...NWS DAMAGE SURVEY FOR 23 MAY 2019 HOWARD COUNTY TORNADO EVENT...

Start Location...Clarksville in Howard County MD
End Location...Columbia in Howard County MD
Date...May 23 2019
Estimated Time...327 PM EDT
Maximum EF-Scale Rating...EF1
Estimated Maximum Wind Speed...95 mph
Maximum Path Width...150 yards
Path Length...5.5 miles
Beginning Lat/Lon...39.2072/-76.9451
Ending Lat/Lon...39.1790/-76.8484
* Fatalities...0
* Injuries...1

...Summary...

A line of showers and thunderstorms crossed the Blue Ridge Mountains
around 2:30 PM 23 May 2019, then tapped into strong thermodynamics and
wind shear, creating a Quasi-Linear Convective System (QLCS) that increased
in intensity as it tracked southeast across central and southern Maryland,
Washington DC, and northern Virginia.  The QLCS spawned an EF1 tornado in
Howard County MD between 3:27 PM EDT and 3:36 PM EDT, with a discontinuous
damage path of 5.5 miles, moving east-southeast at an estimated 40 mph.

This summary is based on a Storm Survey conducted Thursday evening by NWS
Baltimore/Washington Weather Forecast Office staff, and analysis from the
WSR-88D KLWX radar, and the FAA Terminal Doppler Weather Radars (TDWR) for
Dulles International Airport, Washington Reagan National Airport, and
Joint Base Andrews.  The FAA TDWR at Baltimore/Washington International
Thurgood Marshall Airport was out of service this day, thus it was not used
in operations.

The first evidence of tornadic damage was near the intersection of Brighton
Dam Road and MD Route 108 in Clarksville.  Several trees were uprooted in
this vicinity with large branches pulled towards each other, and fell in
multiple directions, except westerly.

As the tornado moved east, more convergent tree damage extended on either
side of Cedar Lane around Corina Court in Columbia.  One eyewitness in this
location who was interviewed saw the tornado knocking down trees, resulting
in swirling debris.  Most trees in this location were uprooted, but a few were
snapped.  Trees here were both softwood and hardwood. One tree fell into the
roof of a house.  Another resident in this area reported getting the wireless
emergency alert on their phone, followed moments later by strong winds, which
knocked down large trees.

Tree damage was also noted along Shaker Drive between Seneca Farm Road and
Wayover Way, where numerous large trees were uprooted, with a couple of trees
snapped, falling to the north.

The most significant damage noted was near the 9400 block of Patuxent Woods
Drive, where a grove of hardwood and softwood trees were snapped about midway
up their trunks, falling haphazardly.  The roof of a nearby office building
lost part of its roof, which blew towards the east.  Trees were down further
to the east, but it is likely that this was due to straight-line winds as
radar analysis showed the tornado vortex broadening rapidly.

There were other towns in Howard County in close proximity to the tornado
that experienced significant wind damage, including Savage and Highland.
However, from radar observations and conceptual models of tornadoes spawned
by quasi-linear convective systems, it was determined that the wind damage
in these locales were likely due to straight-line winds. Strong straight-
line winds can produce damage equivalent to EF0 and EF1 tornadoes.

The National Weather Service Baltimore/Washington Weather Forecast
Office would like to thank the Howard County Office of Emergency Management
for their assistance in the Storm Survey.

EF Scale: The Enhanced Fujita Scale classifies tornadoes into the
following categories:

EF0...65 to 85 mph
EF1...86 to 110 mph
EF2...111 to 135 mph
EF3...136 to 165 mph
EF4...166 to 200 mph
EF5...>200 mph

* The information in this statement is preliminary and subject to
change pending final review of the event and publication in NWS
Storm Data.

$$

Lee/Hofmann