A Red Flag Warning has been issued for Stephenson, Jo Daviess, Carroll and Whiteside counties beginning Noon Monday, lasting through 8pm. Even though the surrounding counties are not included in the warning, the risk for brush fires to rapidly spread across northern Illinois and southern Wisconsin remains very high.
Southwest winds are expected to strengthen during the day Monday as a rapidly intensifying low pressure system moves into central Canada. The pressure gradient between the low in Canada and high pressure in the Southeast will cause a ‘squeeze play’ over the Plains, Midwest and Great Lakes.
Sustained southwest winds of 30 mph will be common across much of the area, with gusts approaching 40-45 mph at times. Even though we did have rain last Tuesday night, the dormant vegetation is still fairly dry. The combination of that dry vegetation, dry air mass (relative humidity values as low as 30%), strong winds and warmer temperatures will significantly increase the risk for rapidly spreading fires Monday afternoon. Outdoor burning, of any kind, is not advised Monday.
Winds will remain gusty Tuesday with the arrival of a cold front during the afternoon. This will bring in a slight chance for a passing shower late in the afternoon and evening. Following the cold front Tuesday night, winds are expected to increase from the north Wednesday. This will bring highs down into the low 40s for the afternoon.