Europe: Water deficits in Western Europe, surpluses in western European Russia

17 February

The Big Picture
The 12-month forecast period from November 2016 through October 2017 indicates a predominance of water deficits in Western, Central, and Northern Europe and the Baltics, which may be of exceptional severity in southern Finland and the Baltics.

Water surpluses are forecast in far western European Russia, parts of Eastern Europe, and along southern Spain’s Mediterranean coast.

Impacts
Flooding along Spain's southeastern coast in December claimed 5 lives, forced hundreds from their homes, closed schools, blocked roads, and destroyed crops. Valencia and Murcia were the worst hit areas, and Spain's armed forces were called in for support in Murcia.

Ripple effects of the excessive rainfall in Spain were far-reaching as some supermarkets in Britain rationed vegetables. Spain's Murcia Province is one of the biggest lettuce producers on the continent and Britain imports more than 60 percent of its cabbages, cauliflower, and lettuce from Spain. Following the rain, Murcia suffered its coldest January in 11 years and its largest snowfall in decades, further reducing vegetable output. Severely cold weather in Spain and Italy caused a shortage of courgettes, also known as zucchini, in British markets as well.

Water specialists in France are closely monitoring conditions in the southwest, where rainfall deficits have reached 50 percent in some areas. Météo France says that the largest precipitation deficits are found in the Deux-Sèvres and Charente-Maritime regions. Rivers in the region are of concern, especially the Garonne, and reservoirs are in critical condition after months of drought. The Adour basin is at 44 percent of capacity, the Neste basin is 35 to 40 percent, and the Dropt is 49 percent. Under normal rainfall conditions levels would be 100 percent at this time of year. Without significant rainfall in February this winter could be the driest in France since 1959.

Forecast Breakdown
The 3-month composites (below) for the same 12-month time period show the evolving conditions.

What is most noticeable in the February through April map is the decrease in the extent of dark red in Scandinavia – indicating a retreat of exceptional water deficits – and the increase in the extent of blue in western European Russia – indicating the emergence of surpluses. Exceptional deficits are forecast to persist in Estonia and Latvia. A transition from deficit to near-normal water conditions is forecast for the United Kingdom and Ireland. Deficits ranging from moderate to extreme are expected in much of Western and Central Europe with some shifts in extent and severity from prior months’ observed conditions. Note the emergence of deficits across most of the Iberian Peninsula and in eastern Czech Republic, western Slovakia, Hungary, and to the south. The forecast for Italy, too, shows an increase in deficits while Switzerland transitions from deficits to surplus.

Widespread surpluses are forecast to emerge in western European Russia, and surpluses will continue to emerge in Belarus, along rivers in Ukraine, and in northeastern Romania.

The May through July forecast indicates a retreat of surpluses in Eastern Europe and western European Russia, and the continued emergence of deficits throughout much of Europe. The pink area in Russia indicates both deficits and surpluses as surpluses recede and deficits emerge. The most severe deficits – exceptional deficits – will continue to be in the Baltics and Finland. Moderate to severe deficits will continue to emerge in southern Sweden; southern Norway will transition from surplus to deficit, while surpluses emerge in the northwest.

The final forecast map – August through October – indicates a pattern similar to the prior three months though with a slight decrease in deficit intensity.

(It should be noted that forecast skill declines with longer lead times.)