The Infrared Sounder (IRS), onboard Europe’s latest meteorological satellite, marks a significant advancement in atmospheric observation capabilities. With high vertical resolution and a horizontal resolution of 4 km at sub-satellite point (SSP), combined with a revisit time of 30 minutes over Europe, IRS provides an unprecedented stream of high-quality atmospheric data. These enhancements are expected to substantially improve the performance of numerical weather prediction (NWP) models, particularly in the context of severe storm forecasting.

A piecewise linear regression (PWLR) retrieval method, developed at EUMETSAT, will be employed to accurately and precisely derive thermodynamic parameters—such as water vapour, temperature, and ozone profiles—from IRS observations. The retrieval will also provide uncertainty estimates along the derived profiles. Combined with cloud information, these profiles can be used to supplement regional models for nowcasting, for the purpose of more accurately and quickly identifying areas of potential instability and associated weather phenomena like convection, precipitation, and severe storms. Additionally, a suite of instability indices will be generated centrally within the Level 2 processing facilities, ensuring continuity with existing Global Instability Index (GII) products (e.g., from MSG) and consistency with future MTG-FCI-based outputs.

In this presentation we will demonstrate IRS's potential to contribute to nowcasting applications, highlighting key atmospheric products derived from the sensor. These include vertical profiles of temperature, humidity, and ozone as well as derived instability indices—all essential for the early detection and prediction of convective activity. Special focus will be given to the quality and availability of IRS products and their potential to significantly increase the reliability of short-term severe weather forecasts.

How to cite: Stapelberg, S., Bhat, H., Warnach, S., Goukenleuque, C., Crapeau, M., Wilzewski, J., Hultberg, T., and Coppens, D.: Level 2 products from EUMETSAT’s first geostationary hyperspectral Infrared sounder mission, 12th European Conference on Severe Storms, Utrecht, The Netherlands, 17–21 Nov 2025, ECSS2025-233, https://doi.org/10.5194/ecss2025-233, 2025.

Profiles of atmospheric temperature and humidity through a vertical column are fundamental to the assessment of convective instability.  Quantities derived from such profiles, such as CAPE, CIN and various instability indices, are well-established as operational nowcasting and situational awareness products. Whilst radiosonde ascents provide the most vertically detailed measurements of upper air quantities, satellite observations are far more numerous, and geostationary orbits in particular combine the advantages of spatial coverage and temporal continuity.   

The MTG-IRS instrument, due to be launched aboard MTG-S in July 2025, will be the first hyperspectral sounding instrument in a geostationary orbit over Europe.  A EUMETSAT Fellowship currently being hosted by the UK Met Office is exploring the potential for MTG-IRS’s sounding capability to improve the detection and characterisation of regions of convective instability.  The context is operational nowcasting, where timely observations can be used by forecasters to assess the accuracy of NWP model fields before those same observations are able to influence the forecast via the next cycle of the data assimilation system.

Instability indices currently generated at the UK Met Office are derived from vertical profiles of temperature and humidity retrieved from SEVIRI radiances and an NWP-derived prior estimate, using an optimal estimation algorithm.  Initial work on the Fellowship project has used hyperspectral IASI data as a proxy for MTG-IRS, in place of SEVIRI, with morning MetOp orbits over Europe coinciding with the pre-convective phase of thunderstorm development.  The behaviour of the optimal estimation scheme and the sensitivity of the retrievals to various aspects of the scheme, such as channel selection, relative weighting of background and observations, and surface treatment have been explored.  The vertical structures of the retrieved temperature and humidity profiles are also useful when comparing the behaviour of different instability indices, and suggest adjustments to the index calculation that might better suit typical local pre-convective environments.

Some aspects of validation will also be discussed.  Whilst case studies are invaluable in understanding pre-convective situations and evaluating retrievals and indices, routine objective verification is also important when developing a product for operational use.

How to cite: Taylor, R.: Exploring the potential of MTG-IRS to diagnose convective instability for nowcasting and situational awareness., 12th European Conference on Severe Storms, Utrecht, The Netherlands, 17–21 Nov 2025, ECSS2025-313, https://doi.org/10.5194/ecss2025-313, 2025.