ENI Time Series Case Study

Setting: Northwestern edge of the San Angelo, TX CWA.

I pulled up the ENI time series for a strong cell that exhibited a high flash rate and saw a large peak followed by a rapid drop-off and a subsequent increase again. I wanted to look at radar to see if it matched up with the trend in strength. The cell in question is the northern-most cell in the short, loosely-connected line along the border of the San Angelo CWA (point 7/northern cell polygon in the image below).

point7CZ_1930 Composite Radar image at 1930Z

The northern-most cell has a reflectivity core peak corresponding to the rapid increase that the flash rate on the time series had been showing. The increase/peak in flash rate occurred between 1928-1932Z.

ENI_1930_2006ENI multi-color time series plot for Point 7

The next two radar images at 1936 and 1942Z, respectively, reflect the rapid decrease and subsequent increase again in the time series plot between 1933 and 1938.

  CZ_19361936Z CZ_19421942Z

The flash rate then began a steady, but quick final decline just before 2000Z.

ENI_1930_2010

This was finally reflected in the reflectivity scans at 2000Z and 2006Z.CZ_20002000Z

CZ_20062006Z

I found myself watching the time series plot when it would take a sharp turn to increase or decrease flash rate and going back to the radar, waiting for it to be reflected there, and it usually did. Since the lightning data comes in more often than/ahead of the radar imagery, the time series plots could be used to anticipate increases or decreases in storm cell strength, potentially aiding in the warning process (ie whether to issue (lead time), continue, or let a warning expire).

~ Regina Phalange

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