Severe Threat for the DMV Tomorrow

 

There is a severe weather threat for the DMV tomorrow, with the main threat being damaging winds. An isolated tornado or (large) hail cannot be ruled out though. The SPC has issued a slight risk(2/5) for most of our region. An enhanced risk(3/5) is possible tomorrow, and I wouldn't be surprised if parts of the DMV get an enhanced risk. There will be modest CAPE and a decent amount of shear. Instabillity will be able to build, even with cloud cover, due to strong warm air advection. And model soundings are also starting to suggest cloud breaks tomorrow. 

 

As you can see, there is a 2% chance of any tornado occuring in the green area 25 miles away from any given point.

 

There is a 5% chance to see 1" or larger(not the chance for less than 1" hail) 25 miles away from any given point in the green area.

There is a 15% chance in the yellow area to see winds 65 MPH or higher winds 25 miles away from a certain point, and a 5% chance in the green area to see winds 65 MPH or greater 25 miles away from a certain point.

 

The HRRR shows modest MLCAPE at 11 AM EDT tomorrow, with 1000-2000 MLCAPE throughout a good part of the region. When the cold front moves across, it will take all the MLCAPE with it. This is when the highest MLCAPE throughout the region is.

 

 

At 1 PM EDT tomorrow, the 18z HRRR shows 30-55 KT of shear throughout the region. This would be enough to support severe weather.

At 6 PM EDT(tomorrow), in Northern MoCo, the HRRR shows a pretty good sounding for severe weather. It has 1500 MLCAPE, and 2000 at the surface, good lapse rates, and a good LCL and EL level, plus a decent crtical angle and storm slinky. However, the shear is really bad. High dew points will help bring in moisture.

Now, let's see the NAM 3KM.

 

 The NAM at 4 PM EDT tomorrow shows isolated pockets of 40-65 kt of shear throughout the region, which is defintely a good amount for severe weather. The NAM 3KM wants a more aggressive solution for sure.

 

Unlike the HRRR, at 8 PM EDT, the NAM shows a lot of MLCAPE throughout the region, with most of the region in 1500+ MLCAPE, and some parts being all the away up to 3000 MLCAPE! This is definitely a very good amount of MLCAPE for severe weather. 

 

This is a sounding from the NAM 3 KM at 6 PM, and its not too shabby. It shows a tornado for Northern MoCo. The LCL is very low, good lapse rates, 2000+ MLCAPE, 2500+ surface CAPE, good crtiical angle. However, the slinky is bad, shear is meh, and SRH isnt that great either. Very good dew point though. I could see this event producing an isolated tornado.

Those are the 2 models that people generally use the most for severe weather forecasting, and they both show severe weather for our area. One is definitely more severe and aggressive than the other. The main threat is damaging winds, there will be substantial CAPE and a decent amount of shear, and you should be prepared tomorrow. There's not much else to say, so I will see you tomorrow!