The Blob (Pacific Ocean) the surface waters of the mid-latitude Pacific Ocean flipping from a cold phase to a warm phase in a cycle known as the Pacific decadal oscillation (PDO). This poorly-understood change happens at irregular intervals of years or decades. During a warm phase, the west Pacific becomes cooler and part of the eastern ocean warms; during the cool phase, these changes reverse. Scientists believe a cold phase started in the late 1990s and the arrival of the Blob may be the start of the next warm phase. The PDO phases may also be related to the likelihood of El Nino events.
Significant wave height or RSMCs. In their weather products, they give ocean wave height forecasts in significant wave height. In the United States, NOAA's National Weather Service is the RSMC for a portion of the North Atlantic, and a portion of the North Pacific. The Ocean Prediction Center and the Tropical Prediction Center's Tropical Analysis and Forecast Branch (TAFB) issue these forecasts. RSMCs use wind-wave models as tools to help predict the sea conditions. In the U.S., NOAA's WAVEWATCH III model is used heavily. A "significant wave height" is also defined similarly, from the "wave spectrum", for the different systems that make up