Just over a month ago, hurricane forecasters predicted that the number of storms will be slightly lower than typical for the forthcoming hurricane season. They’re now expecting slightly above-normal rainfall, owing to warm seas in the Atlantic Ocean, which are ideal for storm strengthening.
This year, the water off the Florida coast is less of a relief from the heat and more of a source of it.
The state of Florida is seeing one of its warmest summers in recent memory. For the past 30 days, Miami has had a heat index of greater than 100 degrees.
However, the sea has experienced some of its warmest readings on record.
Across the Florida Keys, water temperatures are anywhere between 1 and 5 degrees warmer than normal. In Bob Allen, Florida, for example, the water is in the mid-90s, when it usually averages nearly 88 degrees (87.9) Fahrenheit. Those five degrees might not sound like much, but to scientists, it is.
“It doesn’t seem like much, but small temperature changes make big differences in how the atmospheric circulation responds, and that’s obviously critical for what happens with hurricanes,” said Phil Klotzbach.
Klotzbach is a senior research scientist at Colorado State University, which has one of the most well respected hurricane prediction facilities in the country. His group anticipated 15 named storms this season, with seven of them being hurricanes, in late May, but due to record warm temperatures in the Gulf and Atlantic, those figures were revised last week to 18 named storms, with nine hurricanes.
With such figures, this year’s hurricane season would be above-average.
“Given how warm the Atlantic is — that certainly has given me a lot of pause when trying to do these seasonal forecasts because normally in an El Nino year we’d be forecasting a below-normal hurricane season, but because the Atlantic is so warm we’re now forecasting a little bit above-normal hurricane season,” Klotzbach said.
One of the main reasons for that warmth is a lack of trade winds that circle the Earth near the equator. Normally those winds churn the ocean, bringing colder water to the top, but a milder season has caused the warmer water heated by the sun to stay up top.
If a hurricane does form, that warm water would then act as generator for stronger storms like Hurricane Ian which battered the Florida coast last fall after undergoing rapid intensification.
On Tuesday, it was still 86 degrees even after the sun had set. All that warmth allows that water surface temperature to rise even further.What extra-warm oceans around Florida might mean for 2023 hurricanes