Signs of La Nina Developing Continue
Sea surface temperatures in the subtropical Pacific continue to show signs of cooling and if current trends continue, we are likely going to be into an official La Nina by late summer and early fall.
The graphic below shows the changes in sea surface temperatures across the globe compared to a year ago. The blue/purple areas represent a drop in temperature while green and yellow/red represent increases in sea surface temperatures compared to a year ago. Note the stretch of blue and purple between South America and Australia. This is the area where La Ninas and El Ninos form. Also, note how with a few exceptions, sea surface temperatures are colder in many of the ocean basins across the globe.
In addition to observed changes in the sea surface conditions over the past year, computer modeling is also suggesting that La Nina will be in full swing late summer and early fall. The graphic below shows predicted sea surface temperatures from July through September.
Confidence is growing that La Nina will grow and strengthen as sea surface temperatures near the equator across the Pacific will continue to cool. The recent trends of drier than normal conditions in many western and central areas is a sign that La Nina is already impacting the weather patterns across the lower 48 states.