The National Weather Service has placed millions of people across five Mid-Atlantic states and Washington, DC, under a tornado watch on Thursday as severe thunderstorms sweep the region.
The watch remains in force until 10pm ET on Thursday across the Washington-Baltimore-Philadelphia corridor, covering communities surrounding Chesapeake Bay, Delaware Bay and the lower Delaware River.
The Mid-Atlantic corridor is one of the most densely populated regions in the United States, anchored by major transportation routes and large metropolitan centers. Severe weather watches are issued by meteorologists when atmospheric conditions become favorable for tornadoes to develop over a broad area.
National Weather Service forecasters warned that scattered severe thunderstorms and excessive rainfall could also bring damaging winds and isolated flash flooding to the region alongside the threat of twisters.
Areas included in the tornado watch
The alert encompasses 39 counties, seven independent cities and the entirety of Washington, DC, although it does not place every part of the five states under the watch.
Maryland has the largest area affected, with 19 counties included: Anne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil, Charles, Dorchester, Harford, Howard, Kent, Montgomery, Prince George’s, Queen Anne’s, Somerset, St. Mary’s, Talbot, Wicomico and Worcester. Baltimore City, which is legally separate from Baltimore County, is also inside the watch zone.
The Maryland alert stretches from the Washington suburbs and Baltimore region to Southern Maryland and across the Eastern Shore, placing communities on both sides of Chesapeake Bay at risk.
In Virginia, five counties are covered by the watch: Arlington, Fairfax, King George, Prince William and Stafford. The alert also includes six independent cities: Alexandria, Fairfax, Falls Church, Fredericksburg, Manassas and Manassas Park, bringing the severe weather threat to northern Virginia suburbs and the Interstate 95 corridor.
Five southeastern Pennsylvania counties are included under the watch: Bucks, Chester, Delaware, Montgomery and Philadelphia.
The New Jersey portion covers seven counties: Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and Salem, extending from the Philadelphia suburbs to the Jersey Shore.
All three Delaware counties, New Castle, Kent and Sussex, are subject to the watch, while Washington, DC, is covered in its entirety.
Maritime and coastal waters under alert
The tornado watch extends far beyond land, covering 21 coastal and tidal water zones where boaters could face rapidly deteriorating weather conditions.
Covered marine areas include both the northern and southern sections of Delaware Bay. Atlantic coastal waters are also included, stretching from Little Egg Inlet and Great Egg Inlet in New Jersey south past Cape May and Cape Henlopen to Fenwick Island, Delaware, and Chincoteague, Virginia.
Large sections of Chesapeake Bay fall within the watch area, running from north of Pooles Island to Sandy Point, North Beach, Drum Point and Smith Point.
Tidal river zones subject to the watch include the Potomac River from Key Bridge to Indian Head, Cobb Island and Smith Point, as well as the Patapsco River and Baltimore Harbor.
Other affected waterways named in the alert include the Chester River to Queenstown, Eastern Bay, the Choptank and Little Choptank rivers, the Patuxent River to Broomes Island, Tangier Sound and waters surrounding Bloodsworth Island.
Safety advice and storm precautions
The National Weather Service clarified that a tornado watch means atmospheric conditions are favorable for tornadoes, but does not mean a twister has been confirmed. A tornado warning is the signal to act because a tornado has been spotted or indicated by radar.
Residents are advised to keep emergency notifications turned on, monitor local forecasts and identify the safest room in their home before storms arrive. People should charge their mobile phones, ensure emergency alerts are enabled and bring loose outdoor items inside if it is safe to do so.
Families should select a windowless interior room, basement or storm shelter, placing shoes, helmets, flashlights and pet supplies there before storms intensify. If a tornado warning is issued, individuals should move immediately to the lowest floor of a sturdy building, away from windows.
Anyone in a mobile home, vehicle or outdoors should plan immediately how to reach a sturdy building and not wait until a storm is overhead. The weather service emphasized that manufactured homes offer little protection from tornado-force winds, advising people to seek substantial shelter rather than remaining inside a vehicle or mobile home during a warning.
Weather forecast and local warnings
The alert outline was sent to National Weather Service forecast offices serving Baltimore and Washington, Wakefield in Virginia, and Philadelphia and Mount Holly in New Jersey.
These local offices will monitor incoming weather systems and issue more targeted warnings for specific communities as individual severe storms develop.
