Active pattern sets in for the beginning of Spring

 

The Vernal Equinox is tomorrow, signifying the first day of Spring. Spring will officially begin at 4:24pm. This is when the center of the sun is directly above the equator bringing us roughly 12 hours of day and night. The sunrise in Rockford will be at 7am and sunset at 7:08pm!

The sunshine we had from Sunday won't carry over into Monday, unfortunately, as skies turn mostly cloudy by the afternoon and evening. The clouds are the result of a weak upper-level low that'll move through the Midwest and Great Lakes. This will increase moisture in the atmosphere slightly, but our dry surface dew points will likely help to keep most of us dry during the afternoon and evening. Temperatures Monday will continue to warm, reaching the upper 40s for the afternoon.

The beginning of Spring will also bring an unsettled weather pattern to the Stateline. Almost every day this week will have a chance for at least some precipitation. The first arrives Monday, although that is a very small chance. The second arrives Tuesday. The jet stream will turn from southwest to northeast, leaving northern Illinois and southern Wisconsin right under the stronger wind flow. At the same time, a weak warm front lifting through Monday afternoon will merge with a cold front moving in from the north. This will form a stationary boundary that'll stall across the region through the week. Depending on where exactly that boundary stalls will determine just how warm, or cool, we get and when the rain will fall.

Showers appear to move back in Tuesday evening, lasting into Tuesday night. The front will briefly lift north into Wisconsin on Wednesday, bringing temperatures into the mid 50s, but will then quickly fall to the south Wednesday night and Thursday. 

This is the time period that appears to be the best chance for rain here in the Stateline. By Thursday, the front will be quickly moving south as high pressure builds in from the north. Another low-pressure system may develop to the west Friday, moving through the region Friday night and Saturday. If the low is close enough, we could see some precipitation develop during that time as colder temperatures try to move in.