Pacific Ocean To determine the phase of ENSO, the most recent three-month sea surface temperature average for the area approximately to the southeast of Hawaii is computed, and if the region is more than above or below normal for that period, then an El Niño or La Niña is considered in progress. In the tropical western Pacific, the monsoon and the related wet season during the summer months contrast with dry winds in the winter which blow over the ocean from the Asian landmass. Worldwide, tropical cyclone activity peaks in late summer, when the difference between temperatures aloft and sea surface temperatures
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