Sunday, January 20 to Tuesday, January 22, 1985, a polar vortex, coupled
with a large ridge of high pressure, moved polar air into the United States
as far south as Florida. The frigid air mass moved east and
south from the Plains during the day on January 20 with the surface map
showing a massive 1048 mb high over the northern Plains at 12Z January 20
(Figure 2), resulting in frigid air for most of the central and eastern
United States. The 500 mb pattern on January 20 (Figure 2), showed a closed
polar vortex over Michigan. By the morning of January 21, the 500 mb vortex
had moved to extreme Northern New England (Figure 3) producing the coldest
morning of the century for many locations in the Southeastern United
States, including eastern North Carolina.
2. Surface Map at 12Z January 20, 1985 showing 1048 mb Arctic High covering
most of the central U.S.
Figure 3. The 12Z 500 mb Analysis January
20, 1985 showed closed polar vortex over Michigan.
Figure 4. The 12Z 500 mb Analysis January
21, 1985 showed the polar vortex had moved to northern Maine.
Weather Service Daily Weather Maps