March 213 Newsletter

The next SKYWARN meeting is 19-Mar @ 7:00 PM, the third Tuesday of the month.

SKYWARN Newsletter Editor
The current SKYWARN Newsletter editor is retiring after this issue. Anyone that is interested in continuing this line of communications should contact Dave. The Steele County SKYWARN Newsletter will cease publication unitl a new editor is found.

SKYWARN Spotter Class
The next Steele County spotter class will be held on Tuesday, 19-Mar. The class starts at 7:00PM on the 3rd floor of the Owatonna Fire Station. All spotters must take the class every two years to be current.

SKYWARN Spotter Pictures
Don't forget the Trained Spotters page includes pictures of many volunteers. Contact Tom K. NUW if you would like to have your picture added.

La Nada From Multiple Sources
It seems like every year the climate scientists report on LaNina or LaNino event in the Pacific Ocean. The comings and goings of El Nino and La Nina are part of the long-term, evolving state of global climate. Data for this year indicates the equatorial Pacific Ocean is locked in what some call a neutral state. NASA scientists suggested naming the "neutral" ENSO state "La Nada". "La Nadas" make long-range climate forecasting more difficult due to their greater unpredictability. La Nadas have delivered both the wettest and driest winters on record.

Interestingly, one method used to determine the ocean temperature is to measure the height of the ocean water. The height of the water relates, in part, to the amount of heat stored in the ocean below. Water expands when it gets warmer and shrinks as it gets cooler. As the ocean warms, its level rises; as it cools, its level falls. You can see this for yourself by heating a glass of water in a microwave.

Can You PING?
A relatively new acronym, PING stands for Precipitation Identification Near the Ground, a program of NOAA's National Severe Storms Lab. As research attempt to calibrate NWS radar systems to estimate precipitation from radar return signals, they need ground truth, real observations of precipitation at ground level. In this context they are looking for more weather observers in our area to report when precipitation is falling, what type it is (frozen or liquid), and how much has fallen. If you become an observer for them it is easy to report your data via website access or over your mobile device (cell phone). Read more about PING.

Asteroid or Meteor? From Multiple Sources
A couple of astronomical events occurred in February. The large asteroid flew closer to the earth than many orbiting satellites. The same day, a meteor entered the atmosphere and exploded over Russia. The explosion was caused by asupersonic jet of expanding superheated gas. One estimate of the explosion suggests it was the equivalent of a 500-kiloton bomb. So what is the difference between an asteroid and a meteor?

An asteroid is a rocky object in space. They are often considered as leftover fragments from the formation of the solar system. An asteroid is redefined as meteor when it enters the earth's atmosphere. The term "meteor" refers to the fiery aerial display. Most meterors burn and vaporize when they encounter the Earth's atmosphere. The asteroid that is fortunate enought to survive the fiery entry and make it to the planet surface is then redefined as a meteorite. The meteor that exploded over Russia would also be defined as a bolide, or "fireball".

Luckilly, these events occur about once per centruy. The last document occurred was teh 1908 Tunguska explosion in Siberia.

What is hail? From Multiple Sources
We readilly recognize hail when it falls to the ground or across the sheet metal of our vehicles. Thankfully, hail is usually pea-sized to marble-sized and does not cause a lot of damage. The largest documented hailstone was 8 inches in diameter and weighed 1 lb 15 oz. Ouch!!!

We know that raindrops are carried to the upper regions of a thunderstorm by the updrafts. The raindrops freeze into little balls of ice. As the little balls of ice fall, they may collide with other raindrops that instantly freeze onto the smaller hail ball. The process may be repeated many times as the strong updrafts may continue to lift and drop the same ice ball. Eventually the updraft can no longer support the weight and the ice ball falls to the ground.

Large hailstones are fomred by the layers of raindrops being added to the ice ball in the updraft. The number of times a hailstone may have traveled up and down in the storm might be estimated by counting the layers of ice.

Term For The Month From Multiple Sources
Pine Tree Effect
In the winter months northern coastal areas benefit from the adjacent warm bodies of water. The coastal temperatures may be warmer than than the inland areas. We also often hear meteorologists talk about the "heat island" effect, when large metropolitant areas retain solar energy that is returned to the air when the sun goes down. The forests of northern MN provide a different type of effect. A snow covered landscape will reflect about 80 to 90 percent of the sun's energy back into space. The effect is the local temperature may remain cold. A coniferous forest reflects back about 10 to 15 percent of the solar energy. The trees absorb some of the solar energy. The longer wave lengths bounce off the trees and heat the surrounding air. You can see this effect when looking at temperature maps. The "pine tree effect" may be in effect when the air temperature of northern MN is higher than the open areas to the south.

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Steele County SKYWARN
Owatonna, MN