Cyclone Floris (Ning) is a game changer – a catalyst for meteorological chaos
At the threshold of the second ten-day period of August 2025, Europe is experiencing an unprecedented meteorological scenario, defined by a powerful cyclone Floris (Ning according to the nomenclature of the Free University of Berlin). Storm Floris was named on August 1, 2025 by the Meteorological Service, on the same day it was also named Ning by the Free University of Berlin. Floris is classified as a Shapiro-Keizer cyclone, a type characterized by a warm core surrounded by cooler air to the north, west, and south.
This rare intense cyclone for August is becoming a key player in the continent’s atmospheric dynamics, creating a unique synoptic situation: on one side, a strong cyclonic influence in the north, on the other, a recovering subtropical ridge in the south. The current week represents a turning point between these two diametrically opposed atmospheric regimes.
Last week’s weather apocalypse: Atmospheric collapse revealed
The past week has provided a textbook example of how the collapse of a heat dome can unleash unprecedented atmospheric fury over continental Europe. The weather pattern followed a classic, but extreme, scenario: a powerful high-altitude trough cut through a previously dominant ridge, creating colossal instability.
In Paris, the temperature at Orly airport reached 37.2°C before a sharp drop in temperature during thunderstorms. Météo-France recorded supercell thunderstorms with precipitation of 25-50 mm in 1-2 hours, hail of 3-5 cm in diameter, wind gusts up to 120 km/h and continuous lightning.
The most destructive phase occurred when the increased potential for tornadoes and very large hail (5 cm and more) was realized. One documented supercell maintained a coherent structure over 260 kilometers for 5.5 hours – evidence of extraordinary atmospheric energy.
This summer has systematically shattered temperature records across Europe. France and the Benelux countries experienced the largest deviations from average values, with anomalies of +10°C to +14°C above the climate norm, according to ECMWF data confirmed by Météo-France. These are not marginal increases – we are dealing with temperature anomalies that would have been considered statistically impossible just two decades ago.
Heat indices have reached life-threatening levels, with temperatures on the Italian island of Sicily rising to 44°C during the peak of the recent heat wave. Particularly worrying from a climatological perspective is their persistence and spatial scope – entire countries have experienced extreme heat stress simultaneously.
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Se emitieron advertencias meteorológicas para millones de personas en Escocia, norte de Inglaterra e Irlanda del Norte.
Cyclone Floris: The Arctic Orchestrator of European Weather
Structure and Dynamics of an Exceptional Storm Formation
Cyclone Floris is a classic example of a Shapiro-Keyser cyclone, a rare atmospheric structure with a warm core surrounded by cold air masses. The weather is rarely this windy in August, making it more dangerous. The storm’s frontal system wraps around its centre, forming a distinctive comma in the cloud cover.
Floris’ explosive cyclogenesis-development occurred at a remarkable rate, resulting in record winds in Northern Ireland – gusts of up to 145 km/h (90 mph) knocking down trees across Scotland. The Met Office issued an amber wind warning for Scotland, indicating a potential risk to life and property.
Mechanism of action and continental Europe
The position of Floris over Finland and the Scandinavian region creates a unique synoptic configuration. The cyclone acts as a powerful “atmospheric vacuum cleaner”, sucking cold Arctic air masses southward while blocking the northward advance of the subtropical ridge.
The key effect is the creation of a sharp temperature gradient: the cold sector of the cyclone cools Scandinavia and northeastern Europe to 16-22°C, while the southern regions remain under the influence of the recovering heat dome. This contrast creates ideal conditions for intense cyclogenesis and the development of frontal systems.
Heat dome mechanics
The fundamental driver of this summer’s extreme weather has been an unusually persistent and intense subtropical ridge – what meteorologists call a “heat dome”. This high pressure system acts as a lid on the atmosphere, trapping heat at the surface, creating downdrafts that inhibit cloud formation and precipitation.
When such systems finally break down, the stored atmospheric energy is released explosively. The temperature gradient between the superheated air mass and the incoming cooler air creates a huge instability, measured in CAPE (Convective Available Potential Energy) values exceeding 4000 J/kg – in the “extreme” category, supporting the development of supercell thunderstorms.
Current status of MeteoAlarm in Europe
MeteoAlarm serves as an early warning system that visualizes and aggregates warning information from 38 European National Meteorological and Hydrological Services. As of 4 August 2025, active warnings include:
Critical Heat Warnings (Red):
Southern Spain (Andalusia, Extremadura)
Southern Italy (Sicily, Sardinia, Calabria)
Southeastern France (Provence-Alpes-Côte d’Azur)
Severe Weather Warnings (Orange):
Central Germany (Thuringia, Saxony) – potential for thunderstorms
Eastern Austria (Burgenland) – risk of severe storms
Northern Switzerland – potential for heavy rain and hail
General Weather Warnings (Yellow):
Most of Central Europe Temperature and Storm Patterns
Weekly forecast to 10 August 2025
ECMWF and WRF model analysis
The latest monthly weather forecast for Europe for August shows a cooler start to the month over central parts, but a new subtropical ridge pattern is now forecast to return with a low pressure area locked in the north, creating a new heatwave scenario over the continent.
Daily breakdown including Floris influence:
Monday 4 August: Peak impact of Cyclone Floris. The cyclone’s centre over southern Finland is generating powerful westerly and northwesterly flows over northern Europe. The storm hits the UK with gusts of up to 145 km/h, causing chaos for transport and power grids. The cold sector of Floris cools Scandinavia to 15-19°C, while the frontal system extends to Central Europe, bringing thunderstorms and a temperature drop to 22-26°C in Germany and Poland. Southern Europe remains isolated from the cyclonic influence with temperatures of 35-39°C.
Tuesday, August 5: Floris slowly moves northeast, but its influence remains. Occluded fronts stretch from the Baltic Sea through Poland to the Alps, creating a strip of instability. The temperature contrast between the cold sector of the cyclone (Scandinavia 14-18°C) and the southern regions (Spain 38-40°C) reaches a critical 22-24°C at a distance of 1,500 km. This gradient activates the jet stream and creates the prerequisites for intense mesoscale processes.
Wednesday, August 6: A critical transition day under the cyclone’s dictation. Floris weakens over northern Scandinavia, but its extensive circulation continues to modulate the atmospheric dynamics. Secondary cyclonic activity is formed over Central Europe – “daughter” cyclones develop along frontal zones. WRF models show the beginning of the recovery of the subtropical ridge, but under the constant “pressure” of Arctic air masses from Floris. Temperatures: Scandinavia 16-20 °C, Central Europe 24-28 °C, Mediterranean 39-42 °C.
Thursday, August 7: Floris effect: long-range modulation of the atmosphere. Despite the geographical distance of the cyclone center, its influence is manifested through teleconnections – modification of planetary waves and the jet stream. Cold air masses attracted by the cyclone create a stable temperature contrast, preventing the rapid establishment of a thermal dome. The subtropical ridge is strengthening more slowly than usual: France 30-34°C (instead of the predicted 32-36°C), Germany 28-32°C, Spain 42-44°C.
Friday, August 8: Gradual dominance of the heat dome with the Floris modulation persisting. The cyclone over Northern Scandinavia still generates cold advective flows creating frontogenesis over Eastern Europe. This leads to the formation of mesoscale convective systems along the temperature boundaries. ECMWF shows the establishment of heat, but with regional variations: Western France 36-39°C, Eastern France 33-36°C due to frontal activity, Germany 31-35°C, Spain 43-45°C.
Saturday, August 9: Floris aftereffect and peak heat. The residual circulation from the cyclone creates wave disturbances in the jet stream, generating local areas of convergence and divergence. This leads to a mosaic distribution of temperatures instead of uniform heat. The most extreme temperatures are reached in zones farthest from the Floris influence: Central Spain 45-47°C, Southern France 39-42°C, but with local “cool islands” in the frontal influence zones 35-37°C.
Sunday, August 10: Floris-initiated convective activity. Temperature contrasts created by the interaction of the cyclone and the heat dome reach critical values for mesoscale cyclogenesis. Intense convective complexes are formed along the boundaries of air masses. The potential for supercell thunderstorms is greatest in the zone 200-400 km from the boundary between the cold masses (legacy of Floris) and the heat dome. CAPE values reach 4500-5000 J/kg in the convective zone.
Precipitation and storm forecast under the influence of Floris
Cyclone Floris is dramatically changing the convective potential of Europe. Instead of the typical suppression of thunderstorm activity for the heat dome, the presence of Arctic air masses creates powerful frontal zones with extreme instability.
Monday-Tuesday: Direct impact of occluded Floris fronts. Intense precipitation (30-60 mm in 6 hours) in a strip from the Baltic to the Alps. Hail up to 3 cm in size in supercells along the most active parts of the front.
Wednesday-Thursday: Secondary cyclones forming on frontal waves. Mesoscale convective systems with potential for stationarity – flash flood hazard in foothill areas.
Friday-Sunday: Floris-modulated convection. Temperature contrasts of 15-20°C over short distances create explosive-type thunderstorm development. CAPE values of 4000-5000 J/kg in convergent zones – potential for tornadoes and destructive hail with a diameter of 5+ cm.
The most dangerous interaction zones are those between the cold masses of Floris and the heat dome: the Hamburg-Prague-Vienna line poses the greatest risk for Sunday supercell outbreaks.
Iberian Peninsula:
Heat epicenter throughout the week. A stable southwesterly flow maintains the influence of the Saharan air mass. Nighttime temperatures may not fall below 25°C in many places – dangerous for vulnerable populations without adequate cooling.
France:
Experiences the most dramatic temperature rise, from comfortable conditions on Monday to potentially dangerous heat by the weekend. The Loire Valley and Rhone Corridor are particularly at risk due to topographic heat channeling.
Germany and Central Europe:
Located at the epicentre of the Floris influence. The early week is characterised by frontal activity with temperature differences of 8-12°C per day. By the weekend experiences the most dramatic temperature contrasts – from a cool 28°C in the frontal influence zones to 36°C in the heat dome sectors.
Scandinavia:
Remains under the direct influence of the cold Floris sector throughout the forecast period. Temperatures 14-20°C with strong winds and heavy rainfall. Finland experiences the most intense cyclone with gusts up to 100 km/h and waves in the Baltic Sea up to 4-5 meters.
British Isles:
Maximum impact early in the week. Scotland experiences damaging winds with widespread tree felling and power outages. By midweek the cyclone shifts eastwards but residual effects maintain unsettled weather.
Outlook
Medium-term forecast (11-20 August)
ECMWF ensemble runs indicate possible formation of secondary cyclonic systems in the frontal wave zone left by Floris. There is a 65% chance of a new intense cyclone developing over Central Europe by 15-17 August.
The subtropical ridge, currently held back by the influence of Floris, may compensatorily strengthen after August 12, leading to even more extreme heat in the third ten-day period of the month.
Seasonal implications
Floris may become a trigger for the restructuring of the entire seasonal pattern. There is a risk of establishing a stable meridional circulation regime with repeated intrusions of arctic air masses with abnormally warm periods.
This could lead to the formation of a “multipolar” autumn with extreme temperature fluctuations and increased storm activity.
The Founder and Chief Meteorologist at Pogodnik.com. With over 15 years of operational experience in synoptic analysis and climate forecasting, he specializes in storm tracking, magnetic storms, and atmospheric dynamics. A recognized expert in Ukraine’s meteorological sector, he maintains strategic collaborations with global agencies, including NOAA and ECMWF, to ensure high-precision data integration. His analytical reviews and scientific contributions are regularly featured in leading media outlets dedicated to weather science and environmental trends.
