Damp, mild, & volatile

So how did you like April 2011? I personally couldn’t complain. It wasn’t that hot and only occasionally chilly. In fact, the quick summary is slightly warm and slightly wet but occasionally volatile.

Left: Temperatures (as approximated by air pressure around 18,000 feet or 500 mb) were colder than average in the north (blues/purples) and warmer than average across the south (greens). Right: April snow cover departures from normal since 1967.

The contrast between the colder than average air over Canada and warmer than average air in the South intensified weather systems moving across the country, resulting in violent severe weather outbreaks - two of which impacted the mid-Atlantic region. The first occurred on April 16 when four tornadoes struck the region, and the second on April 27-28 with 11 tornadoes in the region.

The Richmond Times Dispatch reported with eight months to go, 2011 is already the second deadliest year for tornadoes in Virginia since 1950. The fifteen tornadoes that struck last week in Va. represented the fourth-biggest outbreak in the state in modern records.

April temperatures since 1871 in Washington, D.C.

The National Weather Service publishes nice monthly assessments usually within a week of the close of each month.

You can click on your closest airport location here and the latest month should be available soon:

Reagan National (DCA)

Dulles Airport (IAD)

Baltimore-Washington (BWI)

Historical Washington, DC data provided by NOAA and Speedwell Weather.

(CWG’s Jason Samenow contributed to this report)