4 Map Overlays
Overlays are the map layers you toggle on top of radar, per panel. Tap most overlay features to open a detail view. This chapter catalogs them by category.
4.1 Severe weather
| Overlay | What it shows |
|---|---|
| NWS Warnings | Tornado / Severe Thunderstorm / Flash Flood warning polygons, color-coded by type |
| SPC Watches | Storm Prediction Center watch polygons (Tornado, Severe Thunderstorm, Fire Weather) |
| MCDs | Mesoscale Convective Discussions |
| Convective Outlook | SPC Day 1–3 outlooks; pick the day and hazard layer (categorical risk, or tornado/wind/hail/any-severe probabilities) |
| Local Storm Reports | Spotter-submitted tornado, wind, hail, and rotation reports as point markers |
| NHC Tropical | National Hurricane Center tropical tracks and forecast cones |
Warnings and watches can be read aloud; see Accessibility & Speech.
4.2 Radar coverage & sites
| Overlay | What it shows |
|---|---|
| Radar Mosaic | Composite multi-site reflectivity across a wide area |
| Radar Sites | WSR-88D / TDWR site markers; tap to switch the active site |
| Single-Site Radar Data | Full-resolution radial texture from the selected site |
4.3 Lightning & storm tracking
| Overlay | What it shows |
|---|---|
| Lightning | Real-time cloud-to-ground strikes (USPLN feed), colored by age |
| Storm Tracks | SCIT storm-cell tracks with forecast motion vectors |
| Storm Attributes | TVS (Tornado Vortex Signature), Mesocyclone, and SCIT rotation markers |
4.4 Surface analysis
| Overlay | What it shows |
|---|---|
| Surface Grid | Interpolated surface field: choose temperature, dewpoint, pressure, wind, visibility, or ceiling |
| Surface Values | Individual station readings at mesonet sites |
| Wind Particles | Animated wind flow (particle or streamline mode) |
| Surface Stations | Mesonet station location markers |
4.5 Geography & basemap
Tapping any overlay feature opens a detail view with its full information.
The Basemap is an editable PMTiles vector map. Toggle it on/off, pick a theme (Light, Dark, Satellite, Weather), and enable individual layers: state boundaries, roads, water, waterways, land use, buildings, and place names. A separate State Boundaries overlay is also available. See Settings.
4.6 Your locations
| Overlay | What it shows |
|---|---|
| Saved Locations | Your saved points by category (Home, Work, Family, Friend, Venue, Storm Chase, Other), each with a custom icon/color |
| Current Location | Your device’s GPS position |
Managing saved points is covered in Saved Locations.
4.7 Spotters
| Overlay | What it shows |
|---|---|
| Spotter Positions | Live spotter locations; icons distinguish chasers, stationary spotters, emergency vehicles, and media |
| Spotter Reports | Individual observation icons (tornado, rotation, hail, wind, …) |
Spotters support extensive filtering; see Spotter Network.
4.8 Activity tracking
When replaying a chase, additional overlays appear: a GPS Log Trail from a loaded .gpl/.gpx file, a real-time Chase Trail, and the current GPS Log Position marker. See Animation & Archive.
Overlay toggles apply to the panel you set them on. With multiple panels you can, for example, keep one panel clean for radar structure and load another with warnings, spotters, and storm attributes. See Panels & Layout.