PDC Updates | Jan 5, 2010
NOAA El Nino
PDC provides a list of links to El Niño-related resources maintained by the National Oceanic and Atmospheric Administration (NOAA). The December 2009 image of sea surface temperatures above is from NOAA's main El Niño Page.

The periodic current of warmer sea water in the Pacific, called El Niño, is occurring now. This phenomenon is defined by climatologists at the University of Illinois Urbana-Champaign this way: "El Niño (Spanish name for the male child), initially referred to a weak, warm current appearing annually around Christmas time along the coast of Ecuador and Peru and lasting only a few weeks to a month or more. Every three to seven years, an El Niño event may last for many months, having significant economic and atmospheric consequences worldwide. During the past forty years, ten of these major El Niño events have been recorded, the worst of which occurred in 1997-1998. Previous to this, the El Niño event in 1982-1983 was the strongest. Some of the El Niño events have persisted more than one year."

PDC Senior Weather Specialist Glenn James describes the effect of the current El Niño as likely to negatively impact rainfall totals. "In the Hawaiian Islands," he said, "the period of late autumn into the winter months is referred to climatologically as the wet season. Typically, this is a period during which we see frequent, rain-bearing cold fronts passing through the island chain and bringing good, soaking precipitation. For the 2009–2010 wet season, however, Pacific cold fronts have been "losing steam" before arriving. This is taking its toll on Hawaii's overall rainfall amounts, leaving the state in a relatively dry period."

James added, "The El Niño phase of the ENSO cycle is the most likely culprit, weakening these frontal passages, reducing the amount of replenishing rainfall. These dry aspects of the Islands' wet season will be occasionally punctuated by storms, perhaps even bringing local flooding conditions to the entire state. The dry winter, which when accompanied by a drier than normal spring, also can lead to drought conditions in the following summer and early autumn months. These droughts, at times in the past, have sometimes become severe, which can lead, in turn, to a busy wildfire season."

For additional, related information, refer to:

  • A plain-language definition of El Niño appears in some of PDC's hazard-related glossaries.
  • In a study of Dengue Fever in Hawaii, PDC pointed out some possible connections to El Niño.
  • University of Illinois Urbana-Champaign provides an online guide to El Niño.
  • Climate Progress news runs a sometimes "heated" discussion of El Niño and provides useful links.
  • The National Weather Service issued an analysis of the current El Niño on December 10, 2009.
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