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El Nino chances drop to 50/50, climate forecasters say

By Scott Dance, The Baltimore Sun

11:54 AM EDT, October 4, 2012

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The likelihood of El Nino strengthening this fall and winter fell from about 70 percent to 55 percent in a climate forecast released Thursday.

While some indicators show the climate phenomenon has been developing in recent months, others favor more neutral conditions, or at least a weaker El Nino than was previously expected.NOAA's Climate Prediction Center detailed the forecast in a monthly update that extends an El Nino watch that has been in effect since June.

The center expects continued conditions on the borderline between neutral and a weak El Nino, still with a possibility of El Nino strengthening before the end of the year, the forecast says.

The forecasters place the odds of an El Nino at just above 50 percent through November, then dropping slightly below that in December and to 40 percent and below after that. Starting in January, odds of neutral conditions are considered most likely, growing to about 65 percent odds by March.

The World Meteorological Organization last week also downgraded its expectations of El Nino, calling for a weak version to set in by the end of this month. Earlier this year, forecasters had expected El Nino to set in by August or September.

El Nino is known for bringing a dual jet stream pattern that can cause cold northern air to converge with moist southern air over the mid-Atlantic, according to this simple description of the phenomenon and its counterpart, La Nina.

AccuWeather meteorologists said Wednesday they are already seeing signs of that dual jet stream pattern and expect it to bring above-average snowfall to Maryland this winter.

In general, El Nino winters are known for above-average snowfall in the Baltimore area.

Have a weather question? E-mail me at sdance@baltsun.com or tweet to @MdWeather.