014

Bárðarbunga started erupting this morning for the first time. The eruption is small, and it is being extremely carefully monitored.


Friday, August 22, 2014

Marine Pushes, and Their Effect on Summer High Temperatures

Thursday, August 21, 2014
11:03 p.m.

We "only" reached 70 degrees today. At 6 degrees below average for a high temperature, it's fairly cool, but not extraordinarily so. The last time we didn't hit 70 was on July 24th, meaning it's been nearly a month of consecutive 70 degree-or-higher days, with some days much higher (Sea-Tac hit 96 on August 11). That's pretty impressive.

We may have kept our streak going, but setting a new record for consecutive days above 70 is not going to be easy. The record is 61 days (thanks Scott Sistek), so we'd have to keep our streak going into the end of September to set a new one. It'd be pretty amazing if we broke that record, but the chances of doing such a thing are next to nil.

Why did we have such a downward shift in temperatures today? It's not like we had any massive rainstorm come through the area or anything. Besides, even on August 13, our rainiest day of the summer (0.85 inches at Sea-Tac), the temperature got up to 74 degrees. What made this day different.

The answer, my friends, lies in the all-too-familiar phenomenon we call the marine push. Also known as our "natural air conditioning," it occurs when pressure over land is lower than that over the ocean, and cool, moist maritime air flows into Western Washington. Strong marine pushes generally are associated with thick stratiform cloud decks extending into Western Washington all the way to the foothills of the Cascades. As the day goes on, the sun often "burns through" these clouds, but if the push is thick enough, the sun won't be able to disseminate the stratus clouds, and the surface won't heat up as much as a result. Those are the types of pushes that give you particularly cool days, sometimes as much as 10 degrees below average.

Let's take a look at the marine push event that occurred today. All of these images were gotten from the UW weather loops website. It's a great website with satellite, radar, and model loops and time series of general observations throughout our area. They even have lightning strike data available. In addition, they have an archive of tons of previous satellite and radar images, so you can look at all your favorite storms from the past. I've relived many a storm through this awesome feature.

10:00 a.m.

11:00 a.m.

12:00 p.m.

12:45 p.m.

2:00 p.m.

3:00 p.m.

You can see that it took a while for the clouds to clear out. At 10:00 a.m., they were widespread throughout Western Washington and spread far into the Cascade foothills. They gradually declined in extent and depth, and were gone completely by 3:00 p.m. It wasn't the strongest marine push of all time, but it was enough to cause a cloudy morning.

This coming week looks to feature a decrease in the magnitude of these pushes, and by early next week, they may not be happening at all. However, these pushes will return later in the week, and we will cool down again as a result.


Wednesday, August 20, 2014

Lake Washington Beach Temperatures

Wednesday, August 20, 2014
10:27 p.m.

Here fishy fishy
One reason I love warm summers like the one we have been having is because of the excellent fishing they provide. When the water is warmer, the fish are hungrier, and thus grow to larger sizes. This was probably taken in 2004 +- a couple years, but whatever summer it was, I remember that there was a pretty long sunny stretch that was particularly good for fishing.

Let's take a look at the water temperatures at the beach closest to my house - Madrona Beach. All of these temperatures (and fecal coliform levels) for beaches in the lake can be found here.

The temperature has stayed in the low-mid 70s since July. That's absolutely extraordinary. How does this compare to recent years?


2013 was pretty impressive, with a stretch of around for the month of July, climbing into the low 70s for August. Temperatures are measured in Celsius to the nearest degree, so the decimal point is misleading. The temperature wasn't actually 71.6 degrees for five straight weeks. 2012 was a little cooler, and 2011 was much cooler, with temperatures not making it above 21 degrees C.

This data is only for one beach, and is therefore not a good measurement of the lake as a whole. However, it still highlights the relative warmth of the lake from one year to another.

It's easy to see why the lake is so warm this year. We had the second-hottest July on record with an average temperature of 69.2 degrees, 3.5 degrees higher than normal, and August thus far (as of August 20) has an average temperature of 70.7 degrees, 4 degrees higher than normal. The lake temperatures are higher than the average atmospheric temperatures because the water absorbs radiation coming from the sun, heating it further. It's the same concept as an asphalt road on a hot sunny day. It takes a lot of energy to heat water, and Lake Washington is extremely deep - over 200 feet deep in spots - and this prevents the lake from getting too warm as mixing occurs throughout the summer. However, water has a very low albedo (it absorbs almost all the radiation incident on it), so it is very efficient at storing heat. Moreover, because water has such a high heat capacity, it will store this heat well into September and October.

So there you have it. Warm atmospheric temperatures and lots of sunshine = warm water, and warm water = good fishing. And you think Madrona Beach is warm? Check out Lake Sammamish Beach in the shallower Lake Sammamish.

80 degrees? That's starting to get a little gross.


Tuesday, August 19, 2014

Back From Camp!

Tuesday, August 19, 201411:26 a.m.

Hidden Valley Camp - 2003. 
Hidden Valley Camp - 2014.

It's really surreal how time flies. At least I can take solace in the fact that I'm still just as much of a goofball now as I was back then.

This was my 8th summer up at HVC. I was a camper from 2003-2008, then a "camper leader" in 2010. This summer was my first summer on staff. When I was a camper, the only staff job I could ever imagine having was a group counselor, but I'm very happy to have had a job in the kitchen this year. I learned a ton from the man in charge, Steve Stimpson, most notably how to manage my time effectively. I know I will take the lessons I learned from him with me for the rest of my life. I'm also now extremely good at baking for 170+ people. I've got some work to do as far as baking for one person goes though.

Now that I'm back, I've got some serious work to do. I've got a saxophone solo to transcribe, I've got meteorology internships to look into, and of course I've got weather blogs to write. My weather blog productivity will soar in the upcoming days.

Before I sign out for now though and continue to unpack, I'd like to emphasize how amazing this experience was. If you have kids and are interested in sending them to summer camp, definitely check out HVC. And if you are my age +- several years and looking for a summer job that may be the most rewarding experience of your life, talk to me or email the camp director (he's awesome) directly at hiddenvalleycamp@earthlink.net.

It's good to be back!