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DON'T GET FOOLED!
One of the great joys of cloudwatching is the variety of ways Mother Nature
presents Her evidence - proving or disproving our theories and assumptions about
what we see. The weather watcher is constantly challenged by new circumstances
and every storm adds to your understanding and respect for the complexities
of the atmosphere. What we take for granted confounds us; what we perceive as
obvious hides the truth eloquently; what we see and appreciate for its simple
beauty speaks quiet volumes of wisdom. As your experience grows, the context
for tour understanding widens until surprises enrich rather than confuse your
knowledge of the sky.
False funnels
There are several tornado/funnel look-alikes which can easily fool you at first
glance. Disqualifying such "false funnels "is very important for minimizing
erroneous reports as well as reducing your anxiety while storm spotting.
Scud tags and inflow tails
Whenever you have air rising rapidly at the edge of cool, moist outflow, lower
cloud fragments (scud) will form in mid-air or under the base in the shape of
small points, lumps, etc. protruding downward. These scud tags change shape
constantly and do occasionally take the form of a tapered cloud that looks like
a funnel. They are most common along the gust front, near ragged lowerings,
or along any cool-warm boundary. They are best differentiated from true funnels
by location, since a true wall cloud is absent or found elsewhere in the sky.
However, they are also less smooth-edged, more transient, more ragged or fragmented,
and rising rather than rotating.
A more organized structure that sometimes appears when a new,intense updraft
forms adjacent to rain or outflow, is an inflow tail. This is a low,
often ragged, and thick cloud extending down at an angle below the main cloud
base. It is a brief event but can be quite frightening if close by. Again, location
and the absence of a wall cloud will disqualify this cloud as a tornado threat.
The edges of wall clouds or lowerings also assume pointed shapes briefly, but
without classic, persistent funnel features. When a tail cloud forms on the
rainy side of the wall cloud, however, it may indicate overall intensification
and the entire structure should be watched.
124 W/NE, 125 E/E, 126 NW/NE,
127 SE/S, 128 SW/SE, 129 N/E
Examples of false funnels. All of these are scud rising in updrafts that have
drawn some of the moist air in from nearby outflow. In 127 and 129, the updraft
is under the rain-free base and shows you where the next, strong tower may be
along the axis. All examples are transient, having a funnel-like shape for only
seconds before becoming less deceiving.
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Created :
2002-08-26
Modified :
2002-12-31
Reviewed :
2002-12-31
Url of this page : http://www.msc.ec.gc.ca /education/severe_weather/page41_e.cfm
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