Yesterday our neighborhood was hit with severe weather. Severe thunderstorms raced through and took down a lot of trees. Fortunately, we were spared, but others were
not so lucky. Being a meteorologist, I (Rob) had to go out and survey the
damage to determine if it were straight-line winds from a microburst
(downdraft), or a tornado. Of course, Tom and the kids joined me, and Tom took the photos.
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| My map showing location of microburst and damage |
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| North facing tree down west of Moylan Drive |
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| North facing tree down west of Moylan Drive |
The M Section of Bowie appears to have experienced a
downburst from a thunderstorm around 2:05 p.m. EST on Thursday, April 6, 2017. I'm
a meteorologist and hours after the storm I drove around and took photos and
analyzed the damage. Many trees were down throughout the M Section but there
was a pattern to their collapse. It was not a tornado. It was a downburst.
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| North facing tree down west of Moylan Drive |
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| Northeast facing tree down east of Moylan Drive |
DEFINITION OF A DOWNBURST - A downburst is a localized area
of damaging winds caused by air rapidly flowing down and out of a thunderstorm. The downdraft speeds in a thunderstorm must
be unusually high and the air flows close to the ground/surface. It isn't necessary for a thunderstorm to generate
hail or tornadoes for it to create a downburst. Downbursts over a small area of
less than 2½ miles wide and peak winds lasting less than 5 minutes is called a
Microburst. Microbursts may induce dangerous horizontal/vertical wind shears,
which can adversely affect aircraft performance and cause property damage.
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| Northeast facing tree down east of Moylan Drive |
NOTE: Damage from downbursts can be so severe that it is
mistaken for tornado damage. When examined, however, the damage pattern from a
downburst will be either straight-line or divergent, indicating the winds were
flowing outward, rather than in a circular, converging pattern as in the case
of a tornado.
THE STORMS - All of the storms were coming up from the south
and pushing to the north-northeast in the 2 p.m. EST hour. According to the
National Weather Service radar (that I was watching), the only tornado warning
issued by the National Weather Service (who observed radar indicated rotation
in a cloud) was northwest of Washington, D.C. and far from Bowie, Maryland.
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| Northeast facing tree down east of Moylan Drive |
THE DAMAGE - Throughout the west side of the M Section that
includes the loop of Memphis Lane to the loop of Madonna Lane (which basically
form a south to north oval), all of the trees downed were facing north. That part
of the M Section is divided from north to south by Moylan Drive (a long street
with a double yellow line). East of Moylan Drive, many of the trees were facing
a northeast and easterly direction.
LOCATION - So, I estimate that the microburst occurred somewhere
between 2 p.m. and 2:05 p.m. and was centered near the Memphis Lane loop (and
streets within), causing the northerly direction of damage, while the eastern
side of the microburst caused trees east of the thunderstorm to fall facing the
northeast and east. Think of a microburst as pushing your left hand down hard
on a desk and your fingers spread out. The palm of your hand would fall into
the Memphis Lane area, west of Moylan Drive, and your thumb and index finger
would extend over the east of Moylan Drive.
