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 weather advisory Significant weather advisory A significant weather advisory (alternately termed as a "significant weather alert" or a "special weather statement", the terminology varies depending on the local National Weather Service Weather Forecast Office) is issued when Doppler radar indicates a strong thunderstorm is producing small hail or high winds whose strength does not reach the criteria to be designated a severe thunderstorm. It does not necessarily account for lightning or flooding. This alert product was created in the early 2000s, and is sometimes a precursor to a severe thunderstorm warning. Many versions of the First Warning weather alert system used by