NWS Jacksonville » Weather Stories » Interpreting Weather Radar Images

Interpreting Weather Radar Images

by Matt Zibura (Meteorologist, NWS Jacksonville)

Weather radar has greatly advanced over the years and has become a valuable tool in detecting precipitation.  This includes severe thunderstorms, tornadoes, hurricanes, hail, and even rainfall amounts.  Along with precipitation, National Weather Service 88D Doppler radars (http://www.weather.gov/radar_tab.php) are also capable of detecting several non-precipitation features.  Below are some examples that show some radar features commonly seen here in Florida.

seabreeze image

East Coast Seabreeze Front

The east coast seabreeze front is often seen as a thin line on radar that parallels the coastline.  This boundary usually moves inland during the afternoon hours during the summer months.  This is often a trigger for thunderstorm development as it encounters hot temperatures over inland areas.

outflow image

Outflow Boundary

This feature is formed by downdrafts from showers and thunderstorms and is usually accompanied by strong, gusty winds.  Similar to the seabreeze front, outflow boundaries can often cause new thunderstorms to form.

smoke plume image

Smoke Plume

Due to the high sensitivity of the 88D weather radar, areas of smoke can sometimes be detected.  These smoke plumes are usually cause by large brush fires which occur in Florida during the normally dry spring months.  The above image shows a smoke plume over Baker county with wind spreading the plume into northern Columbia county.

chaff image

Chaff

Sometimes mistaken as rain, chaff is actually small pieces of aluminum released by military aircraft during exercises.  The chaff usually is detected by weather radars as bands that are oriented perpendicular to the wind flow.

anomalous propagation image

Anomalous Propagation

Also called "false echoes" or AP, anomalous propagation often occurs at night and in the early morning hours due to a low-level temperature inversion that forms.  Under these atmospheric conditions, the radar beam is bent down toward the ground resulting in echoes that are ground targets and not precipitation.

 


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