A Link Between Lightning and Tornadoes?

^{Image Credit: NASA MSFC}

Data such as those in the top image are intriguing scientists with the possibility that high altitude lightning indicates the formation of tornadoes and severe storms.

In April 1995, NASA launched a small instrument, called the Optical Transient Detector (OTD), into earth orbit. The purpose of the instrument is to observe lightning above clouds, such as lightning that travels entirely within a cloud or between clouds above a storm. This lightning cannot be seen from the ground.

Data from the OTD show that while a storm is forming, it produces lightning within a cloud and between clouds. Only after the storm has developed does it generate cloud-to-ground lightning, which is visible from the ground.

On April 17, 1995, the OTD passed over a severe storm in Oklahoma. The rate of lightning flashes during its passage over the storm peaked at 60 per second and then decreased. Overall, the OTD saw nearly 200 flashes during its three minute pass (see top image above). A few minutes later a tornado touched the ground.

From observations such as these, scientists believe that a high rate of lightning flashes indicates the formation of a tornado. They know that lightning tells where strong air motion is occurring, where large quantities of water are forming, and suggests where heat that helps power air motion is given off by condensing water vapor. These are all important factors in understanding the formation of a storm.

More Cool Stuff:

To learn more about the OTD and lightning detection from space, check out the following two sites of the NASA Marshall Space Flight Center Global Hydrology and Climate Center:

http://wwwghcc.msfc.nasa.gov/otd.html and
http://wwwghcc.msfc.nasa.gov/lisotd.html

Check out the two NASA press releases of April 12, 1996, and September 25, 1995, that describe the OTD and some of the science results obtained with it. The September 1995 press release describes the results featured in the Observation of the Week above:

http://www.hq.nasa.gov/office/pao/NewsRoom/releases96.html
http://www.hq.nasa.gov/office/pao/NewsRoom/releases95.html

To learn more about weather and to locate educational materials about our weather and climate, check out the Washington, DC, National Broadcasting Company weather homepage, WeatherNet4:

http://wxnet4.nbc4.com

Data and information about our weather are available from the National Oceanographic and Atmospheric Administration (NOAA):

http://www.noaa.gov

In particular, check out the National Climate Data Center:

http://www.ncdc.noaa.gov/ncdcglance/ncdcglance.html

and the National Weather Service:

http://www.noaa.gov/nws/nws_intro.html

Check out other observations in the Observation of the Week Archive.