Cloudy skies at night are a good thing; Not so good during the day

The temperature spread from lows this morning to highs this afternoon won't be very large.  In fact, our temperatures haven't moved much from where we were at 8am; 49°!  The low stratus clouds won't break up much this afternoon and with a breeze from west this will limit how far temperatures rise through the afternoon. 

While cloud cover during the day cools the atmosphere, cloud cover at night actually helps trap warmth in.  When skies are clear at night any heat that was stored throughout the day is lost back into space once the sun sets.  On clear and calm night this sets the stage for temperatures to drop significantly.  However, when clouds are present this acts as a blanket and helps hold temperatures up.  The problem we face this week and weekend is trying to determine when cloud cover will be present and when skies will clear.  The biggest concern is for the weekend.  Cold air aloft will be in place throughout the Great Lakes Saturday and Sunday.  If skies are clear during the overnight the potential will be there lows to drop in the low 30s...upper 20s.  However, if skies don't clear then overnight lows will be warmer.  If freezing temperatures aren't reached this weekend there's a good chance they may be reached next week.  Another push of cold air next Wednesday could bring 20s into the forecast.  Stay tuned!