WASHINGTON — A season of warmer ocean waters that has been expected to produce a Niño episode and perhaps bring relief from the continuing drought may turn out to be a bit weaker than advertised, according to climate experts.

The periodic emergence of warmer waters in the eastern equatorial Pacific can be one of the most telling calls that a climatologist can make. A powerful Niño can drive global patterns of drought, storm, snow and flood, with big consequences for farmers and fishermen, relief organizations and reservoir operators, schoolchildren and ski bums.

But after seeing signals for months that a moderate Niño might be arriving right about now, the more likely case appears to be an episode that is weak indeed: probably short, and hardly nasty or brutish.

Scientists who predict the weather months in advance pay close attention to back-and-forth swings in what they call El Niño Southern Oscillation, or ENSO, which includes the mirror-image oceanic cooling called La Niña that probably made the past year’s drought worse. And recently they have been peering at their computer models from the edge of their seats, eager to detect the latest change.