Running through the Alphabet this Hurricane Season

Despite a very active hurricane season, South Florida will end September without any tropical threats

So far the Atlantic hurricane season has been proceeding at a blistering pace. With 17 tropical or subtropical storms this year (including an unnamed storm back in January), it ties 2005 and 2011 for the 3^rd most storms to date (only 2020 and 2021 had more). In a typical hurricane season, we only see 10 or 11 storms through the last week of September and the 30-year average (1991-2020) for an entire hurricane season is 14 named storms. No matter how you slice it, we’re already in extra innings but so far South Florida eluded Mother Nature’s crosshairs.

Philippe to weaken but bring unsettled weather to the northeastern Caribbean to start next week

Since our last major (Category 3 or higher) hurricane in the Atlantic back on September 13^th (Hurricane Lee), we’ve seen a run of storms – namely Margot, Nigel, and now Philippe – hit a low ceiling over the open Atlantic. Though Margot and Nigel did manage to attain hurricane status, Philippe this week fell well short. The storm was no match for strong wind shear and Philippe is barely hanging on as a tropical storm this morning over the central Atlantic.

Because Philippe weakened more quickly than originally forecast, its track forecast has been shifted noticeably southward from previous forecasts.

Model forecast trends for Philippe overt the past week. Earlier forecasts (cooler colors) showed Philippe strengthening and turning sharply northeast. More recent runs (warmer colors and bold black line) depict a weaker Philippe continuing westward and closer to the islands. Credit: Tomer Burg/University of Oklahoma

Though this means it will move much farther west and closer to the northeastern Caribbean islands by this weekend, it’s expected to have unraveled before it makes its closest point of approach. Depending on how close Philippe’s leftovers get, it may increase the potential for heavy rainfall in parts of the Leeward Islands westward to the U.S. Virgin Islands and Puerto Rico from Sunday through next Tuesday.

Future Rina’s uncertain future

Meanwhile about 750 miles southeast of Philippe and over 1,000 miles east of the Caribbean is Invest 91L. Satellite observations continue to show a better-defined area of low pressure. Once showers and thunderstorms become more persistent near the low-pressure center, a tropical depression or storm (Rina) will likely form.

What happens to the system thereafter is anyone’s guess. Models are all over the place, both in future track and intensity. The European model suggests a weaker system moving farther west under a stronger subtropical high while the GFS indicates a much stronger Rina hooking right into the open Atlantic.

Comparison of model forecasts for Invest 91L through next week. Reds indicate forecasts from the European ensemble models (western tracks) and greens show forecasts from the American GFS ensemble models (eastern tracks). The long-range forecast for 91L is highly uncertain at this time but the system poses no immediate threats to land regardless. Credit: Tomer Burg/University of Oklahoma

Regardless, future Rina doesn’t pose any immediate threat to land in the days ahead.

Quiet into next week close to home

The tropics should stay quiet into early next week closer to home. As always, we’ll keep an eye to the very warm waters nearby for any mischief but September will end on a quiet note for South Florida.