Severe Thunderstorm Watch, Air Quality Alert Issued In Maryland

MARYLAND ? The threat of severe thunderstorms prompted the National Weather Service to issue a severe thunderstorm watch for 21 counties and Baltimore City in Maryland Wednesday. Much of the state is under a "code orange" air quality alert as well, due to the potential for hazy conditions from the western wildfires.

The severe thunderstorm watch is in effect until 8 p.m. on Wednesday, July 21, for the Baltimore-Washington area and southern Maryland.

During the watch period, officials said damaging wind gusts and large hail are the primary threats.

These jurisdictions are included in the severe thunderstorm watch:

• Anne Arundel County
• Baltimore City
• Baltimore County
• Calvert County
• Caroline County
• Carroll County
• Cecil County
• Charles County
• Dorchester County
• Frederick County
• Harford County
• Howard County
• Kent County
• Montgomery County
• Prince George's County
• Queen Anne's County
• Somerset County
• St. Mary's County
• Talbot County
• Washington County
• Wicomico County
• Worcester County

A "code orange" air quality alert has been issued for the Baltimore-Washington area Wednesday, July 21, in part due to a smoke plume. The Maryland Department of the Environment declares code orange when air pollution concentrations may be unhealthy for sensitive groups.

Smoke from wildfires in the western United States will result in hazy skies and a rise in fine particulates in the air in the Mid-Atlantic, according to officials.

Wildfires are burning in 13 states, where 83 fires have torched more than 1.29 million acres as of Wednesday afternoon, according to the National Interagency Fire Center. Officials said more than 19,300 firefighters are battling the blazes, which span Oregon, California, Montana, Nevada, Idaho, Washington and Wyoming.

"Highest hourly concentrations will be during the morning and early afternoon hours," forecasters said of the large smoke plume descending on the Mid-Atlantic. "A front will make its way through the area Wednesday evening. Fine particulates will begin to clear out in its wake but given how high concentrations will be initially, expect generally [unhealthy for sensitive groups] conditions across most of the state for a 24-hour period."

Children, older adults, heart/lung disease sufferers and asthmatics are considered sensitive; they should avoid strenuous activity and outdoor exercise Wednesday to minimize the effects from the air quality, according to the Maryland Department of the Environment.

Anne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil, Charles, Frederick, Harford, Howard, Kent, Montgomery, Prince George's, Queen Anne's and Talbot counties are under the air quality alert as well as Baltimore City and the District of Columbia.

Get more information about ozone and fine particles online or by calling 410-537-3000.

Forecasters anticipate better air quality Thursday and Friday.

After northern winds arrive Thursday and Friday, officials said cleaner air will move into the region, "although some diffuse smoke may still linger for a period of time."

Isolated severe thunderstorms with damaging wind gusts are possible Wednesday afternoon and early evening, according to the National Weather Service, which issued a hazardous weather outlook for the Interstate 95 corridor and the Maryland portion of the Chesapeake Bay.

Severe thunderstorms could also occur Sunday and Monday, according to the hazardous weather outlook.

See the latest forecast from the National Weather Service.