Thursday, October 18, 2012

Equal Chances of Winter

NOAA released its winter outlook today, calling for "equal chances" of above and below average temperatures across our region for the coming winter.

By equal chances, NOAA's forecast believes there is not a strong enough lean one direction or another that winter will be colder or warmer than average overall.  Individual months may vary, which ultimately may impact the final destination for winter temperatures.  However, overall there is no strong lean one way or the other for our neck of the woods for the coming winter in their eyes.


NOAA forecasters speculate that the warmest conditions will reside in the Mountainous West and across the High Plains, with cooler than average conditions possible over much of Florida.

“This is one of the most challenging outlooks we’ve produced in recent years because El NiƱo decided not to show up as expected,” said Mike Halpert, deputy director of NOAA’s Climate Prediction Center. “In fact, it stalled out last month, leaving neutral conditions in place in the tropical Pacific.”

El Nino had been firing up earlier this summer and at one point it looked like we were heading towards a legitimate El Nino event in the coming winter. However, we've seen ocean temperatures in the eastern Pacific wane a bit over the past few weeks and the promise of an El Nino event this winter has waned a fair bit.

That said, the "neutral" or "La Nada" winter can still produce a litany of cold and snow if other factors, such as the NAO or Arctic Oscillation (AO), play out to benefit the East Coast.

“The Arctic Oscillation can certainly play a large a role in outcome of winter, but at this point can only forecast on weekly to two-weekly basis,” Halpert said. “At this point it (the long range or seasonal impact) still has us stumped.”

An interesting statistic with the AO is that October's AO state has agreed to the overall winter state of AO 35 times in 62 years back to 1950. It's a bit better than a coin flip. However, over the last thirty years the AO has oscillated from agreement to disagreement between October and winter on a multi-year basis...three years in a row it would agree, two it wouldn't.

Our streak is at five years running as of last October...so eventually the streak will come to an end...the question is when.   That part is still up to debate but it may very well drive much of the result for the coming winter.