Fiona Heads East, Next Wave Could be a Threat

 Good morning all!

The Atlantic tropics got off to a very quiet start this season, but have been heating up recently.  

Fiona

Hurricane Fiona, after lashing Puerto Rico with devastating flooding (AP Article) and knocking out the power grid, is now near the Turks and Caicos Islands as a Category 3 hurricane. The storm will recurve well East of the Continental U.S., but could be a threat to the island of Bermuda, and also maritime Canada as it transitions into a large exatropical storm in a few days.

Figure 1: 5-day NHC forecast for Hurricane Fiona (https://www.nhc.noaa.gov/)

Next Wave(s): Invest 98L

There is one system way out in the North-Central Atlantic that could become a brief TS, but won't bother anyone.

The system I am most concerned about is a wave currently just north of South America, moving towards the Windward Islands and Caribbean. This was just tagged as "Invest 98L" this morning, and is currently given a 50% chance of development by NHC.

Figure 2: NHC Tropical Weather Outlook from 8 am Tue, Sep 20, 2022, showing Fiona and two other systems of interest.

Figure 3: Infrared satellite image of Invest 98L (https://www.weathernerds.org/)

98L is forecast to move near the Windward Islands, Trinidad, and Tobago, and into the far SE Caribbean over the next few days. It could well develop into a tropical storm then.

After that, the storm is likely to move through the Caribbean, where conditions look favorable for intensification, with light upper level winds and warm waters.

It's still too far out to be certain about the track, but "ensembles" (a bunch of slightly different versions of the same model, run to give an idea of the possible spread) show it could be anywhere from near Cuba to near Honduras in a week.

Figure 4: ECMWF Ensemble Forecasts for Fiona (Top) and 98L (Bottom). (https://www.weathernerds.org/)

Lots to sort out still, but the pattern does suggest a possible Gulf threat in 7-10 days. No need to panic yet, but I recommend making sure your hurricane plan is ready to go anywhere along the Gulf Coast and Florida, and keep a close eye on the tropics as we round out September.

Andy

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