• Bryan Norcross

Tropical indicators show a quiet week ahead

The atmospheric conditions across the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico continue to be hostile to tropical development. And there’s no indication things will change this week.



To get a system to form and organize, a set of supportive conditions has to come together.


In the Pacific, La Niña conditions have clearly developed, which would enhance tropical development if everything else were conducive. But other factors are in the negative column.


Last year, a bubble of atmosphere that was very supportive of storm development sat over the warm waters of the western Caribbean well into November, and major hurricanes developed. This year, a similar bubble is forecast, but it’s more transient. It’s not forecast to stay in one spot long enough for a storm to have time to spin up.


The atmospheric wave called the MJO that alternately supports and limits tropical development has been in the suppressed phase this month so far. Long-range computer model forecasts show it becoming somewhat more supportive of development the last week of the month.


The water in the western Caribbean is very warm. It’s always supportive of tropical development this time of year, but this year it’s extra warm.


All of this means that hurricane season isn’t necessarily over. Conditions could still line up toward the end of October to produce a storm.


The calendar is working against that happening, of course. The further we get into the fall, the more often cold fronts dip south, which hold off any tropical problems. But in between fronts, sometimes the ingredients come together to allow a storm to form.


There have been lots of hurricane seasons that have ended before this date, but none of them game roaring out of the gate in the same way as this year. So we have to wait a while before we can nail the coffin shut on Hurricane Season 2021.