March 2015 may have featured more up-and-down temperature variability than February, but it still wound up being the third March in a row that was colder than average.
Colder than normal temperatures, above normal snow, and above normal precipitation were recorded at all three area stations. As usual, Reagan National Airport recorded the lowest snow amounts and smallest temperature difference from normal:
You can see the highly variable weather through the month in the chart below, which tracks the temperature departure from average through the month at National. There was almost an even balance between our cooler and warmer than normal days at National, but the colder anomaly days were slightly more frequent and intense:
With three cool March outcomes in a row, it is interesting to look at the 2000s trend at National. Despite having the warmest March on record in 2012, the long-term trend of the 2000s is in the negative (cooling) direction for the month.
The -1.5F temperature departure from average was fairly minor though in the entire period of record as shown in the entire history comparison below. 2015 ended up being the 74th coolest March in the record back to the late 1800s. In the chart below, you can see the warmest years on the left, beginning with 2012, and the coldest on the right, ending with 1885.
On the precipitation side, the 4.04 inches that fell at National ends up as the 52nd wettest for March in long-term history. It helps boost us to a 0.54 inch surplus for the year-to-date, so no water shortages, and none are expected in the near future at least.
In terms of snow, March 2015 was the third snowiest of the 2000s, but still well below last year’s amazing 12.7 inches tally. However, you can see on the chart below that the top five snowiest March periods of the 2000s include the last three years now (2013-2015). Will this trend continue? I’ll have a future blog post on winter trends.
Assuming we see no measurable snowfall in April, the season looks to conclude at about 18.3 inches for National, which would make it the fourth snowiest of the 2000s. But interestingly, it becomes the first back-to-back above normal snow winter since the late 1980s. We’ve had a few powerhouse snowy winters in the 2000s, but we haven’t managed to get two above normal seasons in a row until now.
Snow totals are quite chaotic for D.C. as the right conditions and the right storm or two can help to blow up the numbers, while other seasons remain very limited. Getting an actual “average” 15.4-inch season is quite rare, although we did it in 99-00 as shown below.
Temperature and precipitation records
We had a few cold and snowy ones with most of them found at our shortest historical record Dulles airport location.
Record snow on Thursday, March 5, 4.8 inches surpassed the prior record of 4.4 inches from 1888
Record snowfall on Thursday, March 5, of 3.6 inches bested the old record of 1 inch set in 2001
Record low temperature on Friday, March 6, of 9 degrees beat the prior record of 15 degrees from 1978
Record low maximum on Friday, March 6, of 26 degrees beat prior record of 32 degrees set in 2007
Record low on Saturday, March 7, of 2 degrees beat the old record of 14 degrees from 1985
Record low maximum on Saturday, March 28, of 37 degrees beat the old record of 39 degrees set in 1996
Record low on Friday, March 6, of 10 degrees beats prior record of 13 from 1901 and prior years
Record low on Saturday, March 7, of 6 degrees bested the prior record of 10 degrees from 1960
The weather pattern
March experienced some degree of pattern variability, but the prevailing story was one of warmer/drier high pressure ridging in the West, with cool to cold upper level low pressure troughing over Eastern Canada and dipping into the Northeast. The Mid-Atlantic was on the dividing line, but we managed to see more cooling vs. warming on the whole. You can see how the entire U.S. fared for March 2015 below with the Northeast being the coolest spot and the West again taking most of the warmth.
For the second year in a row, the cooler to colder Eastern pattern was driven more by high pressure ridging from the Western U.S. up toward Alaska than by anything on the Atlantic side. This jet stream pattern configuration kept the West mostly warm and dry (we had some days in the 90s already in Burbank) with cool to cold air most dominant in Eastern Canada occasionally bleeding into the Midwest, South, and down the East Coast.
For further information
The National Weather Service publishes nice monthly assessments about five days into the start of the next month. You can click on your closest airport location here: