AUBURN — A dozen senior members, parents and cadets from the Maine Wing Civil Air Patrol 77th Squadron visited the National Weather Service Office in Gray recently to learn about the services provided by the weather service meteorologists.

They toured the facility and were briefed on the impressive video displays of barometric pressure, temperature, winds and rainfall. The meteorologists described the workings of the newly installed NEXRAD (next generation) weather radar that allows them to tell the difference between rain, sleet and snow, because the radar shows the droplets in three dimensions.

If the droplet is round it is ice, because raindrops flatten out as they fall from the sky. The meteorologists can even see migrating birds on the radar in the spring and fall. Those taking the tour asked lots of questions including: why is the snow fall measuring station in the woods but rainfall is measured in the field? Answer: because the snow may melt in the sun on the field or blow away in the wind, giving an inaccurate measurement.

The highlight of the visit was the cadets assisting the meteorologist inflate and launch the weather balloon that the Weather Service sends up twice a day to record wind speed, direction and barometric pressure at higher altitudes. Instruments attached to the balloon include a GPS to provide a precise location for the wind readings.

The transmitter sends back information for more than two hours until the balloon bursts, at 115,000 feet, and the instruments parachute back to earth. The instrument packages are returned about 20 percent of the time, but not in Maine. The prevailing wind direction from the northwest sends most of the balloons and instruments out to sea.

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