Seesaw Temperatures This Week

A FREEZE WARNING is in effect for north central Illinois and southern Wisconsin effective until 9 am cdt.  The combination of building high pressure, light to calm winds, clear skies, and low dew points will allow temperatures across the area to fall below freezing by daybreak.  The sprawling high pressure that has caused the chilly weather for the past few days will slide southeast of the area on Monday.  A fairly tight pressure gradient will develop between the departing high and the next approaching cold front over the northern plains.  It will be mostly sunny on Monday with a southwesterly wind at 10 to 15 mph in the morning increasing to 15-25 mph by late morning with gusts above 35 mph during the afternoon.  Dew points will be very low resulting in low relative humidity.  The combination of strong winds, low humidity, and dry cornstalks in area fields will result in an elevated fire risk.  So a RED FLAG WARNING  has been issued by the National Weather Service from 8 am on Monday morning until 9 pm cdt on Monday evening.  The risk of wildfires is quite high.  A series of cold fronts will move rapidly southeast across the upper mid west this week.  There could be some light rain showers late on Tuesday into Tuesday evening with the first front approaching and moving through the area.  No gulf  moisture will get entrained into this front, or the next two fronts, so precipitation amounts will be very light for most of the week. Temperatures will swing up and down this week with a rise in temps before frontal arrival, and a fall in temps the next day.  This pattern will break as the weekend approaches.  Then, a major low pressure storm system is expected to develop eastward out of the plains beginning on Friday night, and continue through the weekend.  It appears at this time as if plenty of gulf of Mexico moisture will be drawn northward into the system, and there is potential for some fairly significant rainfall Saturday and Saturday night which will include thunderstorms.