The apps

Every tilt of the radar, on every device you own.

The site hands you the warning and the mosaic. The app hands you the whole volume scan, every storm cell scored while it is still a cell, and alerting that follows you instead of a list of addresses.

Get the app, free See what it does

40s
Median, forecaster send to broker: 157
NEXRAD sites, every tilt

Desktop, base reflectivity with cells tracked

The desktop app showing base reflectivity across a squall line, ten storm cells tracked with their cones drawn, and one cell open in the inspector.

The phone app showing Level II reflectivity with tracked storm cells outlined and the cell sheet open.

What you open it for

More detail than most apps

NEXRAD Level IIEvery tilt, every moment WXA/SA storm analysisCells scored, tracked, projected Alerting that follows youGPS follow, not just saved pins Spotter reportingBearing, size, photograph Push that gets throughPer place, per hazard, per channel SPC outlooksCategorical and probabilistic Stations and sea stateSurface truth under the radar

The desktop app with the radar product list open, showing the Level II reflectivity, velocity, spectrum width, correlation coefficient and differential reflectivity moments, and the seven tilts in the current volume. — Desktop: the product list open, with the Level II moments and the tilts in this volume underneath it.

Phone: Level II reflectivity with the tilt picker open

The whole volume scan, not a flattened picture of it

The app holds its own connection to our Level II service, so you get every elevation angle and every product the radar puts out. Climb a storm tilt by tilt and find the rotation at the height it is actually happening, instead of guessing from the lowest slice. This is the part that cannot be a web page: the site draws Level III tiles at the 0.5 degree cut, and it always will.

Every site, both networksThe WSR-88D network and the TDWR terminal radars, so airports and the coast are not a gap.

Pro and upThe one layer in the app that is not on the free plan. Every other thing on this page, including every National Weather Service warning, is free on every platform.

Level II is served to the apps from l2.wxalerts.org. The website renders Level III tiles and never Level II, which is why this page is where the claim lives.

The desktop app tracking nine storm cells, each listed with its motion and its hail and wind probabilities, and one cell open in an inspector showing the last hour of tornado, severe, wind and hail probability. — Desktop: tracked cells with their cones, and one cell open in the inspector with its last hour of probabilities.

The phone app with three tracked cells outlined on Level II reflectivity and the cell sheet open, showing the cone lead selector and each cell with its motion and probabilities.

Every cell tracked and scored while it is still a cell

Each convective cell carries a severe probability, a rotation probability and its own motion, refreshed every couple of minutes. Tap one for where it has been, where its motion puts it next, and how hard it is working to get there. It says rotating, with a high probability of damaging wind, hail or a tornado. It never says tornado detected, because that is not a claim the data supports.

A dot per scan on the trackTwo minutes between dots, so the spacing tells you the speed without reading a number.

A cone, not a lineWhere the storm might be out to the lead you pick, drawn wider behind the straight-line guess because storms under-run it.

The probability scale tops out at its observed ceiling rather than at 100, because a scale implying 100 is reachable makes every real storm look mild. How it works, and how well, is written up in the docs.

Desktop: follow mode with the position marker, its heading, and a warning polygon ahead

Follow mode on, with the position marker and the warning polygon it is about to enter.

Phone: follow mode centred on the user with a warning polygon ahead

Saved places cover the house. The app covers you

A list of addresses cannot answer the question you have while driving toward a storm. Turn on follow and the app keeps the map on your position and tests every warning polygon against where you actually are, so you are told when you cross into one rather than when a county line moved.

The polygon, not the countyYour position is tested against the official CAP geometry, so you are not woken for a warning eighty miles away.

Your location stays yoursNo location history is kept. Follow mode is evaluated on the device, and the rest of the app works with the permission off.

Saved places and their rules still do the waking when the app is closed. Follow is the extra case, for when you are not at any of them.

Desktop: the live map with the spotters-in-the-field layer on and a report open

The spotter camera in storm mode, with the compass tape and reticle over the preview.

Phone: the spotter camera in storm mode, compass tape and reticle over the preview

File what you saw, from where you saw it

A certified spotter files from the app, in the weather that produced the report. The camera reads the compass while you aim it, so what you send carries the direction you were actually looking rather than one recalled afterwards, and the hail form speaks in the reference objects a spotter already uses.

The bearing comes off the shutterA compass tape sits over the live preview and the direction is recorded at the moment you take the picture. Aim the phone at the ground and it refuses, because a bearing off a flat phone would look exactly as trustworthy as a real one.

Hail in the sizes you already useThe SKYWARN reference objects, or a number if you measured one. The reticle is there to remind you to get a coin in the frame: no phone can size a stone from a bare photograph, and we do not pretend one can.

The report lands before the photographTwo separate sends. One bar of signal under a storm gets the report to a forecaster in seconds and the picture follows when it can, so a failed upload costs the picture and never the report.

And you can show up on the mapA switch in your spotter profile puts you on the public live map while you are out: your handle, rounded to about 100 metres, gone 30 minutes after your last update. Off unless you turn it on.

Spotter reports are unofficial and are never National Weather Service reports. A photograph travels with the report to us and is not published on the live map.

Desktop: the per-place alert rule matrix, hazards by channel

The rules for one saved place, hazard down the side and channel across the top.

Phone: a lock screen carrying a tornado warning

A warning on a muted phone is not a warning

Every place you save gets its own rules, channel by channel and hazard by hazard: call for a tornado, text for a thunderstorm, push for an advisory. We take the National Weather Service on three independent feeds and send whichever arrives first, so one feed going quiet does not take your warning with it.

Median 40 secondsFrom the forecaster pressing send to the alert being on the broker. Measured, not a ceiling, and the docs say exactly what it does and does not cover.

Push, email and webhooks on every planTexts and phone calls on the paid ones, because those cost real money per message.

Route one place to more than one person, so the alert reaches whoever is actually standing there at 3 AM.

Desktop: the SPC Day 1 categorical outlook with a probability layer and a mesoscale discussion

Day 1 categorical with the tornado probability layer over it.

Phone: the SPC outlook with the day selector and the risk legend

Tomorrow, in the Storm Prediction Center's own colors

Convective outlooks with the categorical ladder and the probability layers for tornado, wind and hail, plus watches and mesoscale discussions. Drawn in SPC's colors rather than ours, so a Moderate Risk looks like a Moderate Risk to anyone who already knows what one is.

Told when your place moves upAn upgrade on a place you saved is a notification, which is usually the one that decides the day.

Off until you askIt is a forecast rather than something happening now, so it does not sit on top of the warnings unasked.

Outlook, watch and mesoscale discussion products from the NOAA Storm Prediction Center, drawn as issued.

Desktop: the station layer with station plots and one station time series open

The station layer over the metroplex, with one station pinned and plotted.

Phone: the nearby stations list with current conditions

What the air is actually doing, under the storm you are watching

Stations, buoys and a temperature map over the same view, so you can watch a gust front cross the mesonet ahead of you instead of inferring it from reflectivity. Tap any station for its own page and its last 24 hours. Connect your own and it joins the network other people are reading.

Every station has a pageThousands of them on the site, one per station, with the same numbers the app is drawing.

Buoys for the coastWind, wave and water temperature on their own ramp, because the point of the layer is that it is showing the water.

Observations from NWS and FAA ASOS/AWOS sites, state mesonets, NDBC buoys and contributing personal stations.

Get it

We cover everyone, including Linux

iPhone & iPadiOS 16.4 or later, one universal build. Critical alerts can break through silent mode and a focus.Coming soon

AndroidAndroid 9 or later, from Google Play.

macOSmacOS 13 or later, Apple silicon and Intel. Alerting from the menu bar with the map closed.Coming soon

WindowsWindows 10 or later, 64 bit. The package is self-signed for now, so add its certificate to Trusted People on the local machine before opening it.Signing certificateDownload

LinuxA 64 bit AppImage for Wayland and X11. Needs glibc 2.35 or newer (Ubuntu 22.04, Debian 12 and up) and libfuse2; mark it executable and run it.SHA-256 checksumsDownload

What it costs

The app is free. Level II is not.

Warnings, storm analysis, outlooks, stations and push are in the free app on every platform, with no ads and nothing that keeps you safe behind a paywall. Level II is the exception and it is on Pro and up: every tilt of every site is a radar feed we pay to move, and it is the one thing here that costs us more the more you use it. A plan also buys capacity: more places to watch, more people to wake, and the channels we pay for per message.

See the plans Donate instead

FreeEvery National Weather Service alert for one place you care about, with no card and no expiry.$9.99 / moFor a household with more than one address to watch: the house, the school, the place the horses are.$19.99 / moTen sites, and five people at each of them, so the alert reaches whoever is actually standing there.Phone calls are included on every paid plan, and an add-on on the free one.