The National Weather Service is warning of a dangerous combination of high winds and subzero cold this morning, with low temperatures of minus 15 degrees and a wind chill of minus 35.
A wind chill warning is expected to remain in effect until noon.
In such conditions, people should limit their time outdoors or at least bundle up and avoid exposed skin, said meteorologist Dan P. Kelly at the National Weather Service in Buffalo.
Prolonged exposure to low temperatures could lead to frostbite or hypothermia, he said.
The extreme conditions are expected to let up this weekend, however, with temperatures in the teens and light snowfall across Jefferson, Lewis and St. Lawrence counties.
Saturday looks like it will be the beginning of a little bit warmer trend, said meteorologist David R. Thomas, also with the weather service in Buffalo. Like a heat wave almost.
Monday will be a different story.
A cold front will drop the temperatures right back down to the low single digits, and it looks like another lake-effect snowstorm could bring up to a foot of snow in the Tug Hill and Jefferson/St. Lawrence county area, Mr. Thomas said.
Wind speeds in Watertown on Thursday night were 10 to 20 miles per hour. Mr. Thomas said that will continue tonight at the same speed.
An additional problem for drivers could be reduced visibility because of blowing snow. Visibility may drop to a half-mile or less.
The bitter cold weather has residents talking. Watertown Daily Times Facebook users reported what the temperature was at their houses on Thursday morning.
Brenda Thornton wrote it was minus 17 degrees in Stockholm when she woke up at 6:30. Candice Sayers Zeller wrote it was minus 10 in Chaumont, and Elaine Perry wrote it was minus 13 in Norwood.
Meanwhile, a reader from outside the area, Tom Myers, wrote that the weather was 66 degrees and foggy in Florida.