Long range forecasters: September more likely to be warmer than cooler

Long Islanders weary of August’s frequent steamy conditions may want to tamp down hopes for a much cooler September.

Long range forecasters said Thursday that they’re expecting a slight tilt toward warmer rather than normal temperatures, on average, for next month.

The area of the Northeast that includes Long Island is more likely to see overall warmer-than-normal conditions than to see cooler temperatures or right around normal, said Dan Collins, seasonal forecaster with the Climate Prediction Center, which is under the umbrella of the National Oceanic and Atmospheric Administration. That’s based on long-range computer models, he said.

September’s average overall temperature at Long Island MacArthur Airport is 65.6 degrees. The month’s daily highs average out to 73.8, and daily lows to 57.5.

As of day end Wednesday, the overall average temperature at the airport this August has come in at 78.4 degrees, which is 4.6 degrees warmer than normal, with rainfall averaging just over 3 inches above normal.

Looking ahead to expectations for September’s precipitation, there were no strong enough signals as of Thursday to make a call for above, below or right around normal, Collins said.

Looking even further ahead, El Nino is brewing, and expected to be in full swing for winter, forecasters said Thursday.

At this point and not an official forecast, that climate pattern was looking likely to be weak to moderate in strength, Collins said.

El Nino, originating with especially warmer sea surface temperatures in the tropical Pacific, is a pattern that rotates every few years with its opposite pattern, known as La Nina, as well as with neutral conditions, meaning no El Nino or La Nina in place at all.

While impacts from El Nino can vary, “often, the polar jet stream stays farther north,” allowing the northeastern U.S. “to have a milder winter,” said Jessica Spaccio, climatologist with the Northeast Regional Climate Center. This depends on its strength and other contributing factors, she said.