Wet leaves on road surfaces can be as dangerous as a coating of snow and ice, so we almost never hope for rain this time of year.

But tonight and tomorrow morning would constitute an exception. The dryness is getting serious.

The respective Pennsylvania and New Jersey environmental protection departments have the entire region under "drought watch."

The U.S. Drought Monitor, a government-academic partnership, has placed all of Philadelphia and Bucks Counties and the lower half of Montgomery County in a state of "moderate dought."

In the last 30 days, precipitation is running about a third of normal throughout the region.

Pennsylvania reports that many streams are running about as low as they can get with "a number of groundwater wells at emergency status levels."

The Delaware River at Trenton, for example, is at 8.03 feet; flood stage is 20; the Brandywine at Chadds Ford, at 1.71 feet; flood stage is 9 feet.

Don't expect any rain tonight and Tuesday to wipe out deficits. First of all, it's not a sure thing.

Secondly, the upper level of forecast predictions is about three-quarters of an inch. Rainfall the last 30 days is better than 2 inches below normal.

As we've observed, recent years have been generous with rainfall, and the region has enjoyed a long interval without a drought crisis.

Don't be surprised if that changes.