With an upcoming January thaw approaching from the 8th to the 14th (tentatively) I wanted to gather information on recent "thaws" in January. First let's start with the definition of the January thaw:
In the United
States, a period of mild weather popularly supposed to recur each year,
in later January; most pronounced in the Northeast and, to a lesser
extent, the Midwest.
The daily temperature
averages at Boston, computed for the years 1873 to 1952, show a well-
marked peak on 20–23 January; the same peak occurs in the daily
temperatures of Washington, D.C., and New York City. Statistical tests
show a high probability that it is a real singularity.
The January thaw is associated with the frequent occurrence on the
above-mentioned dates of southerly winds on the back side of an anticyclone off the southeastern United States.
*Courtesy AMS Glossary*
Let's talk about the climate here in the North Country and in particular, Champlain Valley. The coldest time of the year, statistically speaking, is January 13-26. The average temperature at the Burlington Int'l Airport dips to a yearly low of 18 degrees. Thus when temperatures rise above freezing for extended periods of time during the coldest time of the year, the event is labeled a January thaw.
Whether this is a 'meteorological phenomenon' or just a 'media hype' can be argued. I found this article from (Godfrey, Wilks, Schultz) titled, "Is the January Thaw A Statistical Phantom?"
You can say we have had our thaws in the past five years. Here's a look at data from the Burlington airport courtesy NWS:
||THAW AVG TEMP
||MONTHLY TEMP DEPARTURE
A couple of notes. In 2011 our event trickled into December 2010 for two days. I lumped these in because that stretch of weather was extremely warm, nearly 45 degrees. Note though the rest of the month was much closer to average with the monthly departure only +0.2 F.
In 2009 we didn't really have a thaw, but I included the longest stretch of above freezing temperatures I could find. It was only 33 F. You can see that month was cold because the departure was -4.0 F for January 2009.
Certainly the strongest event of recent happened in 2008. In fact, five years ago today (Jan8) the high temperature in Burlington reached to 63 F! It was a nine-day stretch that averaged warmer than 45 F and took the monthly temperature + 7.0 F.
Here's what I am projecting for the Burlington area for this 2013 stretch:
I'm not sure yet what the monthly departure will be for temperature. Through the first week it has been roughly -3.0 F for average temperature in Burlington. This stretch will definitely take us into positive category, but it will only take us halfway through the month. So we'll have to wait and see what happens thereafter. This thaw stacks up around 2nd or 3rd compared with the last five years of data.
-Meteorologist Steve Glazier