Weather forecast

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A weather forecast is a weather forecast over a longer period of time, i.e. over several days or even months , up to an entire season . The possibility of such forecasts is currently still very limited, but could become a reality in the near future due to improved observation possibilities (see weather satellites ) and computer models.

Beginnings and first successes

The first weather forecast for Europe was published in May 2005 by the Neue Zürcher Zeitung . She announced that next summer it would be " around the Mediterranean with a 60 to 80 percent probability above average warm ", while the summer in Switzerland would be " only moderately " warm.

In Europe, weather forecasts are very difficult due to the changeable weather. In other parts of the world , however, they are already common - e.g. B. in South America , where a possible El Niño event can be reliably predicted (as happened in spring 1997 , when the first signs were discovered nine months in advance).

In India , the onset of the monsoon rain and its severity can be predicted (but with a high degree of uncertainty), which is important for smallholders as they can decide whether and when to plant which crops. The effects on Bangladesh can also be predicted.

In the US , the severity of the coming hurricane season can be forecast based on deviations in the average wind distribution in July.

The German Weather Service also tests long-term forecasts over a period of up to five months in advance, on behalf of energy companies such as RWE , E.ON or Vattenfall , because they need the data to estimate the energy needs of the population. The first results are promising.

execution

In a continent like Europe, where the weather changes quickly and often , in contrast to the tropics , measurements that do not change too quickly (in contrast to air temperature or precipitation ) are required for a reasonably reliable weather forecast . These are the temperature of the sea surface (due to the high heat capacity of water ), the snow cover , the soil moisture and the extent of the sea ​​ice . To create the weather forecast, one now relies on experience , e.g. B. on the fact that a stable cold winter in Central Europe is unlikely if the water temperature in the Baltic Sea in December is above average. A hot summer can also be expected in Central Europe when the spring in Northern Europe is very dry, because then less water can evaporate, which means that fewer clouds are formed. While the weather forecast only uses a model of the changes in the earth's atmosphere , a model of the changes in temperatures in the oceans is needed to forecast the weather , which has been difficult so far.

Despite all efforts, a weather forecast will probably never achieve the accuracy of a weather forecast .

Use

Knowledge of the long-term weather situation would be particularly interesting for farmers , hoteliers and insurance companies as well as for energy suppliers.

literature

Web links

  • Long- term weather General information and information on the subject of long-term weather forecasts
  • Weather forecast Long-term forecasts for months and seasons