Record books have already been rewritten in South Florida from historic rainfall last week, and the effects of a near-record strength El Niño may have only just begun.
Mike Halpert, Deputy Director from NOAA’s Climate Prediction Center, says this season’s El Niño continues to strengthen,
“The September-November Oceanic Niño Index, or ONI value, currently ranks second for this particular season, behind only 1997.”
Speaking to the media Thursday, Mike also said that this year’s event has a chance to become the strongest since 1950. He clarified, however, that forecast data suggests it may peak in intensity within the next month.
There was no change to NOAA’s official forecast that calls for the strong El Niño to persist through the winter months, gradually weakening during the spring and summer months of 2016.
“You know we do expect El Niño, even if the departures decrease some, it’s still gonna remain a strong event, certainly through the winter.”
Typically, the greatest affect on the daily weather in Florida from El Niño occurs in January and February. A “split flow” pattern, whereby an enhanced subtropical jet stream develops, sends storm systems into the Gulf Coast States, feeding off the warm waters and dumping copious rainfall across the state. This pattern has already produced record rainfall in South Florida, with Miami receiving more rain than usually falls from December to March – nearly 10 inches – in just the first 10 days of December.
It’s not only extreme rainfall that becomes a byproduct of El Nino in Florida. An elevated risk of severe weather, especially across the central and northern parts of the state, is an even greater concern during strong El Niño winters. The two deadliest tornado outbreaks in Florida’s history occurred in February (1998, 2007) during strong El Niño events.
The extreme weather that may occur this winter might be difficult for Floridians to believe at this point, considering how warm and calm the recent weeks have been. However, Mr. Halpert went on to tell us that it’s really too soon to expect anything extreme from this global phenomenon anyway.
“I think in terms of extremes and if you’re going to see severe weather, that really becomes how the whole jet stream configures itself, likely more January-February than in December at this point.”
The recent record warmth in November and early December, while largely related to atmospheric influences other than El Nino, might be a contributing factor to heavy rain and possible severe weather events in later months. Water temperatures over the Gulf of Mexico are presently 1 to 2°C above normal from the recent lack of cold air.
The Florida Public Radio Emergency Network has made a commitment to track the latest El Nino developments and keep your public radio and television stations informed on how it might affect our state. The new mobile app, Florida Storms, offers detailed mapping, customized alerts, and live streaming from your local Florida public radio station free of charge. Look for it today in the iOS or Google Play store today.
Editors Note: Dan Henry contributed to this story and is a student forecaster at the University of Florida.