(SOUTHERN COLORADO) — We are currently in a La Nina pattern across the nation with a transition to El Nino appearing likely for the summer.
La Nina and El Nino are important aspects of meteorology. They can each play a large role in the weather we see here at the surface. They are also known as teleconnections, which are weather phenomenon that share a relationship or link through significant distances.
In the case of La Nina and El Nino, the relationship between sea surface water temperatures and the atmosphere above are explored. Specifically, the Pacific Ocean along the equator is where activity is closely monitored.
Trade winds, which are winds that are ever present, blow from east to west along the Equator. This sets the stage for pushing warmer ocean water away from the United States. Those warm waters play an important role in the thunderstorms and active weather that can form above.
During a La Nina winter, those trade winds get quite a bit stronger and push the warmer water even further away into the Pacific Ocean. Consequently, cooler water is able to rise from deeper in the Pacific Ocean. Meteorologists call this phenomenon ‘upwelling.’ With the cooler ocean water at the surface, less thunderstorms and active weather form directly above.
The connection back home in the United States typically leads to a shift in our jet stream. This shift can play a significant role in the number of storm systems that the region typically sees. The change in wind patterns often guides these storm systems away from Southern Colorado.
These fairly predictable teleconnections, El Nino and La Nina, lead to a reasonably good understanding of impacts for weather at the surface. Across the US, a few patterns regularly pop up during La Nina winters. Southern Colorado is right on the edge of the warm and dry ‘bubble’, which often leads to less active winters. Cooler air likes to settle in over the Canadian border. Easier access to moisture usually leads to wetter conditions over the Pacific northwest and portions of the Ohio River Valley.
As far as what’s ahead for us, the Climate Prediction Center (CPC) is keeping an eye on a pattern that largely reflects what these La Nina conditions typically look like.
For the month of March, the CPC is highlighting the potential for above average temperatures and drier than normal conditions here in Southern Colorado. The overall expected outlook for March lines up quite nicely for what the United States tends to see during a La Nina winter. Beyond the immediate region, the Pacific northwest may see abundant moisture as could areas around the Ohio River Valley.
If we know anything about Southern Colorado though, it’s that our weather likes to play by anything but the rules. Our lovely Rocky Mountains usually see to that.
