Whether it is heavy rainfall, snowfall, freezing rain or heatwaves, many weather situations today appear more extreme and, above all, more persistent. For operational managers in municipalities, transport companies, maintenance services and infrastructure organisations, this means increasing pressure on planning, resources and response capabilities.
One of the key drivers behind this trend is a large-scale atmospheric circulation pattern known as meridionality.
When Weather Patterns Become Stagnant
The winter of 2025/26 clearly demonstrated how significantly the usual westerly circulation weakened over extended periods. Instead of frequent weather changes, the atmosphere was dominated by large north-south wave patterns. As a result, high- and low-pressure systems remained nearly stationary for days and, in some cases, even weeks.
For operational teams, this has one direct consequence: weather situations persist for longer periods, placing sustained pressure on roads, infrastructure, personnel and logistics.
Meridionality Explained: When the Jet Stream Becomes Blocked
Under normal conditions, weather across Central Europe is strongly influenced by westerly winds. Low-pressure systems move in from the Atlantic and are followed by high-pressure systems, creating a relatively regularsuccession of changing weather conditions.
During meridional weather patterns, this process changes significantly. The jet stream begins to develop large meanders, promoting pronounced north-south movements of air masses.
The consequences are clearly noticeable:
- Weather systems move much more slowly or become almost stationary.
- High- and low-pressure systems can block one another.
- Periods of cold, wet, hot or dry weather last considerably longer.
- Extreme weather events can intensify and occur repeatedly.
Meridionality at a Glance
Meridionality describes an atmospheric circulation pattern in which air masses are transported primarily in a north-south direction.
Typical characteristics include blocking high-pressure systems, a slower progression of weather patterns and prolonged weather situations.
From an operational perspective, this means that weather may become less predictable in detail, but more predictable in terms of its duration—provided that the development is identified at an early stage.
Winter Maintenance Under Critical Conditions: Ice, Freezing Rain and Sustained Operational Pressure
Meridionality becomes particularly critical during winter when stationary air mass boundaries develop. In these situations, air masses with different temperatures remain in place for extended periods without either side gaining dominance quickly.
In extreme cases, this can lead to frequent and difficult-to-predict transitions between different forms of precipitation, including snow, sleet and freezing rain. Even slight temperature variations around the freezing point can determine whether precipitation falls as rain or turns into ice almost immediately.
Freezing rain is one of the most hazardous winter weather phenomena for road operations, as it freezes instantly upon contact with cold surfaces and can create extremely slippery conditions within a very short period of time.
Practical Tip: Anticipate Critical Weather Situations Early
When a stable air mass boundary is expected to develop, operational decisions should not be based solely on current conditions, but also on the forecast evolution over the coming hours.
Temperatures close to 0°C are particularly critical, as even small fluctuations can rapidly change the type of precipitation and the resulting road conditions.
Winter Operations Planning: When Standard Procedures Are No Longer Enough
For winter maintenance services, the challenge rarely lies in a single snowfall event. The real difficulty arises when the same weather pattern persists or repeatedly redevelops over many hours or even several days.
In practice, this results in significantly shorter windows for preventive action, a substantial increase in de-icing material consumption, and prolonged demands on personnel and vehicles. At the same time, requirements for shift planning and logistics increase considerably, while conditions must be continuously reassessed whenever temperatures remain close to the freezing point.
Under these circumstances, standard operating procedures quickly reach their limits. Accurate forecasts, up-to-date observational data and flexible decision-making become essential.
Predominant wind direction in Central Europe within the temperate zone: from west to east, commonly referred to as the “Westerly Wind Zone”.
“Winter weather in Central Europe has traditionally been dominated by westerly weather patterns. As a result, many winter seasons have been comparatively mild. An analysis of the large-scale weather patterns during the winter of 2025/26 revealed that westerly weather situations were almost entirely absent. The traditional ‘Atlantic engine’ barely got started throughout the entire season. A situation of this magnitude is exceptionally rare within the last 140 years.”
Gregor Neubarth, Graduate Meteorologist and Deputy Head of Meteorology at Weather Solutions.
Summer Impacts: Heatwaves and Pressure on Infrastructure
The effects of meridionality do not end with the winter season. The same blocked circulation pattern can produce the opposite effect during summer.
Blocking high-pressure systems inhibit the exchange of air masses, allowing warm air to remain over the same region for days or even weeks.
The consequences include prolonged heatwaves, increasing drought stress on urban green spaces and trees, and growing water demand. At the same time, employees working outdoors face greater exposure to heat, while roads and railway infrastructure experience increased stress due to prolonged high temperatures.
As a result, the operational challenge shifts from winter maintenance to water management, infrastructure maintenance and heat protection measures.
Practical Tip: Reallocate Resources Early
During persistent high-pressure situations, it is advisable to plan additional resources for irrigation, cleaning operations and infrastructure inspections at an early stage.
In these cases, the duration of the weather situation is often more significant than its intensity.
Managing Extreme Weather More Effectively: What Meridionality Means for Operational Planning
Meridional weather patterns affect operations throughout the entire year, as both winter and summer can be influenced by the same persistent circulation structures.
For this reason, infrastructure operators require tools that not only respond to short-term weather changes but also identify prolonged periods of operational stress at an early stage.
High-precision local weather forecasts, continuously updated information and reliable warning systems form the foundation for effective decision-making. Equally important are flexible personnel and resource planning processes, supported by robust operational decision-making tools.
Conclusion: It Is Not the Event That Matters Most, but Its Duration
Extreme weather situations are defined not only by their intensity but also by how long they persist. This is precisely what makes meridional weather patterns so challenging.
Those who recognise early signs that a weather situation is becoming stagnant can plan operations more effectively, allocate resources more efficiently and significantly reduce risks.
MeteoFocus helps you identify persistent weather situations at an early stage, enabling faster, more informed and more effective operational decisions.
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