Turf MD: Be ready for El Nino to dominate the weather pattern

Over the last two or three years, La Nina has influenced winter weather throughout much of the country.

Karl Danneberger, Ph.D

This winter, that will change with an El Nino likely to dominate the weather pattern. The occurrence of an El Nino is thanks to Southern Oscillation (ENSO).

ENSO refers to the yearly cyclic variation in surface ocean temperatures and rainfall that occurs across the equatorial Pacific Ocean. ENSO is a significant global climate driver by changing the global atmospheric circulation, which in turn influences temperature and rainfall.

El Nino and La Nina refer to the extremes in the ENSO cycle. When the Pacific Ocean surface temperatures are warmer when compared to the average water surface temperature of the ENSO cycle, we refer to this as an El Nino.

Conversely, a La Nina occurs when the surface temperatures are cooler than average.

In the United States, we experience the greatest impact of an El Nino during the winter months from October through March. The impact of El Nino on the weather for a given portion of the country is not always predictable as there is no guarantee when it comes to the weather, especially when it occurs over a large geographical area like the United States.

However, given past El Nino events, we can draw upon that knowledge and predict within a reasonable range what will occur this winter and how that might influence management practices on golf courses nationwide.

What to expect

El Nino has the potential to accentuate turfgrass stress conditions. If we look at general trends associated with El Nino, we can expect changes in weather patterns across the country.

In southern parts of Texas, Louisiana, Mississippi, Alabama, Georgia, South Carolina and the northern part of Florida, cold and wet conditions are expected. These cool conditions are due to the shift southward in the jet stream that occurs during an El Nino phase. Along the jet stream storms increase in frequency and bring wetter conditions.

From a turfgrass management perspective, I might expect an increase in the potential for cold injury to southern turfgrasses through the southeast, especially along the jet stream path. Additionally, increased rainfall and potentially snow could increase the potential for flooding. In general bermudagrass and zoysiagrass have excellent flood tolerance.

In areas north of the jet stream, like the Midwest, expect drier and warmer temperatures compared to the averages. Being optimistic, warm and dry conditions may extend the golfing season in some areas. In areas where more play occurs, the potential for wear injury can increase. Wear patterns from golf cars and areas of golfer concentration like putting greens and tees will need to be monitored and practices instituted to account for increased wear.

In parts of the Midwest and northern Great Plains that have suffered degrees of drought during the fall, the increased potential for drier conditions could increase the potential for desiccation injury.

In the Mid-Atlantic area, El Nino is often associated with cooler temperatures. Increased precipitation in the form of both rain and snow is also expected. Microdochium patch could become severe, especially in areas where moderate levels occur during a normal winter.

Understanding what an El Nino is and how it might affect your local weather this year can warn you of potential turfgrass issues that could arise this winter. Now is the time to anticipate and identify potential turfgrass problems and develop strategies to address them.