Articles | Volume 7, issue 2
https://doi.org/10.5194/wcd-7-915-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wcd-7-915-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
12 Jun 2026
Research article |
| 12 Jun 2026
| 12 Jun 2026
Predictability of cyclones associated with heavy precipitation events in the Sahara
Guorong Ling
Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
Hilla Afargan-Gerstman
CORRESPONDING AUTHOR
Oeschger Centre for Climate Change Research, Institute of Geography, University of Bern, Bern, Switzerland
The Fredy and Nadine Herrmann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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Lara C. Mercier, Hilla Afargan-Gerstman, Matthew D. K. Priestley, Jens H. Christensen, and Daniela I. V. Domeisen
EGUsphere, https://doi.org/10.5194/egusphere-2026-1805, https://doi.org/10.5194/egusphere-2026-1805, 2026
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The study examines how extreme extratropical cyclones in the North Atlantic will change in a warming climate using historical and future projections of CMIP6 models. It shows that while near-surface temperature gradients are weakening, increased moisture is likely to make future storms more intense, suggesting a shift toward moisture-driven dynamics. Our findings provide new insights for improving long-term climate adaptation and risk management for high-impact weather in the midlatitudes.
Yair Rinat, Moshe Armon, and Efrat Morin
EGUsphere, https://doi.org/10.5194/egusphere-2026-972, https://doi.org/10.5194/egusphere-2026-972, 2026
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In the coming decades Mediterranean floods are expected to change due to increased urbanization and climate change. We simulate floods under different conditions and show that future rainfall will likely reduce flood magnitudes, but increased urbanization will make them higher. Flood intensification is more pronounced at upstream sections and when soil moisture is high. As future flood trends may change between different regions further research is needed to cope with upcoming challenges.
Blanca Ayarzagüena, Amy H. Butler, Peter Hitchcock, Chaim I. Garfinkel, Zac D. Lawrence, Wuhan Ning, Philip Rupp, Zheng Wu, Hilla Afargan-Gerstman, Natalia Calvo, Alvaro de la Cámara, Martin Jucker, Gerbrand Koren, Daniel De Maeseneire, Gloria L. Manney, Marisol Osman, Masakazu Taguchi, Cory Barton, Dong-Chan Hong, Yu-Kyung Hyun, Hera Kim, Jeff Knight, Piero Malguzzi, Daniele Mastrangelo, Jiyoung Oh, Inna Polichtchouk, Jadwiga H. Richter, Isla R. Simpson, Seok-Woo Son, Damien Specq, and Tim Stockdale
Weather Clim. Dynam., 7, 411–437, https://doi.org/10.5194/wcd-7-411-2026, https://doi.org/10.5194/wcd-7-411-2026, 2026
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Sudden Stratospheric Warmings (SSWs) are known to follow a sustained wave dissipation in the stratosphere, which depends on both the tropospheric and stratospheric states. However, the relative role of each state is still unclear. Using a new set of subseasonal to seasonal forecasts, we show that the stratospheric state does not drastically affect the precursors of three recent SSWs, but modulates the stratospheric wave activity, with impacts depending on SSW features.
Ellina Agayar, Moshe Armon, Michael Sprenger, and Heini Wernli
EGUsphere, https://doi.org/10.5194/egusphere-2025-5942, https://doi.org/10.5194/egusphere-2025-5942, 2025
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This study examines the hydrometeorological features of the major floods of 2008, 2010, and 2020 in western Ukraine. All cases were linked to upper-level PV anomalies. We also conducted a climatological analysis of PV structure associated with 22 summer heavy precipitation cases (2000–2022), highlighting their key role in determining the location and intensity of flood-inducing rainfall events in the Carpathians.
Joëlle C. Rieder, Franziska Aemisegger, Elad Dente, and Moshe Armon
Hydrol. Earth Syst. Sci., 29, 1395–1427, https://doi.org/10.5194/hess-29-1395-2025, https://doi.org/10.5194/hess-29-1395-2025, 2025
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The Sahara was wetter in the past and may become wetter in the future. Lake remnants are evidence of the desert’s wetter past. If the Sahara gets wetter in the future, these lakes may serve as a water resource. However, it is unclear how these lakes get filled and how moisture is carried into the desert and converted into rain in the first place. Therefore, we examine processes currently leading to the filling of a dry lake in the Sahara, which can help assess future water availability.
Philip Rupp, Jonas Spaeth, Hilla Afargan-Gerstman, Dominik Büeler, Michael Sprenger, and Thomas Birner
Weather Clim. Dynam., 5, 1287–1298, https://doi.org/10.5194/wcd-5-1287-2024, https://doi.org/10.5194/wcd-5-1287-2024, 2024
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We quantify the occurrence of strong synoptic storms as contributing about 20 % to the uncertainty of subseasonal geopotential height forecasts over northern Europe. We further show that North Atlantic storms are less frequent, weaker and shifted southward following sudden stratospheric warming events, leading to a reduction in northern European forecast uncertainty.
Ellina Agayar, Franziska Aemisegger, Moshe Armon, Alexander Scherrmann, and Heini Wernli
Nat. Hazards Earth Syst. Sci., 24, 2441–2459, https://doi.org/10.5194/nhess-24-2441-2024, https://doi.org/10.5194/nhess-24-2441-2024, 2024
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This study presents the results of a climatological investigation of extreme precipitation events (EPEs) in Ukraine for the period 1979–2019. During all seasons EPEs are associated with pronounced upper-level potential vorticity (PV) anomalies. In addition, we find distinct seasonal and regional differences in moisture sources. Several extreme precipitation cases demonstrate the importance of these processes, complemented by a detailed synoptic analysis.
Luca G. Severino, Chahan M. Kropf, Hilla Afargan-Gerstman, Christopher Fairless, Andries Jan de Vries, Daniela I. V. Domeisen, and David N. Bresch
Nat. Hazards Earth Syst. Sci., 24, 1555–1578, https://doi.org/10.5194/nhess-24-1555-2024, https://doi.org/10.5194/nhess-24-1555-2024, 2024
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We combine climate projections from 30 climate models with a climate risk model to project winter windstorm damages in Europe under climate change. We study the uncertainty and sensitivity factors related to the modelling of hazard, exposure and vulnerability. We emphasize high uncertainties in the damage projections, with climate models primarily driving the uncertainty. We find climate change reshapes future European windstorm risk by altering damage locations and intensity.
Hilla Afargan-Gerstman, Dominik Büeler, C. Ole Wulff, Michael Sprenger, and Daniela I. V. Domeisen
Weather Clim. Dynam., 5, 231–249, https://doi.org/10.5194/wcd-5-231-2024, https://doi.org/10.5194/wcd-5-231-2024, 2024
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The stratosphere is a layer of Earth's atmosphere found above the weather systems. Changes in the stratosphere can affect the winds and the storm tracks in the North Atlantic region for a relatively long time, lasting for several weeks and even months. We show that the stratosphere can be important for weather forecasts beyond 1 week, but more work is needed to improve the accuracy of these forecasts for 3–4 weeks.
Haggai Eyal, Moshe Armon, Yehouda Enzel, and Nadav G. Lensky
Earth Surf. Dynam., 11, 547–574, https://doi.org/10.5194/esurf-11-547-2023, https://doi.org/10.5194/esurf-11-547-2023, 2023
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Extracting paleoenvironmets from sedimentologic and geomorphic records is a main goal in Earth sciences. We study a chain of processes connecting causative Mediterranean cyclones, coeval floods, storm waves generated by mesoscale funneled wind, and coastal gravel transport. This causes northward dispersion of gravel along the modern Dead Sea coast, which has also persisted since the late Pleistocene, resulting in beach berms and fan deltas always being deposited north of channel mouths.
Francesco Marra, Moshe Armon, and Efrat Morin
Hydrol. Earth Syst. Sci., 26, 1439–1458, https://doi.org/10.5194/hess-26-1439-2022, https://doi.org/10.5194/hess-26-1439-2022, 2022
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We present a new method for quantifying the probability of occurrence of extreme rainfall using radar data, and we use it to examine coastal and orographic effects on extremes. We identify three regimes, directly related to precipitation physical processes, which respond differently to these forcings. The methods and results are of interest for researchers and practitioners using radar for the analysis of extremes, risk managers, water resources managers, and climate change impact studies.
Yoav Ben Dor, Francesco Marra, Moshe Armon, Yehouda Enzel, Achim Brauer, Markus Julius Schwab, and Efrat Morin
Clim. Past, 17, 2653–2677, https://doi.org/10.5194/cp-17-2653-2021, https://doi.org/10.5194/cp-17-2653-2021, 2021
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Laminated sediments from the deepest part of the Dead Sea unravel the hydrological response of the eastern Mediterranean to past climate changes. This study demonstrates the importance of geological archives in complementing modern hydrological measurements that do not fully capture natural hydroclimatic variability, which is crucial to configure for understanding the impact of climate change on the hydrological cycle in subtropical regions.
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Short summary
This research examines how well storms that bring heavy rain to the Sahara can be predicted. Using satellite observations and ensemble weather forecasts, we show that predictability varies by season, location, and circulation pattern, with an upper limit of about ten days. These insights can improve early flood warnings and support better planning for scarce water resources in desert regions.
This research examines how well storms that bring heavy rain to the Sahara can be predicted....
