Update 10:20 a.m.: The National Weather Service has issued a wind chill warning for southern Wisconsin, including Dane County, from 6 p.m. Sunday to noon Tuesday.
The Weather Service said wind chills will be "life-threatening" at 40 below to 50 below both Monday and Tuesday mornings.
"This will be the coldest air we've experienced since the arctic blast in February of 1996," when temperatures tumbled as low as 29 below in Madison, the Weather Service said.
A wind chill advisory is in effect from midnight Saturday to 6 p.m. Sunday as the cold blast moves in.
A winter weather advisory also has been issued until 6 a.m. Saturday due to southerly winds gusting as high as 35 miles per hour causing considerable blowing and drifting of snow that already has fallen. No new snow is expected.
"Roads oriented east to west and out in rural areas will be most affected by the blowing and drifting," the Weather Service said. "Be prepared for unexpected and rapidly changing road conditions."
Saturday will provide only a brief respite from what has been a bitterly cold winter across south-central Wisconsin, according to forecasters.
The coldest air of the season is expected Sunday night into Tuesday, with records in reach and dangerous wind chill values down to 50 below, the National Weather Service warned on Friday morning.
Temperatures fell to the teens below zero early Friday morning, with light south winds producing wind chill values of 30 below to 15 below and prompting a wind chill advisory until 10 a.m.
“This will result in frostbite and lead to hypothermia if precautions are not taken,” the Weather Service said. “If you must venture outdoors, make sure you wear a hat and gloves.”
Officially, it was 12 below in Madison at 5:53 a.m., with a wind chill of 24 below, while records were set for Jan. 3 in Green Bay at 18 below, a degree colder than the prior record, and in Antigo at 25 below, 3 degrees colder than the older record.
While a high near 12 is expected in Madison on Friday under partly sunny skies, south winds are forecast to pick up to 15 to 20 miles per hour and gust to 35 mph in the afternoon, producing blowing snow and continued wind chills of 25 below to 15 below.
“Blowing snow will likely cause visibility restrictions in open and rural areas,” the Weather Service said. “Visibilities may drop to less than one mile at times. Drifting snow will cause snow covered roads, especially in open areas on east-west oriented roadways.”
Temperatures are expected to keep rising to around 20 by 4 a.m. Saturday, with blowing snow continuing as south winds rise to 20 to 25 mph, gusting to 35 mph and producing wind chills of 10 below to zero.
There’s a 40 percent chance of snow on Saturday, mainly before 9 a.m., under mostly cloudy skies with a high near 27 by 11 a.m., then falling to around 14 the remainder of the day. Winds again will be strong out of the southwest at 10 to 20 mph, gusting to 30 mph and turning out of the northwest in the afternoon.
The coldest air of the season begins to move in Saturday night when the low is expected around 2 below, with northwest winds around 10 mph producing wind chills of 20 below to 10 below.
Highs Sunday through Tuesday aren’t even expected to reach above zero at near 1 below, 13 below and 3 below, while lows Sunday night through Tuesday night should be around 21 below, 20 below and 10 below.
That is near Madison’s record coldest highs for Monday and Tuesday of 14 below and 9 below, and the record lows for Sunday night through Tuesday night that range from 29 below to 23 below, according to the Weather Service.
On top of the cold, winds are expected to blow up to 15 mph on Sunday and Monday.
“Dangerous wind chill values are expected to drop to between 35 and 50 degrees below zero Sunday night and remain in that range through Tuesday morning,” the Weather Service said. “Wind chill watches and warnings will be required.”
In Green Bay, where the Packers will meet the San Francisco 49ers in an NFC playoff game on Sunday, the high is expected near zero with northwest winds blowing at 9 to 13 mph and gusting to 22 mph. The low should fall to around 21 below Sunday night.
Madison skies should be mostly sunny Sunday, partly sunny Monday, mostly sunny Tuesday, then mostly cloudy Wednesday and Thursday as temperatures begin to moderate and snow chances return at 20 percent Wednesday and 30 percent Wednesday night and Thursday, the Weather Service said.
Highs are expected near 14 and 26 on Wednesday and Thursday, sandwiching a Wednesday night low around 10.
27 Storm Track meteorologist Brian Olson also expects bitterly cold temperatures to threaten records after a near-normal Saturday, with temperatures moderating back to around normal late next week.
Olson forecasts highs in Madison Friday through next Friday near 15, 26, 1, 12 below, zero, 18, 27 and 31, and overnight lows around 15, 3 below, 21 below, 20 below, 7 below, 14, 15 and 22.
The only precipitation mentioned in Olson’s forecast is some possible light snow Wednesday night.
Thursday’s high in Madison was 11 at 3:22 p.m., 16 degrees below normal and 42 degrees below the record high of 53 for Jan. 2, set in 1897.
Thursday’s low in Madison was 10 below at 11:57 p.m., 22 degrees below normal and 12 degrees above the record low of 22 below for Jan. 2, set in 1879.
Officially, a trace of precipitation was recorded at the Dane County Regional Airport on Thursday, leaving Madison’s January and 2014 total at a trace, 0.08 inches below normal. The meteorological winter (December through February) precipitation total (rain plus snow converted to liquid) stayed at 1.62 inches, 0.2 inches below normal.
Officially, 0.2 inches of snow fell on Thursday, 0.2 inches below normal, boosting Madison’s January and 2014 total to 0.3 inches, 0.5 inches below normal. For meteorological winter, Madison has received 22.4 inches, 8.1 inches above normal. For the snow season (since July 1), Madison has received 25.9 inches, 7.5 inches above normal. Madison’s snow depth is 7 inches.
Madison’s record snowfall for Jan. 2 is 10.2 inches in 1999.