April 7, 2011 in Washington Voices

La Nina keeps wet weather coming

Randy Mann
 

We’re in the first week of April and the moisture continues to fall. In fact, the first three months of 2011 were among the wettest in recorded history across parts of the Inland Northwest.

Total precipitation last month at the Spokane International Airport was 3.25 inches, the third-wettest March in recorded history. The normal is only 1.53 inches. The greatest amount of precipitation in March was 3.81 inches in 1995. Despite the near-record moisture, Spokane only received 3.3 inches of snow. In the past, when March was very wet, snowfall totals were usually much higher.

With the cloudy and rainy conditions, it certainly felt much cooler than normal. But thanks to some 50-degree temperatures toward the end of last month, the average temperature at the airport was only 0.2 degrees below normal. The mean temperature for this March was 39.3 degrees.

One of the reasons why we are seeing the abnormal wet weather pattern is the influence of La Niña. La Niña is the cooler than normal sea-surface temperature pattern in the south-central Pacific Ocean.

Earlier this year, it appeared that the moderate La Niña was weakening as sea-surface temperatures were beginning to warm up. Within the last several weeks, ocean waters near the South American coastline have been cooling down once again. It’s too early to tell, but if La Niña continues to regain its strength, then our cool and wet spring may drag on into June.

I still believe La Niña will weaken over the next few months. Therefore, it still looks as if we’ll have a warm and dry late spring and summer season. A strong stationary ridge of high pressure is expected to build into the region by late May and last through at least early September. This should mean many days this summer with afternoon highs near or above 90 degrees. Don’t be surprised to see at least three or four afternoons with readings near or above 100.

But, if ocean temperatures along the equator remain below normal through the end of this year, then our summer season may not be quite as warm and the winter of 2011-’12 may once again produce above-normal snowfall totals across the Inland Northwest.


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