US NOAA sees active Atlantic hurricane season with up to 5 major hurricanes

HOUSTON (ICIS)–Atmospheric and oceanic conditions are “conducive” for an above-average Atlantic hurricane season, with 3-5 major hurricanes, officials at the National Oceanic and Atmospheric Administration (NOAA) said in a webcast update on Wednesday.

The season, which began on 1 June and runs through 30 November, already saw one hurricane, Hurricane Elsa.

An active hurricane season has the potential to disrupt operations and logistics at the many refineries and petrochemical plants along the US Gulf Coast, putting further pressure on strained supply chains.

NOAA scientists currently predict that the likelihood of an above-normal 2021 Atlantic hurricane season is 65%.

There is a 25% chance of a near-normal season and a 10% chance of a below-normal season.

OUTLOOK:
–  15-21 named storms (winds of 39 miles/hour (63 km/hour) or greater), including
–  7-10 hurricanes (winds of 74 miles/hour or greater), of which
–  3-5 could become major hurricanes (Category 3, 4, or 5 with winds 111 miles/hour or greater).

The outlook includes five named storms that have formed so far, including  Elsa.

Matthew Rosencrans, lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center, pointed to a mix of competing oceanic and atmospheric conditions that favours above-average activity for the remainder of the Atlantic hurricane season, including the potential return of La Nina in the months ahead.

Atlantic sea surface temperatures are not expected to be as warm as they were during the record-breaking 2020 season, he said.

However, reduced vertical wind shear and an enhanced west Africa monsoon all contribute to the current conditions that can increase seasonal hurricane activity.

These conditions are set against the backdrop of the ongoing warm phase of the Atlantic multi-decadal oscillation, which has been favouring more active hurricane seasons since 1995, he said.

He also noted the impact of climate change, which increases the intensity of storms, with more storms reaching Category 4 and 5.

Also, with climate change, storms that do form and make landfall create more rainfall, and there is an increased risk of coastal flooding, he said.

NOAA’s outlook did not cover how many of the expected storms may make landfall.

Thumbnail photo shows a hurricane. Image by Shutterstock