A ridge of high pressure off to our east has continued to allow the area to loll in relatively idyllic weather conditions for so late into November. This all begins to change after Sunday evening.
In the interim clouds will continue to be on the increase through the day Sunday. The Tri-States will lie juxtaposed between two pieces of upper-level energy and this energy will bring a disturbance that passes just south of our area Sunday evening. There may be just enough vertical push in the atmosphere far enough north of the path of this aforementioned disturbance to engender very light rainfall across portions of Pike and Scott counties in IL on Sunday afternoon, but if this does materialize (15% chance) it will be marginal and amount to less than 0.10" or so. Otherwise cloudy and breezy albeit mild conditions remain the story for the entire region Sunday.
A robust cold front will pass through the region, from northwest to southeast, by late Sunday afternoon. Winds are poised to be gusty throughout the day Sunday with a shift to the NNW later in the afternoon. Overnight Sunday temperatures will drop into the low to mid-20s. Surface wind gusts near or above 25 mph will cause wind chill values to approach the lower teens by sunrise on Monday. This will be the coldest air thus far this season. Cooler temperatures into the upper teens will arrive overnight Monday into Tuesday morning, and while winds will subside and mollify the wind chill threat a bit for Tuesday morning, wind chill values are still forecast to be in the upper teens or low 20s Tuesday morning.
A return to slightly milder, drier weather looks to be the atmospheric modus operandi thereafter through the middle of the workweek based on the present model data.