Summer 2008 forecast for Europe - update

Summary: New data provides an additional support for our earlier forecast of a hot summer in western Europe. A colder than normal summer is expected in eastern Europe. The area with precipitation deficit now also includes the western and eastern Mediterranean.

Fig. 1. Forecast of surface air temperature anomalies in Europe for the summer (JJA) of 2008.  The blue (red) contours and the letter C (W) indicate colder (warmer) than normal temperatures. CL means near normal. The base period for calculating anomalies is 1971-2000. The numbers at the contours are confidence factors of the forecast.

Fig. 2. Same as Fig. 1, except for precipitation. The orange (green) contours and the letter D (W) indicate drier (wetter) than normal conditions.

Discussion

Temperature

Spring data that became available so far further supports our previous forecast of anomalously warm summer over much of western Europe. For example, the March-April 2008 precipitation pattern is characteristic of warmer than normal temperatures in central Europe (rule 487). 

Previously, our confidence in above normal temperatures in the U.K. was reduced due to a record Eurasian snow cover in January 2008 (rule 322). Since then the area covered with snow has shrunk so much that became a record low in March 2008. As a result, our confidence in anomalously warm summer in the U.K. has increased.

There is also new evidence that summer temperatures in eastern Europe, despite the anomalously warm spring there, are more likely to be colder than normal (rule 347). Overall, the summer forecast for Europe is quite consistent with that for the United States (see, for example, rule 404).

Precipitation

With more data available, the projected area with dryer than normal conditions in the summer of 2008 has been expanded. Rule 311, for example, links the spring circum-global teleconnection index (CGT) with the summer precipitation pattern over Europe. The index was strongly positive in March 2008 and is expected to remain positive for the entire spring (MAM) 2008. This would favor anomalously wet conditions over north-central Europe and dry conditions in southern Spain and the eastern Mediterranean. This is generally consistent with the forecast from the U.K. Met Office. As a result, the area with drier than normal conditions in our forecast now includes western Europe and the Mediterranean. Wetter than normal conditions are likely in eastern Europe.