Heat Waves Analysis of 2023 Summer in Eastern Part of Romania and Atmospheric Instability Events Which Succeeded Between Them

Abstract The purpose of this paper is a general climatic characterization of the 2023 summer in the region of Moldavia, in eastern part of Romania, but with focus on the analysis of the context in which the most intense tropical air advections occurred in this region. The most significant and lasting tropical air waves were in July and August. From a thermal point of view, June had only one interval in which the maximum temperatures exceeded, for 3 consecutive days, the threshold of 30ºC (between 22 nd and 24 th of June). Instead, in July there were three intervals in which the maximum temperature exceeded this threshold, for more than 3 days in a row (between 01 st - 06 th , 15 th - 22 nd , 24 th - 26 th of July), and August had the longest such intervals (between 03 rd – 06 th , 13 th – 29 th of August). Also, in August, there were four consecutive days with maximum temperatures that exceeded the heat wave threshold (26 th -29 th of August). Without achieving new absolute temperature records (the highest maximum temperature in this interval being 39˚C at the Iași meteorological station, on August 28 th ), the last heat wave was notable in terms of duration of manifestation. Considering the definition given by the World Meteorological Organization (WMO) in 2020, according to which heat waves are considered those periods of time that are unusually warm in relation to multi-year averages and that last more than 2 consecutive days, we can frame the tropical air advection of July and August in the category of heat waves.