It’s been about five months now since the North Pacific Mode, a useful measure of the “Blob” spatial pattern, turned negative. Cooler than normal sea surface temperatures across the northern North Pacific (but south of the Bering Sea) kept the NPM in the negative phase all winter, and the December-February average of the NPM index was the lowest since 2000-2001.
Here’s a recent weekly SST anomaly map derived from NOAA’s OISST data (1971-2000 climatology); the region of below-normal SSTs in the northeastern Pacific Ocean is now quite extensive and basically resembles the opposite of the notorious Blob pattern.
So is the Blob dead? From a surface perspective, the answer is definitely yes; but subsurface data indicate that warm conditions are still lingering below 100m depth in the northeast Pacific.
Here’s the latest vertical cross-section along 45°N, showing that the cool water in the northeast extends down to about 100m depth…
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