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
Storm analysis / Echo near the ground
Lowest radar echo, live analysis
Over Trout Valley, New Mexico, where the map opens. The whole country
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. 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 lowest echo map shows
The echo at the lowest height the radars see at each place, from every radar in the national network joined into one analysis and cleaned of ground clutter, birds and insects. It is the nearest the radars come to what is reaching the ground; far from a radar, its lowest beam passes thousands of feet over it.
How to read it
- 10 to 20 dBZ
- Drizzle, flurries or the faint edge of a shower.
- 20 to 35 dBZ
- Light rain or steady snow.
- 35 to 45 dBZ
- Moderate rain, the body of a storm.
- 45 to 55 dBZ
- Heavy rain, a thunderstorm’s core.
- Over 55 dBZ
- Torrential rain, and hail likely.
What it is for
- Compare with the radar: rain the radar shows high up that is gone here may be drying before it lands.
- See the rain under a storm, not the hail and rain held aloft.
- Read a winter storm’s snow near the ground.
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 every 10 minutes, played as a loop of 1 to 24 hours. As data: /radar/now.json?show=low, the times of its frames.
In the Field Book
- WSR-88D radarFB-INS-005
- ThunderstormFB-EVT-001
Over a state
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With it
Severe AlertsWeather by stateForecast accuracyInstrument atlas
Beside it
How well the radars see
Radar view
Latest
How well the radars see each place, in percent: where the radar picture can be trusted, and where rain and snow can fall unseen.
0100%
What is falling
Rain or snow
Latest
What is falling at each place: rain, cold rain, snow, showers and storms, or rain with hail, every ten minutes.
RainHail