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19185
From: akira, [DNS_Address]
Subject: What you need to know about record-breaking heat in the Atlantic
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What you need to know about record-breaking heat in the Atlantic The ocean heat could fuel an unusually active hurricane season. map showing record warm temperatures in the Caribbean Over 90% of the tropical Atlantic is experiencing record or near-record warm sea surface temperatures for late May. by MICHAEL LOWRY MAY 22, 2024 Waters across the Atlantic’s tropical belt — extending from the coast of Africa through the Caribbean — are hotter now than in any other late May on record, with over 90% of the area’s sea surface engulfed in record or near-record warmth. The extent of marine heat has never been greater heading into a hurricane season, outpacing by wide margins the previous late May record- holder in 2005, a year remembered for one of the most active and destructive hurricane seasons in modern history. The climate is changing, and our journalists are here to help you make sense of it. Sign up for our newsletters and never miss a story. Weekly News from Yale Climate Connections Eye on the Storm News An image showing how much hotter the Atlantic basin is in 2024 than it was in 2025. About 67% of the tropical Atlantic experienced record or near-record warm sea surface temperature anomalies in late May 2005 using 1981-2024 records, a notably smaller extent than May 2024. The Atlantic Main Development Region (area outlined by the black boxes above) is the warmest on record (since 1981) going into a hurricane season. Although record-setting sea surface temperatures alone don’t guarantee a busy hurricane season, they do strongly influence it, especially when the abnormal warmth coincides with the tropical belt known as the Main Development Region, or MDR, the area where 85% of Category 3, 4, and 5 hurricanes form. When considered alongside a developing La Niña — the periodic cooling of the equatorial Pacific that reduces storm-busting Atlantic wind shear — the unprecedented ocean heat is driving up seasonal hurricane outlooks higher than ever before. Colorado State University — the group that pioneered seasonal hurricane forecasts in the 1980s — issued its most aggressive April forecast last month in almost 30 years of doing such preseason outlooks. NOAA, the parent agency of the National Weather Service, will release its first 2024 hurricane season outlook May 23, and expectations are for similarly bullish numbers. What’s behind the record-breaking Atlantic heat? The exceptional warm-up of the North Atlantic began in earnest last spring and continued through the 2023 hurricane season. Despite one of the strongest El Niño events on record, which would typically deter hurricane activity, the Atlantic churned out 20 named storms last season, the fourth- highest number since 1950, according to NOAA. Forecasters largely credited the record-warm tropical Atlantic for counteracting the heavy hand of El Niño. Read: What is El Niño? Although a rapid transition from La Niña to El Niño last year along with human-caused global warming remain the primary factors behind the Atlantic’s ongoing hot streak, they don’t fully explain the abrupt jump into uncharted territory. A significant reduction in global sulfate emissions since 2020 from new shipping regulations and an increase in stratospheric water vapor from an explosive South Pacific volcanic eruption in 2022 are also likely contributors. However, the jury’s still out on these players, and so far both appear to have only fractional effects on the recent temperature spike. That leaves scientists closely monitoring the progress of El Niño in the eastern Pacific, which is already beginning a transition to La Niña. In theory, the transition out of a strong El Niño should begin to cool the Atlantic to levels more in line with the current trajectory of global warming. So far, this hasn’t happened. Locally, the Bermuda or Azores High in the Atlantic continues to remain much weaker than average. This semi-permanent area of high pressure controls the east-to-west flowing trade winds across the Atlantic tropical belt. With a weaker subtropical high, the Atlantic trade winds slow, which reduces ocean mixing that cools surface waters. This feedback loop further warms the Atlantic across its primary hurricane breeding ground. What do record-hot ocean temperatures mean for the Caribbean? The epicenter of the Atlantic heat wave is the Caribbean, where waters are averaging 84.7 degrees Fahrenheit for the week, a weekly temperature never seen before August, and already reaching well above the 1991-2020 average annual peak that typically isn’t hit until September. Chart showing Caribbean sea surface temperature (1981-2024). Temperatures in May 2024 exceed any recorded since 1981. The Caribbean is home to some of the strongest Atlantic hurricanes ever recorded. Half of the 40 Category 5 Atlantic hurricanes since 1851 formed in the Caribbean, including Hurricane Wilma in October 2005, the most intense Atlantic hurricane ever observed. But strong winds aren’t the only threat when sea surface temperatures rise. When water temperatures warm from 80 to 85 degrees Fahrenheit, studies show tropical rainfall — one of the deadliest calling cards of tropical storms and hurricanes — increases by a factor of five. This amplifies the concern for flooding rains for those islands and land areas bordering the Caribbean, especially early in the hurricane season when waters are usually in the low 80s. Don't miss the premiere of our extreme weather trivia competition. On June 7 at 12 p.m. Eastern, Jeff Masters, Bob Henson, and John Morales go head to head in a stormy battle. Subscribe to the Yale Climate Connections YouTube channel so you don't miss a thing. |
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[19186]
19186
From: akira, [DNS_Address]
Subject: Dr. Jeff Masters
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