They say when the United States sneezes, Cayman catches a cold. In this case, when the US stays warm, Cayman’s hurricane season could run longer.
Weather experts predict parts of US southern states will experience weather approximately 60% hotter and drier than usual as an ongoing drought continues to grip the region.
This warmer winter weather is expected to stretch into February and forecasters say it could mean an extension of an already record-breaking 2020 hurricane season.
“The North Atlantic is definitely having an active hurricane season for two main reasons,” said Jhordanne Jones, a graduate research assistant at Colorado State University. “[First] the Atlantic was incredibly warm, and [second] the Pacific was much cooler than the Atlantic.”
The Atlantic hurricane season runs for six months, from 1 June to 30 Nov. This period coincides with the summer months, or the wet season of the tropics, and generally ends as cooler weather shifts from the northern hemisphere towards the equator.
The cooler weather would normally help to lower the sea surface temperature and suppress the formation of hurricanes. However, forecasters fear the warmer-than-usual winter temperatures will result in sea surface temperatures remaining high.
In addition to these high temperatures, Jones said cooler Pacific waters will also help to make for more favourable storm conditions.
“This particular pattern of warm Atlantic/cool Pacific is a main indicator of enhanced hurricane activity,” said Jones. “It reverses the winds over the Atlantic. Normally, winds flow from the Pacific to the Atlantic preventing developing storms from moving across the Atlantic Ocean.
The increased heat and arid conditions in the southern US are fuelled by the drought and further strengthened by a current La Niña weather phenomenon.
In a weather bulletin, Mike Halpert, deputy director of the National Oceanic and Atmospheric Administration’s Climate Prediction Centre, said, “With La Niña well established and expected to persist through the upcoming 2020 winter season, we anticipate… a cooler, wetter North, and warmer, drier South, as the most likely outcome of winter weather that the U.S. will experience this year.”
A record breaking season
On 9 Nov., the development of Tropical Storm Theta made the 2020 season the most active one in recorded history with a total of 29 named storms. That’s now up to 30 with the formation of Hurricane Iota.
The 2020 season is the second time in recorded history that forecasters have used up preapproved storm names and were forced to utilise the Greek alphabet. The previous recorded of most named storms came in 2005. The year 2020 has now tied the 2005 record for the most activity, with 31 tropical depressions.
The 2005 season also stretched into January 2006. Jones said current weather conditions could see the 2020 season repeat a similar trend.
“Since the Pacific is forecast to maintain its La Nina state well into the winter, it is very possible for the North Atlantic to have more storms develop in November and possibly December,” said Jones. “We have seen this happen before in the 2005 hurricane season. And even now, the Atlantic hurricane season remains particularly active even though we approaching the end of the official season.”