The National Weather Service is replacing its WSR-88D radar network with next-generation S-band systems. But even new radars cannot see below ~3,000 ft AGL — where tornadoes touch down, where storm surge forms, where the Guadalupe River children had no warning. This tool maps those blind zones and identifies where 5G/6G cellular infrastructure can supplement radar coverage through Integrated Sensing and Communications.

The WSR-88D fires its beam at elevation angles starting at 0.5°. By the time that beam travels 100 kilometers from the antenna, it is already 1,500 feet above the ground. At 200 kilometers — well within the radar's nominal 230km range — the lowest beam clears 10,000 feet. This is not a flaw; it is physics. The curvature of the Earth and the geometry of the radar beam mean that everything happening below that altitude is simply invisible to the radar. Tornadoes form at the surface. Flash floods fill creek beds at the surface. Storm surge advances at the surface. The children on the Guadalupe River were at the surface.

Even placing new S-band radars in better locations only partially addresses this. The blind zone shrinks, but it never disappears. A 230km-range radar will always have a low-altitude gap within its own coverage footprint. The only way to sense weather at the surface is with sensors at the surface — or close to it.

A 5G base station transmits millimeter-wave and sub-6GHz radio signals continuously. Those signals interact with the atmosphere — they are attenuated by rain, scattered by hydrometeors, Doppler-shifted by wind. For decades these effects were treated as noise to be engineered around. ISaC — Integrated Sensing and Communications — flips this: the interference is the data.

By analyzing the signal received at a base station relative to what was transmitted, you can extract rainfall rate, wind speed, and atmospheric moisture along the signal path. Link-level attenuation correlates directly with precipitation intensity — this is well-established in the commercial microwave link literature going back to Messer et al. (2006) and has been demonstrated operationally in Israel and the Netherlands. 5G extends this to dense urban and suburban networks with far greater spatial resolution than the sparse commercial microwave backhaul links studied previously.

The hardware ask is modest: a software-defined passive sensor module added to an existing base station, plus a firmware update to log received signal characteristics. No new towers. No new spectrum licenses. No civil construction. The sensing capability rides on infrastructure already paid for by the carriers. MITRE's AI-WIN partnership — with Nvidia, T-Mobile, Cisco, and Booz Allen — is actively briefing NTIA on the spectrum sharing framework that would make this operational.

Neither technology alone gives you the full picture. NEXRAD sees storms clearly from 3,000 feet up to 70,000 feet — it captures the full vertical structure of convection, the rotation signatures of tornadoes aloft, the anvil geometry of supercells. 5G sees what is happening at street level across dense networks of links, but with no vertical resolution and limited range per link (~20–50km depending on frequency band). Together they are complementary in almost every dimension:

The gap zones shown in red on this map are where NEXRAD coverage at low altitude is weakest and 5G tower density is high enough to provide meaningful supplementation. These are the highest-value ISaC deployment zones — where a software update to existing cellular infrastructure could close a life-safety gap that no amount of new radar construction can fully address.

3D geospatial globe · NEXRAD station data (NOAA ROC) · Altitude beam modeling (VCP-12 elevation angles) · OpenCelliD global cell tower API (CC BY-SA 4.0) · FCC Antenna Structure Registration (ULS bulk data) · AI-WIN ISaC framework (NTIA/MITRE) · ESRI partnership layer · ITU-R P.838 attenuation model · PSO/GWO radar placement optimization

The world's largest open cell tower database: 40M+ towers across 180+ countries, crowdsourced under CC BY-SA 4.0. Free API key at opencellid.org. Supports filtering by radio type (NR = 5G), carrier MCC/MNC, and bounding box. Updated continuously by the community.

The authoritative US record of every registered antenna structure. Covers all towers over 200 ft AGL or near flight paths. Contains lat/lon, height, owner, and structure type. Not a live API — data is released as bulk downloads from FCC ULS. Download the CO (Construction/Operation) table for tower coordinates.

Additional authoritative datasets for international coverage: