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This
module compiled with information courtesy of the official NOAA Storm
Spotters Guide. |
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SECTION TWO: |
As in the other sections,
you can click on the glossary image wherever you see it, and the
glossary will open in another window. Just close that window when
you are ready to continue. |
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In
this section, you will concentrate on identifying the features of
storm structure. This is very important to know what the storm is
doing, which way it is going, and keeping yourself in a safe position.
The best viewing position if ideally to the right of the storm.
Most commonly, many of the storms will move from SW to NE. Thus
the best viewing position would be southeast of the storm.
This
would change somewhat in HP cells, but that will be covered in the
Advanced module. Keep in mind, storms have no sense of direction,
and do not know which way is north. They can move in any direction,
and with the proper knowledge of storm structure and the movement
of the storm, you can put yourself in the best viewing position.
For our purposes here, we will assume that the storms are moving
SW to NE. |
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In
the two images above, we see a side view drawing of a supercell.
The direction of movement in both is from left to right. Note that
the anvil is blown downstream in the direction of the movement of
the storm. This is a key way to identify the general direction of
the storm visually. The varies elements of the storm are identified
and color coded in the second drawing to make identification easier.
Make yourself very familiar with these terms and their location. |
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Below
we see a photo of a supercell storm. Since it is difficult to get
the entire storm in one photo, we will have to take a look at different
elements of the storm structure in different photos. |
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In
the above picture, we are looking SE at the storm. Movement is from
right to left, SW to NE. We are to the NW of the storm. The various
elements outlined are color coded as follows:
- DARK
BLUE area in the upper center/ this is the Backsheared
anvil.
- PINK
area within the dark blue in the upper areas / this is where
mammatus clouds are likely to be seen later
- ORANGE
area on the right side / this is the Flanking Line
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YELLOW
area in the middle / this is the main updraft area
- BLUE
box area near the bottom / this is the rain free base
- PINK
box near the bottom / this is the area to watch for wall cloud
and tornado development. Note that this is directly below the
main updraft area
- DARK
GREEN
box / this is where large hail would be occurring
- LIGHT
GREEN
box / this is where smaller hail would fall
- BLUE
box
to the left / this is where the heaviest rain would fall. If
we could see further to the left we would see the rain getting
lighter and lighter.
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In
this photo from a distance, we can see some of the larger storm
features. This storm is moving which way?
You got
it, right to left. Remember the direction the anvil is being swept
is the general direction of movement of the storm. Features are
anvil, the overshooting
top, the backsheared anvil,
the main updraft region, and in the
boxes in the lower part of the storm, we would expect to see the
rain-free base, the area of wall
cloud/tornado development, the areas of large
and smaller hail, and the areas
of heavy, moderate
and light rain. |

Image
was submitted by a viewer of this site. |
In
the above picture, we can see the Mammatus clouds, which appear
as lumps on the underside of the anvil of an departing storm. This
was taken in San Angelo, Tx. This storm was moving left to right
here, with the updraft to the right of this picture. |
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