Extreme Cold Wave + Heavy Snow (Comment Added at 3:30pm CST)

Extreme cold is moving into the Lower 48 states. In addition to travel and 

logistics issues, I am concerned about power outages. 

No change in this forecast indicated as of 3:30pm CST.

The NWS watch/warning maps have been updated. 

Above is a forecast of below normal temperatures (i.e., -40.0 = 40°F below normal) for Tuesday night. The extreme cold will move south and east.

As of 3:30pm Sunday, here's a depiction of National Weather Service watches/warnings:

Color code:

• Orange = blizzard warning
• Pink = winter storm warning
• Light brown = high wind warning 
• Bright green = flood warning 
• Dark blue = winter storm watch 
• Purple = winter weather advisory 
• Dark brown = high wind advisory 

Here is a map of current power failures (3:30pm):

There are more than a million people without power. 

Let's focus on the central U.S. as the snow and cold event will cause major disruptions. 

Starting Monday, heavy snow will begin with plummeting temperatures in the central Great Plains. The entire winter storm watch area (dark blue) will have at least five inches of snow with nearly a foot of snow near the Lake of the Ozarks. This will be fluffy snow that will blow around and drift, causing extreme travel problems that will certainly affect Interstates 49, 35, 44 and, possibly, 70. Airport closures are possible on Tuesday. 

Below are the temperatures as forecast for 10am Tuesday. 

Below are forecast snow amounts as of 6pm Wednesday. 

The heaviest snow will move into the Middle Atlantic States Wednesday and Thursday.

The above map is the probability of 4" or more of snow from 7am Wednesday to 7am Thursday. The bright blue is a 90% chance.