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F0 Tornado in Southern Cayuga County
April 18th, 2004
At 143 pm EDT Sunday April 18th, a small tornado touched down briefly
in the southeast part of the town of Scipio in southern Cayuga County.
The tornado was rated an F0 on the Fujita Scale of tornado intensity which
has winds between 40 and 72 mph. A National Weather Service survey team
determined that the maximum winds with this small tornado were about 70
mph. The tornado first touched down on Mather Roads(county route 428)
close to Kennedy Road and tracked east southeast to Fire Lane 10 on Route
38 before lifting by the time it reached Owasco Lake. Most of the damage
from the tornado was to trees which were either snapped off or uprooted.
There was some minor structural damage to several structures in the path
of the tornado including a roof that was partly torn off a home, and a
small boat that was overturned. A row boat was found up in a tree!
Tornado Path (red) in southern Cayuga
County. Purple outlines are areas where there
were strong damaging straight-line winds between 60 and 70 mph. These
straight line winds were associated with the thunderstorm that produced
the small tornado. Click on the purple or red areas on the map or links above where the damage
paths are, to see the damage photographs.
In addition to the damage directly attributed to the tornado, there were
scattered locations around the southern part of the county that had significant
straight-line wind damage from the thunderstorm that spawned the tornado.
This is common as thunderstorms capable of producing tornados often have
areas of intense winds and large hail. The strong straight-line winds
with this storm were associated with what meteorologists call the Rear
Flank Downdraft (RFD) of the thunderstorm. This downdraft often is a precursor
to tornadic development and can have damaging winds. In this event, the
RFD caused more damage than the tornado itself, blowing a roof off of
a house, damaging numerous barns, silos and knocking down many trees.
In some instances the damaging straight-line winds were as strong as the
tornado. The map below highlights the areas that were most impacted by
the straight-line RFD winds (purple) and the tornado (red).
To the right is a schematic of a tornadic
thunderstorm (click on the schematic for a larger image). A key
chacteristic of tornadic thunderstorms is that they rotate or spin
rapidly. It is this spin that can produce a tornado and often damaging
straight-line winds and hail. Damage from straight-line winds can
come from the Rear Flank Downdraft as in the case above and also from
the Forward Flank Downdraft of which we did not see much if any damage.
The main point to remember is that there could be significant damage
from other parts of a thunderstorm that produces a tornado. So, even if
you don't get directly hit by the tornado, you could still have damaging
winds and large hail. So when the National Weather Service issues a tornado
warning, even if the tornado does not hit your location, you could still
see damaging winds and large hail. It is important to heed all warnings
for your safety.
The image to the right shows a Doppler Radar wind signature that prompted
National Weather Service Meteorologists in Binghamton to issue this
tornado warning for southern Cayuga County
(click on the image for a larger view). It was the development of
the strong winds from the rear flank downdraft of the thunderstorm
that likely led to the development of the tornado in this case.
For a more in-depth look at the April 18th, 2004 severe weather event, read the case study on our
Posted May 18, 2004