World and Nation

An El Niño Winter

An El Niño Winter

NOAA, the National Oceanic and Atmospheric Administration, recently stated that El Niño would be a dominant factor in this winter’s climate. But how is it that one phenomenon apparently restricted to the tropics can affect climate around the world? Well, it’s all due to the circulations in the atmosphere and ocean in the equatorial Pacific. Normally, there is great upwelling of the waters to the west of Peru; cold, nutrient-rich water is brought up and is blown westward by the trade winds, creating a “cold tongue” of water near the equator. More convection is seen to the west; but when El Niño conditions set up, the trade winds decrease; cold, nutrient-rich water does not upwell as much; and warmer waters set up further to the east than normal. As low pressure tends to coexist with warm waters, the pressure field in the Pacific tropics shifts, changing surface pressures and weather patterns, across the globe. However, despite all of these changes in the atmosphere, New England will not be affected significantly. For us, there are equal probabilities for a relatively cold or warm winter and for a relatively wet or dry winter.

But for the next few days here in Cambridge, we should see fairly mild and seasonably comfortable conditions, in great contrast to Sunday’s Nor’easter which dropped large snowflakes on us as the day ended. High pressure off the Atlantic coast is keeping things clearer for us today, and a cold front tonight will pass through tonight bringing clouds with it. A warm front will keep temperatures fairly steady on Wednesday at night. On Thursday, we see the potential for temperatures well in the 60s°F if the cloud cover breaks enough; with any luck, Thursday should make up for this weekend’s stormy weather.

Extended Forecast

Tonight: Partly cloudy with a low near 46°F (8°C).

Tomorrow: Sunny with a high near 64°F (18°C). Light winds from the north. Increasing clouds at night, low around 47°F (8°C).

Thursday: Partly sunny with moderate winds shifting from the southwest to the northwest. High in the mid-upper 60s°F.