Arrow-right Camera
The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Weak El Niño could mean mild tropical storm season

Randy Mann

The latest sea-surface temperature analysis continues to have an expanding area of warmer ocean waters along the equatorial regions and along the west coast of South America. There is only a very small area of cooler waters near the South American coastline.

Within the last several months, there has been a dramatic reversal from cooler ocean temperatures, La Niña, to the warmer side, El Niño. Since late 2008, there has been a back and forth pattern of warming and cooling of sea-surface temperatures.

It now appears we’re in the beginning of a weak El Niño, the warmer than normal sea-surface temperature pattern. This phenomenon is also showing signs that it may become stronger over the next few months. Australian and Japanese scientists are already stating that we may have a weak El Niño.

If the ocean warming persists, then this tropical storm and hurricane season will likely be less severe. Ocean temperatures off the coast of Africa, where tropical storms typically form, are cooler than average. El Niño patterns often alter upper-level jet stream flows that become less favorable for major hurricane development.

During La Niña years, our region often experiences drier and warmer summers with cooler and wetter fall and winter seasons. Ocean temperatures were generally below normal, plus there was extremely low sunspot activity when we experienced some of the harshest winter conditions in recorded history in 2008 and early this year.

Normally during El Niño, much of the moisture falls south of our region. Los Angeles and most other cities in the southwestern U.S. see above-normal amounts of precipitation, mudslides and extreme beach erosion.

Although El Niño is still weak, I’m still predicting a rather short but very hot and dry summer in the Inland Northwest. The warmest weather should be sometime around the July 7-15 full-moon cycle. It’s possible that we will see an afternoon or two during that week with readings flirting with 100 degrees. Another hot spell may also be around the full moon in early August.

This fall may be wetter and cooler than in the past few years. If El Niño continues to expand, the upcoming winter season may be a bit drier than normal with more rain than snow.

Contact Randy Mann at randy@longrangeweather .com.