30 June 2021

Tropical Depression 5 close to forming east of Lesser Antilles

Invest 97L, the wave that exited the African coast on Sunday, has been transitioned to Potential Tropical Cyclone 5 (still not a tropical depression).  Last year's season moved along at a record-breaking pace, but hang on... the fifth depression formed on July 4 in 2020 and was named on July 6.  There is little doubt now that 2021 will eclipse those records. 

As a refresher, NHC introduced the term "potential tropical cyclone" in 2017 (see season intro), and it refers to an Invest that is likely to produce tropical storm conditions on land within the next 48 hours... it gives them the ability to issue watches and warnings for a tropical cyclone that has not yet formed but is expected to.

This low pressure system is centered about 1200 miles east of the Lesser Antilles and is moving west-northwest at 21 mph, which will bring it to those islands on Friday morning.  Tropical storm watches have been issued for the islands highlighted in yellow below.  The next name on the list is Elsa.  Elsa is a brand new name to the lists, and it replaces Erika which was retired after the 2015 season.

Models have generally been bullish with this for the past few days, though not unanimous.  Some of them bring it to hurricane intensity in the next 2-3 days, then crossing Hispaniola and/or Cuba which always introduces a lack of confidence in the intensity forecast.

Any impacts to the U.S. mainland are still uncertain, but the earliest it would reach the closest area (south Florida) would be late Monday into Tuesday.  There are many other options open to it, so at this point, unless you're in the Lesser Antilles, just wait but pay close attention.

Very few storms have formed this far east so early in the year. I found six tropical cyclones that formed east of 50W prior to July 3 since 1851 -- three of those became tropical storms and only one became a hurricane (in 1933).  The most recent was Bret in 2017.  This one doesn't count as a formation yet, but this map gives you an idea of how exceptional it is in history if it forms in the next few days.

For completeness, Invest 95L is passing through the Lesser Antilles now, but is rapidly losing what organization it had and is not expected to make a comeback.

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