february 7th 2020 early morning tornado outbreak

An poorly forecasted and historic severe weather/tornado outbreak occurred across the mid atlantic during the morning rush hours on February 7th, 2020. 

The 2 main ingredients for a tornado event of this magnitude are very strong wind shear and high amounts of instability. The wind shear on this morning was incredibly strong, with over 400 m/s^2 of 0-1km storm relative helicity, and over 100 kts of 0-6km wind shear which is just off the charts. That is almost unheard of in our area. The surprising thing is that there was very low instability with cape coming in at less than 200 j/kg. That typically would not support an event of this magnitude in our area. However, the extreme shear and potent jet stream dynamics (200mph winds at 35,000 feet) were able to overcome the lack of instability and produce 5 tornadoes (4 in our viewing area) in maryland alone along with widespread wind damage. This many tornadoes in just one day is unprecedented in the state of MD for February.

Below is a map from the National Weather Service showing all the wind damage and tornado reports from that morning. 

The first tornado in our area occurred in Dickerson, which is in extreme southwestern Montgomery county. This tornado resulted in mainly tree damage, but 2 barns had significant roof damage as well. Additionally, a metal windmill tower was blown down. The final area of damage was noted at a farm house where numerous shingles were torn off the roof. This tornado was rated EF1 and had winds of 95mph. The tornado traveled only 1 mile and was on the ground for just 60 seconds (from 7:28am until 7:29am). The tornado was 150 yards wide.

The second tornado occurred just to the southeast of the first tornado, in Boyds. The tornado took down many trees, before striking a dog training facility. Here, several structures were damaged and a storage building was flattened. There were also 2 2x4 boards that were blown into 2 structures and impaled them. This tornado was rated EF0 and had winds estimated around 80mph. Again, this one was on the ground for only 1 minute and traveled 2.3 miles. This tornado was only 75 yard wide. 

A third tornado touched down in Monrovia which is in eastern Frederick county. Along its path, several structures were heavily damaged, including 2 barn structures that were flattened. After that, significant tree damage occured as the tornado traveled NE across I-70 and to the NW of Mount Airy, where many trees were blown down. The tornado was rated a mid range EF1 with 105mph winds. This tornado traveled 6 miles and was 150 yards wide. It was on the ground 7:44am until 7:40am. 

The final and longest track tornado occured in Westminster and tacked up into downtown Manchester resulting in intermittent damage along the way. There was a mix of tree and powerline damage in Westminster as well as roof and siding damage. The tornado traveled NE into Manchester where significant tree damage occurred. The tornado was rated EF1 with max winds of 90mph. It traveled 10.3 miles from 8:03am until 8:14am and was about 100 yards wide. 

Forecaster Jack