The Boston area has received more snow in the past two and a half weeks than most locations, outside of the lake-effect snow belts, receive in one season. Winter really kicked in on January 24 with the blizzard, and it has been "pedal to the metal" ever since. In the last week of January Boston's Logan Airport measured 31.7 inches of snow. In the first 11 days of February another 41.3 inches accumulated, bringing the total to 73 inches (more than six feet!) of new snow since January 24! Boston set a record for the most snow recorded in a 30-day period, with 71.8 inches, breaking the record of 58.8 inches set in February 1978. The average season snowfall for Boston is 43.8 inches. The latest "frosting on the cake" was 14.8 inches of snow on Monday February 9, which tied the daily maximum snowfall record set in 2013. However, there were reports of 20 to 31 inches of snow at locations in Norfolk and Plymouth Counties south and southeast of Boston.
|Daily snowfall for Boston since January 16, 2015 through February 12, 2015|
The total snowfall in Boston so far this season is 78.5 inches, which is far from the record of 107.6 inches in the winter of 1995-1996. However, winter looks to be far from over.
The U.S. Cooperative observer at Blue Hill, MA, just south of Boston, tallied 36 inches of new snow the last week of January and another 47.7 so far this month, for a total of 83.7 inches! Yesterday morning Blue Hill reported 38 inches of snow on the ground. CoCoRaHS observers around the Boston area are reporting anywhere from 26 to 39 inches of snow on the ground.
|Snow depths reported by CoCoRaHS observers in Boston, February 12, 2015|
|Snow depth across the Northeast February 12, 2015.|
Note that the highest amounts are along the Massachusetts and Maine coasts
|Sledding off the roof in Boston.|
Photo by Eric Fisher via Facebook.
Interestingly, winter in the Northeast was rather tame and mild up until January 24. Through January 23 Boston had received only 5.5 inches of snow, which at that point was 14.5 inches below normal. Temperatures were running near to slightly above normal. To give you an idea of how much things have changed in two weeks, take a look at this plot of the Accumulated Winter Severity Index (AWSSI) for Blue Hill, MA. The AWSSI is an index that a colleague, Barbara Mayes-Boustead, and I developed to measure the severity of a winter using readily available daily temperature and snow data. You can read more about this index here. What's interesting is that the plot of the index shows that the Boston area was bordering on a mild winter until January 24, but since then the winter has moved into the Extreme category (the top 20 percent of severe winters). The average AWSSI for the Boston area is 674, and the record (since 1950) is 1196 in the winter of 2002-2003. The value as of February 11 is 827.
|Plot of the Accumulated Winter Season Severity Index for Blue Hill, MA.|
|Plot of the 2014-2015 AWSSI for Blue Hill. The solid black line is the average,|
and dashed lines are one standard deviation above and below.
The steep climb of the AWSSI is likely continue based on the current upper air setup. A strong upper level trough is forecast to establish over the eastern two-thirds of the country, and that means a steady flow of Arctic air into the central and eastern U.S.
|500 millibar forecast for 7:00 a.m. Wednesday, February 18.|
|6 to 10 day temperature outlook issued February 12, 2015|
for the period February 18-22.
Disturbances moving through this trough are likely to result in storm development at some point next week, but exactly when and where is hard to pin down right now. However, the Quantitative Precipitation forecast chart for the 7-day period does show where it's possible that precipitation will fall and how much. You can follow developments on the NWS Weather Prediction Center website.
|7-day Quantitative Precipitation Forecast for the period|
7:00 p.m. EST February 12 through 7:00 p.m. EST February 20.
Since last week U.S. snow cover has dropped to 24.9 percent, but a significant portion of the snow is in the Northeast. It's not likely to go anywhere soon.