No need to ponder it much today, amid all the sunshine and blustery winds, but there is a substantial and welcome rainstorm due here by Thursday night.

If the forecast holds up, we can expect the rain to start Thursday evening, or soon after midnight Friday as a storm makes its way up from the Gulf. We could receive as much as a quarter-inch by Friday morning, with another half- to three-quarters of an inch during the day Friday. If the upper numbers prove accurate, this would be the wettest 24-hour period we've seen (at BWI) since Oct. 26.

It is - at least in the I-95 urban corridor - expected to be all rain.

And we can still use the moisture. January precipitation has been running almost 2 inches below the long-term averages, and we still have a large deficit to erase before the spring and summer months arrive. Much of Maryland - nearly half, according to the U.S. Drought Monitor - remains in official drought conditions.  Streams are low and the ground water levels in many wells are still slipping. Here's a tracing for groundwater levels over the last 30 days in a USGS well in Granite, Baltimore County:

So let the patter of rain on your roof Friday morning be a welcome sound. Grab an umbrella, step outside, put a smile on your face and think of Gene Kelly.