WASHINGTON - If we are being honest, Thursday could have started a little better in Washington, D.C. Heavy rain pushed through Northern Virginia and into the District just after 5 a.m. this morning, making the morning commute a mess. Several road closures were reported due to standing water this morning with the majority of them being reported in Stafford County, Va. Over a quarter inch of rain has already fallen in the District, adding on to a July rainfall total - which just 5 days into the month had already surpassed June’s total rainfall.
The culprit for these storms is a stalled out frontal boundary draped across the region along with a moisture rich atmosphere. Showers and storms that develop along these frontal boundaries tend to come with very heavy rainfall. With these fronts moving very slowly, the storms tend to be slow movers as well, which means the potential for flooding and flash flooding. Much of Northern Virginia, the District of Columbia, and several counties in Maryland are under a Flash Flood Watch, which has been extended until 2 a.m. Friday. Weather models suggest anywhere between 2 and 5 inches of rain is possible in those locations that do get stuck under these heavy, slow moving storms this afternoon and evening.
The real issue with a forecast like todays is determining who will see the heaviest rain and when they will see it. The problem is that there is no easy answer. Weather models handle weather situations like this one rather poorly. The only thing we can say for certain is that the stalled front will remain in the region throughout the day, and that really at any time - with a little daytime heating - we could kick up another heavy round of thunderstorms. Much like last night when the Nationals game was canceled, we cannot promise that this evening’s game gets off without a hitch either. The best advice we can give is keep the umbrella handy. Also remember to NEVER cross a flooded roadway, as only 6 inches of moving water has enough force to move a vehicle.
Friday morning should see improving conditions but still a few light showers around the region. Sunshine should gradually return in the afternoon, but a pop-up shower or thunderstorm cannot be ruled out ahead of a cold front which will pass the region during the evening and overnight hours. Once the front gets through, the entirety of the D.C. region will be in the clear for what will be a beautiful weekend featuring more sunshine and lower humidity.