Post by ppat324 on May 1, 2010 7:48:49 GMT -5
5/1 - West Michigan – Lake Michigan shoreline residents from Grand Haven to Whitehall reported seeing "the lights of Milwaukee" Wednesday night along the western horizon.
They didn't actually see the Wisconsin shoreline, but a rare and complex atmospheric condition that creates a reflected image of the Milwaukee-area coastline for a brief time. Observers reported seeing the lights before and after 10:30 p.m.
Those seeing the Milwaukee lights were most likely observing a "fata morgana" mirage, caused by differences in temperature between the water and air.
The weather-based phenomenon reveals not just the "glow" of Wisconsin's biggest city on the horizon. Observers see actual lights of buildings and objects, such as the red blinking beacons of large communication towers.
"It's an optical illusion," said Dennis Donahue, the marine superintendent of the National Oceanic and Atmospheric Administration Great Lakes Environmental Research Laboratory's Lake Michigan Field Station in Muskegon.
"It is caused by the difference in temperature of the air and the water," explained Donahue, a veteran Great Lakes mariner. "I have seen the effect in Lake Superior and across the Saginaw Bay."
And for some magical moments every few years or so, the effect is observed on the eastern shore of Lake Michigan, allowing for the lights of Milwaukee and other Wisconsin cities to be seen.
Paul Kara was at his Norton Shores home a quarter-mile south of the Muskegon Heights water filtration plant Wednesday night. He said he watched the rare light show for 45 minutes.
"We've seen this about a half-dozen times," said Kara, who has lived for 19 years along the lake. "This was not the best. Sometimes they are far more dramatic. I swear sometimes you can see vehicles driving along the (Hoan Bridge) highway."
The "fata morgana" mirage is described in the "American Practical Navigator" of the U.S. Department of Defense's Mapping Agency.
The characteristic of a true "fata morgana" is that it is seen on a narrow band near the horizon. Atmospheric conditions can distort the object being observed -- in Wednesday night's case the Wisconsin shoreline.
The Milwaukee lights can be larger than normal and brighter. Changing temperatures make the mirage change rapidly -- alternately compressing and stretching the zones of light.
When observed at one point Wednesday night from Muskegon, the lights could be seen from the city of Milwaukee and several cities north and south. The light pattern looked like a flotilla of 1,000-foot lake freighters all lit up on the horizon, yet the lights weren't boats.
The "fata morgana" effect can be observed on land or at sea and at night or day, according to federal instructional materials. In calm weather such as Wednesday night, a warm layer of air rests over colder denser air, forming an "atmospheric duct," which acts as a refracting lens.
What happens to the light rays is similar to what happens at night with radio waves of certain frequencies, as when AM radio stations can be heard from hundreds of miles away.
Muskegon Chronicle
