Why is it so warm in the North Atlantic?

Sea Surface Temperatue North Atlantic

The overall recent warming of the North Atlantic, particularly in the northeastern sector and the Atlantic Main Tropical Cyclone Development Region may be, in large part, due a combination of the Atlantic Multi-decadal Oscillation (AMO) being in its warm phase which raises the base sea surface temperatures in the North Atlantic and  warming resulting from the recent reduced trade winds in the tropics.

June 2023 North Atlantic surface pressure anomaly

Strong Warm AMO Pattern

Strong Warm AMO Pattern

Sea surface temperature (SST) anomalies in the Tropical North Atlantic have been increasing since April due mainly to a weakening and southward displacement of the Azores-Bermuda ridge. This weakening has reduced the trade winds.



The dominant cause of the warm SSTs  is due to weather patterns that reduced surface wind speed, which reduced evaporative cooling, and less cloudiness. 

Other factors include CO2 emissions, lower amount of sulfate particles from cleaner shipping fuels, Hunga-Tonga eruption, and low levels of African dust.

Since late June, the Azores-Bermuda ridge has begun to restrengthen somewhat and SSTs have fallen, however, they remain warmer than normal. 

Sea Surface Temperature for the Atlantic Main Development Region

About Fred Pickhardt

I am a marine meteorologist and sailed briefly with American Export Lines in the Far East trade after graduating from State University of New York Maritime College. I have extensive experience in weather analysis, weather forecasting, optimum ship routing, vessel performance evaluations and forensic weather event reconstructions. I founded Ocean Weather Services and as Owner and Chief Consultant currently provide optimum ship routing services and forensic marine weather reports to the maritime industry.
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