Destructive Straight Line Winds Slammed Delmarva On Tuesday. 90-100 MPH Winds Estimated

2022 Severe Weather Season on Delmarva keeps delivering more and more destructive thunderstorms as the year goes on. From freak destructive hail across Dorchester and Wicomico counties back in May, Tornadoes in Western Maryland, to now one of the most destructive high wind events in several years across Caroline, Kent, and Sussex Counties.

Radar Loop From KDOX radar 7-8pm

So let’s dig into the atmosphere across the region on Tuesday. On Monday models where not handling the environment well what so ever with only a few isolated strong storms. It took until Tuesday morning to understand the environment was very conductive of a localized severe weather outbreak. If there was a checklist of what ingredients are needed to support destructive downburst winds, we had all the boxes checked for yesterday. We had very steep mid and low level lapse rates which is a combination alone supports great mixing of the atmosphere. A lapse rate is the rate of temperature change with height. The faster the temperature decreases with height, the “steeper” the lapse rate and the more “unstable” the atmosphere becomes. Plenty of moisture to work with the atmosphere with PWAT values exceeding 2 inches region wide. Precipitable water is the amount of water potentially available in the atmosphere for precipitation, usually measured in a vertical column that extends from the Earth’s surface to the upper edge of the troposphere.

High moisture content within thunderstorm increases the chances for wet microbursts. A microburst is a localized column of sinking air (downdraft) within a thunderstorm and is usually less than or equal to 2.5 miles in diameter. Microbursts can cause extensive damage at the surface, and in some instances, can be life-threatening. We had enough instability in the atmosphere both at the surface level and into the mid portions of the atmosphere. CAPE values (Convective Available Potential Energy) were on the order of 1500 j/kg in the mid portions of the atmosphere and surface based CAPE on the order of 3000 j/kg. Those values indicate we have a modestly unstable airmass in place for vigorous thunderstorm development. And finally we have wind shear. With a trough digging in across the region we had sufficient wind shear up to 50kts to help sculpt and give these storms structure, as well as a source of stronger winds to tap into.

Diagram of Downbursts/Microbursts

Now that we got the environment sampled from yesterday, lets dive into the storm that caused prolific damage from Denton to Farmington.

Radar around 7:24pm Near Denton, MD

Our damage path started when we had a well defined line of storms started moving across Talbot county before moving into Caroline County around 7pm. Watching from the radar perspective, I started to notice a big increase in radar returns using Base Velocity. This tool is used to sample wind speeds within storms and they were accelerating very quickly southwest of Denton. I knew at that moment we got some major issues on our hands. I sent out a alert to residents from Denton to Farmington to seek a sturdy shelter immediately knowing we have significant Microburst in progress. At this moment only a base level Severe Thunderstorm Warning was issues for the region for winds of 60 mph. Which at this point, radar return showing surging winds of 80-90 mph around 1000 feet above the ground. Significant wind damage was already in progress with power poles snapped, large trees uprooted and some structural damage. Even one confirmed injury with a gentlemen suffering a concussion when taking shelter in a Camper in Denton. Where he was thrown with his camper from the strong winds and a tree falling on it. He is in stable condition which is great news.

Radar View From Andrewsville On The MD/DE Line

Our storm begins to gain intensity as it crosses over the MD/DE line into Andrewsville. Radar signatures still holding steady with 80-90 MPH winds roughly at 800ft above the surface. Many reports out that way of power poles being snapped, significant tree damage with several roofs being blown off from chicken houses and outbuildings. Consistent with ongoing radar returns, significant straight line winds were continuing to rip across the county in Kent & Sussex counties.

Radar Snapshot ~ 7:38PM – Radar Returns Reaching 100 MPH Around 700ft In Harrington / Farmington

Now we enter I would say the max intensity of this destructive wind even near the Harrington region where I have seen some of the worst damage. With radar coverage so close to where this storm occurred, it was a blessing to have such incredible radar data to judge the strength of these winds. At this point when a rare “Destructive Severe Thunderstorm Warning” was issued for areas of Kent and Sussex Counties.

These are new type of warning from the National Weather Service to be issued to give greater threats to thunderstorms who are capable of destructive winds or hail. Winds need to be at least 80 MPH or hail greater than the size of baseballs. These warnings will trigger mobile phones similar to how you would receive a Tornado Warning for your area. This is our second SVRD to the Delmarva region this year with the last one occurring in May across Ocean City Maryland. Damage across Harrington include several structures losing roofs and one pole barn suffered a full collapse on the rear side. Debris were thrown hundreds of feet into other homes and opens fields. Several power poles snapped along Route 14.

A resident with a TV antenna tower folded under the power of the winds yesterday. Now those take some very strong winds to topple over. Last year in Milford through Slaughter beach, a EF-1 tornado caused similar wind speeds of at least 90 mph to topple one of these. The only difference the one in Slaughter Neck was twisted at the point of the failure where as Tiffany had in Harrington was folded in the same direction of the wind. 90-100 MPH of Straight Line Winds appear likely through this region in reference to radar data to support it. Goes to show that you do not need a tornado to create significant damage. Straight lines of this magnitude are similar to a EF-1 tornado and can cause significant threat to lives and property.

A big thank to everyone who sent us photos and information for this case study of the destructive winds across our region.

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