If you think it’s been an unusually quiet hurricane season, you’re right: The last time we went from July 15 through Aug. 19 with no named storms in the Atlantic was 1982, according to Colorado State University meteorologist Phil Klotzbach.
Could this be the calm before the storm?
History says yes: Over the years, the period from Aug. 20 through Sept. 11 marks the sharpest increase in named tropical systems in the Atlantic, AccuWeather said.
The latest hurricane forecast released Monday shows the rest of August appears to favor a quiet pattern for tropical storm and hurricane development in the Atlantic Basin, according to Colorado State.
The Atlantic Basin includes the Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico.
“Wind shear has been quite extensive across the Atlantic Basin the past few weeks and is, in part, one of the reasons why we have not seen any tropical storm development across the Atlantic Basin since mid-July with Barry,” according to AccuWeather hurricane expert Dan Kottlowski.
Wind shear – strong winds at higher levels of the atmosphere – can tear apart developing storms. “Long-range forecasts show less extensive shear but still enough to cause problems with westward-moving tropical waves, or disturbances, during the next week or so,” Kottlowski said.
Extensive areas of dry air and dust from Africa have also kept a lid on shower and thunderstorm formation in the Atlantic, AccuWeather said.
This hasn’t been the case in the Pacific Ocean, where four hurricanes have formed. The National Hurricane Center gives a pair of Pacific weather systems a good chance of becoming tropical storms within the next five days, one of which is dumping heavy rain across portions of Guatemala and Mexico this week.
Pacific hurricanes seldom have a direct impact on the mainland USA.
The only hurricane to form this year in the Atlantic was Barry, which hit Louisiana in July. “It’s pretty common to have only had one hurricane this late in the season,” Klotzbach said. “It happens about half of the time.
“It’s actually not that uncommon to have had no hurricanes through Aug. 19 – the most recent time that this occurred was in 2015,” he said.
Looking into September, “conditions are expected to become not only much more conducive for tropical storm formation but may also lead to multiple occasions with more than one named system spinning in the Atlantic Basin at the same time, as well as a late and strong finish to the season,” Kottlowski warned.
Overall, five to nine hurricanes are expected to form in the Atlantic Basin this year, the National Oceanic and Atmospheric Administration said in a forecast released this month.
The months of September and October have brought some of the most powerful and damaging hurricanes to the USA, AccuWeather said. In September 2018, Hurricane Florence killed 53 people and caused $24 billion in damage. One month later, Hurricane Michael killed 49 and resulted in $25 billion in damage.