The past six months have been rather quiet for “blob watchers”, as the North Pacific temperature patterns have been mixed and variable. The North Pacific Mode has been oscillating between negative and positive phases with some regularity, and the PDO did the same thing for the second half of 2017 before turning modestly positive so far this year. It’s a bit unusual to have a … Continue reading North Pacific Forecast
Last week a paper by Yu-Chiao Liang and co-authors was published in the Journal of Climate discussing the connection between North Pacific “blob” warming and atmospheric flow patterns spanning the North American continent from the North Pacific to the North Atlantic. Among other interesting results, the authors showed that variations in sea surface temperatures in the “blob” region of the northeastern Pacific are rather closely … Continue reading Atmospheric Connection to the Blob
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 … Continue reading The Blob in Hibernation
Just a few weeks ago I highlighted the return to a strongly positive phase of the North Pacific Mode (NPM), caused by persistent high pressure over the northeastern Pacific Ocean during summer. Well, it didn’t last long. The circulation pattern has undergone a dramatic reversal, with numerous strong storms across the North Pacific, and sea surface temperatures have dropped precipitously in the “blob” region. The … Continue reading Dramatic Changes in Recent Weeks
Those who follow North Pacific temperature patterns closely are well aware that the past summer brought a dramatic expansion of above-normal temperatures at the ocean surface across the northern North Pacific Ocean, reversing the cold anomalies that developed last winter during the strong El Niño episode. The two maps below illustrate the change, based on OIv2 SST data. The late winter pattern was very characteristic … Continue reading Subsurface Conditions
In my post last month I mentioned that the recent reversal of the North Pacific Mode (NPM) phase was related to this winter’s El Niño event. In other words, when we saw El Niño developing last year, we might have anticipated that “the Blob” would probably lose some of its surface signature over the course of the winter; it wasn’t a surprise. The chart below illustrates … Continue reading Negative NPM Here to Stay?
Carol Janzen and Rick Thoman have graciously invited me to contribute here, and it is a pleasure for me to do so. By way of introduction, I’m Richard James, a meteorologist with Prescient Weather and an Alaska weather enthusiast. Last September I gave a talk about the North Pacific Mode (NPM, “the Blob”) and Alaska winter climate at the University of Alaska Fairbanks – see here for … Continue reading Subsurface Warmth Persists