Heavy rain due, Tuesday into Wednesday

The clouds are the forerunners of the frontal system that will bring us a warm and very wet air flow from the Gulf and the Atlantic on Tuesday as the high we're enjoying today moves east. The clockwise flow around that high, coupled with the counter-clockwise flow around the low to our north and west, will draw warm, moist air into the region from the southwest for Tuesday and Wednesday.

Temperatures late tonight, instead of falling as they normally do, will likely reverse course and rise, forecasters say. The rain is expected to reach the Baltimore area in the afternoon, with the heaviest amounts expected overnight Tuesday into Wednesday - as much as 1 to 2 inches. The chances of precipitation are put at 100 percent, with a chance of some thunderstorms developing.

Flash flooding could be a risk, forecasters said. With vegetation mostly dormant, more of the water will run off. Urban flooding is also a possibility where rain amounts are heaviest in storms. Here's AccuWeather.com's take on it.

Once the strong cold front passes Wednesday morning, temperatures will drop out of the 50s, into the 40s, with gusty winds out of the northwest. Any precipitation will end, and skies will clear for most of us. But forecasters hold out the possibility of snow showers on the western slopes of the Appalachians. We may also read of lake effect snows along the lee shores of the eastern Great Lakes.

Temperatures here will stay below normal through the weekend, Dec. 4 and 5, when a "weak clipper system" is expected to pass through. That holds at least the potential to deliver our legendary Dec. 5 snowfall in Baltimore. More on that soon.

But for now, the forecast just says the clipper "may have enough moisture associated with it to bring precipitation to the area ... At the moment, the only probabilities of precipitation are across the higher elevations in the form of snow showers."

(SUN PHOTO: Frank Roylance. Williamsburg, Va.)