Tropical Storm Humberto became Hurricane Humberto Wednesday morning, narrowly avoiding setting a new record for the latest formed Atlantic hurricane in the season. The storm formed off the Cape Verde islands just off the coast of Africa, has been heading west, and the latest from the National Hurricane Center is that it will maintain strength and continue north-northwest at around 14 mph.
The first hurricane of the Atlantic season has had sustained winds of 85 mph, though the storm could weaken a bit in the next two days. As the storm travels north, the air will become drier, wind shear will increase, while ocean temperatures will grow cooler — which could make the tropical cyclone weaken back down to a tropical storm.
Humberto should remain over open water and does not pose any immediate threat to land.
Some critics of mainstream climate science have tried to point to the relatively quiet 2013 Atlantic hurricane season (a “goose egg” on the scoreboard) as a reason to doubt the link between climate change and extreme weather.
Yet Humberto has not set a record for the latest hurricane to form in the Atlantic. Hurricane Gustav was the first hurricane of 2002, forming at 8 a.m. EDT on September 11th of that year. Initial reports of Humberto placed the time its winds strengthened to hurricane force at 5 a.m. EDT, though recent data from the National Hurricane Center puts that time at 8 a.m. So though we won’t know for certain for a few months, it appears that Humberto is either the second-latest or tied for the latest hurricane to form in the Atlantic season in the satellite era.
Dennis Feltgen, of NOAA’s National Hurricane Center, told E&E News that one reason there have been plenty of tropical storms but no hurricanes until Humberto is dust and dry air blowing off the Sahara. “This year’s Tropical Storms Chantal, Dorian and Erin each dissipated when they ran into this environment,” he said.
Historically, September 10th was the climatological peak of hurricane activity, meaning that on average that date has had the highest number of storms since recordkeeping began.
There is a low pressure system (currently called Invest 93L) in the Gulf of Mexico over the Yucatan peninsula that appears to have the rotation and spiral bands which could make it a tropical depression. The system is moving slow enough, and Water temperatures are high and the air is moist enough that Jeff Masters of Weather Underground said it’s possible it could turn into a tropical storm or hurricane before making landfall on the Mexican coast. An Air Force hurricane hunter plane should investigate Thursday afternoon to confirm.
The previous tropical cyclone to hit the Atlantic, Tropical Storm Gabrielle, weakened into a tropical depression as it passed by Bermuda on its way toward Nova Scotia.
All tropical cyclones move west, following the trade winds, and these maps from NOAA show where they tend to travel, and where the highest wind speeds tend to be.
CREDIT: (Credit: NOAA)
The 2013 Atlantic hurricane season just passed the halfway mark, and so far, activity has been very low compared to recent years. The experts like to track the hurricane season using a number called Accumulated Cyclone Energy (ACE), which is the square of each storm’s wind speed, taken every six hours. Added up over a whole season, an average year will see that number around 110. So far in 2013, ACE is at 16. So while there is plenty of time for tropical cyclones to pick up their pace, the season is off to a slow start. Capital Weather Gang points out that through the end of August, eight seasons have had a weaker start going by ACE.
This regularly-updated graph from Weather Underground shows the trend of increasing cyclone energy over the last 40 years:
CREDIT: (Credit: WeatherUnderground)
Meteorologists have gotten better at storm tracking as satellite technology has improved. They are using modern techniques to go back and reanalyze previous storm data to better classify storms over the last 30 years. They’re even asking asking the public to help through a crowdsourcing website called Cyclone Center.
This year they might also be getting some help from an unexpected ally: underwater gliders. A fleet of 12 to 16 autonomous underwater robotic vehicles is descending into the ocean from Nova Scotia to Georgia and collect data on ocean conditions until late October. After gliders already in the water during Hurricane Irene in 2011 provided data that gave scientists a clearer picture of all the variables that affected that storm, researchers thought of trying to collect real-time data.
CREDIT: (Credit: NOAA)
A hurricane moving over one of the gliders would mean that meteorologists would receive data from all sides of the storm, improving forecasting and allowing the world to understand cyclones more completely.