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
Live radar / Echo tops
Storm tops, live radar
Over Fire Weather Watch for Northern Lake Including Gravelly Valley, Eastern Lake Including Clearlake and Middletown, where the map opens. The whole country
How tall each storm stands, in feet: the higher the top, the stronger the storm and the more likely hail and wind. 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 storm tops map shows
How high each storm reaches, in thousands of feet: the highest the radar still finds rain or hail. Ordinary showers stop near 20,000 ft; a top over 45,000 ft is a towering storm, the kind that brings hail and damaging wind.
How to read it
- Under 20,000 ft
- Showers and light rain.
- 20,000 to 35,000 ft
- Thunderstorms.
- 35,000 to 45,000 ft
- Strong storms, reaching high into the sky.
- Over 45,000 ft
- Towering storms that can bring hail and damaging wind.
- Over 55,000 ft
- The strongest supercells, their tops punching above the anvil.
What it is for
- Tell a shower from a thunderstorm when both look alike on the radar.
- Find the storms growing fastest: a top that climbs quickly is a storm strengthening.
- See which storms an airliner must fly around.
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 the last hour. As data: /radar/now.json?show=tops, the times of its frames.
In the Field Book
- Overshooting top and above anvil plumeFB-SKY-042
- Cumulonimbus architectureFB-SKY-041
- WSR-88D radarFB-INS-005
Over a state
AlabamaAlaskaArizonaArkansasCaliforniaColoradoConnecticutDelawareDistrict of ColumbiaFloridaGeorgiaHawaiiIdahoIllinoisIndianaIowaKansasKentuckyLouisianaMaineMarylandMassachusettsMichiganMinnesotaMississippiMissouriMontanaNebraskaNevadaNew HampshireNew JerseyNew MexicoNew YorkNorth CarolinaNorth DakotaOhioOklahomaOregonPennsylvaniaRhode IslandSouth CarolinaSouth DakotaTennesseeTexasUtahVermontVirginiaWashingtonWest VirginiaWisconsinWyoming
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
Forecast, each 12 hours
Thunder
For
The chance of a thunderstorm in each 12 hours for seven days: where storms are likely, before any radar sees them.
080%