Tropics Fall Silent for Now

Disturbances struggle with dry, dusty air as they roll into the Atlantic high off the African continent

Wednesday morning satellite showing a large tropical wave embedded in Saharan dust (orange shades) over the eastern Atlantic (right side of image). Credit: NOAA

When we’ve looked across the Atlantic on August 21^st in most years of the satellite era – 56% of years to be exact – we’ve seen at least one tropical depression, tropical storm, or hurricane. Just last year at this time we had Emily, Gert, Franklin, and soon-to-be Harold churning simultaneously. Today, however, we’ve cleared the board in the wake of Hurricane Ernesto and the Atlantic looks to stay dormant at least through the early part of next week.

Of course after the near-record start across the Atlantic, we can use the break to catch our breath. Although we’re running about average in the named storm department so far, the number of hurricanes, and their strength and duration, is far outpacing typical seasons. There are many seasons we don’t see a single U.S. hurricane landfall, and we’ve already recorded two. We’ve not seen as many of the weaker systems that spin up from non-tropical sources, so 2024 has been a year of quality over quantity.

As we discussed in yesterday’s newsletter, a number of short-term obstacles will hold down development odds in the Atlantic for now. One of the main impediments this week is the northerly launching point of tropical disturbances rolling into the Atlantic from Africa.

24-hour forecast trends (out 4 days) in westward moving African Easterly Waves or AEWs, the seedlings for tropical storms and hurricanes this time of year. Notice the tracks of the tropical waves that have already moved into the Atlantic north of the Cabo Verde Islands off Africa (red box). Typically tropical waves leave the African continent near or south of the Cabo Verde Islands. The northerly displacement has put the disturbances in a much drier and dust-laden environment, which has stifled development odds. Credit: Quinton Lawton/University of Miami

The disturbances are rolling through the western Sahara where they’re getting mixed up in loads of Saharan dust, which are getting heaved into the tropical North Atlantic with them. The dry environment is starving the disturbances of the more humid-laden air, especially in the middle part of the atmosphere, that’s needed for development.

So for the next week or so, don’t expect much in the way of tropical mischief. As we covered yesterday, by later next week, we may begin to see a little more liveliness across the Atlantic as we turn the calendar to September, the peak month of the hurricane season. In the meantime, take the time to review your hurricane plans and replenish any necessary supplies, particularly beginning this Saturday as Florida enters another two-week disaster preparedness sales tax holiday.