Echo near the ground
Lowest echo
Latest
The echo at the lowest height the radars see, every ten minutes: the nearest the radars come to the rain and snow reaching the ground.
1070 dBZ
Storm analysis / How well the radars see
Radar coverage, how well the radars see
Over Mineral Springs, Arkansas, where the map opens. The whole country
How well the radars see each place, in percent: where the radar picture can be trusted, and where rain and snow can fall unseen. How to read it.
The rings are the storms the radars detect, the larger ring a severe one; each line runs to where its storm will be in an hour if it keeps its present speed and heading. Rotation and hail are what the radars detect and the analysis measures, not warnings: the official watches and warnings in force are drawn on the map in their own colours and set out in full under Alerts.
What the radar view map shows
How well the radars see each place, in percent, as the analysis rates it: high near a radar with a clear view, low where the beam passes high over the ground, where mountains block it, or where it passes above the freezing level into snow. Where the view is poor, rain and snow can fall unseen.
How to read it
- 80 to 100%
- A clear view, near a radar.
- 50 to 80%
- A fair view; light rain or snow low down can be missed.
- 20 to 50%
- A poor view: far from a radar, or blocked by mountains.
- Under 20%
- The radars see little here.
What it is for
- Judge whether a dry radar picture means dry weather.
- See the gaps in the mountains of the West where the radars are blocked.
- Know when to trust the gauges and the stations over the radar.
How it is made
The storm analysis joins every radar in the national network every two minutes into one picture of the country on a grid about two thirds of a mile across, cleaned of ground clutter, birds and insects, and measures from it what no single radar shows: the largest hail, the turning of the wind, how high a storm’s heavy echo reaches above the freezing level, and what is falling, read with the temperature of the air. Storm Station keeps it every ten minutes for a day, the gauged rain and the radars’ view each hour, and draws it at every zoom from the analysis’s own grid.
A frame each hour, played as a loop of 6 to 24 hours. As data: /radar/now.json?show=rqi, the times of its frames.
In the Field Book
- WSR-88D radarFB-INS-005
Over a state
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With it
Severe AlertsWeather by stateForecast accuracyInstrument atlas
Beside it
Reflectivity
Radar
Latest
Rain, snow and hail across the country now, from every radar in the national network, a new picture every five minutes.
1070 dBZ
Rain, checked by gauges
Gauged hour
Latest
The rain of each hour, in inches, checked against the rain gauges: the truest measure of an hour’s rain, posted about an hour after it ends.
.0112 in