* Flash flood watch 6 p.m. tonight through 6 a.m. Monday *
6 p.m. update: Setting aside a couple of isolated showers, radar is pretty quiet around the region this evening. Short-term modeling suggests showers and storms could become a bit more numerous overnight and especially into early Monday morning, but it should be a pretty nice summer evening for most prior. Any showers and storms that do develop could be slow-moving and put down locally heavy rainfall.
Please be weather alert later today into tonight and Monday morning because nearly all of the area is under a Flash Flood Watch from 6 p.m. today until 6 a.m. Monday. Slow-moving showers and storms will probably develop late this afternoon and especially into mid-evening. Heavy or even torrential rain could be seen across parts of the area along with frequent lightning. Showers and an embedded storm or two remain in play through the Monday morning rush but should start to dissipate tomorrow afternoon.
Through tonight: Mostly cloudy skies remain entrenched as we conclude Sunday afternoon and temperatures peak in the mid-80s. The overly humid air and a cold front draped across the area will help to focus shower and storm development starting late this afternoon. By early or mid-evening, showers and storms become widespread. Some parts of the area may see a period of torrential rain within the stronger and slower-moving storm cells that form, with rainfall rates reaching one to two inches per hour. Other hazards will include frequent lightning and perhaps even strong wind gusts, although the severe storm threat is more muted compared to that of a night ago. Heed any flash flood warnings that may be issued and have a flood preparedness plan in place.
Lows will slip to around 70 or the low 70s, while winds blow from the east at around 5 mph.
View the current weather at The Washington Post.
Tomorrow (Monday): Showers and a few embedded storms will probably be ongoing across parts of the area as we wake up for work. Flash flooding could still be an issue, so drive carefully and allow for extra time on your commute. The cold front will have dropped south of our area later in the morning, but a disturbance swings across, keeping showers — some heavy — intact until midday. Drier air starts to filter in thereafter, which should suppress much of the precipitation to our south for the afternoon. We’ll see cooler highs, in the upper 70s to near 80, and lower humidity, with dew points in the upper 60s. Winds are northeasterly at around 8 to 12 mph.
Excessive rainfall outlook for tonight into tomorrow: The NOAA/National Weather Service’s Weather Prediction Center has placed the D.C. area in a slight risk for excessive rainfall over the next 18 hours. This means there’s a 10 to 20 percent chance that parts of our area experience flash flooding within this period. A forecast precipitation map shows that one-quarter to one-half inch of rain is expected, although some of us will probably receive substantially higher rainfall amounts as the stronger, slower-moving storm cells traverse parts of the area tonight into tomorrow morning.
Want our 5 a.m. forecast delivered to your email inbox? Subscribe here.