To keep informed on how the Atlantic hurricane season is developing, I find that hurricane expert Philip Klotzbach of the Colorado State University does a good job at that at Twitter.
A warmer planet does not mean more hurricanes
As the peak of the hurricane season approaches (September) he recently tweeted below average activity was forecast for the next two weeks:
— Philip Klotzbach (@philklotzbach) August 16, 2018
That’s good news, especially in light of the fact that global warming experts, who seem not to understand how hurricanes develop, warned that these Atlantic cyclones would keep getting more frequent and stronger. Data suggest this has been hardly the case.
Detrimental wind shear, cool sea surface temperatures
So what’s been keeping the lid on hurricanes in the tropical Atlantic development zone this year?
Klotzbach mainly points to two 2 factors: sea surface temperatures (SSTs) and vertical wind shear. A couple of days ago he tweeted that wind shear in the region has been “above average” and that this tends to “reduce hurricane activity”:
Latest output from the Climate Forecast System model calls for above-average vertical wind shear in the Caribbean and tropical Atlantic in September – the climatological peak of the Atlantic #hurricane season. Strong shear reduces hurricane activity. @TropicalTidbits pic.twitter.com/sBt9mAmGIh
— Philip Klotzbach (@philklotzbach) August 14, 2018
Here Klotzbach even tweeted that vertical wind shear was “detrimental for hurricane formation.”
Shear 5th strongest since 1980
On August 10, the Colorado State University hurricane expert tweeted that wind shear had been at the 5th strongest in close to 40 years:
30-day-averaged shear in the Caribbean (10-20°N, 90-60°W) is the 5th strongest on record (since 1980). Since 1980, the only years with stronger shear from July 10 – August 8 were: 1986, 1987, 1997 and 2015. All of these were below-average Atlantic #hurricane seasons. pic.twitter.com/hm4bIdgVWK
— Philip Klotzbach (@philklotzbach) August 10, 2018
Mid August Tropical Atlantic surface temps cool
Although the tropical Atlantic surface has warmed up a bit, sea surface temperatures still remain cool there, which, according to Klotzbach, “for mid August are the coldest since 1994” and thus tend to suppress hurricane formation:
While there has been some recent anomalous warming, tropical Atlantic (10-20°N, 60-20°W) sea surface temperatures (SSTs) are still the coldest for mid August since 1994. Cooler tropical Atlantic SSTs tend to suppress #hurricane formation. pic.twitter.com/6KJJgDtfjG
— Philip Klotzbach (@philklotzbach) August 13, 2018
Unfavorable peak season hurricane formation conditions
Klotzbach sums up the forecast for the upcoming peak season in his tweet accompanying the first diagram above.
Latest output from the Climate Forecast System model calls for above-average vertical wind shear in the Caribbean and tropical Atlantic in September – the climatological peak of the Atlantic hurricane season. Strong shear reduces hurricane activity.”
Good news. But when it comes to weather, things can turn on a dime.
PS: Another great place for hurricane information is Tropical Tidbits.