National Observatory of Athens: What causes hail this time of year

Intense instability is expected to prevail in the new week in much of the country, according to forecasts of the National Observatory of Athens / meteo.gr. Thunderstorms will occur which in places will be accompanied by hail. On the occasion of this development, meteorologists explain where the hailstorms are attributed at this time.

According to experts, hail is a common phenomenon in our country in late spring and early summer as relatively cold air masses from northern Europe often find their way south. The presence of cold gas masses in the atmosphere in combination with the intense heating of the soil during this period, create conditions of instability. In the presence of adequate amounts of moisture, instability often leads to thunderstorms, some of which produce hail.

Hail begins to form in storms under special conditions of intense instability and change of wind speed at height that creates turbulence within the clouds. Consecutive upward and downstream currents lead it to different heights as quartz granules grow when water vapor condenses and freezes on them.

Many times the instability itself is quite intense, and when the brief wind is weak, strong up and down currents are created again in the storms that favor the production of hail, as will happen in the coming days in Greece.

At the National Observatory of Athens / meteo.gr from 2020 began the effort to develop forecast products for hail, which is the most difficult parameter (form of precipitation) in the weather forecast.

Using a number of atmospheric parameters in supercomputer computing algorithms, the National Observatory is now able to predict with relative accuracy the maximum amount of hail that is going to hit an area over the next 48 hours.