Forecasting tools for HF radio propagation
The MUF300 map is user-friendly forecasting tool for predicting real-time HF radio propagation. However, because it is based on a simplified model that does not account for geomagnetic storms and blackouts caused by Elevated X-ray Flares and/or Proton Ejections, the estimation's accuracy is insufficient for commercial radio service purposes. Other reasons for low ionospheric parameter accuracy include insufficient measurement coverage of the Earth and errors in estimating ionosphere parameters from vertical sounding data.
There are several hundred ionosondes that can take measurements. The vast majority of these are concentrated in a few areas of the world, with large areas remaining unmonitored. As a result, that map is an interpolation. While the guessing process is fairly accurate in areas close to MUF measurement stations, the uncertainty in areas far from any measurements is much higher. Only the numbers within the colored dots scattered across that map represent actual measured data.
The idea to predict HF propagation based on Ionospheric Monitoring and Prediction System has been described years ago. See for example this PDF.
The following applications can forecast HF radio propagation (a few days in advance):
Each of these tools/services has advantages and disadvantages, and the tool selected will be based on the user's specific needs and requirements. It should be noted that none of these services can provide perfect predictions because radio propagation is affected by a number of variables that are difficult to predict completely.
You may find more detailed information in the main webpage, here. See also an index for HF Radio Propagarion.