A Rainy Sunday

A ridge of high pressure provided the Stateline with lots of sunshine, low humidity, light winds, and temperatures into the middle 50's on Saturday afternoon.   It was a great day to get outside and enjoy the last full day of winter.  The vernal equinox occurs late Sunday afternoon, so it will be officially spring when the sun goes down on Sunday night.  A weather system over the plains is pulling itself together tonight.  Winds from the southeast, and eventually from the south, will tap Gulf of Mexico moisture into the system, and scatter some showers into northern Illinois overnight.  Rain will become widespread on Sunday morning, and some thunderstorms will be embedded within the rain as it lifts across the Stateline.  Some locally heavy rainfall amounts of over an inch may occur in those areas that have thunderstorms on Sunday. Showers and thunderstorms will come to an end on Sunday evening with the passage of a warm front to our north followed quickly by a cool front from the west.  A weak bubble of high pressure will provide quite a bit of sunshine on Monday, and it will be relatively mild with an afternoon high temperature in the middle to upper 50's.  The high will fade from the picture during the afternoon as a new low pressure storm center begins to pull itself together over the eastern slopes of the Rockies.  A stationary front will set up across central or southern Illinois, and a strong inflow of gulf moisture will intersect with the front bringing rain and thunderstorms to northern Illinois on Monday night and Tuesday.  Once again there is the potential for some locally heavy rainfall as this system moves across the Stateline.  The path of the low appears as if it will be across central Illinois on Wednesday morning.  By that time lots of cold air from Canada will have been drawn into the circulation of the storm.  The net result for residents of northern Illinois will be that rain will probably mix with wet snow on Tuesday night into Wednesday morning.  It will be windy, too, along with chilly temperatures in the middle to upper 30's.  On Wednesday afternoon it will probably be warm enough that any precipitation that occurs will be in the form of rain, but by Wednesday night, with temperatures dropping into the 20's, precipitation will change to light snow before ending.  Admittedly, it is still quite far off to be very precise about what will happen with this second storm system, and forecast confidence is not very high.  One thing to be fairly sure of, however, is the fact that after the second storm departs off to the east... it will be cold on Thursday and Friday of next week.  It will not feel like spring at all with highs on Thursday and Friday only near freezing. 
By Meterologist
Eric Nefstead