From weather.com;
"Harsh, Dangerous, Long-Lasting Cold
by Tim Ballisty , on Jan 4, 2010 11:03 am ET
The Eastern two-thirds of the United States will be in the grips of a long-lasting spell of harsh, arctic cold.
We are already in the midst of the first wave of the cold air invasion. The second and likely even colder air mass will begin its descent over the eastern United States on Wednesday morning.
By Sunday morning, the cold wave will have made its way as far south as the Florida Keys."