Winter Misery Index: Where Winter Weather Has Already Been Extreme Through Early January
Published: January 10, 2018
As we approach the midpoint of meteorological winter, which runs from December through February, parts of the United States have already suffered through extreme winter weather conditions in the first half of the season.
According to the Accumulated Winter Season Severity Index (AWSSI), nearly two-dozen cities from the Great Lakes and Northeast to the mid-Atlantic and South have seen an extreme season of cold and snow through early January.
(MORE: First Week of 2018 Was the Coldest on Record in Dozens of Cities in the East)
This index takes into account the "intensity and persistence of cold weather, the frequency and amount of snow and the amount and persistence of snow on the ground," the Midwest Regional Climate Center said. Wind and mixed precipitation, such as freezing rain, are not a part of the index.
For any given location, the start date of the winter season is defined as when the first measurable snowfall (at least 0.1 inches) occurs or when the first high temperature of 32 degrees or lower is recorded. The start date is Dec. 1 for any location that does not see either of those happen before that date.
The index uses five categories – mild, moderate, average, severe and extreme – to rate the severity of winter weather at any given point in the season.
AWSSI national index values as of Jan. 10, 2018. City locations are color-coded based on the severity of the season so far, as shown by the legend at the top.(Dr. Barbara Mayes Boustead and Steven Hilberg, Midwest Regional Climate Center)
"The categories are site-specific ... because what constitutes a severe winter, say, in Washington D.C. or Atlanta would be considered mild in Chicago or Minneapolis," said Dr. Barbara Mayes Boustead, a co-creator of the AWSSI and a forecaster at the National Weather Service in Omaha, Nebraska.
Across the eastern third of the Lower 48 states, 22 cities have had "extreme" winter weather conditions as of Jan. 10, according to the index, but several more have had "severe" winter conditions across the East, Midwest, upper Mississippi Valley, Plains, Mountain West and even the South.
Nine cities have had a "mild" winter so far, all in the West. Note that mild doesn't just refer to temperatures, but winter weather conditions have been mild compared to average, based on the index's factors mentioned above.
(MORE: 2017 Was Third-Warmest Year on Record for U.S.)
Let's take a look at some individual cities and see just how harsh or mild their winter has been through this point in time.
The Harshest So Far: Great Lakes, Northeast, Mid-Atlantic and South
A two-week-long bitterly cold, Arctic outbreak beginning around Christmas played a large role in the following cities experiencing "extreme" winter weather conditions. Winter storms Benji in early December and Grayson in early January also helped send some cities into the "extreme" category.
- New York City: The two-week period from Dec. 26 through Jan. 8 was the second-coldest such period on record in New York City with an average temperature of 17.9 degrees, about 16 degrees below average. Temperatures remained below freezing for all 14 of those days, with the lowest reading of 5 degrees occurring on Jan. 7. Looking at just the first week of January (Jan. 1-7), it was the coldest start to any new year on record with an average temperature of 16.4 degrees, smashing the previous record of 21.4 degrees set in 1981. The Big Apple also picked up 9.8 inches of snow on Jan. 4 from Winter Storm Grayson, which underwent bombogenesis as it hammered the Eastern Seaboard.
- Washington D.C.: Our nation's capital picked up 2 inches of snow from Winter Storm Benji on Dec. 9, the first measurable snowfall of the season. Dulles Airport, northwest of Washington D.C., picked up 4 inches of snow during Benji. Similar to New York City, the bitterly cold air also affected the mid-Atlantic region, giving Washington D.C. its fourth-coldest first week of the year (Jan. 1-7) on record with an average temperature of 19 degrees, about 17 degrees below average. Additionally, Winter Storm Grayson brought 0.8 inches of snow to Reagan National Airport on Jan. 4.
- Birmingham, Alabama: Birmingham saw a rare early-December snowfall when Winter Storm Benji dumped 4 inches on the city Dec. 8. This is more snow than Birmingham averages in an entire winter, only 1.6 inches, based on 1981-2010 data. More recently, the first week of January was the third-coldest start to any year on record with an average temperature of 28.9 degrees. The low temperature dipped down to 11 degrees on Jan. 2, which was 23 degrees below the average early-January low of 34 degrees.
The black line shows the rise into the "extreme" category on the AWSSI in New York City
by early January.(Midwest Regional Climate Center)
Mild: Portions of the West
A lack of persistent cold and snow played a role in the "mild" winter conditions that more than a half-dozen western cities have seen to this point.
- Denver: The Mile High City has seen a measly 6.8 inches of snow this season through Jan. 9. Denver averages 60.1 inches over the entire season and typically sees 27.5 inches by the end of December. In addition, temperatures are currently running about 4 degrees above average for meteorological winter (since Dec. 1).
- Albuquerque, New Mexico Albuquerque is in the midst of its second-warmest meteorological winter on record as of Jan. 9, with temperatures running about 4 degrees above average. The city has only picked up a trace of snow this winter. It typically receives 10.3 inches in an average winter, with 4.2 inches of that usually falling by the end of December.
- Salt Lake City, Utah: Salt Lake City is another location lagging behind in the snowfall department. Only 8 inches of snow has been measured this season through Jan. 9, which is over 18 inches below average for this point in the season. An average winter sees 26.2 inches of snow by Jan. 9. Average temperatures for meteorological winter are also running about 4 degrees above average.
The black line shows that Denver is currently in the "mild" category on the AWSSI.(Midwest Regional Climate Center)
Brian Donegan is a digital meteorologist at weather.com. Follow him on Facebook, Twitter and Instagram.
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