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Precipitation Type and Tendencies
what it is and where it's moving

The type of weather associated with a cluster of radar echoes is identified by letter abbreviations. A table of the common weather symbols has been given below:

Tornado written out Freezing Drizzle ZL
Waterspout written out Ice Pellets IP
Funnel Cloud written out Ice Pellet Showers IPW
Severe Thunderstorm T+ Snow ZL
Thunderstorm T Snow Showers SW
Rain R Snow Pellets SP
Rain Showers RW Snow Grains SG
Freezing Rain ZR Ice Crystals IC
Drizzle L Hail A

These abbreviations appear as small white letters. For example, RW was reported in eastern Texas, which indicates "rain showers".

However, many of these reports are combinations of two or more abbreviations as in South Carolina, where "TRW" was near the yellow and green radar echoes. "TRW" is a combination of "T" (thunderstorms), "RW" (rain showers) and actually means showers and thunderstorms. Further west in northern Georgia, a "TRW++" was reported near the pink and red radar echoes, which indicates the presence of showers and severe thunderstorms in the area. The extra "+" is there to emphasize that these are very intense storms.

Precipitation tendency indicates a change of the intensity of precipitation during the last time period. This information is represented by either a white "NC", "+", or a "-". The "NC" reported in the panhandle of Florida, indicates that the intensity of the precipitation during the past hour has "Not Changed".

In Georgia a "-" reported, which means that the intensity of precipitation has decreased. This makes sense because the line of heavier precipitation (indicated by the yellow, pink and red radar echoes), was moving out of Georgia and into South Carolina. This also explains why there was a "+" indicated in South Carolina, where the intensity of the precipitation is on the increase, due to the heavier showers and thunderstorms approaching from the west.

Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.