Summer 2010 forecast for Europe

Summary. In the summer of 2010 mean seasonal temperatures in Europe are forecast to be close to their climatological (1971-2000) values, being slightly above normal in western Europe and near or below normal in eastern Europe. Even in western Europe, however, temperatures will likely be colder than in the summer of 2009. In terms of temperature anomalies, July will probably be the coldest month in comparison to June and August. Temperature conditions are expected to improve by the end of summer.

Discussion

Fig. 1. Winter and summer temperatures in Berlin.

After a very cold winter of 2010 in Europe, one may ask, is the summer going to be anomalously cool was well? In Berlin, for example, the correlation between winter (DJF) and summer (JJA) temperatures (smoothed by 5-yr running averages) is moderately strong (r = 0.59 for the period since 1930). Both time series experience a warming trend, so that temperatures in the past two decades were predominantly above the 1971-2000 average (Fig. 1). If the trend is removed, however, the correlation coefficient between the unsmoothed winter and summer temperatures drops to almost zero. Therefore the past cold winter does not provide any clue of what the forthcoming summer is going to be.

Fig. 2. CFS forecast for summer 2010.

Unfortunately, little help is provided by the climate models as well. While some models, such as the CFS, predict a generally cold summer for Europe (Fig. 2), other, such as the Met Office model, show that summer temperatures will be above normal virtually all over Europe.  

The analysis of empirical-statistical rules in the ECliPS's knowledge base suggests that seasonal temperatures in the summer of 2010 will likely to  decrease compared to the previous summer in western Europe, but still remain above the 1971-2000 average (Fig. 3).  A more substantial temperature decline is expected for eastern Europe. In contrast, temperatures in southern Scandinavia will increase from the previous summer.  Overall, the highest probabilities are for near-normal temperature category over much of Europe.

Fig. 3. Summer (JJA) 2010 SAT forecast.

Monthly temperature forecasts for June, July and August are presented in Figs. 4-6. As with the mean summer temperatures, June temperatures over western and central Europe are forecast to decrease compared to June 2009, but still remain above normal, except, probably, in Spain (Fig. 4). In the latter case, it would feel like a cold summer, because in the last 16 years, there were only two years when June temperatures were below normal.

In July, colder than normal temperatures are expected for the area from Great Britain to Poland (Fig. 5). In Great Britain, July 2009 was a soggy and relatively cold month. July 2010 may be even colder. In contrast, there is a good chance that July temperatures in Spain will be above normal.

Fig. 4. June 2010 SAT forecast.

Fig. 5. July 2010 SAT forecast.

Fig. 6. August 2010 SAT forecast.

Some improvement in temperature conditions is likely toward the end of summer. In August (Fig. 6) and possibly September, monthly temperatures are forecast to be above normal over much of Europe. However, many rules for August-September have not been triggered yet, and this forecast will be updated sometime in early July.