Cold Start to December
December 07, 2011 10:45 AM
After a record warm and dry fall, December and the start of winter arrives with record cold temperatures.Just as Fall came in like a lamb, Winter has come in like a lion. Temperatures dropped well below normal Tuesday night due to an arctic air mass, snow covered ground and prime radiational cooling. The areas with more snow cover saw the coolest temperatures and some in north-west Iowa even broke records. Sheldon, Iowa tied their record low of 19 degrees below zero while Sioux Center, Iowa had no problem breaking their record with temperatures at 11 degrees below zero. Although it was cold in Sioux Falls our record was hard to beat at 22 degrees below zero. When wind was factored in, the wind chill values at multiple times was between 40 and 30 degrees below zero.
(Tuesday December 6th Morning Low's)It only seems fitting to bring up a recent ranking of coldest cities in America by the web-site: The Daily Beast. The web-site ranked the top 25 coldest cities in the United States by the average winter temperature, the coldest day, warmest day and the percentage of days with snow on the ground. Not surprisingly, four cities in our area ranked fairly high on the list. Coming in at the fifth coldest city in the United States is Watertown. Not so surprising for a city which set records last year for annual snowfall amounts.One spot down in 6th place lies Aberdeen
Down the list coming in at #8 is the largest city in South Dakota: Sioux FallsAlso making the list was Sioux City, Iowa at #12. The coldest city in America was Fairbanks, Alaska. For a full list of America's Coldest Cities you can visit The Daily Beast Web-site HERE Cold Weather is making it's return after a warmer Wednesday. A large Canadian trough will dip south bringing with it very cold air Thursday and Friday. Friday morning is starting to look very similar to last Tuesday morning when the majority of the area saw below zero temperatures.
(300 mb chart Nam valid 12Z Friday)High pressure moves back in Friday morning just in time to line up with a shot of cold Canadian air. Clearing skies and calming winds will lead to ideal radiational cooling allowing all the day time heating to escape.
(850 mb Temperature chart in celsius valid Friday 12z)Colder air will arrive Wednesday night and Thursday morning. Friday morning has the potential to be the coldest night this season for some areas. In Sioux Falls it is not looking like record low's as our record low is 19 degrees below zero. So even though we are talking cold air, this is not all that unlikely for South Dakota in December. Factoring in how warm the fall was this colder weather is comparatively much cooler.