The opening days of November have been slightly below normal in temperature. While daily highs have averaged 3.8 degrees below normal, lows have been relatively mild, averaging 3.2 degrees above normal. On Tuesday, deepening low pressure in the vicinity of lake Huron is forecast to become a pattern changing system, placing much of the central and eastern U.S. in a northwest air flow. In response, temperatures are forecast to plunge in coming days. Monday afternoon, readings across the Canadian prairies held in the teens. It is this reservoir of polar air that will be tapped, as several cold fronts pass across the Great lakes through the upcoming weekend. Forecasts suggest temperatures across our area will average 12 to 16 degrees below normal during the period from Friday through Tuesday. This translates to a chill more typical of mid-December. No significant snowfall is expected during this cold snap, but the area may get a dusting Thursday night into Friday.