WMO forecast: Weak El Nino could arrive next month

The world has been on watch since June for an El Nino climate pattern to develop by the fall. While it hasn't yet, it could arrive next month, albeit a weak version of it, according to the World Meteorological Organization.

Sea surface temperatures in the Pacific (a signal used to determine the presence of an El Nino or La Nina) rose to El Nino levels in July and August, but signs have not yet appeared in the atmosphere, according to a new El Nino update from the WMO. Forecasters consider it more likely that a weak El Nino will develop than that what are considered "neutral" conditions will continue.

The El Nino could arrive by October and last through the winter, the WMO said. That onset is a month later than previous forecasts from NOAA's Climate Prediction Center, which had also previously expected the El Nino to reach moderate strength.

If the WMO forecast is accurate, it could be relatively bad news for snow lovers in Maryland eager for a strong El Nino.

Any winter with an El Nino is likely to bring higher-than-normal snowfall in the Baltimore region, according to the National Weather Service's Baltimore/Washington forecast office. In an average year, Baltimore gets about a foot and a half of snow; in an El Nino year, seasonal snowfall is typically more than two feet.

But when distinguishing snowfall among the varying degrees of El Nino strength, a weak El Nino brings the least snowfall. On average, a weak El Nino brings about two feet of snow, a few inches more than normal but also a few inches short of what we might get in a moderate El Nino, the type that is heaviest on snowfall in Baltimore, on average.

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