Warm and Dry Octobers

 

This October has been unusually warm and dry.  Saturday’s rainfall was this month’s first and only rain event that’s produced 0.1”/+ in the Nation’s Capital with 0.3” of rain at National Airport.  My colleagues and I on the WUSA9 Weather Team don’t expect any additional rainfall during the upcoming work week. 

If no more rain were to occur this month, then it would finish as D.C.’s eighth driest ever and driest since 2000 with only 0.42”.  That’s what makes this month unusual as six of the last 10 October’s have been wetter than average in the Nation’s Capital.  Longtime Washingtonians may recall the record rainfall in October 2012 due to the remnants of Hurricane Sandy.  The tropics have been relatively quiet this month and that’s eliminated a common source of heavy rain in the Mid-Atlantic Region during the fall.

D.C. Area weather headlines this month have been dominated by quiet weather as Washingtonians have largely been under the influence of an area of high pressure.  This same weather feature that’s suppressed rainfall for most of October has also contributed to making it an exceptionally warm month.  Fifteen of the first 16 days of October were warmer than average.  In fact, eight days this month were at least 8° warmer than average, including six days with June-like highs in the 80s.

While today will be the second consecutive cooler than average day, it would take a prolonged cooler than average stretch to bring October’s average temperature down significantly.  Average monthly temperatures (combining daily high/low temperatures) through October 16 were nearly 7° warmer than average at National Airport and more than 8° warmer than average at Dulles Airport.

NOAA’s temperature outlook from the Climate Prediction Center for the final week of October is for warmer than average temperatures in the Mid-Atlantic Region.  That, in combination with the lack of widespread, significant rainfall over the next two weeks, all but guarantees this October will finish among the Top 10 warmest and driest in the Nation’s Capital.

Driest Octobers in Washington, D.C.  (Source: NOAA)

1.  Trace – 1963
2.  0.02” – 2000
3.  0.28” – 1930
4.  0.29” – 1874
5.  0.34” – 1896, 1892
7.  0.40” – 1920
8.  0.44” – 1924
9.  0.53” – 1882
10.  0.59” – 1998
11.  0.66” – 1952
12.  0.67” – 1928
13.  0.69” – 2001
14.  0.75” – 1934
15.  0.79” – 1909, 1879
17.  0.86” – 1918
18.  0.90” – 2016
19.  0.97” – 1901
20.  1.08” – 1941