Fig. 1-4: The Climate Impact Co. Europe East System HDD forecast and forecast change (top) plus the Europe West System HDD forecast and forecast change (lower).
Discussion: So far, November was marginally warm and December very warm as measured by selected city HDD observations (Fig. 1 and 3). To emphasize the warm bias of the December 2023 forecast, the observed value is compared to the forecast value for both the East and West selected cities SYSTEM projection (Fig. 2 and 4). The warmer than normal observations are interesting due to the early season arctic air presence enhanced by snow cover over Northwest Eurasia during early winter. Despite the nearby frigid air mass, the lack of snow cover prevented much cold influence instead enhanced a mild climate in December. In January, the colder air over Northwest Eurasia settled southward yielding a chilly first half of the month for Europe. However, the chill is likely to reverse somewhat milder the last third of January leaving HDD count close to normal which is a milder change from the previous forecast. The February and March HDD outlook is left alone depicting warmer than normal values for each month.