11.  A plume of moist air will stream north through the Mississippi Valley to the central Great Lakes as breezes from the south quicken ahead of a weak cool front.

12.  A weak cool front moving through the Ohio Valley will yield scattered showers from southern Illinois to northern Missouri Tuesday.

13.  A weak cool front will graze northern New England and upstate New York, possibly accompanied by a brief thundershower.

14.  A weak front accompanied by thundershowers will sweep off the Atlantic coast during the afternoon.

15.  A weak front across northern and eastern New England will be the focus for patches of clouds and a few showers.

16.  A weak front in the Dakotas will promote a few potent thunderstorms during the heat of the afternoon.

17.  A weak front stretching from Wisconsin to Michigan will spark a few thunderstorms.

18.  A weak front will approach the Northwestern Coast will clouds and some scattered showers.

19.  A weak front will produce isolated showers in the Northwest.

20.  A vigorous jet stream will push numerous weak fronts across the northern part of the country over the next several days.