You may be enjoying the past couple warm months in Calgary. November and December 2023 have been fabulous – unless you are a farmer. Calgary weather has seen warmer early winters but those usually occur with the help of a Chinook or a strong southern air mass – none of these are the case this year. Whether or not November 2023 to March 2024 will be the warmest winter ever in Calgary is something only time can tell. We do seem to be living in a two-month-long Chinook but something else is going on.
El Niño and La Niña are climate phenomena that occur due to variations in sea surface temperatures in the tropical Pacific Ocean. These events have significant impacts on weather patterns worldwide, including Calgary weather.
El Niño is characterized by warmer than average sea surface temperatures, while La Niña is characterized by cooler than average sea surface temperatures in the tropical Pacific Ocean. Both events have distinct effects on atmospheric circulation patterns, leading to changes in weather patterns.
Temperature: During El Niño, Calgary experiences above-average temperatures during the winter months. The warmer sea surface temperatures in the Pacific Ocean disrupt the normal atmospheric circulation and result in a weakened polar jet stream. This weakened jet stream allows warmer air masses to move northward, leading to milder winters in Calgary.
Conversely, La Niña tends to bring colder than average temperatures to Calgary during the winter. The cooler sea surface temperatures in the tropical Pacific Ocean strengthen the polar jet stream, allowing frigid Arctic air to move further southward, resulting in colder temperatures in Calgary.
Precipitation: El Niño typically leads to increased precipitation in Calgary during the winter months. The warmer sea surface temperatures in the Pacific Ocean enhance the evaporation of moisture, which is then transported by the atmospheric circulation towards Calgary. This increased moisture availability results in above-average snowfall and rainfall in the region.
On the other hand, La Niña tends to bring drier conditions to Calgary, particularly in the southern part of the province. The cooler sea surface temperatures in the tropical Pacific Ocean alter the atmospheric circulation, leading to a decrease in the transport of moisture towards Calgary. This reduced moisture availability results in below-average snowfall and rainfall in the region, potentially leading to drought conditions.
Other Weather Conditions: El Niño and La Niña also impact other weather conditions in Calgary. During El Niño, there is an increased likelihood of experiencing more frequent and intense winter storms. These storms can bring heavy snowfall and strong winds to the province. Additionally, the warmer sea surface temperatures associated with El Niño can also influence the development and track of tropical storms, which can indirectly impact Calgary’s weather.
During La Niña, Calgary may experience fewer winter storms, as the cooler sea surface temperatures tend to suppress storm development. However, when storms do occur, they can be more intense and bring heavier snowfall. La Niña can also enhance the risk of cold air outbreaks, leading to prolonged periods of frigid temperatures in the province.
Scientific research and data have provided valuable insights into the relationship between El Niño, La Niña, and weather patterns in Calgary. Historical records and climate models have helped identify these patterns and understand the underlying mechanisms driving these phenomena.
Understanding the impacts of El Niño and La Niña on Calgary’s weather is crucial for various sectors, including agriculture, water management, and energy. Farmers can adjust their crop choices and irrigation practices based on the anticipated precipitation patterns. Water managers can plan for potential droughts or floods, while energy producers can anticipate changes in energy demand due to temperature variations.
El Niño and La Niña have significant impacts on weather patterns in Calgary. El Niño brings milder winters, increased precipitation, and more frequent winter storms, while La Niña brings colder winters, drier conditions, and fewer but more intense storms. Understanding these effects is essential for adapting to and mitigating the potential implications on various sectors in the region.
