August 16, 2012 in Washington Voices

Weather: El Niño shows signs of weakening

Randy Mann
 

We haven’t received any measurable moisture at the Spokane International Airport since July 20, when .25 inches of rain fell. Temperatures have also climbed to above normal levels. For July through the middle of August, the average reading at the airport was about 2.5 degrees above normal.

For the summer, we’ve already seen 16 days with temperatures at or above 90 degrees. It looks like we’ll see a few more by early next week.

For the last several months, a new El Niño, the warmer-than-normal sea-surface temperature event in the south-central Pacific Ocean, was forming. During El Niño years, we often see milder winters with much less snow. Last month, it appeared that we were heading toward one of those years as El Niño was increasing.

However, the latest sea-surface temperature data indicates that ocean temperatures off the West Coast of South America and along the equatorial regions are falling. Also, there is a small and intensifying pool of cooler-than-normal ocean waters along the coast of South America. It’s too early to tell, but it’s starting to look like this new El Niño may be short-lived. In fact, that region of cooler waters needs to be watched very closely. In this pattern of wide weather extremes, it’s possible that we may be talking about a new La Niña by early 2013.

Based on the current data, it looks like we have a very weak El Niño. According to Australia’s Bureau of Meteorology, an agency that watches El Niños and La Niñas very carefully, “observations show a resumption of warming across the central tropical Pacific Ocean.”

With the recent overall trend of ocean warming, this may be one reason for the extreme heat and dryness for much of the U.S. that has led to widespread damage to the corn crop. However, there has been some minor relief that could be related to the weakening of this El Niño. Recent reports still indicate some of the worst crop losses in history.

Over the next 45 days or so, we could see a few isolated showers or thunderstorms, but most of the heaviest precipitation should remain over the higher mountains. The rest of the summer and early fall still looks drier and warmer than normal. But, if ocean temperatures cool down rather quickly, then all bets are off.

Contact meteorologist Randy Mann at randy@longrangeweather.com.


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