Cold, bitter, frigid, arctic blast and of course polar vortex are words we are all hearing a lot of this week. You might be wondering, is this really THAT cold? The answer is maybe, but it depends where you are and how you look at the statistics.
First, the coverage of the cold air over so much of the country is notable. Often in November one section of the United States sees arctic air, but itís unusual for two-thirds of the lower 48 to see this type of widespread outbreak of cold.
Over the past 7 days if we look at the entire country there have been a lot of cold records being set. The chart below shows for example, 1360 daily low maximum records. This means those places had cold high temperatures which were records. Simply put, those cities and towns saw their coldest daily highs ever recorded. These records are for a particular date, not all-time.
With so many records falling itís not surprising we are hearing about it on the local and national news outlets and itís front and center in many newspapers as well. You can follow my forecasts here and on Twitter @growingwisdom
The record cold highs have far outpaced the record warmth this year, but the overnight record lows are about half of the overnight record warmth. Part of the warm nights is likely heat island affect as many of the places where records are kept stay warmer at night with all the buildings, sidewalks etc. The chart below shows how many all-time records have been broken this year. Notice there have been some all-time cold records broken this week.
Snow on the ground across the country pushed over 50% yesterday. This number is over double what we typically see this time of year and in comparison to the past decade itís far above anything weíve seen.
Last week parts of the Rocky Mountain States saw some record lows. You can see in the image below a few of those records. Some spots in Minnesota stayed under the freezing mark for longer than they had in decades this time of year.
This Weekís Cold
This current shot of cold air is coming farther east and impacting the east coast more than the previous outbreak. Locally temperatures will stay in the 30s 4 of the next 5 days. In terms of the past 20 years, this is cold.
The chart shows the number of days under 40 in Boston in November since 1994, the average is 2 and the maximum has been 6, that was last year. We could break that number in the next twelve days, but it would be tough. We will certainly be colder than the average.
Further, if you expand the period of record to include all the data the average jumps to 9 and the maximum goes up to 13! I canít fit all those numbers since 1875 on one chart.
The cold does go into the Deep South as well. Florida has frost and freeze watches up for tonight and there are possible record cold temperatures being set in Alabama.
You can see some of the predicted cold readings and what the records are on the following graphic.
Here in New England I donít expect many, if any, daily records to be set. In Boston the record low daily highs and the records lows are just way out of reach even in this particular pattern. This doesnít mean you wonít be talking about the cold and saying things like ďitís too early for thisĒ or ďIím not ready for this yetĒ.
We have short memories. Last year was also quite cold in November. The month averaged 2 degrees below normal. We had already had one day colder than anything we have seen this month so far. The data for November 2013 is below.
So whatís the bottom line on the cold? You decide, but dress warmly while youíre thinking about it.