An Unusual First Half of April

April is an important transitional weather month in North America.  Washingtonians can infrequently experience exceptionally cold, March-like days in April as well as summer-like temperatures on occasion during the month of April.  However, DC Area residents should remember that average high temperatures are in the 60s for almost the entire month making it an especially nice time of year to spend time outdoors.  

Washingtonians finally got to experience some long-awaited late spring/early summer-like weather during the last few days with high temperatures in the mid-80s on Friday and Saturday.  The last time the Nation’s Capital experienced consecutive days with high temperatures in the 80s was October 5 – 10, 2017.  Following cooler than average temperatures on seven of the first eleven days of April, three consecutive days of high temperatures of at least 78° occurred began April 12.  That led the monthly average temperature to be within 0.1° of average over the first half of the month.

Although rare, DC residents have experienced 90° April heat in two of the last five Aprils, including April 10, 2013 (91°) and April 29, 2017 (91°) that were both daily record highs.  By comparison, Washington, D.C. had low temperatures at or below freezing on three days in April 2016.  DC’s warmest April temperature on record is 95° which has occurred four times (most recently on April 17, 2002).  DC’s coldest April temperature is 15° from April 1, 1923.  However, DC’s coldest April temperature at National Airport (that opened in 1941) is 24° that’s occurred twice (most recently on April 7, 1982).

The first half of April 2018 saw DC’s drier than average weather pattern continue with only 0.18” of rain occurred through April 15.  However, some very beneficial rain occurred early yesterday with widespread 1” to 2” rainfall totals that were common across the DC Metro Area.  Although it was much-needed rainfall, since so much rain occurred over such a short period of time some localized flooding occurred.  Yesterday’s total of 1.88” of rain at National Airport was DC’s highest daily rainfall total since July 28, 2017 (3.31”).  It was also DC’s largest April rainfall total since April 30, 2014 (2.70”).

Although no severe weather occurred in the immediate DC Metro Area with yesterday’s heavy rain, some severe weather did occur from Florida to central Virginia.  Some of the DC Metro Area’s largest severe weather outbreaks have historically occurred during the month of April.  For example, three tornadoes were confirmed locally as part of a larger severe weather outbreak on April 19, 2013.  Also, two weak tornadoes touched down within DC city limits on April 6, 2017.  They were only the ninth and tenth tornadoes to occur within the District of Columbia.  Maryland’s strongest tornado on record also occurred in La Plata, Maryland on April 28, 2002.

This post was filed from Hamilton Island, Australia where I have been looking into some local weather and climate issues for a few days.