April 13 (Bloomberg) -- A storm system gaining strength in Colorado may bring thunder, snow and hurricane-force winds as it moves east this weekend.

An earlier system moved off the coast of northeastern Maine today as the latest storm blanketed parts of Colorado with about 4 inches (10 centimeters) of snow. Seven more inches of snow are forecast as it moves into the Plains, according to the National Weather Service's Hydrometeorological Prediction Center in Camp Springs, Maryland.

``This kind of storm will have a huge impact on travel,'' said Dale Mohler, senior meteorologist with State College, Pennsylvania-based AccuWeather.com. ``The storm will really set in Sunday afternoon.''

By April 16, the system may be as strong as a Category 1 hurricane, with winds above 74 miles per hour (119 kilometers per hour) and stretch from Maine to Florida and as far west as the Mississippi River, Mohler said.

Thunderstorms moved into Oklahoma and Texas today, and nickel-sized hail fell, the weather service said. A tornado watch was in effect for northern Texas until 7:45 p.m. local time.

Nascar canceled qualifying for the Samsung 500 auto race at Texas Motor Speedway, where hundreds of campers and motor homes are parked, after the National Weather Service's thunderstorm and tornado warnings. Track operator Speedway Motorsports Inc. sounded sirens at about 5:50 p.m. local time to warn spectators to take cover from the severe weather. Nascar warned its teams to pack up cars and transporters, and to disconnect propane gas- fired appliances.

No Major Damage

By about 6:30 p.m. Dallas time, the storm had passed through the racetrack area without causing major damage. Fort Worth television station KTVT said it had reports of buildings damaged by weather in that city, which is about 15 miles (24 kilometers) southwest of the racetrack.

The northern edge of the system will bring snow to the Ohio Valley, upstate New York and northern New England this weekend, and the precipitation will turn to rain further south, the weather service said. New York City and Boston are forecast to get soaked by rain and whipped by strong winds April 15 and 16, the weather service said.

The National Guard in New York state is being put on alert, the Associated Press reported. Governor Eliot Spitzer asked residents to be aware of the weather conditions and ``plan accordingly,'' according to AP.

Boston Marathon Threatened

Organizers for the Boston Marathon, scheduled for April 16, are tracking the storm, which could bring wind gusts of 50 miles per hour (80 kilometers per hour). The marathon has never been postponed in its 110-year history, and the run would be canceled, rather than rescheduled, if the weather created unsafe conditions.

Severe weather, including thunderstorms, hail and wind will move along the southern edge of the nor'easter, through the Mississippi Valley and into the southeast by late in the weekend, forecasters said. The system may produce tornadoes, particularly from Nashville, Tennessee to New Orleans, Mohler said.

The storm follows another weather system that grounded hundreds of flights in Chicago and dumped about 10 inches of unseasonable snow in the Midwest and Northeast.

To contact the reporter on this story: Courtney Dentch in New York at cdentch1@bloomberg.net.

Last Updated: April 13, 2007 20:14 EDT