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Davis Weather E-news
February 2017
In This Issue:
Anemometer new product announcement

AeroCone: The Aerodynamic Rain Collector

There's a new shape in your future!  Vantage Pro2's rain collector has gone from its nice, solid, tapered barrel shape, to a wasp-waisted, aerodynamic silhouette!

Our engineers looked at what happens when a high wind gust whips the rain sideways toward the collector.

With the classic shape, the wind hits the collector, and then flows up and over. This turbulence causes the flow to accelerate over the top, and can whip some of the precipitation right past the mouth of the cone. The error is usually small, depending on the speed of the gust and the rain rate, and lasts only as long as the gust.

But since we are always looking for the best of accuracy, even in the worst of conditions, we did a little remake of the shape. The new shape, besides looking totally awesome, allows the wind to go around the rain collector, reducing the turbulence that can create an error.

While they were at it, the design team added a notching system inside the cone that allows the debris screen to lock in. No more blown out debris screens!

The new rain cone is called AeroCone, and is currently shipping with all our new Vantage Pro2 stations. It is backward compatible with all Vantage Pro2s, so if you live where wind gusts are common and would like to reduce this wind-driven rain error, you can just switch out the new cone for the old with an AeroCone Replacement Kit.

However, if you currently have a rain collector heater, you won't want to order the new cone. The rain collector heater is compatible only with the classic style cone. (What about future AeroCone owners who want a rain collector heater, you ask? Never fear. They'll be able to get a classic shape cone with the heater. )

Some of these guys are already in the field!  Check out this one, installed by Ed Mansouri of WeatherSTEM at Heinz Field in the Pittsburgh Steelers livery.

That, if we do say so ourselves, is a beautiful weather station. Go Steelers!

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Davis on the Open Road

See Scott Slater. Scott has had a weather station in many stationary locations, including his home and vacation property since 1998. This made Scott very happy. But Scott and his wife love to camp and take to the open roads in their travel trailer, and this made Scott very sad.

Hear Scott lament: "I can't be without my weather stations, even on vacation!"

So Scott, being Scott the Brilliant, decided to install a station on his travel trailer, "with little effort and cost. "

"The criteria in my design," Scott told us, "was that I needed to have a setup that was secure as well as quick and easy to set up and take down while camping. I purchased two 8' [2.4 m] sections of extension pipes which can lock together with a push button. One of the two sections pipes gets cut, one end of the cut pipe mounts permanently to the tongue jack with clamps, the other end of the cut pipe mounts to the base of the sensor suite. The full section of pipe basically mates with the pipe on the base of the sensor suite, with the opposite end mating with the pipe permanently attached to the tongue jack. It sets up and comes apart in less than 30 seconds. The console is mounted inside the trailer using heavy duty Velcro. " 

Now see Scott. He is one happy camper.

"It works like a charm, is easy to set up and put away, and makes weather on the road a blast. Even my wife is finding the weather station is an essential part of camping. " 

And one happy Davis customer! "I really enjoy Davis weather equipment. It's so reasonably priced, reliable, robust, accurate and intuitive too. Plus the technical team is always a pleasure to work with if I have a problem, which I have to say has been a long, long time ago. Thanks, Davis for making such great weather instruments that are versatile enough to be used in so many places. "

Scott's Vantage Vue in the working position on the front of their travel trailer.

Close-up view of the pipe mounted to the tongue jack. Note that the top of the pipe mounted to the jack is tapered to accept the base of the full section of pipe. This allows the pipe to be rotated so the sensor suite points north. The top pipe mounted to the sensor suite mates with the full section securely with the push button.

Here's the station broken down and ready for storage.

The mast pipe is clamped to the tongue jack with a combinations of two sizes of conduit hanger clamps bolted together that can be purchased at any local home improvements store.


AnemometerWeather Check Quiz Question 1:

On a clear, sunny day, Scott and his wife had set up their camp chairs beside the trailer and were relaxing with a cool drink and watching their Vantage Vue wind cups turn lazily in the light breeze.

"Honey," said Mrs. S, "the temperature is 78° F [26° C] outside. That's because the sunshine is warming the air as it spills down on us, right?"

What did Scott answer? (Remember, they don't call him Scott the Brilliant for no reason!)

(Click here for answers. )

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Not Gone With the Wind

Peter Benning lives in the windy town of Dylife, Powys, Wales in the UK. He wrote to tell us how his wind turbine saved his 10-year old Vantage Pro2.

"I'm sure it is not a record, but we had a storm the other day and the wind peaked at 83 mph [134 kph]. It may have been more, but the mast and frame it was attached to was blown over! Fortunately the frame fell up against my Proven 6kW wind turbine (see pictures), which saved it from hitting the ground. The wind turbine is supposedly rated up to 150 mph [240 kph]; it just cones itself to reduce its surface area to the wind and still produces maximum power."

Peter installed the Vantage Pro2 next to the wind turbine to make sure that the location of the wind turbine was the best. It was, said the Vantage Pro2, and so far the turbine has produced close to 135 million watts of electricity - averaging approximately 15mWh per year (15,000 units of electricity).

"We probably use 10,000 units a year and export any excess to the National Grid. This is a two-way system, in that when there is no wind we have to import the electricity and when it's very windy (anything over 15 mph [24 kph]) we export to the grid. To minimize the amount we 'give away', we have a monitor, which if it detects that we have excess generation, it sends a radio signal to special sockets in parts of the house and will either switch on a fan/oil heater or a water boiler. We get paid a small amount from the energy company and a slightly larger payment from the government for providing green energy. I maintain the turbine myself and lower it each year (it is hinged at the base) to service. It takes a couple of days of hard work!"

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Just a Normal January Day in the Arctic Circle

Millbrook Group is a UK-based company that provides testing facilities for automotive companies. They are known for their cold weather test tracks in the UK and at Test World in Finnish Lapland.

Our Finnish distributor, Ilkka Lilja Oy installed a weather station at their outdoor track, called Mellatracks, located 300 km (186 miles) north of the Arctic Circle. The outdoor track is open October through April, but they also offer year-round indoor facilities with natural snow and ice so testers can put their engines, drivers, fuels and tires through all the paces.

Ilkka just had to share this screenshot of the Mellatracks page on WeatherLink.com.

AnemometerWeather Check Quiz Question 2:

Quick! How low did it get on January 4 in ° F?

Extra Credit: True or False: The coldest place in the Northern Hemisphere is in the Arctic Circle.

(Click here for answers. )

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AnemometerWEATHER 101

We Can Take All This Pressure - and Forecast Tomorrow's Weather

You think you are under a lot of pressure? Well, we are REALLY under a lot of pressure! Like 14.7 pounds/6.7 kg per square inch on our poor little skulls! Almost 15 pounds/7 kg of air, stretching up from our bald spots to the very edges of the atmosphere. (How far is that you ask? The experts can’t even give you an absolute number, but it’s something like 6,000 miles/ 10,000 km. But really, the part that has all the weight, or most of it, goes only about 3 miles/5 km.

Well, so what, you might say, if you are not a weather nut, and you notice that your skull has yet to cave in.

But being a weather nut, you know that atmospheric pressure is a weather-making, law-obeying (it obeys the gas law: Pressure = Temperature x Density x a Constant), forecasting necessity. The most interesting thing about atmospheric pressure is not the absolute value (or station pressure which corrects for temperature, gravity and instrument error), at any point in time and space. It is the changes and comparisons that make it valuable. The little arrow on your Vantage Vue console, tilting downward, has more predictive value than the actual number.

The number is also valuable, but more as a comparative number rather than an absolute one. If we know the station pressures in San Diego and Denver, we really don't know all that much about the weather, because the folks in San Diego have a lot more air over their heads than those in Denver, so their station pressure is going to be higher. We need to correct both those readings for altitude so they read as if both stations were at mean sea level in order to compare them. The station pressure in Denver might be 894 mb, and the station pressure in San Diego might be 1000 mb, but adjust the Denver reading to sea level and they are almost the same. (That's why, when setting up your console, you put in the elevation of your console. )

The effect of altitude on atmospheric pressure allows pilots to measure it and get their altitude, instead of dropping a measuring tape down to the runway. Pressure decreases with altitude at a pretty steady rate of 10 mb for every 100 m, so if your know the pressure up here and down there, you can get your altitude. Meteorologists can use mapped adjusted atmospheric pressure to see where high and low systems sit. The systems generally move from west to east, so we can use those maps to predict what will happen in the coming days. When a high pressure system approaches you from the west, you can "see" it coming by the subtle rise in pressure, followed by a drop as the system passes. You'll also see an increase in temperature, with a decrease when it passes, and a shift in wind direction. Approaching low pressure systems let you predict clouds and rain. Now that's a handy weather variable!

Atmospheric pressure causes wind to blow, because, as anyone who has ever over-inflated a balloon knows, air moves from high pressure to low. It is affected by temperature (cool air is more dense and therefore heavier; it sinks and pushes downward); and humidity (more water vapor, less pressure). So that subtle change in your barometric pressure encapsulates a whole lot of meteorological factors and provides a whole lot of information. No wonder it is such a good indicator of current and future weather.

Bonus Gift for the True Techies in Our Midst

Earles L. McCaul, of Tucson, Arizona, would fit right in here at Davis. Smart as a whip, and handsome too. (We're just assuming about the handsome part, because, well he loves weather, sooo. . . . ) Back in 201,2 he sent us an article about how he uses a Vantage Pro2 to measure his evaporative-cooler efficiency. It was a techie-nerd delight - with formulas galore.

Well, Earles has prepared another little gift for you. This time, his subject is barometers, in techie terms. Check it out here, and yes, there will be math.

Thanks Earles! We eagerly await the next installment!

AnemometerWeather Check Quiz Question 3:

This question comes from a really good article on Live Science by meteorologist and astronomer Joe Rao, titled "Atmospheric Pressure: Definition & Facts. "

If you were climbing to the summit of Mauna Kea (13,796 feet 4206 meters) and were told to stop at the Information Center and acclimatize before proceeding, and you said this:

“Well, of course, after all, the amount of available oxygen at such a high altitude is considerably less as compared to what is present at sea level.”

Would you be right or wrong?

Extra Credit: I like pressure. I like to feel the weight of that column of atmosphere pressing down on me. Where in the world would be the best place to make my home?

Extra Extra Credit: Quick! Convert 1013.25 mb to hPa.

(Click here for answers. )

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AnemometerTECH TIPS

Call Tech Support if You Have an Issue, Unless it's a Barn. . .

"I have an unusual problem with my Vantage Pro 2 weather station," Jackie Ericson complained. "My readings are all a bit off. "

"Source of problem? My neighbor erected a barn in front of it! Grrrrrr. That pole is set in concrete. "

AnemometerWeather Check Quiz Question 4:

True or False:
The steel in that barn is recycled.

(Click here for answers. )

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Anemometer I Spy a Davis Station


At the ACL Festival

While attending the 2016 Austin City Limits Festival in Austin Texas with another 450,000 people (it's the largest music festival in the nation), David Wahlgren spied this Vantage Vue high above with the best view in the house. 

"Mine is just not mounted that high," David wrote, "but it's good to know that I have a just as dependable a station."

On Netflix

We were totally engrossed watching an episode of the Netflix Original series called "The OA," on the edge of our seat really, trying to figure things out and worried to pieces about the fate of our favorite characters…when, hey, what’s that?? A Vantage Pro2 on the mad scientist’s lair! 

Suddenly we weren’t in such a hurry to find out what happens to them. In fact we had to stop and rewind several times to admire it! He can’t be all bad if he owns a Vantage Pro2, right??

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AnemometerMail Bag

This Love Letter Arrived Just in Time. .

…for Valentine's Day!

Peter Turoff of LaGrangeville, New York took the time to write us a particularly nice little love note!  We're blushing, really we are, but okay, we'll share with you!

"I am absolutely floored," Peter gushed, "with my ongoing experience with my Davis Vantage Pro weather station I purchased on June 4th of 2002. It is still going strong and not obsolete after more than 14 years! I just took an hour out of my day to take pictures, look up purchase date and create this email because you deserve recognition for outstanding achievement."

"Today happens to be a very windy day in New York and my 14+ year-old Vantage Pro is accurately measuring the wind speed and chugging along with rock-steady reliability. Thank you for producing such an impressive product on so many levels. It has been virtually maintenance-free this entire time. It continues to give useful information and does not look, act or feel obsolete in any way.

Besides the usual everyday use, Peter also uses his station in pursuing his hobby of being a hot air balloon pilot.

"I check my Vantage Pro before every local flight for wind speed, direction and trending. The barometer is very useful for setting my altimeter. Knowing the dew point is critical to our safety. Pilots need to be wary of morning flights with cool temperatures (especially on a crystal clear night…no cloud cover allows heat to radiate into space cooling the earth and the boundary layer of air). If the temperature and dew point are the same or only 1 to 2 degrees apart, there is increased potential for water vapor to condense and form fog even as it gets lighter out. Flying in fog is incredibly stressful and dangerous"

Awww!!!  We love you too, Peter!!

AnemometerWeather Check Quiz Question 5:

You think 14 is old? How old is the oldest known rain gauge?

(Click here for answers. )

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 What do you think of the E-Newsletter? How can we improve? How do you use your Davis weather products? E-mail us at news@davisnet.com.


Question 1:. "That's because the sunshine is warming the air as it spills down on us, right?" What did Scott answer?

Actually, they call her "Mrs. S, the Even More Brilliant." So Scott said, "Dearest, you are making a joke aren't you?"

Mrs. S, laughing, said, "Of course! Everyone knows solar energy has very little effect upon air! It warms the surface of the Earth, and the air molecules in contact with the heated surface bounce against it, gaining energy by conduction, then shooting upwards. As they rise a little above the surface, they collide with other, more rapidly moving molecules, and this raises the temperature of the dense air near the surface. This warm air rises, becoming less dense, and causing the thermometer in the Vantage Vue to report 78° F [26° C]. When are you going to start supper?"

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Question 2: Quick! How low did it get on January 4 in ° F?

-40° C is -40° F. The one time we all agree that it is darned cold.

Extra Credit: True or False: The coldest place in the Northern Hemisphere is in the Arctic Cirlce.

False. It is in far eastern Russia. If you think it's cold at Mellatracks, check out the temperatures in the Russian villiage of Oymyakon. With a recorded temperature of -90° F/-68° C, Oymyakon is the coldest place in the Northern Hemisphere, and the coldest permanently inhabited place in the world. Read about here.

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Question 3: “. . . the amount of available oxygen at such a high altitude is considerably less as compared to what is present at sea level. ” Right or wrong?

Wrong, says Joe Rao. It's not that there is less oxygen available, its that there is less pressure to help you get it where you need it.

"In fact," Roa writes, "21 percent of Earth's atmosphere consists of life-giving oxygen (78 percent is composed of nitrogen and the remaining 1 percent a number of other gases). And the proportion of that 21 percent is virtually the same at sea level as well as at high-mountain altitudes. ...[T]he pressure of all the air above our heads is the force that pushes air into our lungs and squeezes oxygen out of it and into our bloodstream. As soon as that pressure diminishes (such as when we ascend a high mountain) less air is pushed into the lungs, hence less oxygen reaches our bloodstream and hypoxiation results; again, not due to a lessening of the amount of available oxygen, but to the lessening of atmospheric pressure."

Extra Credit: Where in the world would be the best place to make my home?

Siberia! While the Standard Atmospheric Pressure is 1013.25 mb, and the Earth's average sea level pressure is 1011.0 mb, sea level figures in excess of 1030 mb are common in Siberia.

Extra Extra Credit: Convert 1013.25 mb to hPa.

Here's a hint: 1 mb = 1 hPa.

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Question 4: True or False: The steel in that barn is recycled.

We can say true with confidence because almost all American steel is recycled -- at least 2/3 of the steel in this buidling is recycled. Steel can be recycled repeatedly without loss of strength.

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Question 5: How old is the oldest known rain gauge?

They've found one in India that dates from 300 b.c. Palestine, China and Korea had them 2000 years ago. In fact, the Korean King Sejong the Great, whose reign was called the Golden Age because of the great cultural, educational, and scientific advances, standardized a rain guage in 1441 so he could assess land taxes based on a farmer's potential harvest.

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Each month after the E-News goes out, we receive messages back. Sometimes the messages are in response to a story we shared; other times they are a request for help of some kind. We read all the emails, answer those we can, and pass the rest on to the appropriate departments. If you're interested in the fastest possible reply, news@davisnet.com may not be the best place to send your message. Questions about how things work should be addressed to tech support directly at support@davisnet.com. For general information about the products, contact sales@davisnet.com.

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Well, that's it for this edition. You'll be hearing from us again next month!
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