So long, La Niña
In its latest monthly advisory, issued Thursday, NOAA’s Climate Prediction Center all but sounded the death knell for the 2016-17 La Niña. Sea surface temperatures in the benchmark Niño3.4 region have remained in the weak range for La Niña (0.5°C to 1.0°C below the seasonal average), and the subsurface cold relative to average across the equatorial Pacific has almost completely vanished. In a new ENSO Blog entry, NOAA/CPC’s Emily Becker reviews global weather conditions and how they’ve stacked up against La Niña expectations (fairly well, especially for temperature).

Models are close to unanimous in bringing the Niño3.4 region into the neutral range over the next couple of months. There are some model indications of a weak El Niño kicking in by summer 2017. That wouldn’t shock me, given the continued predominance of a positive Pacific Decadal Oscillation. Positive PDOs are associated with a higher frequency of El Niño events, and the PDO has now been in positive territory in each month from January 2014 through December 2016—the first time this has happened across three consecutive calendar years in records that go back to 1900. Even so, NOAA’s Emily Becker isn’t ready to predict a 2017-18 El Niño: “A three-year series of El Niño/La Niña/El Niño has only happened once since 1950, in 1963/1964/1965. This doesn’t make it impossible that El Niño could develop, but it means that we aren’t counting on it.”

Wunderground

La Nina Conditions Likely To Become A Neutral ENSO Within The Next 1 To 2 Months & Remain Neutral Through The 2017 Atlantic Hurricane Season

All signs are pointing towards our current La Nina to become neutral conditions either during February or March. These signs include ocean water temperatures in the eastern and central tropical Pacific, which are gradually warming up to near normal levels. I do think that there is a very good chance that we will see these neutral ENSO conditions persist through the 2017 Atlantic Hurricane Season, however, I’m not convinced that we will see the development of a new El Nino this year, even though some of the climate models suggest the development of a El Nino during this summer or autumn.

There is a large difference between the ENSO climate models with their forecasts. The European model has 80 percent of its members forecasting the development of a El Nino by May or June. On the other hand, most of the CFS model members are forecasting neutral conditions through this summer and autumn. As I have already mentioned, I am leaning much more towards the idea of a neutral ENSO starting during either February or March and continuing through this summer and autumn. One big reason why I don’t think we’ll see a El Nino this year is because a quick turnaround from La Nina to a El Nino is rare.

What Does This Mean For The 2017 Atlantic Hurricane Season? I still think that the 2017 Atlantic Hurricane Season may be near or slightly above average. This means that there is still the potential for 12 to 14 named storms with 5 to 7 of those storms becoming hurricanes and 2 to 3 of those hurricanes becoming major hurricanes. This forecast is based on the following: (1) A neutral ENSO; (2) Above average amounts of unstable air; (3) An active phase of the Atlantic Multi-Decadal Oscillation (AMO).

Now, if, and that is a big if, we see the development of a El Nino during this summer or autumn, it could mean a quieter hurricane season than what I am forecasting right now.

Crown Weather