National Weather Service Forecast Office

Below is the second section of the on-line spotter training. After completing this section... you will be ready to pass the short quiz and begin providing The National Weather Service with important reports.

Tornadoes
(Enhanced F Scale)

Tornadoes
(Enhanced F Scale Cont.)

Tornado Look Alikes
(Roll Clouds)

Tornado Look Alikes Second
(Wall Clouds)

Tornado Look Alikes Third
(Rain Shafts)

Tornado Look Alikes Fourth
(Rain Shafts)

Tornado or Funnel Cloud

Waterspouts

Shelf Cloud
Classic Shelf Cloud

Debris cloud
Associated With Tornadoes

What to report
Overview of elements to report

How do I report
Overview of what to report

Importance of Spotters

Contact Information
Web address/1-800 number

More Meteorology Training

an image of the description of the enhanced fujita scale

The Enhanced F-scale...which was implemented recently...is a set of wind estimates (not measurements) based on damage. It uses three-second gusts estimated at the point of damage based on judgment of 8 levels of damage to the 28 indicators below. These estimates vary with height and exposure. This scale replaces the F scale or Fujita scale...which was used for many years.

an image of the actual enhanced fujita scale

The Enhanced Fujita Scale category breakdowns.

There are many cloud formations that can look like funnel clouds during a thunderstorm. One of these clouds is a roll cloud or ragged roll cloud. A roll cloud generally occurs on the outflow of a storm...where the cold air from the downdraft interacts with the warm air...giving it a rolling or rotating appearance as seen in the graphic.

Another deceptive cloud associated with thunderstorm activity is the wall cloud. A wall cloud is a generally rain free region of rotating clouds which extends beneath a thunderstorm. This cloud can be a pre-cursor to the formation of a tornado.

Yet another deceptive looking cloud formation and probably the most commonly mistaken for a funnel cloud or tornado is the rain shaft. A rain shaft is a distinct...isolated column of rain falling from a thunderstorm cloud. This often takes the shape of a funnel.
Pieces of clouds can also break away from larger clouds and these often give the appearance of funnel clouds or even small tornadoes. These are called scud clouds.

A great picture of a rain shaft. These can occur more often when the lower levels of the atmosphere are relatively dry.

There is a subtle but very important difference between a funnel cloud and a tornado. A funnel cloud is a circulation that is not reaching the ground while a tornado is a circulation that is reaching the ground.

Something we see here along the coast from time to time is a waterspout. By definition a waterspout is a tornado over water. These are generally weaker than traditional tornadoes but can still pose a threat to mariners and those living along the immediate coast.

One of the better pictures of a shelf cloud or classic roll cloud. This cloud slants down toward the area of rain with a thunderstorm as you can see to the left on this image.

This image illustrates the important difference between a funnel cloud and a tornado. The debris cloud on the ground indicates this circulation is extending to the ground and is indeed a tornado.

Now a quick review on what to report:
If you see a tornado or funnel cloud let us know about it.
If you observe a tornado over the water...betterknown as a waterspout...we want to know about it.

Let us know if you see any of the cloud formations we went over...roll cloud...shelf cloud...or a wall cloud.

When reporting hail...let us know if any hail is falling. Report the size of the hail in reference to coins and balls...see the chart.

When reporting wind damage...use the criteria outlined on the Estimating Wind Speeds slide.

Finally...when reporting flooding...let us know if if the water is standing or flowing. Estimate the depth of the water based on known objects such as telephone poles or stop signs. Also let us know if the area that is prone to flood.

A few more helpful hints when calling in:
Let us know who is calling...sometimes we get false reports and even prank calls so we need to know who is calling.

Of course let us know what weather phenomena you are reporting.

Be sure to tell us when the event occurred and is it happening right now?

Give us a location or reference city since many of the reports occur in rural areas.

Also let us know which direction the phenomena is moving.

a picture emphasizing the importance of spotters

Once again the importance of spotter information cannot be emphasized enough. Your reports add value to warnings and statements and this in turn motivates people in the path of storms to take cover.

When you have something to report...give us a call on the 1-800 line at 1-800-697-3901. You can also visit our website anytime for weather information and forecasta at www.weather.gov/ilm

For more detailed meteorology training visit The Jet Stream Online School

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National Weather Service
Weather Forecast Office, Wilmington NC
2015 Gardner Drive
Wilmington, NC 28405
(910) 762-4289

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Web Master's E-mail: ilm.webmaster@noaa.gov
Page Last Modified: November 23, 2008

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