More from Prof Cliff Mass of the University of WA
The Blob is Weakening
It is sad but true. The Blob, the area of above normal sea surface temperatures in the northeast Pacific, is weakening, particularly near the U.S. West Coast.
The plot of the sea surface temperature anomaly (difference from normal) for today (Wednesday) shows normal or even below normal sea surface temperatures along the west coast and extending well offshore of the Northwest.
This is a major change over the past few weeks. A few months ago the sea surface temperatures off our coast were roughly 5F above normal. No more. There is still some BLOB warmth further offshore, but I suspect that will weaken over time now.
Another way to see that change is to look at one of the offshore NOAA buoys. Take buoy 46089 located off the Columbia River (see map)
In early September, the sea surface temperature at that location was up to around 67F, which is very warm. The temperatures have fallen to about 60F today, a large drop of 7F.
Other buoys have shown the same thing.
Why the change? The upper level flow pattern has changed dramatically. Well into September there was anomalous high pressure over the Pacific (red colors below, Sept 22-28). High pressure is associated with light winds and weaker than normal mixing in the upper ocean. With less mixing of cold water to the surface, the surface temperatures are above normal.
But the pattern has really changed recently, with below normal sea level pressure (low pressure systems with strong winds) now over the Gulf of Alaska. Bad for the BLOB.
We are now going into the stormy season for the North Pacific and it is unlikely that conditions will be good for the BLOB. Expect more weakening during the next week
And this is all good news. Excessively warm water in the NE Pacific is bad for the marine food chain, leading to poor salmon runs and other problems. So although the Blob may be sad, this is positive news for everyone else.
YES!
