Echo tops
Storm tops
Latest
How tall each storm stands, in feet: the higher the top, the stronger the storm and the more likely hail and wind.
560,000 ft
Live radar / Reflectivity
Live radar reflectivity
Over Fire Weather Watch for San Luis Obispo County Mountains, Santa Barbara County Interior Mountains, where the map opens. The whole country
Rain, snow and hail across the country now, from every radar in the national network, a new picture every five minutes. 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 map shows
How strongly rain, snow and hail send the radar’s pulse back, from every radar in the national network joined into one picture. The stronger the return, the heavier the fall. Each picture is checked against the national analysis, and echo it does not confirm is left out.
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; over 65, large hail.
What it is for
- Watch a storm come in and judge when it will reach a town.
- See the shape of a storm: a line, a bow that pushes damaging wind ahead, or a hook at a supercell’s tail.
- Tell where rain turns to snow along a winter storm.
- Check the road ahead before a drive.
How it is made
Every radar in the national network, more than 150 of them, sweeps the sky every few minutes, tilting up through a set of angles. The sweeps are joined into one picture of the country on a grid about a third of a mile across, each place taking the lowest beam that sees it clearly. Each picture is checked against the national analysis before it is drawn, and echo it does not confirm (birds, insects, ground clutter, the beam bent back to the ground) is left out.
A picture every 5 minutes, played as a loop of 1 to 24 hours. As data: /radar/now.json, 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
Falling now
Rain rate
Latest
How hard rain and snow are falling at this moment, in inches of water an hour, a new picture every two minutes.
.014 in an hour
Rain total, 1 hour
Last hour
Latest
All the rain of the last hour, in inches: the quickest way to see where the downpours are falling now.
.0112 in
Forecast amount
Rain, 6 hours
For
How much rain will fall in each 6 hours, in inches, snow as its water: the bands of rain crossing storm by storm.
.0112 in