Many in Michigan are waking up to frigid temps, high wind and snow – the perfect conditions for lake effect snow. Meteorologist Robert J. Ruhf has an excellent article on Lake-Effect Precipitation in Michigan that explains lake effect snow and rain are common in Michigan, especially in late fall and early winter as cold polar air moves across the warmer Great Lakes.
The unfrozen waters are relatively warm when compared with the temperature of the wintertime air mass. Therefore, the temperature of the air that comes into contact with the water increases. The warmed air expands and become less dense, which causes it to rise. This is an “unstable” situation. As the air rises, the temperature decreases until it reaches the dew point, which is the temperature at which the air becomes saturated.. Ice crystals or water droplets will then begin to collect until the force of gravity pulls them down. The result is “lake-effect” precipitation. When the cP air mass is very cold, as is often the case between December and February, the precipitation falls as snow. During late autumn, however, the polar air mass may be warm enough for the precipitation to fall in the form of rain.
“Lake-effect” precipitation can cause substantial intensification of snowfall amounts in very narrow bands, often referred to as “snow belts,” along the leeward (downwind) shores of the Great Lakes. The prevailing wind direction in the Great Lakes region is westerly; therefore, most “lake-effect” precipitation events occur to the east of the lakes.
…An interesting feature of “lake-effect” is that the heaviest bands of snow do not usually occur along the immediate shoreline, but tend to fall several miles inland. Snowfall accumulations are enhanced inland because the air experiences more uplift when it is forced over hills and higher terrain.
Read on to learn lots more about lake effect snow in Michigan including four narrow bands – Keweenaw Peninsula, Leelanau Peninsula, the Thumb and the southwest Lower Peninsula – where geographic features and the shape of the shoreline contribute to more intense snowfall. Hang on to your hats – winter is here!
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