Today starts off chilly and will end wet, and heavier rain will fall Wednesday. I’ve been pointing out the adjustment of models to the east with rain in the increase. Now most of our region is slated in the 1 to 3 inch rainfall range, so local flooding is possible.
Some frost may great you out the door in spots this morning, but the clouds are already here. So dress for a cool day ever though temperatures could hit 60F, that will come with the push of rain from the south into the night. The question is when will the rain arrive. If you are in Virginia or near Washington, the first drops should be around lunchtime. It will take all afternoon for the leading edge to reach metro Baltimore. Two model simulations below show central Maryland to southern PA will stay dry most of the day, but rain will arrive between the afternoon commuter and this evening.
Rain will fall all night, with the heavy push Wednesday morning. The bulk of the rain will be during the first half of Wednesday, then break with scattered showers. That is when we watch the instability and cold front possibly bring us thunderstorms Wednesday afternoon and evening.