Storms tend to be hit-and-miss, not the kind that sweep across an area, and while some locations may see little to no rain, areas hit by the heaviest downpours can expect up to 1-2 inches of rain in 1-2 hours.
The main culprit is the same low pressure system that brought a lot of severe weather to the Plains and Midwest over the weekend, dragging a cold front into the region where it will collide with warm, moist air and churn up storms.
The main source of uncertainty regarding the storm's extent and intensity is cloud cover in the region, which may reduce heating, which in turn may reduce some fuel for the storm.
Still, there will likely be at least scattered strong to severe storms through the evening.
- Potential storm timing: Afternoon through early evening, finishing near or just after sunset.
- rainy percent: Everywhere it's about 60 percent.
- Storm Duration: 30 minutes to an hour, but multiple storms could pass through.
- Most likely impacts: Heavy rain, dangerous lightning, localized gusts of wind and a brief tornado or two.
- Possible impacts: Multiple tornadoes, scattered large hail and scattered flash flooding.
The severe weather conditions are characterized by an active cold front approaching from the west and an atmospheric disturbance causing a concentration of rising air across the DMV in the late afternoon.
Wind shear, which changes speed and direction with height, also increases, contributing to the formation of powerful thunderstorms, while winds from the south continue to bring warmth and moisture closer to the ground, fueling storms and destabilizing air masses.
One confounding factor is widespread overcast cloud cover in the early morning due to remnants of a complex storm system to the west. Until the cloud cover thins, the ground will not heat as much, potentially delaying full destabilization.
More heat is expected this afternoon along with increased wind shear. The convective storm will gradually expand with rising temperatures and an approaching front, becoming more widespread by late afternoon.
Where these storms may converge varies by location. For example, the NAM weather model is predicting locations near the Gulf Coast and southern Maryland. Some of this activity is already underway in southeastern Virginia. Its cousin, the HRRR weather model, has begun developing storms further west, including in central Maryland and Washington DC.
The storm mode will likely be small clusters (multicells) and short bow segments or arcs, with some rotating supercells possible. If there is activity, heavy rain and lightning are possible. Strong to severe gusts of wind called downbursts and dime-sized hail are also possible. A brief tornado or two is also possible.
CWG will be closely monitoring the situation throughout the afternoon and evening and will provide updates in this article.
Jason Samenow contributed to this report.
