ESD Reviews: Extreme Weather and Societal Impacts in the Eastern Mediterranean

Gaining a holistic understanding of extreme weather, from its physical drivers to its impacts on society and ecosystems, is key to supporting future risk reduction and preparedness measures. Here, we provide an overview of the state-of-the-art, knowledge 20 gaps and key open questions in the study of extreme weather events over the vulnerable eastern Mediterranean. This region is situated in a transition zone between subtropical and mid-latitude climates. Extreme weather is mainly governed by the largescale atmospheric circulation and its interaction with regional synoptic systems, i.e., Cyprus Lows, Red Sea Troughs, Persian Troughs, ‘Sharav’ Lows, and high-pressure systems. Complex orographic features further play an important role in the generation of extreme weather. Most extreme weather events, including heavy precipitation, cold spells, floods and wind 25 storms, are associated with a Cyprus Low or Active Red Sea Trough, whereas heat waves are related with either the Persian Trough and Sub-Tropical High-pressure systems in summer, or the ‘Sharav’ Low during spring time. Heat waves and droughts are projected to significantly increase in both frequency and intensity. In future decades, changes in heavy precipitation frequency and intensity may vary in sign and magnitude depending on the scale, severity and region of interest. There are still relatively large uncertainties concerning the physical understanding and the projected changes of cold spells, wind storms and 30 compound events, as these types of events received comparatively little attention in the literature. We further identify knowledge gaps that relate to the societal impacts of extreme weather. These gaps mainly relate to the effects extreme weather may have on mortality, morbidity and infrastructure in the eastern Mediterranean. Research is currently limited in this context, and we call to strengthen the database of analyzed case-studies. We trust that this can only be suitably accomplished by interdisciplinary and international regional collaborations, in spite of political unrest. 35

The Mediterranean region has been identified as a climate change 'hot-spot' (Giorgi 2006;Barcikowska et al., 2020), located in a transition zone between mid-latitude and sub-tropical climates. The eastern Mediterranean is characterized by persistent hot and dry weather conditions during summer and changeable temperatures and rainy spells during winter (Kushnir et al., 2017). The region is influenced by both mid-latitude, subtropical and tropical weather systems , which can 50 lead to a range of extremes including wind storms and hydrological and temperature extremes. Although the eastern Mediterranean is most commonly affected by heat waves and drought, it has also experienced several flood events and cold spells in recent decades.
Current regional climate projections indicate that the eastern Mediterranean may become warmer and drier in the future (e.g., Hochman et al., 2018c;Zittis et al., 2019;Cherif et al., 2020). Moreover, a tendency towards more frequent weather extremes 55 has also been projected (e.g., Samuels et al., 2018). From an environmental point of view, these kinds of extremes are often associated with enhanced flood (e.g., Tarolli et al., 2012;Zoccatelli et al., 2019) and drought potential (e.g., Cook et al., 2016).
In the last two decades, there has been a continuous increase in the number of studies on extreme weather events and their possible impacts on society and ecosystems in the eastern Mediterranean. The region has also been the focus of a number of review papers, dealing with climate variability (Finnè et al., 2011;Lelieveld et al., 2012), climate change impacts on health 60 (Khader et al., 2015), and atmospheric conditions conducive to heavy precipitation (Dayan et al., 2015). However, there has not yet been a review with a broad focus on extreme weather events and a synthesis of the potential future research directions to pursue.
The main objective of this manuscript is to review the state-of-the-art on extreme weather research in the eastern Mediterranean, with a specific focus on the physical understanding, observed trends and future projections. Moreover, we also 65 aim at identifying the key societal impacts associated with such extreme weather events under current and future climate conditions. The paper is organized as follows: Sect. 2 -5 summarize the current knowledge on temperature extremes (heat waves and cold spells), hydrological extremes (heavy precipitation and drought), wind extremes and compound events, respectively. Each https://doi.org/10.5194/esd-2021-55 Preprint. Discussion started: 9 September 2021 c Author(s) 2021. CC BY 4.0 License. extreme temperature indices (e.g., TX90p, TN90p), as reflected in regional climate simulations Zittis 135 et al., 2016;Hochman et al., 2018c). The frequency of cold spells is likely to decrease, and their severity and duration does not show significant changes (Kodra et al., 2011). Specifically, in the eastern Mediterranean and Middle-East, cold spells duration index is projected to decrease by about 3-5 days (RCP4.5 & RCP8.5), relative to the base period 1981-2000, by the end of the 21 st century (Fig. 3 b; Sillmann et al., 2013).
Since many heat wave and cold spell indices are percentile-based, it should be noted here that these indices are extremely 140 sensitive to the selected reference period, especially in a world characterized by continuous warming. As such, the decreasing trend in the magnitude of cold spells is further enhanced and the increasing trend in the magnitude of heat waves is further reduced when a warmer and more recent reference period, e.g., 1981-2010 is used, rather than a "colder" one e.g., 1961-1990(Yosef et al., 2021.

Societal Impacts 145
The current increasing trends in heat waves frequency and intensity, as well as the accelerated projected changes, will affect many sectors of society. For the health sector, heat waves can lead to increased hospital admissions and excess human morbidity and mortality, particularly among the elderly and infirm . A clear relationship between high temperatures and cardiovascular mortality by cerebrovascular disease, ischemic and other heart diseases has been found (Basu and Samet, 2002;Gosling et al., 2009;Lubczyńska et al., 2015). Agriculture and water supply systems are also vulnerable to 150 heat waves, through damage to crops and vegetation along with higher water demand (e.g., Papadaskalopoulou et al., 2020).
An increased energy consumption, e.g., greater demand for air conditioning in homes and offices, infrastructure stress and even shifts in touristic preferences due to the higher temperatures are also expected (Nairn and Fawcett, 2013;Naumann et al., 2020).
Specifically, Cramer et al. (2018) noted that the combination of the aforementioned impacts in the Mediterranean basin may exacerbate their magnitude or could produce successive, more frequent stress periods, which the least resilient countries would find difficult to cope with.

Physical understanding
Heavy precipitation events in the eastern Mediterranean are related to a variety of synoptic systems with distinct dynamics, moisture sources, precipitation yields, intensities, and scales ( Fig. 1 c, Alpert et al., 2004;Dayan et al., 2015;Armon et al., 2018). The frequency and intensity of heavy precipitation events display large regional and local variations (Kostopoulou and 170 Jones, 2005;Nastos and Zerefos, 2009) related to the dominant synoptic systems and to their interaction with local conditions de Vries et al., 2018;Armon et al., 2020).
On rare occasions, intense mesoscale vortices with dynamics similar to tropical cyclones influence the western parts of the 180 region ( Fig. 1 c; Zhang et al., 2019). These are commonly referred to as Mediterranean tropical-like cyclones, or 'Medicanes' -Mediterranean hurricanes (Miglietta, 2019). Medicanes develop in a way analogous to tropical cyclones, via wind-induced surface heat exchange (Emanuel, 1986;Miglietta and Rotunno, 2019). However, some recent studies have reported on cases with different development mechanisms (Mazza et al., 2017;Fita et al., 2018). Precipitation patterns resemble the ones of Mediterranean cyclones, albeit on smaller spatial scales (Flaounas et al., 2018a;Flaounas et al., 2018b;Zhang et al., 2019). In 185 some areas, Medicanes contribute up to 2-5% of extreme precipitation days (Zhang et al., 2019), and often have dramatic impacts even though they are very rare (~1 every 2 years; Nastos et al., 2018).
Except for the Mediterranean Sea, other sources of moisture can also lead to heavy precipitation in the eastern Mediterranean.
The Red Sea Trough is a stationary surface trough extending from the African Monsoon low over equatorial Africa toward the eastern Mediterranean. When associated with an amplified Rossby wave, this system is often termed an Active Red Sea 190 Trough. Under these conditions, it transfers abundant moisture from the Arabian and Red Seas to the eastern Mediterranean, leading to local torrential rains mostly during autumn ( Fig. 1 d and Fig. 2 c, d; Krichak et al., 1997a;de Vries et al., 2013;Armon et al., 2018;Baseer et al., 2019). Precipitation typically occurs in the form of numerous localized thunderstorms and mesoscale convective systems (Krichak et al., 1997b;Dayan et al., 2001;Belachsen et al., 2017;Marra and Morin, 2018).
Despite its relatively low occurrence frequency (<5% of the rainy days; Tsvieli and Zangvil, 2005;Awad and Almazroui, 195 https://doi.org/10.5194/esd-2021-55 Preprint. Discussion started: 9 September 2021 c Author(s) 2021. CC BY 4.0 License. 2016) and the low precipitation efficiency , Active Red Sea Troughs are responsible for ~38% of the flash floods in the semi-arid and arid regions of the Levant (Kahana et al., 2002;Dayan and Morin, 2006). Subtropical jet disturbances may occasionally bring moisture from equatorial regions or other sources to the eastern Mediterranean, in so-called 'tropical plumes' (Fig. 1 d; Rubin et al., 2007;Tubi and Dayan, 2014;Armon et al., 2018). Albeit rarely reaching the region (as only a few events are historically documented), subtropical jet disturbances are characterized by 200 high precipitation efficiency over regional scales, with widespread intense rainfall that may last for several days (Dayan and Abramski, 1983;Armon et al., 2018) and lead to significant impacts especially during autumn (Dayan and Morin, 2006).

Observed trends and future projections
Paleo-climatic evidence suggests the existence of important links between mean climatic conditions and occurrence and intensity of the different synoptic systems inducing heavy precipitation in the region (Enzel et al., 2003;Benito et al., 2015;205 Ahlborn et al., 2018;Armon et al., 2018;Ben-Dor et al., 2018;Armon et al., 2019;Morin et al., 2019;Lu et al., 2020). Our understanding of ongoing and future changes in heavy precipitation events, thus, stems from our ability to detect and predict changes in occurrence and intensity of all these systems (Toreti et al., 2010;Ziv et al., 2014;Merkenschlager et al., 2017;Marra et al., 2019b). Statistically significant trends in extreme precipitation have been indeed reported in recent years (Alpert et al. 2002;Nastos 210 and Zerefos, 2008;Yosef et al, 2009;Mathbout et al., 2018;Ajjur and Riffi, 2020), whose sign and level of significance depend on the studied area. Interestingly, some of these trends were not found to be significant about a decade ago (Zhang et al., 2005;Shohami et al., 2011;Ziv et al., 2014), suggesting that either the records were not long enough to robustly identify statistically significant trends (Morin, 2011), or that the trend has accelerated. Additionally, a complicated dependence of the fine-scale spatiotemporal structure of convective cells on temperature has been reported (Peleg et al., 2018b), implying that climate 215 change might also impact these characteristics.
Climate models consistently project a substantial decrease in the number of Mediterranean cyclones reaching the south-eastern portion of the Mediterranean basin (up to 35% decrease by the end of the 21 st century under the RCP8.5 scenario), along with a decrease in their mean daily precipitation yield (Pinto et al., 2007;Kelley et al., 2012;Zappa et al., 2015a;Hochman et al., 2018aHochman et al., , 2018bHochman et al., , 2020bSamuels et al., 2018). A slight increase in the occurrence frequency of Red Sea Troughs has been 220 reported, accompanied by a decrease of their typical intensities (Zappa et al., 2015a;Hochman et al., 2018aHochman et al., , 2021bSaaroni et al., 2020), although there is still a debate on whether the number of Active Red Sea Troughs is actually decreasing (Hochman et al., 2021b). A decrease in the occurrence frequency of Medicanes is also estimated, together with some evidence for an increase in their intensity (Cavicchia et al., 2014;Romera et al., 2016;Tous et al., 2016;González-Alemán et al., 2019), with yet to be studied impacts on the emerging extremes (e.g., Hosseini et al., 2020). To the best of our knowledge, climate change 225 impact studies on Subtropical Jet disturbances are not yet available. Overall, the sign and significance of changes in heavy precipitation events are still unclear, due to the large uncertainties inherent in the analysis of extreme events (Fatichi et al., https://doi.org/10.5194/esd-2021-55 Preprint. Discussion started: 9 September 2021 c Author(s) 2021. CC BY 4.0 License. 2016; Peleg et al., 2018a;Zittis et al., 2020). Recent findings suggest the sign of change might depend on the event severity, with increasing trends for larger extremes and decreasing trends for smaller, but still rare, intensities. The rarest extremes may thus increase in intensity in spite of the decrease in both occurrence and typical intensity of Mediterranean cyclones, and of 230 the decreased intensity of Active Red Sea Troughs (Fig. 3 c; Marra et al., 2021a). The analysis of synoptic systems in climate models, via detection and tracking algorithms (e.g., Neu et al., 2013;Lionello et al., 2016;Hochman et al., 2019;Saaroni et al., 2020), could help in understanding their future response to climate change, with important implications for the quantification of heavy precipitation event frequency.
Owing to the small spatiotemporal scales of precipitation patterns and their effects on the ground, documenting the local impact 250 of heavy precipitation requires high-resolution observations from weather radars, satellites and cellular links to complement in-situ measurements, as well as post-event surveys (Messer et al., 2006;Morin et al., 2007;Koutroulis and Tsanis, 2010;Miglietta et al., 2013;Amponsah et al., 2018;Rinat et al., 2018;Borga et al., 2019;Diakakis et al., 2019;Varlas et al., 2019;Laviola et al., 2020;Rinat et al., 2021). Atmospheric indices can sometimes provide valuable information at the regional scale (Morsy et al., 2020), but effective forecasting of local impacts is still challenging due to the small scales and short response 255 times of the basins (Collier, 2007;Morin et al., 2009;Borga et al., 2014;Zoccatelli et al., 2020). Recent developments in convection-permitting modeling and nowcasting techniques may lead to improvements (e.g., Coppola et al., 2020), but forecasting the location of small-scale extreme occurrences remains elusive and proper forecasting should adopt probabilistic ensemble approaches (Toros et al., 2018;Armon et al., 2020;Spyrou et al., 2020;Rinat et al., 2021). Risk assessment generally relies on precipitation frequency analysis and intensity-duration-frequency curves (Koutsoyiannis 260 et al., 1998;Koutsoyiannis and Baloutsos, 2000;Ben-Zvi, 2009;Fathy et al., 2020;Nastos et al., 2020), while envelope curves are often used to identify regional upper limits for flood peak discharge (Tarolli et al., 2012;Amponsah et al., 2020). However, the coastal, orographic, and climatic structure of the region, together with the typically small scales of high-impact events and with the relatively scarce availability of long observational records, make extreme frequency analysis challenging (Peleg et al., 2018b;Diakakis et al., 2020;Metzger et al., 2020). The presence of heavy precipitation associated 265 with different synoptic systems and characterized by different scales, intensities and interactions with local features, makes the quantification of risk even more challenging. As such, novel statistical techniques may help in isolating and quantifying trends (Miniussi and Marani, 2020), as well as in understanding the underlying mechanisms (Marra et al., 2019b). Additionally, they could leverage the distributed information from remotely sensed datasets to improve our understanding of the impact of local conditions on the development and statistics of extremes (Marra et al., 2019a;Marra et al., 2021b). 270

Physical understanding
Droughts are periods of abnormally dry conditions, long enough to cause a serious hydrological imbalance (https://glossary.ametsoc.org/wiki/Drought). They can occur at any time or any place in the world and are considered natural disasters. They are generally classified into four categories: (i) meteorological, (ii) agricultural, (iii) hydrological, and (iv) 275 socio-economic droughts (Wilhite and Glantz, 1985). A more recent definition also includes ecological droughts (Crausbay et al., 2017). The timescales of interest depend on the impact under investigation, and usually range from weekly to multiannual.
Here, we primarily focus on meteorological droughts, which are very relevant for the eastern Mediterranean that frequently experiences prolonged dry weather periods. The eastern Mediterranean is located at subtropical latitudes, in which highpressure systems suppress cloud formation and precipitation, particularly during summer. Exceptions can occur in high-280 elevation areas in the northern parts of the eastern Mediterranean (mainly in southern Balkans and Anatolia), where orography and/or convective activity can trigger precipitation also during summer (Funatsu et al., 2009). Prolonged dry periods in the eastern Mediterranean can also occur in other seasons, but these are mainly driven by internal climate variability and largescale modes or teleconnections that can suppress cyclogenesis within the Mediterranean or can shift storm tracks to northern latitudes (Sousa et al., 2011). Spring and summer droughts in the Middle-East have been associated with negative phases of 285 the North Atlantic Oscillation (Vicente-Serrano et al., 2011), while an opposite correlation is found over parts of Turkey and Greece for winter, spring and summer droughts (Sousa et al., 2011;Vicente-Serrano et al., 2011). The East Atlantic Pattern shows a similar spatial footprint to the North Atlantic Oscillation, albeit only for winter droughts, with positive correlations over the western part of the eastern Mediterranean. Remote sea surface temperature anomalies, primarily over the Atlantic, may also show a teleconnection with compound drought occurrences in this region (Sousa et al., 2011). 290 While lack of precipitation is the main driver of droughts, other meteorological variables such as abnormally high temperatures, radiation, evapotranspiration, or low soil moisture can augment drought severity. Besides, due to the growth of population and expansion of agricultural, energy and industrial sectors, the water demand has increased manifold and water scarcity has been occurring almost every year in many parts of the world including in the eastern Mediterranean (Mishra and Singh, 2010).
Several metrics for assessing drought frequency and severity have been proposed. Some of the most widely-used are: the 295 percentage of normal precipitation, the number of Consecutive Dry Days (CDD), the Palmer Drought Severity Index (PDSI), the Standardized Precipitation Evaporation Index (SPEI), the Standardized Precipitation Index (SPI), the Aridity Index (AI), the Standardized Runoff Index (SRI), the Supply-Demand Drought Index (SDDI), and more (WMO/GWP, 2016 and references therein). These indicators are usually based on station observations. Likewise, gridded observations, satellite-based, or reanalysis products are often used for assessing droughts. In such cases, observational uncertainty due to the lack of reliable 300 and consistent observations in the region should be taken into consideration (Zittis, 2018).

Observed trends and future projections
Observed droughts are mostly found to be driven by natural variability, yet the role of climate change in triggering or enhancing droughts has increased in recent decades (Hoerling et al., 2012). A large number of studies based on observations or climate reconstructions investigated past trends of droughts in the eastern Mediterranean region. While the sign and significance of 305 trends strongly depend on the time period under consideration, the majority of analyses suggest an ongoing transition to future drier conditions. Based on wintertime precipitation reconstructions and observations, Lelieveld et al. (2012) provided evidence that the eastern Mediterranean dry period, which started in the early 1960s, was the driest period of the last 500 years. Recent high-impact droughts have thus received great attention, e.g., the 15-year drought in the Levant (1998Levant ( -2012 is the driest period in observational records, and it is very likely drier than any comparable period of the last 900 years (Cook et al., 2016). 310 Nevertheless, considering the 20 th century as a whole, it was one of the wettest periods over the late Holocene , highlighting the strong temporal variability and the dependence on the period under consideration when assessing past changes (Nicualt et al., 2008). The recent severe Syrian drought has become more than twice as likely as a consequence of human interference in the climate system (Kelley et al., 2015). Philandras et al. (2011)  A number of studies have associated anthropogenic climate change with an expansion of the Hadley Cell in annual average 330 and poleward shift of storm tracks that weaken the westerlies at mid-latitudes (e.g. Lu et al., 2007). Since Mediterranean cyclones are a major precipitation-producing weather system in the region (Pfahl et al., 2014;Flaounas et al., 2018b), this feedback mechanism induces regional drying (Seager et al., 2019). About 85% of the area-averaged Mediterranean wet-season precipitation reduction is attributed to such atmospheric circulation responses (Zappa et al., 2015b). However, the significance of this response is still under debate (e.g. Shaw et al., 2016;Garfinkel et al., 2020). Precipitation projections for the eastern 335 Mediterranean are mainly characterized by relatively low levels of significance and robustness Zittis et al., 2019). Mostly, when it comes to RCP8.5 (business-as-usual pathway) and middle-to-end-of-century estimations, a strong and significant precipitation decrease is projected (Samuels et al., 2018;Cherif et al., 2020). However, droughts are also driven by temperature (and thus evapotranspiration) increases, which are found to be quite robust. Future projections for drought risk, expressed in terms of the Palmer Drought Indices, indicate a significant decrease in soil moisture for all seasons, as well as 340 increases in the severity and length of future droughts (Dubrovský et al., 2014;Liu et al. 2018). Based on global climate projections, Touma et al. (2015) underline that the spatial extent, occurrence, and duration of exceptional droughts are projected to increase in subtropical regions (including the eastern Mediterranean) in the 21 st century. Spinoni et al. (2020) utilized regional climate model output and created global SPEI projections. They concluded that the Mediterranean, including its eastern part, is among the global hot-spot areas for severe droughts in the future. They also highlighted the role of temperature 345 and evaporation in future events. Up to 60% additional days of drought conditions, resulting in an increase of about 20-40% in the number of dry years, are expected for the region (Prudhomme et al., 2014;Driouech et al., 2020). Climate projections based on a European modeling domain, that however includes parts of the eastern Mediterranean (Balkans and Anatolia), suggest a robust increase in the length (up to 3-4 additional weeks) and severity of extreme dry spells for the future (Jacob et al., 2014;Spinoni et al., 2018). Similarly, Tabari and Willems, (2018) concluded in expecting less frequent rainy days and 350 prolonged dry periods for the future in the eastern Mediterranean countries. Country-based, high-resolution projections (e.g. for Israel and Cyprus) also highlight that drought indicators, such as consecutive dry days, are projected to increase in future decades (Hochman et al., 2018c;Zittis et al., 2020). While most models agree on an increase in the frequency and severity of drought episodes over the eastern Mediterranean, there is still a large uncertainty depending on the chosen definition of drought, future socio-economic scenario and climate model (e.g., Cook et al., 2014;Dubrovský et al., 2014;Yves et al., 2020). 355

Societal Impacts
Drought impacts are expected to increase in the future, in particular for developing countries in the southern and eastern parts of the Mediterranean (Tramblay et al., 2020). Socio-economic sectors and ecosystems affected by high-impact droughts include domestic water supply, agriculture, livestock production, leisure activities, hydroelectric power production, 360 biodiversity and more. Therefore, the water-food-energy nexus in the broader Mediterranean region is disturbed in various ways when prolonged drought events occur (Lange, 2019;Markantonis et al., 2019). Moreover, parts of the eastern Mediterranean are characterized by pronounced inequalities, and the poor are expected to suffer most from climate change impacts on water and other resources (Waha et al., 2017). For example, the vulnerability of livestock production systems to droughts was recently demonstrated in north-eastern Syria, where herders lost almost 85 % of their livestock as a result of the 365 drought of 2005-2010 (Waha et al., 2017). The amount and quality of water resources are critically affected by prolonged droughts. Such recent events have led to irreversible salinization processes in the aquifers and negative ecological conditions in the Sea of Galilee, Israel (Inbar and Bruins, 2004). Furthermore, projected population and land-use changes are expected to exacerbate the effects of warmer and drier climatic conditions (Spinoni et al., 2020). If the internal water footprint (i.e. total volume of freshwater used to produce the goods and services consumed) of the eastern Mediterranean countries declines in 370 line with precipitation, and the total water footprint of the region increases in line with population, by 2050 as much as half of the total water requirements will need to be provided through desalination and imported water (Chenoweth et al., 2011). The projected transition to warmer and drier bio-climatic conditions will severely affect agriculture, and thus food production, which is particularly vulnerable to drought. Mediterranean crops, e.g. olives, vines and wheat, will be strongly influenced by the combined effect of summer droughts and heat stress (Sen et al., 2012;Constantinidou et al., 2016;Papadaskalopoulou et 375 al., 2020). Interestingly, for some crops, agricultural production in high-altitude regions might be positively influenced. Still, for some eastern Mediterranean agroecosystems, the projected climatic pressure lies outside the limits of resilience (Daliakopoulos et al., 2017). Moreover, severe droughts can favor the preconditions for forest fires, predominantly during the warm and dry part of the year. Summer fires frequently rage across the Mediterranean, often intensified by high temperatures and droughts that are found to regulate fuel moisture (Turco et al., 2017a). Nevertheless, droughts also control fuel availability, 380 making the relationships between fire activity and weather conditions more complex (Turco et al., 2017b). For eastern Mediterranean forests, days with critical fire risk, length of fire season, burnt areas, etc. are expected to increase in the 21 st century, mainly under business-as-usual pathways Çolak and Sunar, 2020;Dupuy et al., 2020). Finally, limitations in water resources due to prolonged drought events and associated impacts are found to trigger or augment conflicts and disputes in the region (Gleick, 2014;Kelley et al., 2015). Regional economic, political, demographic and social drivers, 385 as well as environmental stressors, such as drought, could result in forced migration flows and climate change acts as a trigger favorable to this direction (Black et al., 2011;Tabari and Willems, 2018;Abel et al., 2019). However, there is still a controversy as to the extent to which droughts may influence conflict and political unrest (e.g. Boas et al., 2019).

Wind extremes 390
Surface winds arise from pressure gradients in the atmosphere and are a fundamental component of weather and climate. They are key in controlling air-sea and air-land exchanges of heat, water and chemical constituents, and can pose an immediate societal threat due to direct damage of strong winds and wind gustiness (e.g., Klawa and Ulbrich, 2003;Pinto et al., 2012).
Understanding the variability of winds is vital for estimating wind energy potential (Shata and Hanitsch, 2006;Hueging et al., 2013;Drobinski et al., 2018), and for managing air quality and health aspects (Georgiou et al., 2018), among many others. 395 Understanding the mechanisms underlying the spatial-temporal variability of winds, their extremes and future trends is therefore key for understanding Earth systems interactions, and for reducing societal risks from extreme events, while preparing for their future changes.
In the eastern Mediterranean, strong surface winds of velocities exceeding 20 m s -1 are typically associated with cyclones and prevail predominantly in the winter months. Such intensities can also be found in autumn and spring, and are almost completely 400 absent in the summer months according to 9 years of QuickSCAT data (Chronis et al., 2011), or by estimation of 10-m wind gust anomalies in the ERA-Interim reanalysis (Raveh- Rubin and Wernli, 2015). Using a process-based definition, namely 10m wind speed exceedance of the 98 th percentile in the vicinity of a cyclone, on average, 3-4 extreme wind storm days occur per extended winter season in most eastern Mediterranean locations (Nissen et al., 2010(Nissen et al., , 2014. Strong winds in the eastern Mediterranean are mostly westerly (or north/south westerly) or easterly (Chronis et al., 2011). 405 Naturally, as inferred from the marine or continental pathway of the air masses involved and the orientation of the easternmost Mediterranean coastline, strong westerly and easterly winds in the region differ substantially in their characteristics and impact ( Fig. 5). Westerlies peak upon the passage of Mediterranean cyclones, and are often accompanied by moist flow and heavy precipitation over land (see Sect. 3.1.1; Saaroni et al., 2010;Raveh-Rubin and Wernli, 2015;Martius et al., 2016;Berkovic et al., 2021). Strong easterlies, also peaking in winter, occur at ~10% yearly frequencies very locally in Israel, with wider regions 410 experiencing such winds ~1.4% of the time (Saaroni et al., 1998). The easterly regime has a strong signature away from the Mediterranean coast, such as over the Judean and Samarian Mountains, where the opposing sea breeze is uncommon (Fig. 5 d; Saaroni et al., 1998;Berkovic, 2017).
An immediate impact of strong winds in coastal regions is the potential emergence of storm surges. In the eastern Mediterranean, typically 4-6 events per year occur, based on in-situ data and numerical modeling of storm surges in Alexandria, 415 Egypt (Cid et al., 2016). However, Androulidakis et al. (2015) showed that storm surges in Alexandria, manifested as sea-level height anomalies, do not reach 20 cm and are thus more moderate, compared to other coastal regions in the Mediterranean basin (e.g., Conte and Lionello, 2013). During these times, the wind direction is more often westerly and southerly, compared to climatology, when northerlies dominate. In Hadera, Israel, wind direction during high sea level is anomalously southerly and easterly, compared to climatology, which is dominated by northerly and westerly winds (Androulidakis et al., 2015). An objective classification of the winter surface winds in Israel was shown to be strongly linked to the regional circulation induced by the dominant synoptic systems (Berkovic, 2017). In a systematic classification of radiosonde data from Bet-Dagan, Israel, Berkovic et al. (2021) distinguished recurring winter regimes of boundary-layer profiles, including wind magnitude and direction. The strongest surface winds were southwesterly, with mean magnitudes of 10 m s -1 , followed by less extreme (north) 435 westerly (3-4 m s -1 ) and more moderate easterly or northeasterly directions. Generally, winds under a southwesterly regime were directly linked to the location of the Cyprus Low and the pressure gradient it induces, situations combined with cold temperatures and heavy precipitation (Fig. 5 a, b; see Sect. 2.1 and 3.1.1).
Based on the 10 most extreme large-scale wind gust events in the eastern Mediterranean, Raveh-Rubin and Wernli (2015) found winds peaking upon a substantial regional drying (up to 4 kg m -2 reduction of total column water), cooling of the lower 440 troposphere by 6 K and strengthening of a northerly wind component (i.e., generally westerly winds become northwesterly), over the course of the 36-h leading to peak winds. Such a change is a result of the passage of an upper-tropospheric trough and a surface cyclone ahead of a ridge in the upper troposphere. Focusing on a combined extreme wind and precipitation case in 11 December 2010, Raveh- Rubin and Wernli (2016) showed that, similar to other cases in the Mediterranean, the air masses of strongest winds exhibit a backward-trajectory pathway reminiscent of the cold conveyor belt concept, namely, lower-445 tropospheric jet turning cyclonically around the cyclone center on its cold side (e.g., Smart and Browning, 2014). In addition, wind gust hotspots may also prevail due to deep moist convection embedded in the cyclone's cold air mass that destabilizes above the warm Mediterranean Sea (Ziv et al., 2009;Raveh-Rubin and Wernli, 2016).
In contrast, strong easterlies occur under dry and relatively warm winter conditions induced by a high-pressure system to the north east, often accompanied by the surface Red Sea Trough (Fig. 5 c, Saaroni et al., 1998;Berkovic, 2017). During strong 450 easterlies, quasi-stationary anticyclones with variable locations over Asia or at times, over eastern Europe, exhibit ridge disturbances into the Levant (Saaroni et al., 1996).
Interestingly, high sea level in Alexandria and Hadera is only weakly directly correlated with wind speed or sea-level-pressure (Androulidakis et al., 2015). Although the wind influence on surges in the eastern Mediterranean is weaker compared to northwestern Mediterranean areas, surges in Alexandia, Egypt, and İskenderun, Turkey, are associated with increased frequency of 455 Mediterranean cyclones (Lionello et al., 2019). In their study, based on hindcasts of the 100 most extreme surge events in Alexandria and İskenderun using a barotropic ocean circulation model forced by ERA-Interim downscaled fields, cyclones were frequent in the southeastern and northeastern parts of the Mediterranean, respectively. Detailed mechanistic association between anomalous surface winds, storm surges and the relation to the life cycles of weather systems in the region is generally underexplored. 460

Observed trends and future projections
A decrease in surface wind speeds over land areas in the northern hemisphere have been observed in recent decades, termed wind stilling (McVicar et al., 2012), and in this respect the eastern Mediterranean is no exception, displaying reductions between 0.001 m s -1 y -1 in Greece (1959Papaioannou et al. 2011) to 0.04 m s -1 y -1 in Cyprus (1982Jacovides et al. 2002). However, no consensus has been reached regarding the most extreme winds (Drobinski et al., 2018). Indeed, it 465 should be noted that observed trends of extreme winds have generally received less attention in the literature with respect to e.g., extreme temperatures and precipitation.
A decrease of 2-3 m s -1 by the end of the 21 st century was indicated for the 99.5 percentiles of the 925-hPa winds using the ECHAM5 global climate model (Bengtsson et al., 2009). The trend is consistent with earlier projections of a decrease in intense windstorms in the region (e.g., Pinto et al., 2007). As already discussed, a significant reduction in winter cyclone activity is 470 expected in the Mediterranean region, and in the eastern Mediterranean in particular (e.g., Zappa et al., 2015a;Hochman et al., 2018b). However, uncertainty remains with regard to future projections of the most intense cyclones, with some studies indicating a decrease of cyclone intensities (e.g., Pinto et al., 2007), or frequency (e.g., Nissen et al., 2014;Hochman et al., 2020d). Nissen et al. (2014) focus on windstorms associated with cyclones, suggesting a decrease by 0.5-1 extreme windstorm days per winter season by the end of the 21 st century, from the current mean of ~4 days. The decrease is attributed to reduced 475 cyclone intensities and emerges despite a local increase in cyclone numbers in the eastern Mediterranean in their models (Nissen et al., 2014). However, the return periods of the most severe storms do not change, suggesting that despite their general decrease, windstorms remain an important risk in the region (Nissen et al., 2014). Thus, regional projections of strong winds may be highly threshold-dependent, warranting continued investigation.  (Hueging et al., 2013;Tobin et al., 2015;Mömken et al., 2018;Dafka et al., 2019). Multiple numerical experiments under future scenarios suggest that mean and peak sea-level height trends in the eastern 485 Mediterranean (especially in the northeastern corner) are strongly controlled by sea-level-pressure changes, while mean sealevel height is additionally affected by changes of winds (Androulidakis et al., 2015). Therefore, the expected reduction of storms during the 21 st century suggests a reduction in the area susceptible to sea-level rise extremes (Androulidakis et al., 2015), further suggesting decreasing storm surge rates of ~2% (Cid et al., 2016).

Societal impacts 490
Strong moist winds in winter, often occurring in combination with heavy precipitation, pose the highest societal risk from severe weather in the region (e.g., Llasat et al., 2010), with human casualties and widespread damages. Easterly winds impact agriculture significantly due to their unusual dryness, with warm advection increasing evaporation rates, and cold advection often leading to frost (Saaroni et al., 1996). Occasionally, easterlies are conducive to air pollution, intensifying forest fires and dust and sand storms (Saaroni et al., 1998). There is a lack of systematic studies estimating losses due to winds, wind power 495 potential, especially considering future trends over the south-eastern part of the region (Drobinski et al., 2018). Indeed, the north-western part of the region has received relatively large attention (e.g., Hueging et al., 2013;Tobin et al., 2015;Mӧmken et al., 2018). Altogether, the different hazards imposed by surface winds and their tight involvement in planning decisions, necessitates a better understanding of the underlying mechanisms controlling their variability and trends, in order to better predict extreme wind events on weather and climate scales. 500

Physical understanding
The term 'compound extremes' refers to the combination of multiple extreme events or of multiple drivers that lead to an extreme. Crucially, their combined impact often exceeds the linear sum of their components (Zscheischler and Seneviratne, 2017). Some authors extend the term 'compound' to include temporally clustered or simultaneous but geographically remote 505 events (e.g., Vahedifard, 2016;Baldwin et al., 2019). Here, we focus on the conventional case of spatially and temporally cooccurring drivers or extremes, such as heavy precipitation and strong storm surge leading to extreme flooding or co-occurring high temperatures and high atmospheric humidity. In the latter example, the heat stress, and thus the impacts on the local population, will be more severe than if a very hot and a very humid day had occurred independent of each other (e.g., Sherwood and Huber, 2010). 510 In the eastern Mediterranean, the most impactful compound extremes are those resulting from a combination of temperature and/or hydrological extremes, although other extremes may also show compounding behavior, such as windstorms combined with heavy precipitation (see Sect. 4.1.1;Nissen et al., 2010;Raveh-Rubin and Wernli, 2015;Catto and Dowdy, 2021). The eastern Mediterranean routinely experiences very high summertime temperatures (see Sect. 2) and, although it is generally associated with a dry climate, high ambient humidity levels can be reached locally (e.g., Unal et al., 2013). From a mesoscale 515 atmospheric perspective, hot and humid summertime extremes are favored by a stable low-level atmosphere, which traps near-https://doi.org/10.5194/esd-2021-55 Preprint. Discussion started: 9 September 2021 c Author(s) 2021. CC BY 4.0 License. surface moisture (Ziv and Saaroni, 2011). Regional sea surface temperatures may also play an important role, through the strengthening or maintenance of anticyclonic circulations associated with descending motions and cloud-free skies (see Sect. 2; Unal et al., 2013), and enhancing moisture supply. On a larger scale, the hot and humid extremes are associated with the advection of air masses from southern continental Europe, which undergo adiabatic descent over the eastern Mediterranean,520 and the presence of an upper-level trough (Hochman et al., 2021a). However, we note that the latter authors based their analysis on an index combining temperature and humidity with additional atmospheric parameters, such as the height of the marine inversion.
Although comparatively rare, wintertime cold spells also have severe impacts on the eastern Mediterranean (see Sect. 2), and can be associated with heavy precipitation in the form of snowfall. Such events are often favored by a concurrent upper-level 525 anticyclone over northern or western Europe and a cyclone over the eastern Mediterranean, which together drive the transport of cold air masses to the region, whose moisture and stability properties are affected by the land-sea distribution they encounter along their path (e.g. Alpert and Reisin, 1986;Tayanç et al., 1998). However, the details of the cold air mass transport can differ significantly between individual cold-snowy episodes (Fig. 1 b). The early-winter episode of 1982 described by Alpert and Reisin (1986), which lead to one of few recorded November snowfall events in Israel, was associated with northerly 530 advection. Storm Alexa in December 2013, associated with heavy snowfall in Jerusalem, displayed a similar advection pathway linked to a Cyprus Low type circulation (Fig. 2 a, Hochman et al., 2020d). In contrast, the notable March 1987 cold spell and heavy snowfall, which was particularly severe in Greece and Turkey (as well as in much of the Balkan peninsula), was associated with a north-easterly advection (Tayanç et al., 1998), a characteristic similar to the majority of snowfall events in Athens over the second half of the 20th century (Houssos et al., 2007). A climatology of cold spells leading 535 to snowfall in Jerusalem shows yet a different pattern, with a median north-westerly advection pathway (Hochman et al., 2020d).
Shifting the focus to hydrological extremes, the eastern Mediterranean region is vulnerable to both compound drought and compound flooding episodes. One of the chief sources of compound flooding is the combination of heavy precipitation and strong storm surge in coastal areas. The Mediterranean in general, and the eastern Mediterranean in particular, emerge as 540 regions with a high probability of compound flooding occurrence, associated with the presence of deep low-pressure systems in the region (Bevacqua et al., 2019). Compound drought events are mainly investigated through multivariate drought indices (see Sect. 3.2.1). An intuitive example of a compound drought would be the case where a precipitation deficit co-occurs with unusually high temperatures (e.g. Vogel et al., 2021).

Observed trends and future projections 545
The frequency and duration of heat waves has been increasing in the eastern Mediterranean in recent decades, a trend which is projected to continue in the future, on the background of global warming (Fig. 3 a; see Sect. 2.2). Relative humidity is also expected to show an increasing trend in the region, due to increased lower-level stability (Ziv and Saaroni, 2011). Assuming no change in the statistical relation between temperature and humidity, these two concomitant increases point to an increased occurrence of hot-humid extremes in the eastern Mediterranean. These changes are already visible in the observational record 550 (Ziv and Saaroni, 2011;Unal et al., 2013), and there is evidence for a generalized future increase in heat stress risk across the eastern Mediterranean (e.g., Ahmadalipour and Moradkhani, 2018), with coastal areas being particularly exposed (Diffenbaugh et al., 2007). On the other hand, the frequency of cold spells is projected to decrease globallyalbeit less than may be naively expectedand in this respect, the eastern Mediterranean will be no exception (see Sect. 2). We are however not aware of any studies focusing specifically on future projections of compound cold-snowy events over the region. 555 Large uncertainties still impair our understanding of changes in hydrological extremes over the eastern Mediterranean (see Sect. 3). Models disagree on future changes in compound flooding over the region, and range from moderate increases to strong decreases in the return period of such events (Bevacqua et al., 2019). Observed trends in multivariate drought indices have been the subject of heated discussion in the literature (e.g., Seneviratne, 2012), and studies focusing on the eastern Mediterranean reflect the large uncertainty on the topic (see Sect. 3.2.3). One projection that appears more robust is that of an 560 increased co-occurrence of compound precipitation deficits and high temperatures, which is primarily driven by the increasing frequency and severity of heatwaves (Vogel et al., 2021). Indeed, a positive trend in such events has been observed across most of the eastern Mediterranean in recent decades (Mukherjee and Mishra, 2021).

Societal impacts
Compound extremes in the eastern Mediterranean are already imposing a heavy socio-economic toll. Combined temperature-565 humidity extremes in Greece reached warning levels for public health and the ability of the workforce to carry out normal tasks already in the 1980s (Giles et al., 1990). Although in warm regions one may expect the local population to have developed some degree of acclimatization, cities like Tel-Avivand to a lesser degree Athensdisplay an average summertime temperature-humidity level that is very close to the threshold beyond which an impact on mortality can be observed. This makes these cities vulnerable to even moderately extreme temperature-humidity events already under current climate 570 conditions (Leone et al., 2013). Studies further point to a manifold increase in mortality risk due to temperature-humidity extremes across the eastern Mediterranean by the end of the century, even under moderate climate change scenarios (Ahmadalipour and Moradkhani, 2018). On the opposite end of the scale, cold-snowy events can also have severe impacts on the eastern Mediterranean. For example, the 2013 'Alexa' snow storm ranked as the costliest natural disaster in the region, with an estimated cost of $100 million (https://ims.gov.il/sites/default/files/2020-09/sumdec10_14_2013.pdf). Compound 575 flooding and compound droughts (see Sect. 5.1) in the eastern Mediterranean have repeatedly had detrimental effects on the local population. The former has the potential to damage coastal infrastructure and environments (e.g., the 2010 compound flood in Alexandria, see also Ismail et al., 2012). The latter can compromise food security and may have a role in favoring regional conflicts. As most studies focusing on societal impacts of droughts do not explicitly consider the compound nature of drought, we discuss these in depth in Sect. 3.2. 580 As evident from the above discussion, there is considerable literature on compound extremes in the eastern Mediterranean.
However, a large number of studies only implicitly consider the compound nature of the extremes, for example through the use of multivariate heat stress or drought indices, and do not focus on the dependency of the different variables in favoring the extremes in current and future climates. A clearer focus on the role of concurrent anomalies in several variables or drivers may help in advancing our understanding of compound extremes in the region. 585

Summary and knowledge gaps
Extreme weather in the eastern Mediterranean has detrimental effects on society and ecosystems. Here, we provide a review of the state-of-the-art and knowledge research gaps on this subject. We specifically focus on the physical processes that drive extreme weather, the observed trends and future projections of such events, and finally, the societal impacts these types of events may have. 590 Extreme weather in this region is connected with the governing synoptic systems and their interplay with the large-scale atmospheric flow. The eastern Mediterranean has experienced repeated extreme heat waves in the recent past (Kuglitsch et al., 2010), and their frequency, duration and intensity are projected to increase in the coming decades (Fig. 3 a; e.g., Seneviratne 2012; Lelieveld et al., 2016;Hochman et al., 2018a). Summer heat waves are commonly associated with a shallow Persian Trough at surface levels and a persistent upper-level anticyclone (Fig. 2 e, f). Accordingly, hot air masses are transported to 595 the eastern Mediterranean from continental Europe or the Iranian plateau and undergo adiabatic heating (Fig. 1 a; e.g., Hochman et al., 2021a). Spring heat waves on the other hand are related to the 'Sharav' Low, a low-pressure system migrating along the southern coast of the Mediterranean Sea. When reaching the eastern Mediterranean, together with an upper-level anticyclone, it transports extremely hot and dry air masses from the Sahara, inducing short-lived, but intense heat waves and dust storms ( Fig. 1a and Fig. 2 g, h; e.g., Alpert and Ziv, 1989). Due to their relatively low occurrence, 'Sharav' Lows have 600 received relatively little attention in the literature. On the other hand, winter cold spells are linked either with a persistent upper-level Ω-shaped anticyclone over eastern Europe and a Cyprus Low at surface-level, transporting cold and moist air from the North (e.g., Hochman et al., 2020d), or with an anticyclone over Siberia, transporting cold and dry air masses from that region (Fig. 1 b; e.g., Saaroni et al., 1996). The frequency and duration of cold spells in the eastern Mediterranean are projected to decrease in the coming decades (Fig. 3 b; Sillmann et al., 2013). It should, however, be noted that eastern Mediterranean 605 cold spells have received comparatively little consideration in the literature, perhaps due to the naive assumption that they will no longer occur in a warmer climate.
The majority of extreme weather events, including heavy precipitation and intense westerly wind storms, are associated with Cyprus Lows (Fig. 1 c and Fig. 2 a, Alpert and Reisin, 1986;Nissen et al., 2010). Cyprus Lows are cyclones that tend to develop in the vicinity of Cyprus when cold air is steered by an upper tropospheric mid-latitude disturbance over the warm 610 Mediterranean Sea and then becomes moist and unstable (e.g., Alpert and Reisin, 1986). Similar to other Mediterranean cyclones, Cyprus Lows have been projected to significantly decrease in frequency, persistence and accompanied daily https://doi.org/10.5194/esd-2021-55 Preprint. Discussion started: 9 September 2021 c Author(s) 2021. CC BY 4.0 License.
precipitation amounts under increased greenhouse gas concentration pathways (e.g., Hochman et al., 2018a;2020b). The Red Sea Trough, when accompanied by an upper-level trough or cut-off low, may favor the development of localized heavy precipitation events and flooding mostly in semi-arid to arid regions ( Fig. 1 d and Fig. 2 c, Krichak et al., 1997a;de Vries 615 et al., 2013;Baseer et al., 2019), and occasionally intense easterly wind storms (Fig. 5 c, e.g., Berkovic, 2017). This situation, often denominated Active Red Sea Trough, has recently received ample attention, particularly since there is an ongoing debate on how an increase in greenhouse gas concentrations will influence the frequency and intensity of this system (Alpert et al., 2004;Peleg et al., 2015a;Saaroni et al., 2020;Hochman et al., 2021b;Marra et al., 2021a). We note here that there is relatively little literature related to the physical understanding, observed trends, and future projections of wind extremes in the south-620 eastern part of the eastern Mediterranean.
Compound extremes in the eastern Mediterranean are often linked either with very hot and humid conditions during summer, especially close to the Mediterranean coast, or cold and wet episodes during winter. Hot and humid summertime extremes are induced by a stable atmosphere, which traps near-surface moisture (e.g., Ziv and Saaroni, 2011), whereas, cold and wet winter extremes are again mainly associated with the Cyprus Low system (e.g., Hochman et al., 2020d;see above). Hot and humid 625 extremes are projected to increase in frequency and intensity (e.g., Unal et al., 2013). To the best of our knowledge, studies focusing specifically on future projections of compound cold and wet events over the eastern Mediterranean are not yet available.
Extreme weather events impose socio-economic tolls (IPCC 2013). These are further aggravated in vulnerable regions, such as the eastern Mediterranean (e.g., Lelieveld et al., 2012). Except for cold spells and wind extremes, most of the extremes we 630 focus on in this manuscript are expected to increase in both frequency and intensity in future decades. The situation is more complex for extreme precipitation, whose intensity is projected to increase for the small (convective) spatial and temporal scales and decrease at the larger scales. Four key ways to increase societal resilience to extreme weather are to: ⅰ) reduce the probability of extreme weather by timely mitigation of hazardous climate change; ⅱ) improve the ability to forecast extreme weather and its impacts using conventional and/or novel techniques and early warning systems (e.g., Hochman et al., 2020d;635 2021a); ⅲ) expand the database related to the impacts of extreme weather to support a better mapping of vulnerabilities (e.g., Merz et al., 2020); ⅳ) develop adaptation strategies to cope with the adverse impacts extreme events may have on society, infrastructure and human-controlled ecosystems. In respect to the latter two points, some specific knowledge gaps were identified. These mainly relate to the impacts extreme weather may have on mortality, morbidity and infrastructure in the eastern Mediterranean. We believe that societal resilience to extreme weather in the region can properly be achieved only by 640 true interdisciplinary cross-border collaborations, in spite of recurring political turmoil (e.g., Hochman et al., 2020a, c;Negev et al., 2021).

Key open questions 645
We provide an overview of the research conducted and main knowledge gaps on extreme weather and its societal impacts in the eastern Mediterranean. The following four key open questions, immediately relevant for the eastern Mediterranean countries, have been identified. They should be considered as suggestions for future research initiatives, and are therefore framed as overarching questions:

Can we skillfully predict the onset, duration and intensity of extreme weather events across time scales? 650
The predictability of extreme weather events across scales from daily to long term climate change, including subseasonal to decadal time scales is of special interest. Depending on the time scale the focus should be on single case studies and process understanding, or on analyzing the long-term statistical properties of extreme weather events.

How will extreme weather impact eastern Mediterranean countries?
The direct and indirect influence extreme weather may have on eastern Mediterranean countries is of particular 655 interest. This question calls for interdisciplinary collaboration between meteorologists, climatologists and impact scientists to study the links between extreme weather and its influence on different public sectors in the eastern Mediterranean.

Can we predict the impacts extreme weather imposes on society and infrastructure across time scales?
The impact extreme weather events may inflict does not only depend on the event itself, but also on the economic 660 ability and adaptation measures put in place. These may strongly differ from country to country in the eastern Mediterranean. Therefore, providing regional impact forecasts across time scales is of particular importance. Such forecasts may provide strategic guidelines for national and regional adaptation plans.

How should policy measures change to cope with the impacts extreme weather may inflict upon society?
Since the full impacts of climate change on eastern Mediterranean countries are currently not completely realized, 665 recommendations in the public sector are still based on measures that may have a positive effect irrespective of changes in extreme weather occurrence and/or intensity. Data driven recommendations for specific interventions are therefore of utmost importance.
While we have pointed to some key open questions in this review, we acknowledge that enormous advances in the understanding of extreme weather over the eastern Mediterranean have already been made by the studies we refer to and by 670 many others we could not include. We hope that this review can be considered as a framework for future research on the topic.
Research Venue). This work is a contribution to the hydrological cycle in the Mediterranean Experiment (HyMex) and COST MEDCYCLONES: European Network for Mediterranean Cyclones in weather and climate.

Author contributions
All authors have contributed to conceptual development and writing of the study. All authors contributed through discussions and revisions. 685