In Holland, April 2007 will break a series of records: the hottest, driest, en sunniest April ever. With respect to heat and drought this month does not fit into the bandwidth of previous April months, in spite of its capricious nature. Global warming has made the high temperatures less unlikely, but the main cause is an extraordinarily persistent high pressure system that brought dry, sunny and warm weather to a large part of Europe. This pattern is not predicted to occur more frequently by the current climate models, so as far as we know now it must be ascribed to a chance fluctuation in the weather.
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Other parts of Europe also report extremely warm weather for April. In Switzerland April has up to now been 5 to 7 degrees above the 1961-1990 normals, in England it was the warmest April since the beginning of observations in 1659. In Austria and Sitzerland the drought is a problem for agriculture.
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Global warming has increased the probability of an extremely warm April as the one we observed in 2007.However, on top of this it still was a highly unlikely event, with an estimated return time of more than 200 years. The record warm, dry and sunny weather was caused by a persistent high pressure system over our part of Europe.