Michael F. Kochis

United States. National Weather Service. Forecast Office

The synoptic picture on the morning of February 10th was not particularly threatening. An Arctic high pressure system was situated over the Northern Plains and Wisconsin was experiencing strong cold air advection. Light snow,induced by the lake effect, began across southern Wisconsin around 09Z, probably in response to the influx of the cold air. The gradient winds over all but the. southeast comer of Wisconsin were north to northeast at less than 10 mph, while Milwaukee's winds were northwest around 10 mph. An examination of the wind field at the stations around the south third of Lake Michigan from 09Z to 18Z indicated the formation of a shallow mesolcw centered over south central portions of the lake (Fig. 1-4). Lake water temperature was near 0°C while 850 mb temperatures were -10° to -12°C. Strong 850 cold air advection was just upstream however, with temperatures at Green Bay of -20°C (Fig. 5).

Technical Attachment