Another Agnes?
I don't like the look of this one.
AccuWeather is reporting that that Central Pennsylvania might be hit with a deluge, which it defines as more than six inches of rain. If the worst scenario for Ernesto comes to pass, we are expected to receive 6-10 inches of rain on Friday afternoon and Saturday. You'd better plan to wear Scuba gear if you go out in that.
My Shipoke neighbor, Mike Tapper, was grim-faced and down this afternoon. He said "people are saying" that Ernesto could be another Tropical Storm Agnes. Agnes, which hit in late June, 1972, was the single most destructive flood in recorded Pennsylvania history. The flood crested at 32 feet at Harrisburg, enough to fill both the basements and first stories of homes in Shipoke and many other places throughout the region. That got my attention.
The National Weather Service's Mid-Atlantic River Forecast Center has an informative historical piece on Agnes on its website. There are indeed some disturbing parallels between Agnes and what is being forecast for Ernesto. What caught my eye was that the Mid-Atlantic region received an average of 6-10 inches of rain during Agnes after the storm parked itself over north central Pennsylvania.
But there are some significant differences as well. Agnes made landfall in south east New York and moved west across New York State before looping down into north central Pennsylvania to dump its rain well north of Harrisburg. And while an average 6-10 inches fell throughout the region, the amount that fell in north central Pa. was far greater. Shamokin, which is about 75 miles northeast of Harrisburg in Northumberland County, received an astonishing 18 inches of rain. That was the Agnes record, and they were still repairing things when I arrived there as a young reporter in 1975.
Ernesto is supposed to move north through the Carolinas, Virginia and Maryland before entering south central Pennsylvania and parking over the region when it collides with the cold front. If the worst of the rain falls at or south of Harrisburg, it would seem to me the flood problem would be to the south of us as well. I always tell newcomers to Shipoke that it's not the rain that falls on Harrisburg they have to worry about, it's what falls over the upper reaches of the Susquehanna River that can hurt us.
The other mitigating factor would be the extreme lack of rainfall much of the region has experienced this summer. The rivers and streams are low, and the ground is dry. When Agnes hit, the ground had already been saturated with 2-3 inches of rain. And of course, Ernesto could turn out to sea, eliminate this whole problem, and save this Labor Day weekend. I hope so. Our collective backs in Shipoke are still sore, at least in a metaphorical sense, from the flood scare in late June.
Let's hope we get lucky, but just in case, start making plans for moving your stuff out of harm's way.