To answer the question of what the chances are of a pilot planning a safe flight for a day of convective activity, an investigation of different forecast products has been made. The study focuses on Sweden and the aviation targeted products produced by SMHI. No original evaluations of the products were made or assessed, but the reliability of them was deduced through a literature study comprising evaluations done of the NWP-models behind their production. The performance of convective indices was also examined. To complement this , viewpoints from two experienced aviation weather forecasters were added and analysed. Furthermore , the limitations of the forecasts products were summarized through an analysis of their scope of information.
It was found that all models have[/annotax] trouble handling convection as a cause of the local and turbulent mechanisms involved that are often too small to resolve, too quick to catch and too complicated to describe with simple enough equations. High-resolution models simulate convective events in very realistic detail when it comes to the structure and distribution of the cells but they do not score considerably better than the lower resolution models.
The biggest issue with the forecasts was found to be the uncertainty of when and where a convective cell will develop and which cells will grow to be vigorous CB or thunderstorms. Neither models nor human forecasters seem to be able to predict these occurrences accurately, even with the help of convective and thunderstorm indices . As a consequence, the forecasts are often wrong in the spatial distribution of such activity, resulting in poor prediction scores.
It was concluded that no forecast including details of location and time for individual convective cells should be trusted. However , it was also found that no such details are presented in the examined products. Nor can a pilot get specific information about the degree of any accompanying aviation hazards. As a consequence of this limited amount of information, a pilot can be expected to “trust” the forecasts but is not able to plan an altogether safe flight beforehand.