- Much of the country has had an unusually pleasant start to winter so far.
- It is based on an index that combines cold and snow.
- In more than 20 cities, especially in the northern United States, the start of winter was record mild.
Winter weather has been fairly limited in much of the country so far, to the point of setting records for the mildest start to the season, by one measure.
Record holders and the rest of the moderate cities: According to the Midwest Regional Climate Center's (MRCC) Accumulated Winter Severity Index (AWSSI), more than 20 cities experienced a record mild start to winter through late December.
Among these cities are some of the typically snowy or cold places in America, including Fargo, North Dakota; Marquette, Michigan; Milwaukee, Wisconsin; and Minneapolis-St. pee.
Most parts of the country have had a mild or mild start to the season, at least less snowy and/or warmer than normal.
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AWSSI as of December 27, 2023. All locations with orange or red dots indicate that winters have been less snowy and/or cold than average, so far. Dark red dots indicate cities that experienced a record mild start (low AWSSI value) to the season through December 27.
(Data: Midwest Regional Climate Center)
What does this index mean: The AWSSI, also known as the “Winter Misery Index,” takes into account three factors: the intensity and persistence of cold weather, the frequency and amount of snowfall, and the amount and consistency of snowfall on the ground. Wind and mixed precipitation, such as freezing rain, are not part of the index.
The index uses five categories — mild, moderate, moderate, severe and extreme — to evaluate the severity of winter weather in cities across the United States over the course of an entire cold season.
The higher the index, the longer you will be exposed to snow and/or hail. As the map above shows, AWSSIs have been relatively low in most parts of the country so far.
Below shows the lead index time series, South Dakota, in the western Black Hills region of the state. The black line corresponds to this season's index. Only a Christmas snowstorm — Winter Storm Donovan — has lifted the city's index slightly in recent days, though it was still in record territory as of late December.
The black tracking shows the 2023-24 Winter Misery Index (AWSSI) through December 28 for Lead City, South Dakota, below the previous record AWSSI value so far, which appears at the bottom of the red shaded area below the black line.
(Midwest Regional Climate Center)
Lack of snow: Outside of the western mountains, high plains and northern New England, there hasn't been much snowfall this season so far. according to analysis By New Zealand meteorologist Ben Knoll The Lower 48 has seen its least snowfall this season so far since at least 2008.
The snow that fell did not stay for long. The extent of snow cover was least extensive in late December across the Lower 48 In at least 20 yearsaccording to NOAA.
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Widespread warmth: Then there's the fact that it wasn't very cold in December.
At the time this article was published before New Year's Eve, many cities in the northern tier from Washington state to the Great Lakes region were flirting with or solidly ahead of the pace for the warmest December on record.
This included some of the same places with record low winter misery indexes, as well as Portland, Oregon; Toledo, Ohio; And even the icebox of the country, International Falls, Minnesota.
Dozens of other cities from the Northeast to California were on track for one of their five warmest Decembers.
A different kind of “misery”: Despite all this, there was a different kind of weather frustration, the liquid variety.
Virtually the entire East Coast from Florida to Maine was repeatedly flooded in December.
A pair of wet storms pushed Allentown, Pennsylvania, into the data record for its wettest winter month since 1912, with just over 8.5 inches of rain falling. Several Florida cities, including Punta Gorda and Tallahassee, were on track to enter the 10 wettest December, typically a dry month in the Sunshine State.
Precipitation varies from average for December 1-29, 2023. Wetter than average areas are shown by the blue, purple, and pink lines in the east.
(NOAA)
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Jonathan Erdmann is a senior meteorologist at Weather.com and has been covering national and international weather since 1996. His lifelong love of meteorology began with a close encounter with a tornado as a child in Wisconsin. He studied physics at the University of Wisconsin-Madison, then completed a master's degree working with dual polarization radar and lightning data at Colorado State University. Extreme and strange weather are his favorite subjects. Contact him on X (formerly Twitter), Threads, Facebook And the sky is blue.
The Weather Company's primary journalistic mission is to report on breaking weather news, the environment, and the importance of science in our lives. This story does not necessarily represent the position of our parent company, IBM.
