Blob Mania: Update from Rick Thoman

Sea surface temperatures in the northeast Pacific and most of the Gulf of Alaska remained significantly warmer than normal in January 2016. The “horseshoe-shaped” pattern of warmer-than-average (anomalous) water along Alaska, the west coast of North America, and westward to Hawaii is indicative of a positive Pacific Decadal Oscillation  (PDO) pattern.
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GODAS Image (courtesy of the NOAA/Climate Prediction Center) showing the January  upper 300 meter heat content and sea surface temperature (SST) anomalies (differences from the long-term average).

What does this mean in terms of the “Blob?”

The North Pacific Mode (NPM) Index (image below, courtesy Richard James, Prescient Weather, following Hartman, 2015) has crashed, falling from +1.35 in November to -1.05 in January. This is the most negative value of the NPM since June 2012. So if we consider the NPM loading pattern as the canonical Blob, then we might say the original Blob as we knew it has at long last gone the way of all blobs – away. However, if what we’re interested in is a continued pattern of unusually warm water in the northeast Pacific, well, that’s a story that lives on even though the original Blob mechanisms may no longer be in effect. — Rick

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At the moment, what is telling is the warm water in the Gulf of Alaska is more than skin deep, with significantly warmer-than-average water extending well below the surface. This is seen above in the upper 300 m heat content map and likely means that warm waters in the Northeast Pacific and impacts to ocean ecosystems will persist at least into the spring of 2016 and possibly longer.

–Rick

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