A winter storm taking shape today across the Midwestern plains will tickle the Washington area with snow tonight before giving way to a mixture of freezing rain and sleet that is expected to intensify by Tuesday afternoon and continue through tomorrow evening.

Only light accumulations are expected, meteorologists say, as the storm moves across Oklahoma and Arkansas today and through the Tennessee Valley before moving up the East Coast.

But with surface temperatures expected to stay below freezing, the storm could coat roads with a slick layer of ice in time for the Wednesday morning commute.

The threat exists, according to Accu-Weather meteorologist John Gresiak, of an ice storm intense enough to bring down power lines in some areas. Much of the area was under a winter storm watch through Wednesday.

"This could be a damaging ice storm in parts of the area . . . It will be a very narrow zone, somewhere across the area, that could cause damage," Gresiak said.

Whether the storm is a blast or a bust, Gresiak and other forecasters said, remains to be seen.

A mass of warm air off the coast of the Carolinas could temper the storm, for example, although there is also a chance of fairly significant dousing of ice.

"The critical factor now is: How heavy is the precipitation Tuesday night? How much ice will we accumulate?" said Roger Smith, a meteorologist at the National Weather Service's office for the Baltimore-Washington region.

Both forecasters said there is little chance now for a major snowstorm. Temperatures several thousand feet above the ground remain temperate in this area.

As the storm dissipates on Wednesday and moves into New England, temperatures are expected to drop for the remainder of the week.