Forecasters now say damaging winds, with maybe a "quick inch" of rain, will be the main worry during Friday's frontal passage. And, because the winds will be strong out of the south, people with property along the upper Chesapeake can expect yet another brush with high water. Here's the forecast from Sterling.

The culprit is the same surge of cold air that's brought deep snows to the Rocky Mountains, and is now threatening the southern Plains with severe storms and tornadoes.

The violent weather stems from the clash of the arctic outbreak with warm air in place across much of the eastern half of the nation. Deep low-pressure centers are forming along the front, and steep pressure gradients between those lows and nearby highs are what will generate the strong winds as the front makes its way east.

Here's some of this morning's discussion from the National Weather Service at Sterling:

"AS FOR ANY FLASH FLOODING THREAT...COULD EASILY SEE A QUICK INCH OF RAIN WITH THE FRONT BUT AT THIS TIME LOOKS LIKE DAMAGING WINDS  WILL BE THE MAIN HAZARD THIS TIME. WILL ALSO HAVE TO WATCH FOR WATER LEVELS ON THE POTOMAC AND CHESAPEAKE BAY AS WINDS WILL BE BLOWING STRONG OUT OF THE SOUTH FOR ABOUT 24 HRS.  IN THE GRIDS CAPPED WIND GUSTS AT 30 KTS (34 mph) BOTH OVER LAND AND OVER WATER HOWEVER THESE LIKELY WILL NEED TO BE RAISED IN LATER PERIODS."