1.   As a layer of cold air held steady near the ground, relatively warm, moist air invaded at loftier altitudes.

2.   As a result, winds from the Atlantic will blow from the east-southeast, allowing milder air to invade New England.

3.   As chillier air invades the region, rain will mix with and change to snow near Seattle.

4.   As warm, humid air first invaded the region, the snow began its disappearing act.

5.   A stream of Pacific air will invade the Northwestern states.

6.   After several days of springlike warmth, sharply colder air will invade the middle Mississippi and Ohio Valleys on Wednesday behind a strong front.

7.   In the wake of the low, chilly air will invade northwest Texas on strong winds from the north.

8.   In the wake of the front, unseasonably cool air will invade the Great Lakes region.

9.   Operators shut off a reactor at a Ukrainian nuclear power plant Wednesday after a leak in a pipe caused air to invade a vacuum in the turbine.