Davis Instruments Weather Club

March 2008

In This Issue:

WEATHER STATIONS IN ACTION:

• Vantage Pro2 Plus Helps Champion Gliders Soar Safely
  

  WEATHER 101:

• A Trivia Farewell to Ice
  

  TECH TIPS:

• Be Sure to Register Your Weather Station

  MAILBAG:

• Northern Lights Boo-Boo
• Did Mississippi Blow Away with the Tornados?
• King of Radio Frequency (RF) Interference: the Sun
• Teensy Twister Visits Guatemalan Farm
  
  YOU'RE BRILLIANT!
• Answers to Quiz Questions

WHO YOU GONNA CALL?
• Davis!
  

WEATHER STATIONS IN ACTION:

Vantage Pro2 Plus Helps Champion Gliders Soar Safely

It almost looks like this Vantage Pro2 Plus is feeling a bit wistful about being earth-bound as it watches the gliders at the Western Australia Gliding Championships. Photo by R. Crawford

Story by Robert Crawford

The state of Western Australia conducted its annual gliding championships in January at Beverley. Beverley is a small town in the middle of the grain-growing area of Western Australia commonly referred to as the “Wheatbelt.” Gliders fly from a WWII US training airfield (32°07’30.82” S, 116°56’57.98” E) next to the town.

It was great to have a Davis Vantage Pro2 weather station on site this year, loaned by local distributor Les Cooke Instruments with Australian distributor Ecowatch providing a solar radiation sensor.

John Welsh, Meteorologist for the Championships and Executive Officer of the Gliding Federation of Australia said of the Vantage Pro2, “I found it easy to use and most useful especially for identifying wind direction and temperature rise trends for runway selection and for selecting the best time to launch the fleet of twenty five gliders.”

Pilots at the competition especially seemed to like the large display and the fact that it was portable.

Weather Check Quiz Question 1: To a glider pilot in Australia, what does the term "morning glory" refer to?
A. An eye-opening breakfast of oyster shooters and chilled Bloody Marys.
B. A gigantic roll cloud up to 1,000 km (621 miles) long that rotates backward and speeds along at 60 kph (37 mph).
C. An annual pre-dawn glider race along the west coast from Broome to Exmouth, famous for almost non-existent winds.
D. The name of the craft flown by Lisa Trotter, holder of the Australian Feminine Distance record. E. An unusual double rainbow seen from the air at sunrise and appears to form an arch gliders can fly under.
(Click here for answers.)

WEATHER 101:

A Trivia Farewell to Ice

It seems that lately the weather news is full of extremes – the 2007-2008 Australian summer was too cold, but not as bad as the Chinese winter! Snowfall in eastern Canada was so huge, it created a new form of social bad behavior dubbed “snow rage.” (Quebec City got a record 460 centimeters [183 inches] of snow dumped on it this year!)

Luckily, spring hit the Northern Hemisphere on March 20, when the sun was directly over the equator, and we must say, not a moment too soon. Spring has much going for it. Days become longer and warmer, daffodils bloom, spring peepers peep, and best of all, snow begins to melt. Spring also has some terrific holidays like Easter, when people decorate eggs and eat chocolates; Passover when families feast at a special Seder; and May Day, when English kids decorate poles by dancing around them with ribbons. In Iran there's a two-week long holiday, Nowruz, during which people celebrate the first day of spring and the first day of the new year by cleaning their homes, buying new clothes, visiting elders, and having a big picnic. In India, they celebrate Holi by dressing in green and squirting each other with water guns filled with colored water. In Thailand, there's the holiday of Songran during which parades of giant Buddha statues spray water on people. The Effutu people in Ghana have Aboakyere, a deer-hunting festival and in Pakistan boys have kite-flying contests.

(Spring also brings its share of severe weather, including tornados, supercell thunderstorms, floods, and, of course, hurricanes, but we're waxing poetic at the moment so let's not go there.)

So from our spot here on the opening days of spring, we bid farewell (or a shivering hello, in the case of our Southern Hemisphere friends) to winter’s snow and ice, by offering a bunch of random icy facts that you might not know:

• Ice comes in 15 different crystalline structures, (this is more than any other known material), called Ice I through Ice XV. Ice I is the most common regular old ice and snow.

• When water freezes it expands, and this leads to bursting of pipes. (Yes, we know you knew that.) But pipes don’t burst where the ice blockage is. The expansion inside the pipe increases the pressure “downstream” between the blockage and the closed faucet. That’s usually where it bursts – where there is little or no ice. (See the story on Natural Hazard Mitigation Insights' website.)

• You might want to rethink the idea of slurping up a snow cone made from fresh, clean snow. We’ve known for a long time that snowflakes need some sort of particle, called an “nucleator,” to cling to in order to form. Scientists have recently concluded that the most common nucleator is bacteria. (See the story on E-flux Media.

• Effective ice breaker ships have rounded hulls and bows – not sharp pointy ones. The front of the ship rides up over the ice and the weight breaks the ice.

• People who love to crunch on ice may have pagophagia, a type of pica eating disorder.

• “Ice-push” is a weird weather phenomenon where sea, river or lake ice is pushed onto the shore and stacks up in impressive columns and towers. (Here’s a good video of ice-push in Newfoundland.) Also called “ice shove,” it is caused by a combination of wind, current, and temperature change.

• The sea ice around Antarctica hits its maximum area of about 8 million square miles (21 million square kilometers) in September or October. (Here’s a NASA photo to illustrate.)

• Snow has fallen on almost every location in the United States at some time. Phoenix got an inch of snow twice, once on January 20, 1933 and again on the same date in 1937.

• The water content of snow varies greatly. New, dry snow can be as low as 3% or 4% water, but snow that has been compacted on the ground for a long time can be 30% or even 50% water. That’s why snow depth is not a very accurate way to measure water content.

• Two snowflakes can be identical. At least, there is no law of physics that says they can’t.

• Snowflakes are fun -- if you like to build snowmen, are a skier, a polar bear, or you know about Zefrank’s “toy” site.

Well, enough with ice on trees and streets. Bring on ice in nice clear cubes, tinkling around in a glass of lemonade! Until next year, you beautiful, deadly, life-bringing crystals: bye-bye!

Weather Check Quiz Question 2: Why is ice slippery?

Extra Credit 2: Which is not used in reference to snow or ice?
A. Fast
B. Pancake
C. Frazil
D. Anchor
E. Graupel
F. Roostertail
G. Névé
H. Firn
I. Barchan
J. Surface Hoar
K. Watermelon
(Click here for answers.)


TECH TIPS :

Be Sure to Register Your Weather Station

Have you registered your Davis weather station? If you have not, you might miss out on product updates and maximum service and support. If you haven’t returned the warranty card that came with your station, it's easy to register online. Just click here and fill out the form.

MAILBAG:

Northern Lights Boo-Boo

Ron Scheldrup, weather buff and diplomatic genius, responded only moments after getting last month’s E-News to point out an error in our story on the aurora borealis.

“Thanks for consistently putting out such a thoughtful and interesting newsletter!” wrote Ron. “I also know that you sometimes put in some items that are not quite right to see if your readers are paying attention, and I found one of those in the article on the aurora borealis.

“You wrote, ‘The aurora borealis has been seen at much more southern latitudes than Vermont,’ and then you listed an example of London. I'm sure we both know that London is located at about 51°30'N, and since Vantage Pro2 user Robert Linde gave his latitude as about 6° south of that, it was obvious that you wanted to see if your readers could spot that inaccuracy! (You could even ask readers if they could quickly state the longitude of London, and then ask why it would be so easy to remember...).”

Weather Check Quiz Question 3: Okay, Ron. Quick, what’s the longitude of London?

Gary Burk was right behind Ron in catching our, uh, intentional, yes, that’s it, intentional goof. Gary added that Robert in Vermont is also south of Salem, OR, four minutes (4 nautical miles, 7 kilometers) north of Bordeaux, France, and almost 400 nautical miles south of London (458 statue miles, 737 kilometers).

“Part of the problem,” Gary wrote, “is putting maps on two-dimensional paper (or a computer monitor) rather than looking at a globe. One way to think of it is to begin at the Oregon/California border at 42N and travel east around the globe. You’ll be within about 100 miles/160 kilometers of Chicago (7 miles/11 kilometers), New York, Rome (7 miles/11 kilometers), Sofia, and Vladivostok before you return to Crescent City, CA.”

(Another part of the problem, adds the Editor, is moving sentences around without carefully reading how moving them changes the meaning of the text…)

“And why was the Southern Lights question so obvious?” asked Gary. “Melbourne, Australia is at 37.47ºS or within spitting distance of Hayward, California’s relationship to the Equator. Hobart, Tasmania is closer to the equator than Eugene, Oregon.”

Ron went on to add some more geo-planetary info on why Robert in Vermont gets to see the lights when folks on the West Coast usually don’t.

“There is another part to why auroras are more easily visible in the northeastern US than on the west coast. That has to do with the orientation of the earth's magnetic pole which is tipped quite noticeably towards the northeast USA.

“Basically, while Vermont and Oregon are both on the 45th parallel - exactly halfway between the pole and equator - Vermont is much closer to the magnetic north pole (roughly 35° from magnetic north vs. Oregon's 55° distance) and thus its residents more likely to see aurora activity than their western cousins.”

Thanks Ron and Gary! You guys are way smart.

Did Mississippi Blow Away with the Tornados?

Harry Thames of Gulfport, Mississippi, had a bone to pick with us for leaving his beloved home state of Mississippi off our list of states hit by tornadoes back in February. He wondered if we’d have noticed if a chunk of Mississippi just blew away in the storm! We sure would have, Harry!

Harry pointed out that we, like other news sources, sometimes tend to overlook his lovely southern state, which has plenty of wild weather to report. In fact, Harry’s Vantage Pro2 Plus met up with a little weather gal called Katrina.

Here is Harry Thame’s Vantage Pro2 , still standing the day after it survived hurricane Katrina relatively unscathed.

The same cannot be said for his home. Check out the roof over Harry’s bedroom after Katrina. The material on the roof is insulation and bricks from the chimney.

Harry wrote, “The winds came from the south/southeast. The roofing punched holes in the rest of the roof from this end all the way to the other end, knocked a lot of the bricks off the chimney and destroyed the back yard, pool and pool house. The inside was completely ruined. The wind speeds I saw and recorded were around 80 +/- mph (129+ kph) sustained before daylight and until mid-afternoon the day of the storm. I saw one gust of 122 (196 kph) on the console, but I think it may have been a fluke. Even a day later, the wind was still blowing 40+ mph (64 kph) as you can see from the photo. I had mounted the station on three concrete foundation poles (6 inches [15 cm] in diameter and 3 feet [1 meter] deep) on a Davis tripod, with a cyclone corner post as the upright. The winds twisted the ISS about 15 degrees counter clockwise on the mast but didn't break anything. The tripod held as did everything else.”

Harry notes sadly, “there were/are thousands of homes here that are worse than ours. Many true old-time mansions of antebellum style and era only had slabs or pillars left the day after the storm. The destruction was for miles and miles along the coast and many miles inland.”

We promise not to overlook Mississippi ever again, Harry. After all, besides being beautiful, the source of many American catfish dinners, birthplace of some of America’s best writers, musicians, actors, and athletes (including writers William Faulkner, Tennessee Williams, Richard Wright, John Grisham, and Alice Walker; musicians Elvis, B.B. King, Muddy Waters, and John Lee Hooker; actors Morgan Freeman, James Earl Jones and Oprah Winfrey; athletes Brett Favre, Jerry Rice and Walter Payton), it is also the most fun state to spell!

Weather Check Quiz Question 4: Does the Mississippi River begin or end in Mississippi?

Extra Credit: If a raindrop falls today into Lake Itasca, when will it arrive in the Gulf of Mexico? (Click here for answers.)

King of Radio Frequency (RF) Interference: the Sun

In our answer to sources of RF interference in our last issue, Jack Kistler thinks we should have mentioned solar radiation and solar flares. Jacks says that these are “the original common background radiation sources, which have been around since before human-kind transmitted the first ‘man made’; RF signal. They have also been a significant problem in long distance US military communications back when the High Frequency (HF) and Very High Frequency (VHF) frequency ranges were the primary (or the only) means of point-to-point, wireless, long distance communications.”

Righto Jack, we’re adding Mr. Sol to our list!

Teensy Twister Visits Guatemalan Farm

Jorge L. Sánchez García, an Agrometeorologist in Guatemala sent us this photo of a small “twister” in a field on south coastal plains of Escuintla, 80 km (50 mile) southwest of Guatemala City.

“We see them often in the dry season from November to April,” Jorge wrote. “They can go very high as you can see (compare the height of the trees and the size of the field machinery), but up to now haven’t caused as much damage as you get in ‘Tornado Alley’ in the U.S.”

Jorge, we’re glad you’ve only met up with the smaller, gentler cousins of our tornados, sometimes called dust devils. Thanks for the photos – it’s a pretty amazing sight to see that narrow funnel of dust rising into the sky.

YOU'RE BRILLIANT!:

Question 1: B. The famous Morning Glory cloud in Northern Australia can be up to 2 km (1.2 miles) high. Considered a good omen to Aboriginal people because of abundant birdlife to follow, the Morning Glory cloud is the stuff of many gliders' dreams. Similar clouds occur off the Mexican coast in the Sea of Cortez and Sable Island off Nova Scotia. More info and some pretty photos are on the Australian Broadcast Corp.'s website. (A. That's for AFTER one has one's feet firmly back on terra firma. C .The fun and skill in gliding is in riding the movement of air, so no wind means not much fun. D. While Lisa Trotter IS the Australian Feminine Distance record with a maximum distance of 950 km (600 miles), we don't know what she named her glider. E. Nah. But that would be really pretty.)