Severe Weather Risk Sunday

There is a severe weather threat for the entire DMV tomorrow, specifically in the afternoon and evening. The main threat will be damaging winds, but some mostly weak, isolated tornadoes and hail can't be ruled out of the question. 

As you can see, most of the DMV is under a slight risk, and the really northern part of the DMV are in a marginal risk. Just south of the DMV is an enhanced risk, where the risk for dangerous winds are higher. Let's look at the specific categories:

In the slight risk area(brown area), there is a 5% chance for a tornado to be on the ground 25 miles away from any given point in that area. This isn't the chance for at least one tornado to form, but the chances for any location 25 miles away from a given point to see a tornado. This isn't the main threat though, and the northwestern part of the DMV is in the 2% chance for any location 25 miles away from any point to see a tornado.

Most of the DMV is in the 15% chance for damaging winds, and a lot of it is also in the fence like area? What does that mean? It means that we have the chance to see really damaging winds(65+mph), and that there is a 10% or greater chance to see over 65 mph wind 25 miles from any given point in this hatched location. There is a 15% chance for any location in the yellow part to see 55-65+ mph winds 25 miles from any given point.

Most of the DMV is in the 5% chance to see hail 25 miles away from any given point. In the really NW regions of the DMV, there is less than a 5% chance.

HRRR sounding at 2pm EDT.

Ok, this might be scary when you see the "tor" under possible hazard time and something under the supercell category. Instability is not bad(500-750 j/kg); the shear is not too bad; lift is there; and the moisture is more on the bad side. But the sounding itself isn't good. Even if a tornado occured(unlikely), it would be very weak and short-lived. The main threat will just be damaging winds, and I don't think tornadoes will be a considerable threat. You should still prepare though.

The severe storms will be caused by an upper-level shortwave trough intensifies as it moves through the Mid-Atlantic/Northeast and as a surface cyclone deepens in Ontario/Quebec, a cold front moves east with it, which will help create storms in the southeast, Carolinas, and the Mid-Atlantic(paraphrased from the SPC). In the DMV(further north into the Mid-Atlantic) low-level wind fields will be stronger but buoyancy will be less, compared to the more southern parts of the Mid-Atlantic(Carolinas, Southern VA). Over 500 joules/kg MLCAPE will still exist and help the environment further support severe surface gusts, and if greater heating occurs in certain patches, the MLCAPE may get close to 1000 j/kg, and if this occurs, the threat for stronger, damaging winds will increase. Tornadoes are possible, but this far north it is doubtful due to low-level thermodynamics and storm-mode. (paraphrasing SPC). You do NOT want the sun to come out, because that will increase the MLCAPE, which the more there is, the more dangerous the severe weather will be. The timing will be around 10am - 8pm(general DMV). The main severe threat will be in the afternoon for everyone, but there might be some isolated severe weather after 4-6pm in some spots. I will make a nowcast post and give you live updates. I can't provide much more info since I want to put out accurate information and I don't know too much about severe weather, but as we get more outbreaks, I will learn more about severe weather and will be able to inform you more!