Departures from the normal range of sea surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with observed patterns of convective weather in the tropics indicate a strengthening El Nino pattern that should persist at least through the end of the Northern Hemisphere winter.

Sea surface temperatures in the eastern Pacific have ranged as much as 1.5 C higher than average, while below the surface, anomalies ranging from 1.5 to 5.0 C have been observed in the upper 300 m layer, patterns that are consistent with an established El Nino event.

Temperatures at the ocean’s surface have a large influence on the weather above, as thermal energy is transferred from the water to the air. Persistent areas of higher pressure consistently form in the atmosphere above warmer ocean waters, a scenario that NOAA forecasters expect to unfold over the coming months.

Most of the forecast models used to predict the strength and duration of El Nino suggest that it could last into the March-May 2010 period, with its intensity likely peaking within the moderate range and lasting through the Northern Hemisphere winter.

That could be very good news for people who enjoy mild temperatures and less snow in the north-central United States and southern portions of the Canadian Prairie Provinces, where the potential impact of El Nino is expected to include above normal temperatures and below normal precipitation during the winter months.

Map Courtesy Unisys Weather