A frontal boundary draped across Maine together with Southerly moist winds have left us a muggy and warm Labor Day Weekend. The threat of scattered showers and thunderstorms will continue again today, especially this afternoon as temperatures warm up. Temperatures could reach that 80-degree mark again today.
Tonight, the showers should die down after sunrise but the threat will continue as warm air advection continues to leave us with an unstable atmosphere. Abundant moisture will allow for another foggy night with temperatures well above average in the mid 60s (average low for Portland is 55 degrees).
Monday that cold front will begin to move north as a warm front. This will allow for heavy rain showers and thunderstorms to develop again. Depending on the speed of that warm front, we could see an improvement on Monday afternoon.
Improving conditions and definitely more Fall-like temperatures are to be expected for the second half of the workweek.