'Severe' outlook

If you plan to attend the U.S. Open tomorrow in Merion, the weather forecast for tomorrow probably couldn't be more unappealing.

On top of the predicted heavy rains -- up to 2 inches -- the government's Storm Prediction Center sees a "moderate risk" for severe weather throughout the region.

In fact, the "moderate" zone covers all of the Philadelphia and Washington areas, inhabited by about 18 million people.

The term "severe" is a technical one. To quality as severe, as storm has to pack wind gusts of 58 m.p.h. or more.

Even if the storms fall short of the technical threshold, the weather tomorrow should be frisky, if not dangerous.

In its morning discussion, the National Weather Service in Mount Holly warnt that super-cell storms that could spawn tornados will develop.

"It will definitely be a 'keep an eye to the sky' kind of day," it said.

What's more, while the region has had a half-foot of rain since Friday, no major flooding has been reported.

That could change tomorrow.