Season’s First Stratospheric Warming Event

ALERT: First stratospheric warming event of the 2019-20 cold season enhances U.S. cold/turns Europe stormy.

Fig. 1: GFS ENS depiction of the peak intensity (November 10^th) of the season’s first stratospheric warming event.

Discussion: A stratospheric warming event, the first of the season is forecast by all operational models to emerg the first half of November and center itself on the northern North Atlantic basin. The peak of intensity of the event is forecast on November 10^th (Fig. 1). The location is not ideal to produce widespread arctic outbreaks, typical of stratospheric warming events when they occur mid-winter over the polar region. However, this particular event enhances the cold across North America for the first half of November (Fig. 2) and may force the cold to linger into mid-month while in Europe a stormy pattern brings much above normal precipitation for the first half of November and normal to cool temperatures (Fig. 3).

Fig. 2-3: GFS ENS day 1-15 forecast of the cold across the Central and East U.S. and excessive precipitation in Europe (snow in Western Russia) attributed to the stratospheric warming event.