What is Coming El Nino or La Nina?
After the very strong El Nino of 2015, water temperatures in the Pacific cooled to near to a little below normal in the subtropical Pacific between South America and Australia. Since late 2016 to early 2017 water temperatures have been only slightly cooler than normal and a weak La Nina developed.
Although a La Nina developed it was a very weak one. The long range modeling had suggested a strong La Nina was possible in 2017, however, recent trends are showing that the colder waters are not developing as strongly as anticipated.
When conditions reach weak or neutral water temperatures we called this a “La Nada”. It is not an El Nino or a La Nina. These neutral conditions sometimes bring us high variability in temperature and precipitation across the USA. This variability is something we have witnessed so far this season.
The chart below highlights changes in drought state over the past six months in the west.
The weak La Nina/La Nada pattern has brought much above normal precipitation in the far west, especially west of the Continental Divide. This pattern has alleviated much of the drought in the far west.
However, the rain shadow east of the Rockies some dry areas of have shown up over some areas of the High Plains of eastern Colorado.
Over the past 52 weeks the change in drought status has favored the west while dry areas have developed in some areas of the Plains, Southeast and Northeast.
The latest forecasts for water temperatures in the subtropical Pacific are hinting at slightly warmer than normal water temperatures heading into summer and fall 2017. Below is a summary of models predicting subtropical Pacific waters to warm to near to a little above normal as the year progresses (the zero line representing normal).
With the waters not far from normal heading into the rest of the winter and into spring, expect more variability in the weather patterns across the USA.