08/16/2022, 8:03 pm EDT

Europe Month 1-3 Ahead Outlook: Wet weather heading to Europe in September and October.

Executive Summary: In a “gutsy” projection, Climate Impact Company brings beneficial rain to the Europe drought area in both September and October. The drought may continue especially Southern Europe while relief is on the way for areas to the north. The wet weather maker is ejection of upper trough(s) into Europe from the Greenland/Iceland source region in September followed by a weakening of that upper trough while drifting over Europe in October. The autumn season is mild for most of Europe. Western Russia is mostly dry and very warm as drought strengthens. Northwest Russia may gain some rainfall later in the autumn season. Climate discussion: During late spring an upper-level semi-permanent low-pressure trough developed across Greenland, characteristic of positive North Atlantic oscillation (+NAO). To compensate for the upper trough, a downstream upper-level high-pressure ridge formed over Europe (Fig. 1) leading to the anomalous warm and dry summer season to date and also responsible for intensifying drought to historic levels particularly in France. Foreshadowing this potential upper air pattern across Europe and re-enforcing the pattern during mid-summer was intense warm SSTA off the West Coast of Europe, across the Norwegian Sea and throughout the Mediterranean Sea (Fig. 2). Global SSTA models indicate the current pattern is likely to last well into the autumn season (Fig. 3) although there are short-term signs that the persistent upper ridge may be eroding. The updated month 1-3 ahead outlook is based on a constructed analog which accounts for the SSTA conditions identified, widespread dry soils, the possible influence of tropical activity on the general pattern and strengthening La Nina. Fig. 1: The upper air pattern across Europe for May 12 to Aug. 12, 2022.   Fig. 2: Current global SSTA analysis identifies warm waters surrounding Europe. Fig. 3: IMME global SSTA forecast for October 2022 with factors for Europe. September 2022: The persistent Greenland/Iceland upper trough continues. However, some of that energy is ejected toward Italy which weakens the strength of the Europe ridge pattern. Instead, the ridge pattern shifts eastward to Ukraine. The result is much-needed wet weather for France and Italy to Poland while Southwest Russia/Black Sea region is dry. Most of the warm is in far East Europe. Fig. 4-5: The Climate Impact Company constructed analog forecast for September 2022. October 2022: In October, the upper trough fades while shifting east. The eastward shift is enough to cause needed rainfall in U.K., France and eastward to Poland. Dryness dominates Southern Europe and Southwest Russia. The outlook remains mostly warmer than normal for mid-autumn. Fig. 6-7: The Climate Impact Company constructed analog forecast for October 2022. November 2022: The atmosphere cools across the warm open water north of Europe leading to a vast low-pressure trough. Northern Europe turns wet and early season mountain snows accumulate rapidly. The ridge pattern is back, just off the West Coast of Europe. Consequently, West/Southwest Europe is likely dry and warm. Western Russia stays mild with dryness persisting in the Black Sea region.   Fig. 8-9: The preliminary Climate Impact Company constructed analog forecast for November 2022.