11.   A push of polar air into the Great Lakes and interior Northeast will be marked by shifting winds and bands of snow showers.

12.   A surge of polar air will reach from the Great Lakes to the lower Missouri Valley.

13.   A surge of polar air into the Northeast will be accompanied by several inches of snow in the higher elevations of New England.

14.   A surge of polar air into the Plains will keep temperatures far below seasonal levels.

15.   Advancing polar air will reach the Dakotas later Monday, preceded by clouds and flurries.

16.   Brisk winds from the north will push polar air back into the northern Plains and upper Middle West.

17.   But a new push of polar air into New England will retard the advancing sultry weather.

18.   Frequent surges of polar air have kept readings generally below seasonal levels for over two weeks.

19.   High pressure in the central Plains will be associated with a mixture of Pacific and polar air.

20.   However, the warming trend in the Northeast will be brief as a new surge of polar air enters the region.