What impacts could El Niño leave this autumn in Spain? The forecast: more heat, more intense rains, and a lot of uncertainty.

AEMET does not publish a detailed step-by-step “manual” on how it updates its seasonal forecasts during El Niño or La Niña episodes, but based on its official notes and public explanations from its officials, a fairly clear outline can be reconstructed: it is a continuous process based on global observations, numerical climate models, and a cautious probabilistic interpretation of the results.

1. Starting point: climate and ENSO monitoring

According to AEMET itself, its forecasting and monitoring work relies on observation networks and numerical models that anticipate the evolution of weather and climate (institutional description collected in the interview with its president in Demócrata). At the climate scale:

• Long series of temperature and precipitation over Spain are monitored, which are then summarized in seasonal balances (for example, the spring 2026 balance published by MITECO and AEMET, where the season is compared with the 1991‑2020 period and a seasonal forecast is issued for the following summer: note on spring 2026).
• In parallel, the evolution of the ENSO phenomenon (El Niño–Southern Oscillation) is followed. The literature cited in the press and organizations such as OMSA remind that El Niño and La Niña are temperature anomalies in the tropical Pacific capable of altering global patterns of rainfall, temperatures, and winds (explanatory piece on ENSO).

This contextual information (state of the Pacific, other oceanic anomalies, atmospheric circulation…) is the basis that feeds the seasonal forecasting models.

2. Scenario generation with numerical models

AEMET emphasizes that its seasonal scenarios:

• Are based on numerical climate models, similar to those used for weather forecasting but designed for horizons of several months.
• Are always expressed in probabilistic terms, not as a deterministic forecast of specific days. In several official notes (for example, the winter or autumn 2024 summaries, or the spring 2026 balance) there is systematic mention of the “most probable scenario” and probability ranges of 40‑50‑70% that the season will be warmer or wetter than normal.
• Are generated for moving quarters (for example, April–May–June or July–August–September), approximately coinciding with astronomical seasons, and are accompanied by an interpretative comment on what “warmer” or “drier” means in terms of anomaly relative to 1991‑2020.

In El Niño or La Niña episodes, the ENSO signal is incorporated as a starting condition (forcing) of these models: it is not “added manually” over the forecast, but integrated into the physical system that simulates the atmosphere and ocean. What AEMET does afterward is assess to what extent that signal translates into a robust anomaly over Spain.

3. Periodic updating and uncertainty management

AEMET constantly emphasizes two ideas:

• Seasonal forecasts have greater uncertainty than short-term forecasts; the probability of success decreases with the lead time and scenarios may change in subsequent updates.
• Its role is to update the information as new data and new model runs come in, very similarly to what is done with special short-term bulletins (such as the one issued for the August 12 eclipse, which was updated daily as the date approached: note on eclipse).

At the seasonal level, this translates into monthly revisions of the predicted temperature and precipitation anomaly maps. If the actual ENSO evolution differs from what was forecast — for example, an El Niño that remains weaker or intensifies toward a “very strong” episode — the models are re-run with the new observed ocean state and probabilities are adjusted.

4. Interpretation for Spain and public communication

Once the scenarios are generated, AEMET's climatology team:

• Summarizes the results in bulletins and press conferences where probability maps by regions (Peninsular, Balearic Islands, Canary Islands) are presented, as seen in the climate summaries accompanying MITECO notes.
• Emphasizes that seasonal forecasts are a planning tool, not a substitute for daily warnings. Therefore, it is stressed that even if a “warmer than normal” summer is forecast, specific episodes (heat waves, DANAs, storms) must be managed with short-term forecasts and the Meteoalert system.
• In risk contexts (extreme heat, fires, floods) coordinates its messages with Civil Protection or other agencies, to integrate the seasonal signal into emergency management.

In summary, in the face of phenomena like El Niño or La Niña, AEMET does not change its method but strengthens the monitoring of these global anomalies, incorporates them into its climate models, updates seasonal scenarios monthly, and communicates probabilities and limits cautiously: the goal is to anticipate background trends (more heat, more or less rain, more storms), not to promise a detailed calendar of episodes.

The State Meteorological Agency (AEMET) is the national meteorological service and the State meteorological authority. Regarding warnings and alerts, its role is essentially technical and preventive: it is responsible for monitoring the atmosphere, forecasting adverse phenomena, and issuing official risk warnings, which serve as the basis for decisions by Civil Protection and other administrations.

Legal basis of its competencies

• The Spanish Constitution, article 149.1.20., grants the State exclusive competence over the meteorological service. Various resolutions and agreements of AEMET with universities and autonomous communities recall that the Agency exercises this competence as the national meteorological service.
• The Royal Decree 186/2008, which approves the AEMET Statute, develops this function and recognizes it as the State Meteorological Authority, responsible for the direction, development, and coordination of meteorological activities at the national level (art. 8). See, for example, the agreement resolution with the University of Barcelona published in the BOE: text in the BOE.
• The Statute itself connects with the Law 40/2015, on the Legal Regime of the Public Sector, which regulates collaboration agreements through which AEMET articulates its cooperation with autonomous communities for managing adverse meteorological phenomena, as in the case of Illes Balears: agreement with Balearic Islands.
• In the emergency field, the Law 17/2015 of the National Civil Protection System and the various territorial and special plans (floods, fires, etc.) take AEMET warnings as technical reference to activate pre-emergency or emergency phases.

AEMET warnings versus Civil Protection “alerts”

The press and recent parliamentary appearances emphasize a key distinction:

• Meteorological warnings are technical–scientific and issued by AEMET. They indicate that potentially dangerous phenomena (intense rain, storms, wind, snow, extreme heat, coastal phenomena, etc.) are expected with certain thresholds and probabilities.
• Civil Protection alerts (including ES-Alert mobile alerts) are administrative and operational: they are activated by the competent Civil Protection authorities (regional or state) when, in view of those warnings and other factors (orography, exposed population, infrastructure, etc.), it is considered necessary to activate plans, order evacuations, confinements, or transmit urgent instructions to the population.

An article from Demócrata summarizes it as follows: AEMET “is the body responsible for predicting meteorological phenomena and issuing risk warnings,” while the ES-Alert mobile alerts are a Civil Protection tool based on those warnings but decided by emergency authorities, not by the Agency.

Operational functions of AEMET in warnings

In the daily management of meteorological risks, AEMET's competencies include:

• Continuous monitoring and forecasting of the atmosphere through observation networks, radars, satellites, and numerical models, reinforced in singular episodes (for example, special bulletins for phenomena like an eclipse with large public attendance, as explained by the Government in this official note).
• Issuance of official warnings within the National Plan for Prediction and Monitoring of Adverse Meteorological Phenomena (Meteoalerta), with standardized levels:
  • Yellow: low danger, but with possible impacts on sensitive activities or vulnerable groups.
  • Orange: significant risk to people and property.
  • Red: extreme risk, with potential for very serious and widespread damage.
  These thresholds are adapted to the climatic characteristics and vulnerability of each area.
• Priority information in emergency coordination centers (such as CECOPI in major crises), where the AEMET representative “analyzes meteorological evolution” and provides real-time data on rainfall and other parameters, considered official and priority information for decision-making.
• Collaboration with autonomous communities through agreements to:
  • Exchange observation network data.
  • Develop specific forecasts oriented to Civil Protection.
  • Develop adverse phenomenon prediction products adapted to the territory, strengthening resilience and response capacity.
• Naming of storms and high-impact DANAs, in European coordination, linked to the forecast of orange or red level warnings; this practice aims to improve risk communication and institutional preparedness, as explained by MITECO in this note.
• Technical support to Civil Protection and other services (112, transport authorities, health, etc.), providing specific information that allows adjusting the activation of plans and devices in the face of storms, heat waves, snowfalls, forest fires, or other risks.

In summary, AEMET does not “order” emergencies nor decide operational alerts, but it does concentrate the state competence to monitor the weather, forecast adverse episodes, and issue official warnings that serve as the scientific basis for decisions by Civil Protection and other administrations in Spain.

Coordination between national meteorological services and the European framework in the face of extreme climate phenomena is supported by a set of Spanish state regulations, international agreements, and, broadly speaking, the EU civil protection framework. Based on what is recorded in the BOE and official texts, several clear legal pillars can be identified.

1. AEMET Statute as national meteorological service

The core of Spanish regulation is the Royal Decree 186/2008, of February 8, approving the Statute of the State Meteorological Agency (AEMET) (official text).

Its preamble defines AEMET as the National Meteorological Service (NMS) and expressly emphasizes:

• That, according to the World Meteorological Organization (WMO), NMSs are the instrument to fulfill governmental commitments of data and essential product exchange with other countries, among other things for maritime and air transport safety.
• That the then National Meteorological Institute (now AEMET) carries out its mission in close collaboration with meteorological services of other countries, in organizations such as the WMO, EUMETSAT, EUMETNET, the European Centre for Medium-Range Weather Forecasts (ECMWF), and the Earth Observation Group.

Although the detailed articles are not reproduced here, the Statute configures AEMET as the state body responsible for both international data exchange and operational cooperation, which is the legal basis for its coordination with European observation and forecasting systems used in extreme episodes.

2. Civil protection framework and use of meteorological information

From the emergency management perspective, the key piece is the Law 17/2015, of July 9, on the National Civil Protection System (official text).

Its preamble:

• Recognizes that disaster risks — including those derived from climate change — can affect national security.
• Highlights the development of alert systems and the need for integration, coordination, and efficiency among all administrative levels.
• Explicitly mentions the European Union Civil Protection Mechanism, based on solidarity and collaboration among Member States, and states that the law must facilitate compliance with commitments assumed in that international and European framework.

Law 17/2015 itself foresees state networks of information and alert (such as the National Civil Protection Alert Network), which are fed by specialized sectoral data, including meteorological data provided by AEMET, and which are articulated with the EU civil protection cooperation instruments.

3. Specific European agreements on forecasting and observation

a) European Centre for Medium-Range Weather Forecasts (ECMWF)

Spain's participation in ECMWF is channeled through the Amendment Protocols to the Convention establishing the European Centre for Medium-Range Weather Forecasts, ratified by Spain through the Ratification Instrument published in the BOE (BOE-A-2011-2750).

These protocols reform the Convention to strengthen the Centre's objectives: developing medium-range weather forecasting capacity and supplying those forecasts to Member States, with a clear vocation as a joint international program when resources “generally exceed the national framework.” They imply a stable framework for the coordinated access of national meteorological services to European forecasting products.

b) European Organization for the Exploitation of Meteorological Satellites (EUMETSAT)

In the satellite field, coordination is supported by the Amendment Protocol to the Convention establishing the European Organization for the Exploitation of Meteorological Satellites "EUMETSAT", accepted by Spain and published as an Acceptance Instrument (BOE-A-2000-23493).

The amended text sets as EUMETSAT's main objective to establish, maintain, and operate European operational meteorological satellite systems and establishes that:

• EUMETSAT must cooperate as much as possible with governments and national bodies of Member States and third countries, as well as with scientific and technical international organizations.
• It may conclude agreements with these actors to develop its programs.

This obligation of structured cooperation is the legal basis for national meteorological services to receive homogeneous satellite data and for specific products to be designed for extreme risk management.

c) EUMETSAT–National Meteorological Institute (INM/AEMET) Agreement

More operationally, the Agreement between EUMETSAT and the National Meteorological Institute of Spain for the establishment and commissioning of a EUMETSAT Satellite Application Facility (SAF) to support nowcasting and very short-term forecasting (BOE-A-2000-9721) specifies that coordination.

The agreement:

• Defines the legal framework for the design, development, validation, and commissioning of a Satellite Application Facility (SAF) located in Madrid and managed by the then INM.
• Establishes that EUMETSAT finances the project and that all data, products, and software developed will be owned by EUMETSAT but will be freely available to all national meteorological services of the Member States.

This ensures a structured flow of specialized satellite products for nowcasting (key in severe convective phenomena, intense precipitation, etc.) that are redistributed from the national service to the European system and vice versa.

4. Connection with extreme episodes and civil protection

Although other cited regulations (such as the Royal Decree-law 11/2019, on urgent measures to mitigate damage from storms, BOE-A-2019-13409) focus on post-disaster aid, their application rests de facto on the analysis and forecasting services of AEMET and, therefore, on the cooperation network described (ECMWF, EUMETSAT, WMO, and the EU Civil Protection Mechanism).

Overall, the AEMET Statute, Law 17/2015, and the ECMWF and EUMETSAT agreements constitute the legal framework that enables and requires operational coordination, data exchange, and joint use of European observation and forecasting systems by national meteorological services, especially relevant when dealing with extreme climate phenomena.