Dangerous storms will hit more than a dozen states this week

Heavy rain may cause flooding in southern and eastern states this week. (Ben Noll/The Washington Post/Data source: ECMWF)

By Ben Noll

An unusual weather pattern is causing severe storms in the eastern and southern states this week. The phenomenon, called an omega block, forms when two low-pressure systems trap a high-pressure system in between, locking adverse weather in place for days.

On Monday, there were over 125 reports of severe weather in the south and east, including more than 75 reports of hail, over 45 reports of damaging winds and two tornadoes. Afternoon storms downed trees in eastern Virginia, south of Washington.