Mediterranean cyclone with an atypical trajectory: Characteristics and outcome (12-14 november 2016)

Abstract

It is not uncommon for trajectories of Mediterranean cyclones to steer away from the traditional paths identified by specialists. In most cases, Mediterranean depressions bypass the Romanian Carpathian Mountains barrier either in the south or west, which results in the fact that only certain regions are affected by associated phenomena. The interval 12-14 November 2016 was notable in that the entire Romanian territory experienced a vast array of meteorological phenomena linked to the irregular trajectory of a Mediterranean cyclone. The cyclone initially moved along a classic trajectory 4a, after which veered into 1c. The cyclogenesis onset and trajectory were mainly determined by altitude conditions, and the rapid deepening in the Moldavian region was due to several factors acting simultaneously. Precipitation was recorded throughout the country’s territory in the aforementioned interval. In the northern half of the country there were frequent exceedances of 25 mm in 72 hours, up to 85 mm in northern Moldavia. It snowed and the season’s first snow cover was recorded in extensive areas in Transylvania and northern Moldavia, as well as in limited areas in Maramureş, Banat and Crişana, and blizzards were reported sporadically. In the mountains, the snow cover thickness reached 48 cm in 24 hours. Sustained winds intensified rapidly in Oltenia, Muntenia and Dobrogea, as speeds exceeded 80...90 km/h in lowlands, and 120...130 km/h in high mountainous regions, where the blizzard was particularly strong, with reduced or zero visibility. Scattered heavy rain showers, lightning and storm-like winds were reported in Dobrogea. In terms of thermal regime, most of the country shifted from slightly above normal to significantly below average temperatures. In most regions, peak air temperature values decreased by over 10 oC within 24 hours, and several all-time daily lows were recorded. The negative effects were significant. Several roads were closed due to the snow cover and wind-fell trees, material damages were recorded, and 3 people were killed.

Keywords

• atypical trajectory
• cyclogenesis
• altitude