Countywide

Storms could bring flash flooding to Fairfax County this afternoon

By Angela Woolsey
Excessive rainfall risk for D.C. area on July 31, 2025 (via National Weather Service)

After several days of hot, muggy weather, a major cooldown is in store for the D.C. region in the wake of storms expected to land this afternoon (Thursday).

However, the heavy rain will bring a risk of “significant flash flooding,” according to the National Weather Service, which has issued a Flood Watch for the entire area, including Fairfax County.

A Severe Thunderstorm Watch was also issued for 1:15 to 8 p.m.

Scheduled to be in effect from 2 p.m. today until 2 a.m. tomorrow (Friday), the Flood Watch predicts that the region could see 1 to 2 inches of rain, though that could climb to 4 to 6 inches in some areas if they experience multiple rounds of thunderstorms. The rain will likely be heaviest between 3 and 8 p.m., coinciding with the afternoon rush-hour.

“Please have a plan in place to seek higher ground immediately if flash flood warnings are issued,” Fairfax County said in an emergency information blog post.

The county shared a number of safety tips for navigating the coming thunderstorms and showers:

If You’re Driving

  • Turn around, don’t drown. Most flood deaths happen in vehicles.
  • Never drive through flooded roads, even if the water looks shallow.
  • Find another route if you see water on the road.
  • Be extra careful during evening rush hour when conditions will be most dangerous.

At Home

  • Stay indoors during the heaviest rain periods (3-8 p.m.).
  • Move cars to higher ground if you live in a flood-prone area.
  • Avoid basements and lower levels during flooding.
  • Have a battery-powered radio and flashlight ready in case of power outages.
  • Prepare for possible power outages from high winds.
  • Clear your leaves and debris from storm drains ahead of time.

General Precautions

  • Keep children and pets away from storm drains and creeks.
  • Don’t walk through moving water. Six inches of moving water can knock you down.
  • Stay off bridges over fast-moving water.
  • Watch for downed power lines in flooded areas. Read more including who to contact for downed lines and trees.
  • Avoid unnecessary travel during evening rush hour.

Fortunately, once the storms pass, the D.C. region should get some relief from the summer heat and humidity, with NWS forecasts showing temperatures topping out in the 70s and low to mid-80s through next Wednesday (Aug. 6).

See the full Flood Watch for today below:

…FLOOD WATCH REMAINS IN EFFECT FROM THURSDAY AFTERNOON THROUGH LATE THURSDAY NIGHT…

* WHAT…Flash flooding caused by excessive rainfall continues to be possible.

* WHERE…The District of Columbia, portions of Maryland, including the following areas, Anne Arundel, Calvert, Carroll, Cecil, Central and Southeast Howard, Central and Southeast Montgomery, Charles, Frederick MD, Northern Baltimore, Northwest Harford, Northwest Howard, Northwest Montgomery, Prince Georges, Southeast Harford, Southern Baltimore and St. Marys, and northern Virginia, including the following areas, Arlington/Falls Church/Alexandria, Central and Southeast Prince William/Manassas/Manassas Park, Eastern Loudoun, Fairfax, Northern Fauquier, Northwest Prince William, Southern Fauquier and Western Loudoun.

* WHEN…From Thursday afternoon through late Thursday night.

* IMPACTS…Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Flooding may occur in poor drainage and urban areas. Extensive street flooding and flooding of creeks and rivers are possible.

* ADDITIONAL DETAILS…
– Significant flash flooding is possible. Numerous showers and thunderstorms will develop and move across the area Thursday afternoon into Thursday evening. Thunderstorms will be capable of producing very heavy rain, with rainfall rates of 1 to 2 inches in 30 minutes. Widespread rainfall amounts of 1 to 2 inches are expected. Some areas could experience multiple rounds of thunderstorms, with higher rainfall amounts of 4 to 6 inches possible. This could result in numerous instances of flash flooding. Showers and thunderstorms will begin early Thursday afternoon, and the heaviest rainfall is most likely from 3 PM to 8 PM.
– Please visit www.weather.gov/safety/flood for flood safety and preparedness information

PRECAUTIONARY/PREPAREDNESS ACTIONS…

You should monitor later forecasts and be prepared to take action should Flash Flood Warnings be issued.

Graphic via National Weather Service

About the Author

  • Angela Woolsey is the site editor for FFXnow. A graduate of George Mason University, she worked as a general assignment reporter for the Fairfax County Times before joining Local News Now as the Tysons Reporter editor in 2020.