I will start off to say we for sure had a unicorn of hail storm here across areas of Delmarva. I’ve been studying a lot of storms over the years across Delmarva and this one was in the top tier of hail storms for the sure because of the damage it caused just from the hail alone.
Let’s start off with the elephant in the room that this was a long tracked supercell thunderstorm as discrete as you could possibility get. Didn’t have to share resources with other storms in the environment. And I’m going to be real with you, the environment this storm was in for what it produced is actually astonishing. Storms of this magnitude producing widespread 2in diameter hail or greater for this long duration is something you would normally see out in the central plains. With the very cold air aloft and the very unstable atmosphere. Our supercell yesterday was only under 1500 j/kg of MLCAPE where storms I’ve normally seen with this kind of hail has at least twice that if not more. This one lone supercell took advantage of a disturbed free environment all to itself and used the maximum instability the region had. Not to mention tapping in the the 50kt bulk shear in the region to keep supercellular characteristics
This storm first developed just the west of Washington D.C as a single cluster before taking off as a HP Supercell throughout Prince Georges and Calvert County. Confirmed multiple locations with > 2in diameter hail with a single report of 3in in Diameter in Chesapeake Beach in Calvert County. Before moving across the Chesapeake keeping the same intensity across Delmarva.
Here’s what took me by surprise. Normally getting large hail of this size, you need a storm that is very tall in the atmosphere. On radar estimates, we had on average 40-45 kft (40-45,000 feet) cloud tops with one singular overshooting top to 45 kft. Normally seeing 2in hail you need very cold cloud tops closer to 50-55kft and cold temperatures aloft which is something we do not get here in the warmer seasons. Looking at radar from KDOX and GOES-16 Satellite we had one persistent updraft on the southern side of the storm. The hail core was astonishing. We had the updraft all the way to the very top of the storm at 40kft which is amazing for how small of an area it covered.
Keep in mind I want to share with you the logistics of how strong of a updraft is needed to suspend >2in hail in a storm. For the reported 2 to 3 in Diameter hail you need a updraft speed of 70-85 MPH upward velocity. Looking at some the hail sizes and shapes we have a mixture of round and spikey hail meaning there has been some warmer air with some melting on the way up. Even more evidence that there was some strong upward forcing of water molecules in this small but potent updraft.
Impressive damage across areas of Dorchester and Western Sussex County from this one storm yesterday. Severe damage to vehicles, windows blown out, siding a complete loss. Not to mention reports of a hail accumulations for areas around Cambridge. Very common for hail sizes around baseballs causing significant damage to property.
Goes to show you, Delmarva can defy the odds of getting Central Plains type of storms. Whether it’s a tornado outbreak, a derecho or in our case this time around, a severe hail event. Always remember, it can only take one storm to make a disaster. We had a very rare event happen yesterday that unfortunately had some devastating consequences. Luckily nobody was hurt and property can be rebuilt.