This session welcomes contributions covering mid-latitude storm systems, including but not limited to the following topics:
• Fundamental dynamics of cyclones - in all different stages of their life cycle - and their mesoscale features (fronts, jets, precipitation structures, dry intrusions)
• Role of diabatic processes for the dynamics, predictability, and future changes of extratropical weather system
• Representation of mid-latitude storms in AI-based weather and climate models
• Diagnostics of observed and projected trends in cyclone frequency, intensity, and storm tracks; including potential insights from contributions from measurement campaigns
• Predictability and forecasting on synoptic to sub-seasonal time scales
• Innovative methods, including AI/ML approaches, for cyclone detection, classification, or impact assessment
• Storm-related impacts, vulnerabilities, and risk-transfer mechanisms under a changing climate
By bringing together communities working on dynamics, diagnostics, impacts, field campaigns, and new methodologies, this session aims to provide a comprehensive platform for advancing our understanding of mid-latitude cyclones and their role in the past, present, and future climate system.
Solicited authors:
Suzanne L. Gray, Julian F. Quinting
Orals: Mon, 4 May, 08:30–10:15 | Room M1
Classically, for extratropical weather systems the importance of diabatic effects such as surface fluxes, phase changes of water in clouds, and radiation, has been regarded as secondary compared to the dry dynamical processes. Research during recent decades has modified this view of the role of diabatic processes. A combination of complementary research approaches has revealed that the nonlinear dynamics of extratropical cyclones and upper-tropospheric Rossby waves is affected – in some cases strongly – by diabatic processes. Despite the violation of material potential vorticity (PV) conservation in the presence of diabatic processes, the concept of PV has been of utmost importance to identify and quantify the role of diabatic processes and to integrate their effects into the classical understanding based on dry dynamics.
This presentation will outline the rapid recent progress that has demonstrated how diabatic effects, in particular those related to cloud microphysics, can affect the structure, dynamics, and predictability of extratropical cyclones and Rossby waves. The development of sophisticated diagnostics, growing applications of the Lagrangian perspective, real-case and idealised numerical experiments, and dedicated field experiments have been fundamental to this progress. The presentation will conclude by highlighting important implications of this new understanding of the role of diabatic processes for the broader field of weather and climate dynamics, gaps and the prospects of future progress.
How to cite: Gray, S. L. and Wernli, H.: The importance of diabatic processes for the dynamics of synoptic-scale extratropical weather systems, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2977, https://doi.org/10.5194/egusphere-egu26-2977, 2026.
Extratropical cyclones are a key driver of midlatitude weather variability, including high-impact winter storms with heavy precipitation and severe wind gusts. Cyclone intensification results from the interplay of baroclinic dynamics and diabatic heating, the latter being closely linked to cloud-related processes within warm conveyor belts (WCBs). Focusing on European winter storms, this study investigates structural differences relevant for cyclone intensification between cyclones dominated by diabatic processes and those intensifying primarily through baroclinic mechanisms.
In a first part, we perform a systematic analysis of 247 winter storms affecting western and central Europe between 1979 and 2023, using a combination of a WCB diagnostic and the pressure tendency equation to quantify the diabatic contribution to cyclone deepening. Diabatic processes contribute on average 26.1% to cyclone intensification (median 25.3%), with cyclones exhibiting a relatively large diabatic influence (> 30.7%) showing steeper deepening rates, stronger northward displacement, enhanced precipitation, stronger wind gusts, and increased WCB activity compared to cyclones with a small diabatic influence (< 20.1%), despite similar minimum sea-level pressure. These cyclones are further characterised by warmer and moister WCB inflow conditions, favouring enhanced diabatic heating.
In a second part, we apply piecewise potential vorticity inversion to a limited number of representative cases as a complementary diagnostic to assess the methodological uncertainty in quantifying the role of diabatic processes. Together, these results demonstrate the benefit of combining complementary diagnostic approaches to better constrain the contribution of diabatic processes to extratropical cyclone intensification and highlight their potential for systematic evaluations of weather and climate models.
How to cite: Quinting, J., Christ, S., Leicht, T., Catto, J., and Pinto, J. G.: Assessing diabatic influences on extratropical cyclone development using complementary diagnostics, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14354, https://doi.org/10.5194/egusphere-egu26-14354, 2026.
The Mediterranean storm track is characterized by small but intense cyclones that can cause extreme weather events across the western Mediterranean (WMED). Thus, the aim of this study is to investigate the impact of future climate change on extreme wind, precipitation and compounding cyclones. We use a regional climate model simulation that simulates pre-industrial conditions (1821-1880) and future conditions under the representative concentration pathway RCP8.5 (2039-2098). We show that mean cyclone frequency is reduced by roughly a third in the WMED by the end of the 21st century in our simulation. For precipitation-type extreme cyclones (EXCs), future projections show increased precipitation during and after their most intense phase. During the mature phase of future precipitation EXCs, increased diabatic potential vorticity production contributes to cyclone intensity. Precipitation EXCs also appear to become more baroclinic. Wind speed EXCs are also set to become more extreme under future RCP8.5 conditions. The reason for this intensification is that wind speed EXCs are located in the left exit of a jet streak, which strengthens in the future. This provides more lift for future wind speed EXCs. For both future wind speed and precipitation EXCs, these processes also lead to a lower core pressure. Thus, we find that despite a general reduction of cyclones, precipitation and wind speed EXCs intensify in the future, implying strong socio-economic consequences for the WMED.
How to cite: Doensen, O., Messmer, M., Dolores-Tesillos, E., and Raible, C.: Extreme cyclones in the western Mediterranean under future climate change, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3416, https://doi.org/10.5194/egusphere-egu26-3416, 2026.
Arctic cyclones are synoptic-scale atmospheric low pressure systems that spend the largest part of their lifetime in the Arctic region. As they are associated with strong surface winds and precipitation, their impacts can be important on local populations or ecosystems. In summer, Arctic cyclones can be quite long and are typically cold-core cyclones associated to a tropopause polar vortex above them. Some of these cyclones last more than a month during which their interaction with sea ice might be damaging by enhancing its melting, that is why a focus was made in the recent years on these extremes. The reasons for the longevity of such cyclones are not clear yet and motivate the present study. Our approach consists in studying a single Arctic cyclone of August 2022 as an example and then tracking all summer Arctic cyclones in ERA5 reanalysis. The tracks are separated into different categories (cold-core vs. warm-core or long vs. short) using a newly developed cyclone phase space. Processes maintaining or destroying the structure of the different categories of cyclones are investigated by performing an energetic budget and a potential vorticity (PV) budget. A particular attention is paid on diabatic and frictional processes maintaining or destroying PV at different levels.
How to cite: Besson, M., Rivière, G., and Fromang, S.: Diabatic processes in very long summer Arctic cyclones, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5499, https://doi.org/10.5194/egusphere-egu26-5499, 2026.
Potential vorticity (PV) in mid-latitudes of the Northern Hemisphere is predominantly positive. Nevertheless, recent studies have shown that coherent and elongated negative PV (NPV) features can be generated in the upper troposphere by diabatic heating in a vertically sheared environment. These NPV features may persist for a few hours and interact with the jet, affecting the large-scale flow evolution. However, in contrast to its formation, the dissipation of NPV features is not well-understood, and the involved processes have not been investigated yet.
In this study, we carry out case studies on the dissipation of NPV near jet streams using numerical simulations from the Integrated Forecasting System by the European Centre for Medium-Range Weather Forecasts (ECMWF). Temperature and momentum tendencies from each parametrisation scheme are output, allowing a quantification of PV tendencies due to individual processes along air parcel trajectories. By launching forward trajectories in coherent NPV features, the contribution to the increase in PV, i.e., to the dissipation of NPV, by different diabatic processes are traced and compared. Turbulence appears to stand out as the dominant process that dissipates NPV. Detailed analysis on selected trajectories further demonstrates that the PV increase is usually associated with the tripole pattern of PV tendencies created by turbulence, which can be understood with a two-dimensional framework of the upper-level jet-front system. A special case that is consistent with the framework, but with a reversed tripole pattern is also found in a region of NPV. The study therefore provides further insight and understanding of the process by which NPV is dissipated in the upper troposphere.
How to cite: Lee, M. H. F., Sprenger, M., Joos, H., and Wernli, H.: On the dissipation of negative potential vorticity in the upper troposphere, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8260, https://doi.org/10.5194/egusphere-egu26-8260, 2026.
This study focuses on the co-evolution of synoptic extratropical cyclones (ETC) and mesoscale convective systems (MCS) by comparing databases of Lagrangian tracks for both storm types and locating points which are co-located to identify "coupled" systems. We find that these coupled tracks occur at the southward edge of the regions with the most ETC points, and on the northward edge of the MCS points. Since both of these regions have strong seasonal cycles, the coupled points also show a strong seasonal cycle. During all seasons however the coupled points tend to be concentrated over warm ocean waters in the Kuroshio, Gulf Stream, and over central North America. We also show that ETC systems that contain MCS deepen approximately 50% faster than systems without MCS. Most of the coupled points occur at the initial coupling time for both systems, indicating that for the coupled systems the ETC and MCS are forming at very similar times, for all regions and seasons. To investigate the dynamics behind this, we used ERA5 data around the time of initial coupling and find that the coupled systems are occurring in regions of particularly strong initial frontal conditions, which is followed by a strong intensification of the ETC. The MCS are typically located to the north east of the cyclone center, in a region of uplift surrounding the frontal zone. These results suggest that understanding the distribution of strong fronts is key to understanding the coupling between the different storm types.
How to cite: Fajber, R. and Lach, G.: A Lagrangian climatology of coupled extratropical cyclones and mesoscale convective systems, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13935, https://doi.org/10.5194/egusphere-egu26-13935, 2026.
Extratropical cyclones are responsible for severe and hazardous weather in the midlatitudes. They transport heat, momentum and moisture between latitudes and play important roles in the general circulation. Here, we present a new methodology for studying 6 hourly reanalysis data, based on spectral analysis is space and time, and determine the climatological properties of growing and decaying weather systems in six growth rate bins and two frequency bands. We focus on the seasonal variability of Northern and Southern hemisphere storm track modes for 20-year periods over the last 70 years. Leading Empirical Orthogonal Functions (EOFs) and storm tracks based on 850 hPa meridional winds and streamfunctions are determined for each frequency band and growth rate bin and compared with conventional EOFs and storm tracks that are based on all (growing and decaying) disturbances.
In the Northern hemisphere, results show slow‑growing weather systems exhibit familiar EOF patterns with peak amplitudes across the North Pacific and North America–Atlantic storm track regions near 45–50°N in both frequency bands. In the Southern hemisphere, EOF structures of slow growing modes are similarly focused near 45oS across the Southern Ocean. In contrast, in both hemispheres moderate and rapidly intensifying systems show a systematic equatorward shift in their dominant structures, highlighting the sensitivity of storm‑track latitude to cyclone growth characteristics.
The observed equatorward displacement of explosive storms in both hemispheres is related to diabatic effects such as convection, latent heating and surface moisture fluxes. These are more prevalent in the subtropical regions and include effects such as the transition of tropical cyclones into explosive extratropical cyclones. During extratropical transition, tropical cyclones inject large amounts of diabatic heating in the midlatitude flow triggering downstream Rossby wave trains, and the rapid deepening of new storms that are strongly linked to intensified rainfall.
Our findings reveal how changes in the life‑cycle characteristics of mid‑latitude cyclones influence storm track structure and rainfall distribution. By linking changes in explosive storm development to long‑term shifts in rainfall, this study strengthens our understanding of the mechanisms driving extreme events, including intense precipitation and prolonged drought. The approach provides a valuable framework for diagnosing mid‑latitude storm behaviour and how associated rainfall may evolve under climate change, with important implications for future climate risk.
How to cite: Osbrough, S. and Frederiksen, J.: Seasonal Cycle of Explosive Growth of Extratropical Storms, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15786, https://doi.org/10.5194/egusphere-egu26-15786, 2026.
Extreme extratropical storms present major socio-economic risks and are sensitive to anthropogenic climate change. Whilst robust projections of the aggregate properties of extreme storms have emerged from climate models in recent years, these average together storms with a range of contrasting dynamical structures and the influence of climate change on specific storm structures is much less well understood. Here, we adopt the storm track analogue approach to examine the influence of climate change on four contrasting historical storms impacting the UK: Martin in December 1999, the Great Storm in October 1987, Arwen in November 2021, and Ophelia in October 2017. Analogues are identified in the recently-produced CANARI large ensemble for both the present climate (1980–2010) and a high-emission future scenario (SSP3–7.0, 2070–2100).
Across each region of the UK, the overall number of storms decreases in future while the intensity of the most extreme storms increase, both in terms of precipitation and lower-tropospheric wind speed, aligning well with consensus storm projections. However, the analogues of specific storms exhibit contrasting future responses, indicating that storm-specific changes under anthropogenic warming can diverge from the aggregate signal. For example, whilst there is a reduction in the total number of storms in the region impacted by the Great Storm, there is a marked future increase in the number of storms with a trajectory similar to the Great Storm. Such changes are likely driven by regional variations in the conditions for baroclinic growth, or an increased influence of diabatic effects in future. Since individual storms are typically associated with distinct meteorological hazards, accounting for storm-specific responses is critical for assessing regional impacts and developing adaptation strategies.
How to cite: Harvey, B., Morgan, F., and Martínez-Alvarado, O.: The influence of climate change on analogues of contrasting mid-latitude cyclones over the UK, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18360, https://doi.org/10.5194/egusphere-egu26-18360, 2026.
Extratropical cyclones primarily develop over the western parts of ocean basins, where strong sea surface temperature (SST) contrasts form along western boundary currents such as the Gulf Stream in the Atlantic. These ocean currents are known to intensify extratropical cyclones by supplying moisture to the atmosphere through surface evaporation, which contributes to the diabatic heating associated with cloud formation and precipitation. While previous studies have highlighted the influence of the mean SST and SST gradient on cyclones developing over these currents, they have generally disregarded their meandering nature. Using idealized simulations, we examine the sensitivity of cyclone development to SST meanders of varying size through an analysis of the energy budget. In particular, we show that the moisture supply provided by warm SST anomalies associated with ocean meanders triggers diabatic heating a few hours later within storms. Both the size and phase of meanders relative to the cyclone modulate this energetic response. Such results reveal that not only the SST gradient but also the SST front geometry affect the life cycle of extratropical cyclones. Overall, our analysis provides insights into mechanisms of ocean-atmosphere interaction at the synoptic scale that, integrated over time, may have a noticeable impact on storm tracks at the climatological scale.
Reference: Vivant, F., Lapeyre, G. Meandering ocean currents modulate mid-latitude storm energetics (under review). https://doi.org/10.22541/essoar.175696970.05317808/v1.
How to cite: Vivant, F. and Lapeyre, G.: Extratropical cyclone energetics modulated by ocean meanders, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5565, https://doi.org/10.5194/egusphere-egu26-5565, 2026.
Posters on site: Mon, 4 May, 16:15–18:00 | Hall X5
Extratropical cyclones generate high societal costs across Europe, prompting numerous studies that aim to model their economic impacts. The majority of existing building damage models are limited to the maximum wind gust as their sole predictor, applied either directly or through a derived metric (e.g., the cubic exceedance of the 98th percentile). When these models are applied to insurance loss data on the district level for Germany, the resulting spatial patterns are counter‑intuitive: the highest modeled vulnerability appears in coastal regions that are typically best adapted to wind risk, while the lowest vulnerability is found in areas with the weakest adaptation pressure. This discrepancy raises doubts about the adequacy of the current modelling approach.
In our study we employ a Generalized Additive Model (GAM) based on logistic regression to estimate storm damage risk for Germany. The model is trained with ERA5 meteorological variables and daily monetary damage data ranging from 1997 to 2023 supplied by the German Insurance Association (GDV) for the 400 German districts. Beyond the daily maximum gust speed, we test additional predictors, including daily maximum instantaneous wind speed, gust factor (the ratio of maximum gust speed to maximum wind speed), storm duration and precipitation amount.
Wind speed improves model skill relative to gust speed and produces vulnerability maps that better align with expectations based on societal adaptation patterns. A model that combines wind speed, gust factor, and storm duration yields the highest predictive performance, while precipitation adds no value. Although ERA5 wind speed and gust speed are highly correlated under normal conditions, this correlation weakens significantly during storm events. Consequently, we argue that both wind speed and gust speed variables should be retained in storm damage models. Using the extended model, we identify the districts in central Germany as the most vulnerable to storm damage, overturning the earlier, coastal‑biased results. Our findings demonstrate that relying solely on maximum gust speed overlooks important aspects of storm impacts. Incorporating multiple storm characteristics, particularly wind speed, gust factor, and duration, significantly enhances the explanatory skill of damage models.
In the future we plan to apply this damage model to climate model output data to assess projected storm damage risks under future climate scenarios.
How to cite: Lorenz, R., Trojand, A., Ulbrich, U., and Rust, H.: Modeling storm damage risk in Germany, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3086, https://doi.org/10.5194/egusphere-egu26-3086, 2026.
Severe convective storms are among the most damaging natural hazards worldwide, with insured losses reaching tens of billions of US dollars annually. All severe convective storms originate from deep convective clouds (DCCs), making DCC occurrence a suitable proxy for assessing long-term changes in severe storm activity. However, robust observational evidence of DCC trends over Europe remains limited.
This study investigates long-term trends in DCC frequency over Europe during 1983–2024. We use observations from the Meteosat satellite series, combining data from the first-generation Meteosat Visible and Infrared Imager (MVIRI) and the second-generation Spinning Enhanced Visible and Infrared Imager (SEVIRI). The analysis is based on two spectral channels: the water vapour absorption channel centered near 6.5 µm and the infrared window channel centered near 11 µm. Satellite observations are complemented with atmospheric fields from the ERA5 reanalysis.
To ensure temporal homogeneity between sensors, spectral band adjustments were applied using correction functions derived from Infrared Atmospheric Sounding Interferometer observations. Parallax correction was performed using a cloud-top height estimation method based on infrared brightness temperatures combined with ERA5 temperature data. A Meteosat pixel was classified as a DCC when the brightness temperature difference between the water vapour and infrared window channels exceeded 2.5 K, a threshold established through validation with CloudSat–CALIPSO and Moderate Resolution Imaging Spectroradiometer observations. Additionally, convective available potential energy (CAPE) from ERA5 was required to exceed 500 J/kg.
The results reveal two distinct regional patterns of DCC frequency trends across Europe. Central and Western Europe exhibit positive trends, reaching up to 0.001 per decade in the annual mean, with the strongest increases observed over northern Italy and eastern Austria. The increase is most pronounced during boreal summer (June–August), with trends up to 0.004 per decade, while no significant trends are detected during other months. In contrast, negative trends occur over western France, the Iberian Peninsula, and the Mediterranean Sea, with annual mean decreases reaching −0.004 per decade. In these regions, the sign of the trend varies substantially between individual months.
Due to the relatively short time series and the low frequency of DCC occurrence, only the strongest trends are statistically significant (p < 0.05). Nevertheless, although the absolute trend magnitudes appear small, DCCs are rare phenomena, and the observed changes correspond to relative increases of approximately 10–25% in DCC frequency in parts of Europe. These findings indicate a potentially meaningful increase in severe convective storm risk under ongoing climate change.
This research was funded by the National Science Centre of Poland, grant no. UMO-2020/39/B/ST10/00850. We gratefully acknowledge Polish high-performance computing infrastructure PLGrid (HPC Centers: ACK Cyfronet AGH) for providing computer facilities and support within computational grant no. PLG/2025/018115
How to cite: Kotarba, A.: Trends in Severe Convective Storm Activity over Europe (1983–2024), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4918, https://doi.org/10.5194/egusphere-egu26-4918, 2026.
Cyclones of tropical origin (CTO) occasionally propagate to the midlatitudes, posing a significant hazard to regions that are unaccustomed to hurricane-force winds and extreme precipitation. Notable examples of CTOs that have significantly impacted Europe are Ophelia (2017), Lili (1996), and Leslie (2018). Given the rarity of these types of CTOs, the physical mechanisms that influence their formation, motion, and extra-tropical transition are poorly understood, complicating predictability and disaster risk response. In particular, the processes that enable the survival of CTOs in the midlatitudes are highly uncertain. Previous studies have suggested that the steering and intensification of CTOs is strongly modulated by the interaction with the background atmospheric circulation, but evidence is limited to few remarkable historical examples. In this study, we leverage ensemble hindcasts to construct a large, physically consistent set of plausible CTO events originating in the Atlantic Ocean that recurve eastward and reach the midlatitudes. Secondly, we apply a trough detection algorithm (Schemm et al. 2020) to investigate whether the interaction between cyclones and troughs plays any role in favouring or inhibiting CTO survival in the midlatitudes. The large volume of data provided by ensemble hindcasts is crucial for reducing uncertainty and advancing our understanding of the processes that may lead to CTO impacts in Europe, including how these processes may evolve under anthropogenic forcing.
How to cite: Bianco, E., Ng, K., and Leckebusch, G.: What favours the midlatitude survival of cyclones of tropical origin (CTOs)? , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7050, https://doi.org/10.5194/egusphere-egu26-7050, 2026.
European winter windstorms are one of the most damaging natural hazards in Europe, and when these severe windstorms cluster in time, economic losses and environmental damages are amplified. Our previous analysis on the behaviour of European winter (DJF) windstorms clustering on shorter intra-seasonal timescales revealed distinct intra-seasonal temporal behaviour, where, depending on location, two clear periods of enhanced clustering are identified, one at the middle and one at the end of the season. Here, we investigate the spatial development characteristics of these cyclones (associated with the windstorms) and examine their intra-seasonal variation. To cluster cyclones with similar spatial development characteristics, we first applied dimension reduction via PCA to ERA5 1000 hPa 3-day development fields, then performed k-means cluster analysis as in Leckebusch et al. (2008b).
K-means ‘primary storm clusters’ that contain the highest relative frequency of European windstorms are identified. Further investigation of these primary storm clusters reveals 5 primary storm clusters that show distinct spatially varying windstorm footprint occurrences, which have resulted from a similar grouping of 3-day development fields. For example, among these 5 primary storm clusters, we can make distinctions between the 3-day development fields more likely to give rise to windstorms over Western Central Europe vs Scandinavia. We also reveal depending on the time within the winter season, certain k-clusters contribute more than others, specifically during the 2 periods of enhanced temporal clustering.
How to cite: Feltz, S., Bianco, E., Allen, C., Kruschke, T., Angus, M., Quinn, A., and Leckebusch, G.: Spatial clustering of severe European winter windstorms on intra-seasonal timescales, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6779, https://doi.org/10.5194/egusphere-egu26-6779, 2026.
Atmospheric fronts are a key driver of intense and extreme precipitation across the mid-latitudes, which is projected to increase under global warming. Understanding the physical drivers of these changes is essential to improve confidence in climate projections.
Here, we analyze projected seasonal changes in heavy and extreme frontal precipitation events over Europe using the CMIP6 and EURO-CORDEX ensembles, combining event frequency analysis with frontal composite cross-sections to assess underlying thermodynamic and dynamic processes.
First, we evaluate the representation of fronts in the CMIP6 and EURO-CORDEX ensembles, using ERA5 as a reference. While synoptic-scale conditions are well represented across models, mesoscale gradients and circulation patterns exhibit a pronounced sensitivity to grid spacing, especially impacting the representation of cold fronts and their associated precipitation.
Future projections show an increase in the number of heavy frontal precipitation events by up to 50 % per degree of global warming, while extreme events more than double per degree. Large-scale circulation changes account for most regional reductions in frontal extremes, but contribute only weakly to the widespread increases. Thermodynamic changes, however, dominate the intensification of extremes. Increases in specific humidity are the primary driver of more intense events, while changes in the frontal circulation are minimal, likely because a more stable atmosphere counteracts potential strengthening from enhanced latent heat release.
These results highlight the dominant role of thermodynamic processes in future frontal precipitation extremes and underscore the importance of adequately resolving mesoscale frontal features in climate models.
How to cite: Schaffer, A., Ossó, A., and Maraun, D.: Thermodynamic drivers intensify future European frontal precipitation extremes, while frontal dynamics remain largely unchanged, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7271, https://doi.org/10.5194/egusphere-egu26-7271, 2026.
Clouds strongly affect the dynamics of extratropical cyclones and large-scale predictability through their microphysical and radiative effects. However, the representation of cloud microphysical and radiative processes remains uncertain in current weather and climate models, with key processes such as Secondary Ice Production (SIP) being simplified or neglected. SIP processes, such as rime splintering, ice-ice collisional breakup, and raindrop fragmentation, can increase ice number concentrations by several orders of magnitude. The enhanced ice production can modify the latent and radiative heating of clouds, thereby affecting the dynamics of extratropical cyclones. However, the impact of SIP processes on the dynamics of extratropical cyclones has not yet been quantitatively assessed.
Here we investigate the impact of SIP processes on the cloud microphysics and dynamics of extratropical cyclones by performing hindcast simulations with and without SIP processes using the ICOsahedral Nonhydrostatic (ICON) model. We focus on cyclones observed during the North Atlantic Waveguide and Downstream impact EXperiment (NAWDEX) field campaign. This enables us to evaluate the modeled microphysical and radiative properties of clouds within cyclones against observations. In addition, we apply the potential vorticity error growth framework to investigate how SIP-induced changes in cloud latent and radiative heating influence the dynamics of cyclones and the circulation near the tropopause. Our results can highlight the implications of improved cloud-ice microphysics for model prediction of extratropical cyclones.
How to cite: Keshtgar, B., Waman, D., and Hoose, C.: The impact of secondary ice production on the dynamics of extratropical cyclones, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7768, https://doi.org/10.5194/egusphere-egu26-7768, 2026.
In January 2025, storm Éowyn underwent one of the fastest deepening rates ever observed for an extratropical cyclone, producing wind gusts exceeding 184 km h⁻¹ along Ireland’s west coast and ranking among the five most intense storms to affect the UK in terms of central pressure. The representation of such extreme extratropical cyclones in numerical weather prediction (NWP) models remains challenging, as their structure, deepening, and associated surface weather impacts are sensitive to the choice of NWP model, initial conditions, simulation resolution and lead time, and the representation of diabatic processes. In this study, we investigate how some of these factors influence the simulated intensification of storm Éowyn, using two state-of-the-art high-resolution models in their limited-area mode: the ICOsahedral Nonhydrostatic (ICON) model and the Portable Model for multi-scale Atmospheric Prediction (PMAP). The latter model is currently under development at the European Centre for Medium-Range Weather Forecasts (ECMWF) and ETH Zürich to enable simulation of weather across scales. We also revisit the classical approach of “dry (latent heating suppressed) vs. moist” simulations to quantify the contribution of latent heating to the intensification of Éowyn. Moreover, we perform pseudo-global warming experiments to explore the sensitivity of Éowyn’s evolution with respect to thermodynamic climate perturbations, revealing possible storylines for how the severity of such extreme storms may change in a future warmer climate. We quantify the effect of horizontal resolution and lead time on the storm evolution with quantitative insights into the contributions of thermodynamic and dynamical processes that lead to the rapid intensification of extratropical cyclones and the associated formation of extreme winds.
How to cite: Hauser, S., Papritz, L., and Wernli, H.: Explosive cyclogenesis and high-impact winds in storm Éowyn in January 2025: sensitivities to simulation setup and latent heating, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12653, https://doi.org/10.5194/egusphere-egu26-12653, 2026.
Moist diabatic processes – such as air-sea fluxes, turbulent mixing, cloud microphysics – are key drivers of midlatitude high-impact weather. These processes affect the atmospheric temperature distribution and stability, thereby directly modifying mesoscale circulation patterns. Mesoscale structures, in turn, tend to be the most hazardous features within midlatitude weather systems and are closely linked to forecast uncertainties. We refer to these features as mesoscale moisture-cycling structures (MOCs): anomalies in moisture and wind fields on scales of approximately 1-50 km, embedded within midlatitude weather systems such as extratropical cyclones, their fronts and airstreams. It remains a major challenge to correctly represent moist diabatic processes and their impact on MOCs in numerical weather models.
Recent airborne field campaigns in tropical and polar regions have demonstrated the power of water isotope observations to quantify and disentangle the role of different diabatic processes. Building on this approach, NAWDICiso, i.e. the isotopic component of the North Atlantic Waveguide, Dry Intrusion, and Downstream Impact Campaign (NAWDIC, January – March 2026) aimed at conducting multi-platform observations of water vapour isotopes on two aircrafts (French ATR-42 operated by Safire and German Cessna F406 D-ILAB operated by TU Braunschweig) and at ground-based stations in Brittany (operated at the KITcube together with KIT), Ireland as well as within a European-wide precipitation sampling network to survey the downstream impact of North Atlantic cyclones. This intensive measurement period enables us to capture the imprint of diabatic processes on MOCs through simultaneous observations of stable water isotopes in water vapour and precipitation. Here, we present a first overview of the collected data and selected case studies from the NAWDICiso observation network. These measurements, combined with km-scale resolution isotope and tagging-enabled numerical model simulations, provide the basis for identifying and characterising moist diabatic processes within MOCs. Ultimately, these observations deliver unprecedented three-dimensional insights into MOCs in midlatitude weather systems, which are essential for improving forecasts of the development, intensification, and surface impacts of these weather systems.
How to cite: Thurnherr, I., Aemisegger, F., Sodemann, H., Brennan, K., Connolly, J., Fasnacht, L., Fieldhouse, N., Glock, E., Gribi, P., Hovas, C., Kouwenhoven, R., and Seidl, A. and the NAWDICiso team: Tracing Moist Diabatic Processes with Water Isotopes: Overview of NAWDICiso’s Multi-Platform Observations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13145, https://doi.org/10.5194/egusphere-egu26-13145, 2026.
Most of our fundamental theories for the large-scale atmospheric circulation in the extratropics are based on “dry” atmospheric dynamics. However, our fundamental understanding of the impact of diabatic processes on a range of spatial and temporal scales has significantly improved over the recent decades. This includes the impact of diabatic processes on blocking, Rossby wave propagation and breaking, extratropical and subtropical cyclones, polar lows, jets, and tropical-extratropical interactions among many others. Despite these recent efforts, large uncertainties in representing diabatic processes and their impact remain, leading to upscale error growth and enhanced ensemble spread, highlighting the continued need to further our understanding and to develop new and revise existing paradigms.
Addressing these important research questions requires a large community effort of weather and climate dynamicists, modellers, and observationalists, who can profit from an invigorated mutual exchange. Providing opportunities for these sometimes-disparate research communities to come together is critical for enhancing collaboration and our understanding of how diabatic processes impact various scales and change in a warmer, moister atmosphere.
Hence, the Diabatics 2026 Workshop was organised 28 April until 1 May 2026, focusing on the impact and implications of different diabatic processes on the dynamic evolution of meso- to planetary-scale weather systems, including cross-scale interactions and geographic linkages. Contributions from theory, observations, and modelling (including AI) were featured, including implications of resolving and understanding diabatic processes on predictability on all timescales. This presentation summarises key findings from the workshop as well as recommentions of the community on research priorities.
How to cite: Ndarana, T., Barnes, M., and Spengler, T.: Diabatics processes across scales in the extratropics: Workshop summary and research priorities, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-23197, https://doi.org/10.5194/egusphere-egu26-23197, 2026.
How to cite: Sherlock, D., Bukenberger, M., Pfahl, S., and Kirchner, I.: A June 2023 case study on the effect of cold-frontal convective cells on frontal synoptic flow, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12757, https://doi.org/10.5194/egusphere-egu26-12757, 2026.
Extratropical cyclones frequently exhibit pronounced poleward propagation during their life cycle. This behavior is typically associated with the poleward advection of a low-level PV anomaly by an upper-level PV anomaly located to its west, which can be enhanced by diabatic production of positive low- to mid-level PV (LPV) through latent heat release. In CMIP6 models, the storm tracks tend to be too zonal, particularly in the North Atlantic, and the frequency and intensity of rapidly deepening cyclones are often underestimated. Such biases may partly arise from misrepresentation of the magnitude of diabatic processes and/or from the dynamical response of cyclone propagation to those processes.
The aim of this study is to assess the contribution of latent heating to the poleward propagation of extratropical cyclones and to evaluate how both the magnitude of LPV and the associated dynamical response contribute to the storm track biases in CMIP6 models. Using ERA5 reanalysis and CMIP6 model data for the period 1979–2014, this study applies ensemble sensitivity analysis and cyclone composite methods to quantify the sensitivity of cyclone poleward propagation, measured by the cyclone meridional velocity at the time of maximum intensity, to LPV associated with latent heating. The analysis is conducted over the North Atlantic and North Pacific basins, considering both western and eastern sectors.
In ERA5, preliminary results show that North Atlantic cyclones have larger LPV than North Pacific cyclones throughout the entire development phase. Within the North Atlantic, although latent heating is stronger in western cyclones than in eastern ones, the sensitivity of poleward propagation to LPV is largest for eastern cyclones. In contrast, in the North Pacific, cyclones in the eastern sector show slightly stronger latent heating than those in the western sector. However, the sensitivity of poleward propagation to LPV is largest for western cyclones.
The CMIP6 models evaluated so far are able to capture the overall structure of LPV and the sensitivity of poleward motion to latent heating in extratropical cyclones across both oceans and sectors, as well as the differences between them. However, model resolution appears to impact the accuracy in representing the magnitude of these sensitivities, particularly for eastern North Atlantic cyclones. This may help explain the reduced storm track biases found in higher resolution CMIP6 models.
These results suggest that the poleward motion of western North Pacific and eastern North Atlantic cyclones is more strongly responsive to diabatic forcing via latent heat release, even though the magnitude of latent heating is smaller in those sectors. In contrast, western North Atlantic and eastern North Pacific cyclones appear to be more directly controlled by dry baroclinic processes. Finally, improving the representation of moist processes and LPV generation in climate models is essential for reducing biases in storm track orientation, cyclone intensity, and associated uncertainties in future climate projections.
How to cite: Souza, M., Dacre, H., Leicht, T., Catto, J., Ackerley, D., and Quinting, J.: Sensitivity of Extratropical Cyclone Poleward Motion to Low-Level Potential Vorticity, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13117, https://doi.org/10.5194/egusphere-egu26-13117, 2026.
Sea ice cover in the Arctic has declined significantly during summer over the past few decades, leading to the opening up of Arctic shipping routes. However, the prediction of Arctic cyclones, which plays an important role in shipping safety, still has room for improvement. Cyclones interact with the underlying sea ice leading to potential modification of the cyclone through changes in the fluxes of heat, moisture and momentum into the atmospheric boundary layer from the sea surface. At the same time, Arctic cyclones can have different structures from extratropical cyclones, such as tropopause polar vortices (TPVs), which may enhance the predictability of Arctic cyclones. Therefore, further understanding of the structure and lifecycle of cyclones in the Arctic region is crucial to improving forecasts.
In this presentation, a case study, the third cyclone observed time Arctic cyclones field campaign in 2022 (cyclone3), is discussed, to find out the relationship between the structure and characteristics of the cyclone and precursor fields. Cyclone3 lasted 13 days and travelled from the Greenland Sea across the North Pole to the Laptev Sea before returning to the Greenland sector. Because of its long lifetime and moving track, we can find out how its property changes over different surface types. Ensemble sensitivity analysis (ESA) is used to learn how the spread of cyclone outcomes in the ensemble forecast are related to early state variables, such as surface fluxes and TPVs, to understand how the prediction of cyclone evolution, including the structure and intensity, changes in different cyclone stages, and what that tells us about how upper- and lower-level dynamics interact in the Arctic region.
How to cite: Ling, X., Gray, S., Methven, J., and Volonte, A.: The sensitivity analysis of Arctic cyclone structure and characteristics in ensemble forecast , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16684, https://doi.org/10.5194/egusphere-egu26-16684, 2026.
It is often argued that numerical weather prediction models remain deficient in forecasting specific weather features and that such deficiencies contribute significantly to overall forecast errors. To clarify these claims, we quantify how extratropical cyclones (ETCs), fronts, upper tropospheric jets, moisture transport axes (MTAs), and cold-air outbreaks (CAOs) contribute to short-term (12-h) forecast errors and biases in the ERA5 reanalysis dataset from 1979 to 2022. Employing a feature-based attribution method, we evaluate errors globally, focusing particularly on temperature, moisture, and wind fields, and examine regional and seasonal variations during winter (DJF) and summer (JJA). The presence of weather features is generally associated with increased forecast errors (RMSEs) compared to feature-free conditions. RMSEs are especially pronounced for moisture fields in conjunction with fronts and MTAs, where errors in total column water vapor can be twice as large. ETC-related errors are more pronounced in the low-level wind field. During CAOs, on the other hand, errors are reduced. In terms of systematic biases, wind speeds and moisture are underestimated along western boundary currents, together with insufficient moisture transport along MTAs.
Given that ETCs are the most notable example, where forecasts provide less added value in most cases we also employ a cyclone-centred composite framework for North Atlantic wintertime (DJF) ETCs using the ERA5 reanalysis for the period 1979 to 2022. ETCs are categorised into strong and weak diabatic heating at the time of their maximum intensification. While both groups exhibit a systematic underestimation of cyclone intensity, the error structures are markedly distinct. The weak heating group is characterised by an intensity underestimation near the cyclone core, whereas the strong heating group features a pronounced southwestward displacement bias together with a domain-wide intensity underestimation. After removing the displacement bias, the strong heating group reveals an overestimation of low-level winds within the cold conveyor belt, sting jet, and dry intrusion regions, but a clear underestimation of moisture transport in the warm sector. These biases are accompanied by a pronounced overestimation of 850 hPa kinematic frontogenesis near the centre, likely associated with the wind field errors, and a substantial overestimation of total column liquid water along the bent-back warm front. This overestimated liquid water is likely related to the stronger frontogenesis, which induces an over-intensified secondary circulation. In contrast, cyclones in the weak heating group exhibit an underestimation of wind speed and moisture near the centre, consistent with the near centre intensity underestimation. Our findings highlight the impact of diabatic heating on structural cyclone forecast biases that can guide future model improvements.
How to cite: Yu, Q., Spensberger, C., Magnusson, L., and Spengler, T.: Forecast errors attributed to synoptic features and the role of diabatic heating for extratropical cyclones, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18028, https://doi.org/10.5194/egusphere-egu26-18028, 2026.
Moist diabatic processes significantly impact storm track variability, position, and intensity. The distribution of atmospheric moisture is closely linked to sea surface temperatures (SSTs) through the Clausius-Clapeyron relation. Therefore, midlatitude atmospheric circulation is affected by the spatial distribution of SSTs, especially midlatitude SST fronts associated with oceanic western boundary currents.
We quantify the storm track’s response to moisture availability by performing idealised aqua-planet simulations where we modify the distribution of SST by changing the position, intensity, and width of midlatitude SST fronts. We assess the sensitivity of atmospheric circulation by comparing the water cycle and climatological mean energy cycle resulting from each simulation. Specifically, we find that storm tracks tend to align with SST fronts when these are located in midlatitudes, and that stronger SST gradients enhance storm track activity by increasing baroclinicity and moisture fluxes. The storm track’s latitudinal variability is strongly dependent on the latitude of the SST front, while its amplitude and maximum gradient primarily affect storm track intensity. Two additional experiments where we uniformly increase and decrease absolute temperature highlight the response of storm tracks to climate change: the water cycle intensifies in a warmer climate, but storm track activity appears more sensitive to the total meridional temperature contrast than to absolute temperature.
Finally, we present preliminary results from ongoing work exploring the synoptic drivers of storm track response, including changes in cyclone distribution, baroclinicity, and the role of moist diabatic processes, which significantly impact storm track variability, position, and intensity.
How to cite: Ogawa, F., Marcheggiani, A., Nakamura, H., and Spengler, T.: Impact of the distribution of sea surface temperature on the maintenance of storm tracks, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17992, https://doi.org/10.5194/egusphere-egu26-17992, 2026.
Mediterranean cyclones (MCs) are major drivers of the Mediterranean hydrological cycle (MHC), contributing up to ~70 % of regional precipitation and a substantial fraction of evaporation. Their role in regional water and energy budgets is disproportionately large relative to their spatiotemporal frequency. Despite this importance, the diversity of cyclogenesis mechanisms and their contrasting influences on key components of the hydrological and oceanic systems remain poorly understood, limiting our ability to interpret past variability and anticipate future changes in a warming climate.
In this study, we leverage a process-based classification of Mediterranean cyclones applied to 1-hourly ERA5 reanalysis tracks (1979–2020) to systematically quantify the contribution of different cyclone types to the hydrological cycle and to Mediterranean Sea heat content. The classification separates cyclones by their dominant dynamical drivers — including double-jet, daughter cyclones, thermal lows, and other mechanisms — and enables the decomposition of their individual precipitation (P) and surface evaporation (E) contributions along each cyclone track.
Our results reveal that while MCs produce a net positive annual P − E contribution over the Mediterranean, this residual has declined over recent decades. Importantly, distinct cyclone drivers exert opposing effects on hydrological and heat budgets: precipitation associated with dynamic-driven cyclones (e.g., double-jet systems) has decreased, whereas thermally driven cyclones (e.g., heat lows) have become more frequent and have enhanced evaporation. These divergent trends shift the basin-scale balance toward greater evaporative influence, with implications for regional moisture recycling and drought risk.
We further examine how the different cyclone drivers affect the ocean heat content — a key component of Mediterranean climate feedbacks — demonstrating that while most cyclones act to cool the surface by drawing heat from the ocean, some cyclone types tend to add heat to the upper ocean, generating substantial variability in the direction and magnitude of cyclone-induced air–sea exchanges.
By linking cyclone dynamics, hydrological impacts, and ocean heat content responses in a unified framework, this study advances the understanding of how different cyclogenetic processes modulate regional water and energy cycles. It underscores the importance of explicitly accounting for cyclone diversity when diagnosing Mediterranean hydroclimate variability and projecting future changes — a critical step toward improving risk assessments and adaptation strategies in this climate-sensitive region.
How to cite: Givon, Y., Keller, D., Drobinski, P., and Raveh-Rubin, S.: How Cyclone Dynamics Shape Hydroclimate Trends in the Mediterranean, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2818, https://doi.org/10.5194/egusphere-egu26-2818, 2026.
There are still considerable uncertainties surrounding the frequency and characteristics of extratropical cyclones within climate model projections. Some of the uncertainty may originate from considering all cyclones together rather than examining dynamically distinct groups of cyclones. Here we present a preliminary climatology of wintertime cyclones across the North Atlantic created using piecewise potential vorticity inversion. Cyclones are identified using the Hodges (1999) TRACK methodology on ERA5 reanalysis data from December–February and from 1979–2024 across the North Atlantic basin. We apply the piecewise potential vorticity inversion method to these cyclone tracks to determine whether an individual cyclone strengthens most from upper-, middle-, or lower-troposphere potential vorticity anomalies. Cyclones are analyzed to assess how their structure, development, and large-scale flow characteristics differ between the three classes of cyclones. We aim to perform similar analysis for cyclones in climate model runs of both current and future climate states to assess the biases and projected changes to the different groups of extratropical cyclones.
How to cite: Leicht, T., Catto, J., Maddison, J., Suoza, M., Dacre, H., and Quinting, J.: A climatology of North Atlantic extratropical cyclones using piecewise potential vorticity inversion, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20835, https://doi.org/10.5194/egusphere-egu26-20835, 2026.
The physical processes affecting cyclogenesis and intensfication of midlatitude storms often occur at scales smaller than those resolved by the global climate models, which has previously restricted their use for present and future storm climatology assessments. The Process-based Climate simulation: Advances in high resolution modelling and European climate risk assessment (PRIMAVERA) and the associated CMIP6 High Resolution Model Intercomparison Project (HighResMIP; Haarsma et al. 2016) has highlighted the need for global storm-resolving climate models, with significant improvements seen in the frequency, intensity and structure of mid-latitude storms by increasing resolutions from 100 km to 25 km. The European Eddy-Rich Earth-System Models (EERIE) offer the highest available resolutions (~10 km) that explicitly resolve ocean mesoscale features, furthering our understanding of their impacts on the large-scale circulation, including storm-tracks and jet streams. In this study, we evaluate the historical (1950-2014) simulations from the four coupled EERIE models in their representation of mid-latitude storms and their effects on the eddy-driven circulation. We also present results from the sensitivity experiments (atmosphere-only), which are designed to isolate the impact of ocean-mesoscale eddies on the large-scale circulation. We find that the impact of ocean mesoscale eddies on the climatological storm track remain small, which is expected as the flux-enhancing effect of eddies is largely overwhelmed by the the strong meridional temperature gradients associated with fronts.
How to cite: Dey, I.: Impact of eddy-rich ocean resolutions in the representation of midlatitude storm in global climate models, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21033, https://doi.org/10.5194/egusphere-egu26-21033, 2026.
Mesoscale (~10–100 km) deep convection embedded within the cold-frontal region of extratropical cyclones (ETCs) can lead to high-impact weather. However, such convection remains poorly represented in operational weather prediction models. One key reason is the incomplete understanding of the mesoscale variability of thermodynamic and dynamic variables that leads to localized heavy precipitation associated with embedded deep convection. In particular, the dry intrusion (DI) airstream (characterized by descending cold, dry air from the upper troposphere) can either enhance or suppress embedded convection, highlighting the need for better constraints on its role in frontal dynamics.
The international field campaign North Atlantic Waveguide, Dry Intrusion, and Downstream Impact Campaign (NAWDIC), conducted during winter 2025/26, provides a unique observational perspective on these processes. In this contribution, we present airborne observations of mesoscale variability in frontal structures, with a particular focus on embedded convection and dry intrusions. Vertical thermodynamic and dynamic profiles are derived from a multi-dropsonde system, the “KITsonde” system, which captures mesoscale variability by simultaneously releasing up to four dropsondes with different fall velocity. These profiles are complemented by radiosonde soundings as well as wind and water vapour lidar measurements from a ground-based observation site at the Western Coast of France. The observed profiles are compared with corresponding profiles from weather prediction models using the KITsonde simulator, which predicts KITsonde trajectories and associated atmospheric properties from model data. Through the joint use of observations and simulations, we assess the ability of weather models to capture mesoscale variability associated with frontal convection in NWP models.
How to cite: Yeung, K. L., Kirsch, B., Hoose, C., Miltenberger, A., and Oertel, A.: Observing mesoscale frontal convection and dry intrusions during NAWDIC using multi-dropsonde measurements, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8442, https://doi.org/10.5194/egusphere-egu26-8442, 2026.
Extratropical cyclones are expected to be more diabatically driven in a warmer world, in line with the 6-7% increase in precipitable water per degree of global-mean surface temperature increase. This leads to a preferential strengthening of the most intense cyclones in a warmer climate as a result of increased latent heating (LH), accompanied by a decrease in the strength of weaker cyclones.
In this study, using data from new CESM model experiments, and employing a storm-centric potential vorticity (PV) budget, we estimate the contribution of LH to storm intensification across height and storm lifecycle. We use an objective algorithm to track the cyclones, and a suitable storm-compositing method to compute the spatial and temporal patterns of PV generated from diabatic and adiabatic processes. To isolate the intensification of storms due to PV generation from other processes like storm propagation, we develop a novel storm-averaging methodology.
Using this methodology, we investigate how the magnitude and pattern of PV produced from LH are modified when the sea surface temperature is uniformly increased by 4K. Focusing on the strongest cyclones in the southern hemisphere, we show that the increase in low-level PV generated in cyclones in the warmer model run can be almost entirely attributed to changes in the strength and pattern of LH. By also comparing winter and summer cyclones in our model runs, we obtain a consistent pattern of how the LH contribution to cyclone intensification changes from a cooler to a warmer environment. Finally, we show that our methodology also works well for cyclones in reanalysis data (MERRA2).
Given the socio-economic impacts of severe storms, this study provides valuable insights into the processes that govern cyclone intensification, and how they are expected to change in a warmer world. We also quantify the increase in cyclone strength with warming, which can support policymakers in anticipating and mitigating the effects of these events.
How to cite: Shibu, A., Auestad, H., Ceppi, P., and Woollings, T.: Latent heating contribution to storm intensification across seasons and climates - A potential vorticity approach, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20660, https://doi.org/10.5194/egusphere-egu26-20660, 2026.
