WASHINGTON - A massive storm system that started in the Upper Midwest brought soaking rains and heavy winds to the mid-Atlantic on Thursday, causing widespread power outages, flash flooding and extensive flight delays but largely failing to live up to its fierce billing.

The severe weather was also blamed for two deaths.

The storm came and went in the Washington, D.C., area ahead of the evening rush hour, bringing thunder and winds that knocked trees onto houses, cut power to thousands of homes and traffic signals and led to the brief closure of a bridge that connects to the beaches on Maryland's Eastern shore.

Three tornadoes were reported in Maryland, though there were no immediate reports that they caused significant damage.

"The wind was pretty bad. It was just a squall that came through really fast," said Jim Estes, director of instruction at a golf driving range in Olney, a Washington suburb where one tornado was reported.

In Richmond, Va., a 4-year-old boy was killed by a tree that toppled while he was visiting Maymont Park with his father. Capt. Emmett Williams of the Richmond police said the tree became uprooted from rain-soaked grounds. The father was taken to the hospital with non-life-threatening injuries.

Lightning from a fast-moving storm may have sparked a fire that killed a western Pennsylvania man early Thursday, the state fire marshal said.

Dire predictions from forecasters, including warnings throughout the region of tornadoes and thunderstorms, led to precautions throughout several states.

Maryland transit officials briefly closed the Chesapeake Bay Bridge, a critical artery connecting the Baltimore-Washington area with Delaware and Maryland's Eastern Shore.

Flightstats.com reported that hundreds of flights were canceled and thousands more were delayed at East Coast and Midwest airports on Thursday, with the New York-Washington corridor particularly affected.

As of Thursday night, there were about 30,000 outages in Maryland, the state emergency management agency said, and more than 300,000 in Virginia.

The mid-Atlantic wasn't the only region to get hit Thursday. Lightning lit up the sky over Atlanta on Thursday evening, as a line of thunderstorms moved through north and central Georgia. Georgia Power reported that many customers had lost power as of 8:30 p.m.

In North Carolina, weather forecasters and utility companies reported downed trees and more than 157,000 customers without power, mostly in the Piedmont region.

Still, overall, the storms appear to have caused less wind damage than was feared through early Thursday, said Bill Bunting of the National Weather Service's Storm Prediction Center in Norman, Okla. Whether they were as bad as anticipated, he said, "depends on where you live."

Besides reports of damaging winds and preliminary tornado sightings, the weather service has received reports of hail at least an inch in diameter in locations stretching from southeast Minnesota to Virginia, he said.

In Ohio, storms with swift, straight-line winds soaked parts of the state, knocking down trees and barns and leaving many without power Thursday.

Straight-line winds topping 70 mph were reported and more than two dozen tornado warnings were issued as two rounds of storms pummeled the state, but no twisters had been confirmed, said Phillip Johnson, who was part of the team monitoring developments for the Ohio Emergency Management Agency.

In New Jersey, officials opened the state's Emergency Operations Center on Thursday morning to monitor the storm's progress. The weather service issued a flood watch for most of the state. Forecasters predicted 1 to 2 inches of rain would fall on swollen rivers and streams.

In northern New York, rain sent rivers and streams over their banks, leading to evacuations and road closures.