Where Does December Stand ?

NOAA's Temperature Outlook for early-January 2017

The comparison to last December can be made more effectively as this month enters its final days.  Although this month saw a significant blast of arctic air mid-month, it was relatively short-lived in the Mid-Atlantic Region.  The Nation’s Capital saw its first trace of snow of the season.  However, no measurable snow has occurred yet, which matches last winter to this point.  Washingtonians set a record last winter for latest first measurable snow on record (January 17).

December 16, 2016 was the coldest December day since 2010 and it helped keep this month’s average temperatures closer to average than it would have been otherwise.  National Weather Service data indicates that this month’s average temperature at National Airport through December 25 is 0.8 degrees warmer than average.  Although that’s a far cry from the warmest December on record last year, this month is still poised to finish as the sixth consecutive warmer than average December in Washington, D.C.  Yesterday’s high and low temperatures of 51/35 degrees in the Nation’s Capital were above the December 25 averages of 44/30, but well below last year’s balmy temperatures of 69/57 degrees.

Some very interesting weather occurred on Christmas Day this year with blizzard conditions across parts of the Upper Midwest and mixed precipitation in the northern Plains.  The warm sector of the dynamic area of low pressure also brought severe weather to parts of the Midwest – a relatively unusual occurrence in late December.  Also, multiple record highs were set in southern cities including Dallas, TX, Montgomery, AL and Tampa and Miami, FL.

Temperatures are poised to be warmer than average for much of the upcoming week, with low 60s expected tomorrow in Washington, D.C.  That would be the fourth day this month with temperatures in the 60s in the Nation’s Capital.  By the end of the week, though, my colleagues and I on the WUSA9 weather team will be tracking another push of arctic air with below normal temperatures expected Friday and Saturday.  However, NOAA expects an above average chance for warmer than average temperatures for the DC Metro Region during the first week of 2017.

There are a few rain chances this week but not enough to prevent December from being the tenth drier than average month of 2016.  Through December 25, a total of 2.37” of rain has fallen in Washington, D.C., while the month averages 3.05” of rain according to the National Weather Service.  Nevertheless, that amount is still more rain that occurred in all of October and November combined.  That’s why the latest Drought Monitor Index shows moderate drought conditions continue across a significant portion of the Mid-Atlantic Region.