After a relatively dry November, December will start off rather wet. In fact, Louisville International Airport (Standiford) received 1.8 inches of rain on Friday, after receiving a total of 0.75 inches in all of November. A frontal boundary will sag southeast toward the region, stalling across central Kentucky Saturday afternoon. It then will move back north as a warm front on Sunday. Several areas of low pressure will ride along this stalled front, bringing a few rounds of showers and even a couple of thunderstorms to the Ohio Valley (See the graphic below for position of the front and rainfall Sunday morning).
With this front nearby, a warm and moist airmass will be available for these disturbances as they ride along the boundary. Therefore, rainfall amounts could be quite heavy, with an additional inch or two possible over the next couple of days. The chart below displays a rainfall forecast for Saturday through Monday morning. At this point, the bulk of this rain is anticipated Sunday evening through early Monday.
The last time much of the region received 2+ inches of rainfall over only a few days was way back in September, so this rain is much needed and will be welcomed by area rivers and streams. A strong cold front will push through the Ohio Valley through the day on Monday, bringing much cooler temperatures and drier weather to the region by the middle of next week.