2019 Atlantic hurricane season: Tropical activity may last longer than 2018 as El Nino pattern fades
August 08, 2019; 2:53 PM
The 2019 Atlantic Hurricane season is likely to be "back-end loaded," according to AccuWeather Hurricane Expert Dan Kottlowski.
AccuWeather meteorologists are sticking with their original forecast of 12 to 14 named systems for 2019, which includes both tropical storms and hurricanes for the Atlantic basin through the end of the year. AccuWeather first issued its Atlantic hurricane forecast for 2019 on April 3.
There have been two named systems as of Aug. 8, which is about average.
Of the 12-14 named systems, five to seven are predicted to become hurricanes, and two to four are predicted to become major hurricanes.
A hurricane has maximum sustained winds of 74 mph or greater, while a major hurricane, a Category 3 or greater, has maximum sustained winds of 111 mph or higher.
One of the two to four systems predicted to impact the United States has already taken place. That was Category 1 Hurricane Barry along the upper Gulf coast during the middle of July. Barry brought up to 2 feet of rain, caused flooding, spawned tornadoes and triggered power outages over parts of the south-central United States.
"It is not uncommon for there to be a lull in tropical cyclone activity during part of August or the summer in general," Kottlowski said.
"We continue to see vast amounts of dry air, dust and wind shear over the tropical Atlantic which have been and will likely continue to inhibit organized tropical activity in the short term. However, we expect that to change from late August through September and into October," he said.
These same restrictive parameters are likely to become less extensive and open the door for tropical storm and hurricane formation.
"We expect on a couple of occasions for there to be more than one named system spinning over the Atlantic Basin, which includes the Caribbean Sea and the Gulf of Mexico," Kottlowski said.
"It may be very busy at times, but we have seen that before during the heart of the hurricane season."
A significant factor that AccuWeather forecasters are monitoring is the weakening of El Niño.
This routine sea surface temperature oscillation over the tropical Pacific Ocean is trending from its warm phase to neutral. Over the span of several years this oscillation fluctuates from warm, which is El Niño, to neutral to cool, which is La Niña, and back.
"It's different from last year, when El Niño was ramping up," Kottlowski said.
When an El Niño is in progress, the jet stream tends to dip farther south along the North America coast and over part of the Atlantic Ocean. This tends to scour out the basin by producing strong upper-level winds.
That setup shut down the Atlantic hurricane season fairly early during the autumn of 2018 following Hurricane Michael in mid-October. Only two more named systems formed after Michael, Nadine and Oscar, and neither made an impact on the United States. No named storms formed in November.
"This year, we may have an opposite effect during the autumn with the jet stream well north, perhaps into part of November," Kottlowski said.
"With water temperatures currently well above average in many areas and that anomaly likely to continue well into the autumn, it could mean more named systems roaming around out there right up to the end of hurricane season."
The average peak date in the Atlantic hurricane season is on Sept. 10, while the season continues until Nov. 30.
The National Atmospheric and Oceanic Administration (NOAA) released an update to its hurricane forecast on Aug. 8, 2019.
*Updated* 2019 Atlantic #HurricaneSeason Outlook now calls for: 10-17 named storms of which 5-9 could become hurricanes, including 2-4 major hurricanes. News release + infographics at https://t.co/J7TXP6XJqU #HurricaneOutlook pic.twitter.com/utwvaSe3kw
— NOAA Communications (@NOAAComms) August 8, 2019
NOAA is predicting 10-17 named storms with five to nine hurricanes and two to four major hurricanes for 2019.
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