The end of February last week concluded our three-month meteorological winter. It closed as Washington, D.C.’s first colder-than-normal winter (-0.8F) since 2010-11 and our snowiest (19.3″) since the powerhouse winter of 2009-10 (56.1″).
So far in the 2000s (starting with the 1999-00 winter), we have had eight warmer-than-normal winters and seven colder-than-normal ones. The average of the warmer ones are 2.1F warmer-than-normal and the colder ones averaged 2.2F colder than normal.
This winter, precipitation also ended up above normal (+3.62″). We have had nine dry and six wet years in the 2000s. We have only had four above normal snow meteorological winters in the 200os (99-00, 02-03, 09-10, and now 13-14). You can see how the winter that just finished ranks against the rest of the 2000s along with the new century trends here:
The average temperature of 37.8F was 1.2F below normal, placing 2014 as the 4th coldest of the 2000s and the coldest since 2010’s very cold 34.2F mean temperature. You can see how the month played out in terms of daily temperature anomalies (differences from normal) below. We had two warm periods and two cold periods during the month with our warmest anomaly day on February 21 at about 15 degrees above normal and our coldest exactly one week later on Friday February 28 with 20 degrees below normal. Cold days also outnumbered warm ones overall.
February’s 4.02″ liquid total was very impressive, ranking it as the third wettest of the 2000s behind 2008’s 4.17″ and 2003’s big 6.98″. Normal is just 2.62″. You can see the wet and snowy days of February on the bar chart below. Our biggest snow day was February 13’s 5.9″ of accumulation. We saw eight days (nearly 1/3 of the month) of flakes flying with six of those days actually achieving measurable totals to generate our 11.2″ monthly result. That is the third snowiest of the 2000s, just a bit ahead of 2006’s 8.8″ but way behind the two top performers: 2003’s 28.7″ and 2010’s 32.1″. When it does snow in D.C. winters, it tends to snow hardest in February!
When comparing temperature and precipitation performance to last year, we see some interesting data points. My favorite is that February 2014 saw both higher (69F) and colder (14F) temperatures than last year. We had much more snow “fun” this year even though we had the same number of days of reported snow occurrences. From temperatures to rain to snow, February 2014 was more volatile than 2013.
Despite the increased volatility, only a few records were set:
Record daily precipitation February 3: 1.48″ beating 1939’s 1.1″
Record daily precipitation February 3: 1.33″ beating 1982’s 1.07″
Record daily snowfall February 13: 11.7″ besting 1992’s 3″
Record low February 28: 10F tying 1993
Record daily precipitation February 3: 1.34″ beating 1939’s 1.30″
Record daily precipitation February 13: 1.77″ beating 1972’s 1.65″
The weather pattern
February 2014 followed a similar path seen in November, December, and January with an impressively amplified jet stream pattern in the North Pacific. For much of this winter, the upper level ridge pattern at high latitudes has been over Alaska, which as acted like a see-saw sending bigger Arctic outbreaks south toward us like during January’s polar vortex events. February saw that ridge position shift west a little bit into the Bering Sea. The feature extended more frequently toward the North Pole, favoring a cold-inducing pattern known as the negative phase of the Arctic Oscillation (AO). A subtle warm ridge over drought-weary California also helped to steer strong Canadian cold air supply into the Midwest and East for February. Nationally, it was estimated to be the second coldest February of the 2000s after 2007.
Well, we already know that March 2014 will feature above normal snow since we are currently well above the normal 1.3″ total. But an expected cold-prevailing pattern with more North Pacific to Alaska upper level ridging (like November-February) should keep our odds higher than normal for additional snow chances over the balance of March too. The 3.8″ of snow at National so far would register it as the 2nd snowiest of the 2000s after 2009’s 5.5″, but the month is yet young. Precipitation is expected to be near to above normal.
The National Weather Service final March forecast also favored below normal temperatures for the Mid-Atlantic including Washington, D.C., but they did not make any predictions for precipitation. You can see the NWS March forecast here.
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: