VHF/UHF tropospheric propagation forecast service
Tropocast processes two numerical weather-model sources: regional DWD ICON-EU (0.0625°) and global ECCC GDPS (0.15°). Forecasts for the first 24 hours are available at 1-hour intervals; the remaining horizon is available at 3-hour intervals, up to a maximum of 3 days.
Loading the latest forecast…
Available interfaces
Both interfaces read the same worker-generated forecast dataset. The map supports spatial analysis; the frame view provides a timeline, playback, archive access and embed output.
Georeferenced overlay with source, layer, validity-time and opacity controls.
Rendered Europe and Poland products with timeline, playback, archive and embed output.
Experimental area for a separate HF ionospheric-propagation map. It does not change the VHF/UHF tropospheric forecast.
Forecast update frequency
Source update frequency is independent of the interval between consecutive forecast valid times.
6hours
Forecasts based on ICON-EU data are updated every 6 hours (four times per day). After each source-data update, Tropocast recalculates and renders the available forecast range. In the detailed view, the first 24 hours are presented at 1-hour intervals and the remaining horizon at 3-hour intervals, up to 3 days.
12hours
Forecasts based on GDPS data are updated every 12 hours (twice per day). After each source-data update, Tropocast recalculates and renders the available GDPS forecast range. In the hybrid view, hourly values for the first 24 hours are linearly interpolated from source data available at 3-hour intervals.
Calculation and scope
Tropocast calculates radio refractivity N and modified refractivity M from pressure, temperature, water-vapour content and geometric height, using equations consistent with ITU-R P.453.
Tropocast separates near-surface and elevated propagation potential. The Full view combines both components across 0–3000 m AGL, while the hybrid ICON-EU + GDPS source uses regional ICON-EU data inside its European domain and GDPS as the global background. Map colours encode model-derived propagation potential, not field strength or a link budget. Observed conditions also depend on frequency, terrain, antenna geometry, power and interference.
