1.   As descending air currents within the thunderstorms intercept a zone of fast-moving air aloft, powerful downburst winds will occur, producing damaging gusts in several locations.

2.   A few thunderstorms are possible in northwest Washington as very cold air aloft moves over relatively milder air near the surface.

3.   A cool pocket of air aloft, however, will cause clouds to linger over interior New England.

4.   A jet stream disturbance rotating around a pool of moist air aloft will promote numerous showers from Kentucky and Tennessee to the southern Appalachians.

5.   A return flow of humid air into the southern Rockies will combine with very warm air aloft, producing afternoon thunderstorms from New Mexico to southern Idaho.

6.   Air near the ground, warmed by the strengthening sun, rises into pools of chilly air aloft that still linger from the winter.

7.   But eastern sections will remain under the control of a pool of chilly air aloft which will cause plenty of clouds to persist and scattered showers to develop.

8.   Clouds will crumble over the Northeast on Tuesday night, only to reform again Wednesday as cold air aloft intensifies.

9.   Chilly rains will accompany a pool of cold air aloft pressing eastward into the Pacific Northwest on Sunday.

10.   Circulation around a swirling mass of cool air aloft will bring unsettled conditions to the northern Great Lakes and interior Northeast on Thursday.