Davis
Instruments Weather Club
July/August 2005
In This Issue:
WEATHER 101:
It’s Only July, and We’re Already on Gert
It seems that Mother Nature is really taking the Atlantic “hurricane season” to heart this year. Barely two months into the season, and we’re up to six, as in Gert, named storms. Arlene and Brett, the first two, arrived in June -- opening month! In only 12 of the 154 years since 1851 have there been two or more tropical stores formed in the month of June. Since October is often the really big month for hurricanes, we’re definitely feeling nervous.
Hurricanes are the powerhouses of storms. They are weather at its most violent and destructive. The very beginning of a hurricane may be the innocent meeting of two masses of air over some warm tropical ocean water. Called a convergence, the air masses meet and the air piles up. (Think: freeway on ramp at rush hour.) The result is an increase in air density. To balance this increase, the air begins to rise, heat is released, and pressure is lowered. At the least, we’d see thunderstorms and rainstorms. The air begins to be pulled like a column up and then exhausted out the top. (The opposite of a pile-up of air, it’s called a divergence when more air is leaving than entering. Think of a third lane opening on a two lane rush hour freeway.) The pressure at the surface begins to drop even more. Winds increase as air rushes in to the resulting lower pressure at the surface. Add the Coriolis Force, and it is easy to see how a hurricane or cyclone with high winds and a calm, low-pressure eye is born.
A storm needs a combination of mechanics to make it to the big league. If the rising air is not able to effectively exhaust out of the system, for example, the storm may have to settle for being just a “tropical depression” (with winds under 39 mph). More effective air mechanics can earn it the title of “tropical storm” (with winds from 39 to 73 mph), and a name. When winds reach 74 mph, it’s a hurricane. It’s a hurricane, that is, when it’s not a typhoon (spinning in the western Pacific) or a cyclone (in the Indian Ocean or south Pacific).
Whatever its title, hurricanes and tropical storms bring high winds, rain, and storm surge. Looking at the damage caused by recent storms in Florida – homes reduced to piles of kindling – one might think that the biggest danger of a hurricane is the high winds. But even worse destruction comes in the form of storm surge. The low pressure in the eye of the storm causes the ocean to rise. The strong winds conspire to pile up more water, until a moving wall of water comes charging onto shore.
These storms are notoriously hard to predict and understand. And this year, we seem to be off to a very stormy start, indeed.
Weather Check Quiz Question 1: Is global warming a good thing in terms of hurricanes? That is, how would a warmer world affect hurricanes?
(Click here for answers.)
Extra Credit: Where did the name “hurricane” come from?
A. From the Taino (a language of Central America) word, hurucan, meaning “God of Evil”
B. From the Pacific Island phrase, huhahuhakari, meaning “foul winds from hell’s gate”
C. From the Spanish settlers in what is now Florida who called the storms, “ the howling rains”
D. From Captain Blymore Findlay Huricayne, whose ship, Lady Louisa, sailed through a hurricane off the coast of Haiti in 1792. While apparently in the eye of the storm, Captain Huricayne wrote in his ship’s log: “a mighty winde and rain storm lashed the Lou fiercely, with fourteen hands lost and the mainsail shredded. With a lesser cap’t I greatly fear she would have shuddered herself to smithereens.” The ship’s log was recovered in a trunk found afloat near Kingston Bay. (Click here for answers.)
When Bill Met Dennis
Bill DuBois, of Milton, FL, had some first-hand experience with his Vantage Pro2 and a little storm called Dennis.
“I have wanted one of these systems for quite a while,” Bill wrote. “When hurricane Ivan ravaged the Florida panhandle last September, I monitored it using an old barometer – watching it bottom out at 29.1 inches when the eye passed within 25 miles of my home. After installing my new system I wondered what were the odds that I would get to watch another hurricane as closely? Well, I got my answer when Dennis roared ashore about 17 miles south of my house – heading pretty much due north. My low pressure was 956.9 mb (28.26”Hg) at 3:18 pm July 10th. I was hunkered down in an interior room with a flashlight, battery powered radio, and my Vantage Pro2 console. The highest wind gust I recorded was 53 mph – but my anemometer elevation was about 6 ft – well below the surrounding tree line. An industrial location about two miles from me recorded 106 mph about the same time. As the eye passed over, the wind dropped to about 10 mph. I went out to survey the damage – 14 large trees down, a couple hundred shingles ripped from my roof, storage shed smashed by a tree, and several fence panels blown out. My rain collector bucket was missing – and located about 150 feet away.”
Here’s Bill, having reinstalled his rain collector, ready for any rogue flying branches.
(Tech Tip for Bill and all you Vantage Pro2 owners: the rain collector should stay on, even in a story like this, if it is properly seated. A new design feature bulks up the tabs that hold the collector in place. They are so snug that you may think you’ve twisted the collector in place when you haven’t. Before the next big wind, double check to make sure your rain collector is twisted securely in place.)
“To end the story,” Bill told us, “we’re all fine and the damage can be repaired. I don’t care to do it again, but it was an interesting experience.”
We hope you don’t have to do it again, Bill. (But, see article above…)
WEATHER STATIONS IN ACTION:
Storm Spotters Use Mobile Vantage Pros and Weather Monitors to Warn Holiday Campers
Blackwell Storm Spotters are always ready for extreme weather with their mobile weather stations. The truck on the right has a cabled Weather Monitor II, the center vehicle has an Interceptor Weather Platform using a cabled Weather Monitor II, lightning tracker, and wireless Internet radar, and the white truck has a wireless Vantage Pro2 and wireless Internet radar. All three have ham radio and city communications radios, and APRS tracking devices.
Blackwell, OK, likes to call itself “America’s Hometown.” It boasts a lovely climate, a smack-dab-in-the-middle-of-the-midwest location, a vibrant Native American community, strong industry, and about 7,500 particularly nice residents. Among them are 15 Storm Spotters. That’s a pretty good concentration of Storm Spotters! To put it in perspective: there are as many Storm Spotters as police officers in Blackwell! Why, you may ask, (even though you did notice that “OK” up there in the first sentence)?
Back on May 25, 1955, the east side of Blackwell was destroyed by an F-5 tornado. On May 26, 1955, the city government started a very proactive practice of storm spotting. This proactive approach to emergency management got Blackwell, along with the storm prediction center and the National Severe Storm Laboratory, featured in a Discovery Channel documentary “The Science of Tornados.”
Since then, Blackwell’s Storm Spotters have been ready to go on a moment’s notice. Their readiness was tested very recently. Early in the morning on the July 3th weekend, every Blackwell Storm Spotter was awake and watching the weather data as several storms approached Blackwell.
“As forecast offices started to discuss the atmospheric changes,” wrote Spotter John Utech, “I shot out emails to every spotter that they needed to be ready for that evening.”
“I also called into WBBZ , the local AM news-talk radio station. I knew it was very important to warn the many campers and water enthusiasts out for the holiday weekend that there was a strong possibility of very severe weather after dark.”
John was right. At about 9:45 p.m. on Saturday, the first major storm hit the area, followed by “the kicker” which hit at around 12:15 a.m. on the 4th.
“When the second storm hit, there were three Storm Spotters, equipped with Davis weather instruments, spread across eight miles between the severe storm and the Kay county line just west of the city of Blackwell. The storm was moving east but became a ‘right turner’ as it approached Kay County. As it moved south at a speed of 20 mph, it lined up with the western border of Kay County and then turned to the east, formed a bow echo, and suddenly sped toward Blackwell at 50 mph. That is when I started recording wind gusts of 80 and 85 mph, and sustained winds of 73 mph. Spotters Mickey Phillips and Brett Shipman started getting winds of 90, 95 and then 102 mph with sustained winds of 82 mph.”
The Spotters were able to warn citizens quickly by way of NOAA Weather and the National Weather Service in Norman. Residents across Kay County and campers at lakes and campgrounds were able to take safety precautions.
Blackwell’s devoted Storm Spotters didn’t go home to bed when the winds finally calmed. Instead, they conducted an immediate damage survey of the city. Damage included power outage throughout the entire city, downed trees, and a toppled communications tower (rated to withstand 112 mph winds). But not a single injury, thanks to the speedy warnings of the NWS from reports of the Spotters.
John notes that his team was particularly effective because they have the best of equipment: Davis! (How’d you guess?)
“When I started to design the Scout (the weather station on the pickups in the photo above) and the Interceptor (on the red car in the middle),” John wrote, “I knew that these designs would be used by Storm Spotters. I was also aware that more and more of the National Weather Service forecast offices around the country prefer ‘measured’ readings instead of ‘estimated’ readings. The instruments were going to be placed in the nasty environment known as Tornado Alley. They had to be tough, affordable, dependable, provide a very quick response time, and most of all, accurate.
“So where would I find instruments that were going to be the absolute best for the money?
One day, as I looked at the Storm Prediction Center’s building, I noticed a weather station on the top of the building. I discovered it to be a Davis. I went to the Davis web site, saw the options available, and the decision was made.”
Blackwell’s Storm Spotters aren’t the only Davis weather station users in town.
“If you notice on the Blackwell E.O.C. in the background of the photo,” John notes, “you can see a Vantage Pro proudly functioning, everyday, every year, without fail. It has defied everything that Mother Nature has thrown at it! The City of Blackwell also uses a Davis Weather Wizard for mosquito fogging. The fogging has to be done on a vehicle traveling less than five miles an hour. The city truck’s speedometers won’t read that low so they mounted the Wizard to gauge the truck’s speed, as well as the weather readings required by the Health Department and the EPA for insecticide dispersal.”
Spot on, guys!
University of Victoria Help Bring Weather Research to Schoolchildren
University of Victory climatologist Dr. Andrew Weaver has created the Victoria Micro Meteorological Weather Network with Ed Wiebe, a research associate in the university's climate modeling lab. The network is a joint project between the scientists and a Greater Victory school district, created with a $36,000 grant from a National Science and Engineering Research Canada program that promotes science and education among young people. Its goal is “to foster an interest among schoolchildren and the public in the two sciences that are fundamental to understanding weather—physics and mathematics.
” The network has 22 schools linked so far, and Andrew has applied for money to add another 70 stations! Check out their weather data. For the whole story, click this story in The Ring.
EXTREME WEATHER STATION CONTEST:
It’s a Tie: David E. & David T. and Their 31-Combined-Years of Digitar Weather
This month, it was just too close to call. Two old Digitar tied for this month’s Extreme Weather Station prize.
Despite being the owner of a Vantage Pro, David Erdman still uses his 16-year-old Digitar weather station (above).
“This was my first weather station,” David E. wrote wistfully. “At the time it was state of the art and got me through quite a bit of weather situations. I retired my Digitar when I moved to Florida 12 years ago and purchased a wireless Vantage Pro. (Wow, what a difference!)
“I now use my Digitar to monitor the output on my air conditioning system located in a hall closet. My analog indoor/outdoor thermometer broke on me, so the Digitar does the job just fine, and I'm sure much more accurately.”
Even if David Tucker’s Digitar (above) is not quite the oldest weather station out there, it must have the most interesting job history. Back in 1990, it started out on a Fire Spotting Tower on Snow Hill on the east coast of Tasmania, Australia (below).
“This site is over 2,000 fee above sea level,” writes David T., “and as indicated by the name, it's quite a harsh location.”
After about six years of faithful work, it got replaced by a younger and fancier Weather Monitor II (which is still in service on the tower). But it was not down for long. David moved the Digitar to his home at Swansea, Tasmania, which is at sea level. It has been faithfully displaying, in scan mode, David’s weather for the last ten years.
“Apart from replacing the reed switch and resistor in the anemometer head, the unit has not missed a beat,” David T. told us.
First runner-up Joey knows his Digitar will not be the oldest (at just 13 years, it’s just a kid!), he knew we’d be impress by this photo of it recording a wind gust of 36 mph during tropical storm Arlene, which passed 200 miles west of Key West, FL, in June.
Finally, in the not-a-Digitar division, Ron Faircloth’s Weather Monitor II, installed on top of his home has been faithfully reporting the weather for the past nine years, giving Ron “a lot of enjoyment as well.”
Thanks to all our old weather station owners (no, we didn’t call you “old!). David and David, your Davis caps will be in the mail soon!
Weather Check Quiz Question 2: People in non-urban parts of Tasmania must have happy lungs. Why is the air particularly fresh there? (Click here for answers.)
This Month’s Challenge:
The Most Distantly Traveled Davis Weather Station
All our weather stations start out life in the balmy weather of Hayward, CA. But where they end up is where the fun begins. This month we want to find the weather station that is farthest, “as the crow flies” from its birthplace in Hayward. (Sorry, Stanford University, for this competition we’re eliminating your hard-working Antarctica stations. Not that they aren’t deserving, but they do have the unfair advantage of being at the bottom of the world!) We’ll have two categories, one for an American-based weather station that is furthest from Hayward, and one for a non-American station.
Tell us about your far-flung Davis station (news@davisnet.com). And remember, include photos please! Try to get us the photo by August 15.
TECH TIPS:
Birds on Your Rain Collector? Don’t Pooh Pooh It!
Around here, we usually think of birds and bugs messing up our weather stations in the springtime, but judging from our mailbag, summer time seems to be ewwwww-season. Vantage Pro2 owner John German of Tonganoxie KS, says the bird-dropping problem makes his new VP2 “almost work great.”
Alfred Bogen feels his pain. Alfred wrote to tell us that a few days after installing his Vantage Pro2, he found that it failed to report any rainfall during a “cats and dogs” downpour. When he removed the rain bucket, he found the problem.
“It seems that wild birds took pleasure in using the rain collector as a privy, and regularly perched on its edge, with their rear ends hung over the inside of the collector. In less than a day their droppings would completely plug the outlet orifice. In fact, the next day, after cleaning the collector, two to three inches of rain fell, but again the gauge did not respond. When I removed the collector it was solidly plugged, and was 3/4 full of water.”
Part of Alfred’s solution was to tie a fake owl to the supporting post. (He also got creative with some razor blades, which we don’t recommend over are less-blood drawing anti-bird solutions.)
Julian Thomas, of Finger Lakes, NY, came up with a good solution, too. He used chicken wire to discourage bird visits.
John, Alfred., and Julian, you are not alone. We’ve discussed the problem before, and shared other creative solutions, most of which center on making the rain collector bucket’s edge less appealing.
We’ve had readers tell us that they have had success with commercial bird spikes. (There’s a comparison chart of bird spikes on the Wildlife Rehabber website.) You can also purchase iridescent foil bird tape that scares the feathered guys away with light and wind movement. (Google “bird tape” for retailers.) If you live in goose country (and who doesn’t), the bird tape might have an added benefit of keeping your lawn goose-poop-free, too. One reader told us he wrapped a plastic snake around the support pole, and found that birds steered very clear of his weather station.
The goal is to prevent the birds from uh, using your rain collector (which you have conveniently placed up nice and high and safe), without making it a danger to passing airplanes, curious children, or the weather station maintenance crew. You also need to make sure that your anti-bird device does not interfere with rain entering the collector. If yours is just an occasional problem, frequent checking and cleaning might be enough to keep your rain data on track.
Besides being an amazingly effective rain data sensor and ultra-modern bird-outhouse, our rain collectors can also work as perfect hornet hostels. Case in point:
This is what Jeff Ott of Olympia, WA found when he removed his rain collector to see why no rain data was being reported.
“I was thinking about placing some kind of insect repellent under the cone,” Jeff brainstormed. “Something like a piece of a ‘No Pest Strip’ kind of thing.”
Our Tech Support Guru, Brett, thought this might be a good idea, as long as the insecticide is not moth balls, and is used according to the package directions. Brett and our Tech Support team might have another solution in the form of a set of rubber grommets that will fill the holes on the bottom of your collector and prevent large bugs access to your rain collector, while still allowing water to run out. If you need grommets, send an email to support@davisnet.com with your address and we'll send you a set.
Otherwise, Brett, recommends frequent checking and cleaning of the rain collector and tipping bucket during hornet season. (Too bad you can’t do that from a distance, like from inside the house, under the bed…).
How Much Rain Can A Rain Can Hold?
According to Jason Hicok’s Vantage Pro, it rains in Vinton, IA. He sent us this link to his data for Thursday, June 21, 2005 so we can all see for ourselves. Jason was there for the storm and said that trees were downed and the power went out. (Jason! Push the button labeled “Lamps” for a backlit console!). But even he was shocked to see a rain rate of over 20” per hour.
“Just how much rain/hr can that bucket even handle?” he asked.
Our own Jason, the Davis meteorologist says, “a lot. The amount of rain Jason got is certainly in the measurable range. With that being said, we can't say for sure how dead-on that number is. As the rain rate increases to over 10” per hour, accuracy decreases rapidly.
“The rain rate is a true rain rate,” Jason explains. “That is, the SIM measures the amount of time between tips, so the rain totals may not agree with the rain rate numbers. The rain total will give you average rain rate over the archive interval, but rain rate will give you the highest rate over the archive interval."
Our spec sheets tell us that the rain collector’s maximum reportable rain rate is 100” per hour. There will be a loss of accuracy, but then you might not care because your whole house will probably be floating down the street…
Weather Check Quiz Question 3: Could rain drops be falling, but so far apart that the Vantage Pro would report zero rainfall?
(Click here for answers.)
MAILBAG:
You Say Effect, I Say Force, Let’s Call the Whole Thing Coriolis
Duane Harding Ph.D., of Virginia Beach, VA is a former professor and TV forecaster. He weighs in on the subject of whether it’s the Coriolis “effect” or the Coriolis “force.”
Duane reasons that the Coriolis “is a change of direction, and therefore it’s an acceleration. By extension, Newton’s second law says it’s also a force. An acceleration is a force.
“Think of spinning a yo-yo. If you cut the string when the yo-yo is at the top of the circle, which way does it go? Many people think the yo-yo will go straight up. Actually, it goes forward. At the top of the circle, the yo-yo is moving horizontally, so when you cut the string, it continues horizontally. Without cutting the string, the yo-yo continues in a circle because the string is of constant length and yanks it downward – evermore in a circle. (The orbit of a planet, satellite, etc., has an analogous explanation – it’s gravity, whatever that is (not even Newton knew, nor cared).
“In the case of the Coriolis Effect, it is the rotation of the horizontal plane (the earth) that is responsible for the change in direction, the acceleration.
“The standard textbook explanation is inadequate – a rocket fired from the North Pole, or something moving away of the center of a record player (What’s a record player?) The rocket “turns” because the earth moves away from its actual straight path and the rocket in not attached to the earth.
“That’s intuitive, but shooting a rocket from somewhere else on the earth is not. The problem is that the Coriolis Effect is artificial from the viewpoint of an astronaut – the rocket will appear to him to move in a straight line. The hard part to understand is that clouds really do move in circles as viewed from space. The Coriolis acceleration in not a visceral thing. Even with a Ph.D. in weather, I really don’t understand it, except mathematically. Accept it and move on.”
Makes us kind of wish we’d stayed awake in Physics 101. But we have moved on, Duane! Thank you, Doc!
Harry Maybeck, of Holdernss, NH, comes from another school altogether, one long, long ago in a place far, far away:
“Whether it's a force or not, the Coriolis Force is always there. I believe it was Obi-Wan Kenobi
who told Luke that ‘The force is with you.’”
“So it must be true,” is Harry’s Yoda-like conclusion.
Weather Check Quiz Question 4: Forget the “effect” vs “force” question. Where did “Coriolis” come from? (Click here for answers.)
When G. David Says You’re Right, You’re Right
G. David Thayer says that Bill Clancey’s analysis of the meaning of “chance of rain” we’ve discussed in our last two issues “is absolutely right.” And since it’s G. David, we have to agree.
“The probability that a given location will receive measurable rainfall (0.01 inch or greater) is exactly the same as the percentage of the forecast area that is expected to get measurable precipitation.
“In fact, I had thought of writing you using exactly the same dart board analogy that Bill used in his letter to you. Does that mean we are both great minds or is it a folie à deux?”
Our thanks to both great minds! (No folie there!)
Weather Check Quiz Question 5: What, dans le monde, is folie a deux? How does it relate to the weather? (Hint: “It doesn’t” is an acceptable answer.) (Click here for answers.)
WeatherBug’s Backyard Club Blog is Now Live
Debra Love of WeatherBug, wrote to tell us that they’ve recruited nine weather lovers from across the U.S. to be reporters for their WeatherBug Backyard Club Blog. More reporters are eager to join the team.
Debra wrote, “The reporters will write about and post photos of weather and outdoor-related activities in their neighborhoods, while also interacting with blog visitors. Mark Hoekzema and his editorial department will even use some of the content in the WeatherBug application and in their weather reports.”
Check out the blog and feel free to post your own comments and questions for their reporters to answer.
Check out “wview” for Vantage Pro
Mark Teel, happy owner of two Vantage Pros, wrote to tell us about his new creation
“I have written and distribute (via the GNU GPL license) an open source Linux/Unix/FreeBSD/MacOSX controller and web site generator for the Vantage Pro called wview."
He thought it might interest our readers who might want an always-on weather server solution on platforms other than Windows. Using wview requires Weatherlink and the data logger.
YOU'RE BRILLIANT!:
Answers to Quiz Questions
Question
1:
If you thought you’d found a nice thing to say about global warming, no such luck. Here’s what C. Donald Ahrens says in Meteorology Today: “Studies conducted by meteorologists using mathematical models concluded that if the sea surface temperature s in the northwest Pacific Ocean increased by about 2.2ºC (4ºF), maximum winds in a strong hurricane would increase between 5 and 12 percent.” (Back to story.)
Extra Credit: A. But if you said D, you’re our kind of linguist!
(Back to story.)
Question
2: Tasmania is an island washed by prevailing westerlies, “the Roaring Forties,” that arrive along a continent-free path. The fresh air is carried for thousands of miles across the Southern Ocean. However, just like other city folk, urbanized Tasmanians sometimes seem to be trying to undo their good fortune. Wood smoke, the greenhouse effect, and all the other causes of air pollution are becoming more and more of a problem. Check out Tourism Tasmania’s website and dream of deep breathing. (Back to story.)
Question
3: Yes, but it would slow indeed. According to NWS definition, if the elapsed time between tips of the tipping bucket is greater than 15 minutes, the rain rate is zero. That would be one boring rain “storm.” Drip...zzzz...drop...zzzz... (Back to story.)
Question 4: From Gaspard Gustave de Coriolis. Born in Paris in 1792, Gaspard was a student of mechanics and engineering mathematics, with special interest in friction, hydraulics, machine performance, and ergonomics. Although he introduced the terms “work” and “kinetic energy,” he is most remembered for his paper Sur les équations du mouvement relatif des systèmes de corps (1835), in which” he showed that the laws of motion could be used in a rotating frame of reference if an extra force called the Coriolis acceleration is added to the equations of motion.” Source: The Turnbull www Server of the School of Mathematical and Computational Sciences, University of St. Andrews. (Back to story.)
Question 5: According to Wikipedia, the phrase literally means "a madness shared by two." It’s a rare condition in which a person with a psychotic symptom, such as paranoia, transmits the symptom to another person. Symptoms can be transmitted to more than one person, even a whole group of people. We think we may have witnessed that phenomenon ourselves. Oh, and “it doesn’t.”
(Back to story.)
WHO YOU GONNA CALL?
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