Storm Map shows live NOAA weather alerts, NEXRAD radar, GOES satellite, and SpotterNetwork storm chasers on an interactive map. Use the side panel to control what is shown; use the top bar to search locations and sign in.
Map view
Pan / zoom: drag the map; scroll or pinch to zoom.
Single / Quad view: the ⊞ button in the top-left of the map toggles a four-pane layout so you can compare radar products side-by-side. Drag the dividers to resize panes.
Radar product picker: each pane has a dropdown to choose a national mosaic, a single-station product (Reflectivity, Velocity, etc.), or a GOES satellite layer.
Animation: when a station product is selected, use the play button and time slider on the pane to loop recent frames.
Radar station badges: click a station code on the map to pick a per-station radar product for that pane.
Alert polygons: click any colored polygon to see the full alert (event, headline, area, expiration, hail/wind, instructions).
Top bar
Location search: type a city or county and press Enter (or use ↑/↓ to choose a result) to fly the map there.
Sign Up / Sign In: create an account to sync your settings, overlays, watched chasers, and last map position across devices.
Sign Out: flushes your settings to the server and clears your account info from this browser.
? opens this help dialog (or use Alt+A then ?, with or without Alt on the second key). Press Esc to close any dialog.
Hotkeys
/ — focus location search box.
Esc — close dialogs and search results.
Alt + A then R — toggle radar stations overlay.
Alt + A then A — toggle alert polygons overlay.
Alt + A then M — toggle storm motion arrows overlay.
Alt + + — increase overlay opacity by 10%.
Alt + - — decrease overlay opacity by 10%.
Side panel
Each section is a collapsible accordion. Your open/closed state is remembered.
Alert Filters
Choose which NWS alert types appear on the map and in the Active Alerts list. Enter a name in the field and click Save to save your current selection. Select a saved set from the dropdown to apply it. Use All / None for quick selection. Only alerts intersecting the current map view are shown.
Active Alerts
Lists alerts currently visible on the map. Click an entry to zoom all panes to that alert (and auto-select the nearest radar station).
Overlays
State outlines — US state boundaries.
Radar stations — NEXRAD station labels; click one to pick a per-station product.
Radar coverage — approximate coverage rings around each radar; rings dim for stations not currently selected in any pane.
Alert polygons — colored warning/watch polygons from api.weather.gov.
Pressure fronts — cold/warm/occluded/stationary front lines.
Isobars — surface pressure contour lines.
Storm Spotters — live SpotterNetwork chaser positions.
Webcams — public webcams in view; click an icon to preview.
Precipitation Type legend
The National Precipitation Type overlay is NOAA's MRMS Surface Precipitation Type (SPT) product. Each pixel is classified into one of seven categories:
Code
Meaning
GRIB2 flag
WS
Warm Stratiform rain (surface T > 5 °C)
1
S
Snow
3
C
Convective rain
6
H
Hail (rain mixed with hail)
7
CS
Cool/Cold Stratiform rain (surface T ≤ 5 °C)
10
ST
Tropical / Stratiform rain mix
91
CT
Tropical / Convective rain mix
96
How the algorithm decides:
Snow is assigned where surface temperature < 2 °C and wet-bulb < 0 °C.
Hail is flagged from severe-storm/hail criteria within convective cores.
Remaining liquid pixels are split into convective vs. stratiform by the CSPS (Convective/Stratiform Precipitation Separation) algorithm.
Stratiform is sub-divided into WS or CS based on the 5 °C surface temperature threshold.
Convective and stratiform rain in tropical air masses are reclassified as CT or ST by the Tropical Rain Identification step.
Storm Spotters
Search and sort the SpotterNetwork chaser list (by first name, last name, or online status). Click a chaser to fly the map to their position. Use the bell 🔔 to watch a chaser (you'll be notified and they appear in Chasing); use the eye/follow button to follow them — all panes will re-center on their latest position as it updates.
Chasing
Quick access to the chasers you're watching. Toggle Only show watched in Settings to hide everyone else from the spotters layer.
Points of Interest
Save named locations (home, office, a campground) and see them as orange dots on every map pane. Hover a marker for the name and address. Click a POI in the list to fly all panes to it.
Add by address — type a city, landmark, or street address; pick a suggestion; give it a name and Save.
Use my location — saves your current geolocation (enabled once your location resolves).
Drop pin on map — click the button, then click anywhere on a map pane to drop a pin. Esc cancels.
Delete — click ✕ once to confirm, again to remove.
Settings
Only show watched — limit the storm-spotters layer and list to chasers you've watched.
Units — Imperial (mph, mi, in), Metric (km/h, km, cm), or Nautical (kt, nm, in). Affects alert popups and distance labels.
Notification radius — how close (Off, 10/30/50/100 mi) an alert must be to your location to trigger a desktop notification.
Background alerts — enable a service worker that keeps checking for nearby alerts even when this tab isn't focused.
Polygon opacity — fill opacity of alert polygons.
Overlay opacity — opacity of radar / satellite overlays.
Tips
Press / to jump to the location search box (or Alt+A then / or Alt+/).
Press ? to open this help dialog (or Alt+A then ? or Alt+?).
Press Esc to close any dialog or the search results.
Storm Map is installable as a PWA — use your browser's Install option to add it to your home screen for offline shell loading and background alerts.
When signed in, your map position, alert filter sets, panel state, overlays, watched chasers, and opacity settings are saved to the server and restored on any device.
Sources
Storm Map combines data from these public services. Click any link for the publisher's home page.
Weather alerts — National Weather Service (api.weather.gov) — weather.gov API docs