Climate Change, the Jet Stream, and East Coast Atmospheric Rivers

by Daniel Brouse

How is climate change impacting the jet stream and atmospheric rivers on the East Coast of the USA?

The interactions between various factors, including ocean currents, sea surface temperatures, and atmospheric circulation, contribute to the overall climate patterns experienced on the East Coast.

Climate change can influence the jet stream and atmospheric rivers, impacting weather patterns on the East Coast of the USA. Here are some key ways in which these changes may occur:

Jet Stream:

1. Amplification and Slowing:
  - Climate change can lead to the amplification of atmospheric patterns, including the jet stream. This can result in larger north-south swings, which may contribute to more persistent weather conditions. Additionally, a warming Arctic relative to the mid-latitudes may slow down the jet stream.
2. Stalled Weather Patterns:
  - A slower, more meandering jet stream can lead to the persistence of weather patterns, causing prolonged periods of extreme conditions such as heatwaves, cold spells, or heavy rainfall.
3. Shifts in Track:
  - Climate change may alter the typical track of the jet stream, influencing where it tends to position itself. These shifts can impact regional weather patterns, including precipitation and temperature distributions.
4. Increased Amplification:
  - As the Earth’s poles warm faster than the mid-latitudes, the temperature difference between the Arctic and lower latitudes decreases. This reduction in temperature gradient may lead to a more meandering and slower jet stream with larger north-south waves, a phenomenon known as “jet stream amplification.”
5. Wavier Jet Stream:
  - The reduced temperature contrast between the Arctic and mid-latitudes can make the jet stream more susceptible to large, slow-moving waves. This wavier pattern can result in more persistent weather conditions, including prolonged periods of heatwaves, cold spells, droughts, or heavy rainfall.
6. Increased Blocking Patterns:
  - A wavier and slower jet stream can lead to the formation of blocking patterns, where high or low-pressure systems persist in a particular location for an extended period. Blocking patterns can contribute to prolonged and extreme weather events.
7. Slower Movement:
  - Some studies suggest that the jet stream is slowing down as a result of climate change. A slower jet stream can cause weather systems to move more slowly across the landscape, potentially intensifying the impacts of extreme events such as storms, heatwaves, or heavy rainfall.
8. Changes in Zonal Flow:
  - The jet stream typically flows from west to east in a relatively straight line, a pattern known as zonal flow. Climate change may lead to more frequent disruptions of this zonal flow, causing the jet stream to meander and creating conditions for more extreme weather events.
9. Impacts on Weather Extremes:
  - Changes in the jet stream can influence the occurrence and characteristics of weather extremes, including heatwaves, cold snaps, and intense storms. These changes can have significant implications for local and regional climate patterns.
Atmospheric Rivers:
1. Increased Moisture Content:
  - Warmer temperatures associated with climate change can enhance evaporation, increasing the moisture content of the atmosphere. This, in turn, can contribute to the development of more intense atmospheric rivers, which are channels of concentrated moisture in the atmosphere.
2. Changes in Intensity and Frequency:
  - Climate change may lead to alterations in the intensity and frequency of atmospheric rivers. There is evidence suggesting that these phenomena could become more common and more potent, leading to heavier rainfall events and an increased risk of flooding.
3. Altered Trajectories:
  - Changes in the jet stream’s position and behavior can influence the trajectories of atmospheric rivers. Variations in the jet stream can result in altered paths for these moisture-laden systems, affecting the regions that experience heavy rainfall and potential flooding.
4. Extreme Weather Events:
  - Atmospheric rivers are often associated with extreme weather events, including heavy rainfall and flooding. Changes in the characteristics of atmospheric rivers due to climate change can contribute to an increased likelihood of severe weather events on the East Coast.