Thursday morning, the Climate Prediction Center (CPC) issued their monthly discussion on the El Niño-Southern Oscillation (ENSO), which is typically released on the second Thursday of each month. Their update lowered the chances of El Niño for fall 2017, with chances being lowered from about 45% to 35-40%. No El Niño Watch was issued, meaning the development of El Niño is not imminent. This continues the trend of the past few ENSO discussions: lowering chances of El Niño and increasing chances of ENSO-neutral for the peak of the 2017 Atlantic hurricane season. The primary reason for the chances being lowered was the continued trend away from El Niño on several models, such as CFSv2, CanSIPS, and NMME.

The most likely scenario for the 2017 Atlantic hurricane season is a warm-neutral ENSO, which should have a near-neutral effect on the 2017 Atlantic hurricane season. However, a cool neutral is also possibility, and even a weak La Niña cannot be ruled out (the CPC gives an 8% probability of La Niña in the August/September/October period). At this point, though, I think it is safe to say that we will NOT see a strong El Niño or a strong La Niña this fall.  Since ENSO-neutral years have a near-neutral effect on the Atlantic hurricane season, this season’s activity will be strongly driven by the state of the Atlantic Multidecadal Oscillation (AMO). Most models showed a continued positive phase of the AMO through the fall, with warmer-than-normal sea surface temperatures in the Atlantic Main Development Region (MDR) and the far North Atlantic. This would likely mean that a slightly above-average season is the most likely scenario; however, uncertainty remains high. A weak El Niño is still a distinct possibility, and should not be ignored.

I will be back for another post tomorrow. The Southwest Caribbean system I mentioned yesterday has not really materialized, and I do not think that it is a threat to develop at this time.