NOAA assesses memorable 2019 hurricane season

It was the fourth consecutive above normal year — only the second such stretch in hurricane history

IMAGE-Satellite-Atlantic hurricanes - September 2019 - From Left to Right - Fernand - Dorian - Gabrielle - Landscape

The satellite image from September 3 showed three storms in the Atlantic. Activity ramped up suddenly in late August and September, and the frantic pace continued into October. (Image credit: NOAA)

NOAA released its 2019 hurricane season wrap on Tuesday, noting that this was the fourth season in a row with above normal Atlantic activity. In hurricane history dating back to 1851, there has only been one other such stretch, from 1998-2001.

“Also this year, five tropical cyclones formed in the Gulf of Mexico, which ties a record with 2003 and 1957 for the most storms to form in that region,” NOAA said. “Of those, three — Barry, Imelda and Nestor — made landfall in the U.S.”

There were three major hurricanes this season — Dorian, Humberto and Lorenzo. Dorian, which tied three other hurricanes — the 1935 Labor Day Hurricane, 1988’s Hurricane Gilbert and 2005’s Hurricane Wilma — for the second-strongest winds ever recorded in the Atlantic, made for an especially tense Labor Day Weekend in Florida.

The monster storm, with sustained winds of 185 mph, was forecast to plow into the Florida peninsula around Palm Beach County at one point, but then Dorian’s predicted landfall began edging to the north. It ultimately stalled over Grand Bahama and devastated Marsh Harbor on Great Abaco Island.

025521_5day_cone_no_line_and_wind-1

(Image credit: NHC)

This was the NHC forecast that slapped Florida residents on the evening of Thursday, August 29, as the storm began undergoing rapid intensification. The forecast was for a direct hit on the South-Central Florida coastline. By Saturday morning, forecast models began suggesting a turn to the north.

Residents were glued to forecast models, which are issued every six hours. At one point, the HMON had a wild, heart-thumping hurricane off the coast of Miami with a central pressure of 919 mb — for perspective, Andrew was 922 at landfall.

After pounding the Bahamas, and scaring the wits out of Florida’s East Coast, Dorian finally made landfall in Cape Hatteras, North Carolina, on September 6 as a Category 1 hurricane with 90 mph winds.

It was one of four storms that made landfall in the U.S. during the 2019 season, along with Hurricane Barry, Tropical Storm Imelda (another huge rainmaker that brought catastrophic flooding to Texas), and Tropical Storm Nestor.

“This season’s activity ramped up in mid-August during the normal peak of the season, as we predicted,” said Gerry Bell, lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center.

“The above-normal activity is consistent with the ongoing high-activity era, driven largely by the Atlantic Multidecadal Oscillation, which entered a warm phase in 1995. Conditions that favored more, stronger, and longer-lasting storms this year included a stronger West African monsoon, warmer Atlantic waters, and weak vertical wind shear across the western Atlantic and Gulf of Mexico.”

An average season has 12 named storms, six hurricanes, and three majors.

How did the preseason forecasters do this year? NOAA predicted nine to 15 named storms in its May outlook, with four-to-eight hurricanes and two-to-four majors. It drastically upped its forecast in August, which raised some eyebrows since only two named storms had formed through the middle of the month.

But when the Climate Prediction Center announced that El Niño conditions in the Pacific had ended, NOAA forecasters concluded that the peak of the season would kick into high gear, and they were right.

Colorado State University remained fairly conservative in its forecasts, calling for 13 named storms in April; 14 named storms in June and 14 in August.

Ultimately, the 2019 season beat every single forecaster with 18 named storms — the closest April forecast was from North Carolina State University, which had predicted up to 16 named storms. NOAA predicted up to 17 named storms, but not until its August forecast.

Looking ahead, Colorado State University will release its first 2020 outlook in two weeks, on December 12. The CSU team discusses probable conditions and offers a range of possibilities in that initial outlook, rather than firm numbers.

The UK’s Tropical Storm Risk will also release its initial 2020 forecast that week.

Author: jnelander

Freelance writer and editor

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