We’ve had three named storms so far this season, but it has been very quiet of late. It’s been nearly a month since we’ve seen a named storm. Of course, the season will get more active heading into late August and early September, so we should not let our guard down.
We’ve been quiet for a few reasons. The main reason is that conditions across much of the Atlantic have been unfavorable for tropical development.
For starters, strong high pressure has been positioned across the northern Atlantic. This has done two things. Firstly, it has dumped plenty of Saharan dust into the main-development region (MDR) of the tropics. Dust limits tropical cyclone formation as the dry air associated with it chokes off moisture from the storms, which they need in their developmental stages. Secondly, it has brought some cooler-than-normal waters into the Caribbean and the MDR. Both of these factors may be limiting tropical activity in the deep tropics.
Closer to home, wind shear has been high across the Caribbean. If tropical waves cannot form into cyclones further east, they’ll develop in the Caribbean when they meet more favorable conditions. However, conditions have not been favorable across the Caribbean as of late. A parade of upper-level lows has been moving near the area, which has greatly increased westerly shear over the Caribbean. Tropical systems need calm winds through the atmosphere to develop and wind shear can act to deter tropical cyclone formation.
With all this being said, this hurricane season is behaving as normal seasons do. Conditions usually are not very favorable until August and September. Of course, it’s been different in the hyperactive seasons of the past few years. Does that mean this season won’t be as active as the last two? Well, for starters I never like preseason forecasts as they can sometimes give people a false sense of security or worry. Remember, it only takes one catastrophic storm to make it a bad hurricane season. So yes, numbers do matter, but storm patterns also matter. Lately, we’ve seen more storms moving into the Caribbean and Gulf versus moving out into the open waters of the Atlantic. I believe this is happening because conditions haven’t been as favorable deeper in the Atlantic, so storms have developed further west, which decreases the chances they move safely out to sea. This looks to be happening again, so when wind shear does decrease across the Caribbean, which will likely happen later this month, we could get very busy again, regardless of the overall number. Do I feel we will reach the numbers of the past two years? I’m skeptical, but it only takes one storm.
Historically, the tropics have ramped up in August and early September and I see this year being no different, so stay tuned!