Live weather radar, from the national picture to the nearest site
RR Weather starts with a broad MRMS radar view for regional context, then offers local NEXRAD Level II products when you need to inspect a storm more closely. Source times stay visible so motion never pretends to be newer than the data.
National MRMS radar gives the broad view
Multi-Radar Multi-Sensor data combines information from many radars and related sources into a consistent national mosaic. It is useful for seeing the shape and movement of weather systems across regions without jumping from one radar site to another.
The mosaic is still a processed radar product. RR Weather shows its frame time and loading state because network delay, upstream processing, and browser rendering can separate “now” on the timeline from the actual source time.
High-Res Radar reveals more storm detail
The High-Res Radar source uses Level II data from an individual NEXRAD radar near the selected area. It can show finer storm structure and several radar products, but distance from the site, beam height, terrain, and the chosen elevation angle all affect what the radar can see.
- Reflectivity
- Shows the strength of returned energy. Rain, hail, snow, insects, ground clutter, and other targets can all contribute to a return.
- Velocity
- Shows motion toward or away from the radar along the beam. It does not directly show the full wind speed or direction at the ground.
- Correlation coefficient
- Compares how similarly radar pulses behave. It can help distinguish types of targets, but interpretation depends on the full storm context.
- Differential reflectivity
- Compares horizontal and vertical returns to provide clues about target shape and orientation.
Map layers add context without changing the radar
Place labels, the selected-location marker, official NWS hazard polygons, and optional severe-weather context remain separate from the radar image. Keeping those layers above radar makes their source and meaning easier to follow.
A polygon tells you where an official product applies; a radar color shows returned energy. One should never be read as the other.
Four checks before acting on a radar frame
- Check the timestamp. The newest visible frame may still be delayed.
- Check the source. A national mosaic and a single local radar solve different problems.
- Check the product. Reflectivity and velocity do not measure the same thing.
- Check official alerts. Radar interpretation never replaces a warning or instruction from authorities.