Tropical System Coming Together, Forecast to Impact the Eastern Caribbean Early Next Week

Invest 95L on its way to becoming a tropical depression or storm, with strengthening likely this weekend

Friday morning tropical Atlantic satellite showing Invest 95L (red circle) in the eastern Atlantic and Invest 94L (yellow circle) approaching the Yucatán Peninsula in the western Caribbean. Credit: NOAA

The strong disturbance labeled Invest 95L churning westward through the eastern Atlantic continued to organize overnight and is expected to become a tropical depression or storm later today or on Saturday. The next name on the list is Beryl.

The gathering storm is likely to strengthen as it heads westward this weekend and should begin impacting areas of the eastern Caribbean on Monday. Those with interests in the Lesser Antilles – particularly in the Windward Islands, including Barbados and Trinidad and Tobago – should monitor the latest forecasts and storm information over the weekend.

Track forecasts from the European forecast model ensemble system through next Monday (July 1^st) afternoon. Warmer colors indicate stronger low pressure scenarios. Credit: Tomer Burg/University of Oklahoma

An upper-level area of high pressure is forecast to accompany the developing system as it moves westward toward the Lesser Antilles in the coming days. This should provide an unusually favorable environment for continued development, especially for the time of year, when upper-level winds are generally still hostile across this part of the Atlantic.

Sea-surface temperatures are running at seasonal records ahead, with plenty of heat stored at depth in the waters through the Caribbean.

Ocean Heat Content departure from average centered on the Caribbean showing areas of very deep ocean heat for the time of year. According to records maintained by University of Miami Senior Research Scientist Brian McNoldy, Ocean Heat Content across the deep Atlantic is the highest on record for the time of year. Credit: Brian McNoldy/University of Miami

It’s not surprising then that guidance remains noticeably bullish on strengthening the system quickly over the weekend – perhaps into a hurricane – before reaching the easternmost islands of the Caribbean.

The development of a tropical storm this far east in the tropical Atlantic is uncommon, though not unprecedented. Only five named storms on record have formed in the tropical Atlantic east of the Caribbean (only about 5% of all named storms developing in June), including Bret and Cindy last June. Bret brought tropical storm conditions to much of the Windward Islands, but both Bret and Cindy fell short of becoming hurricanes. Only one hurricane on record has ever been recorded east of the islands in June.

A westward trajectory deeper into the Caribbean is expected for next week, but it’s too soon to know whether the system will survive the trek deeper into the Caribbean or pose any threat to the U.S. Long range models do suggest a more hostile upper-level wind regime if it tries to bend northward rather than continuing westward late next week, which could pose some challenges for sustained development.

Track probabilities for Invest 95L into next weekend (July 6^th) from the overnight runs of the major global forecast models. Models remain in good agreement with the system tracking westward toward the Lesser Antilles for the start of next week and continuing westward into the Caribbean. Credit: Tomer Burg/University of Oklahoma

For now, those of us in South Florida and the mainland U.S. have plenty of time to monitor this one.

A one-two punch for the Lesser Antilles?

In Thursday’s newsletter, we previewed the possibility of another system following in the footsteps of 95L in the eastern Atlantic. NHC is now highlighting this second tropical wave in its outlook, with overlapping areas for development – albeit with slightly misaligned timelines – in the week ahead.

In general, models are much more tepid on development chances with this secondary disturbance, keeping it either a strong disturbance or borderline tropical system as it trails 95L or what develops from it into the Caribbean by mid-week. The primary impact will be additional rains and squally weather to those parts of the Lesser Antilles already impacted by the tropical system ahead of it.

Like its predecessor, the secondary system will continue westward into the Caribbean for late next week, but forecast models are less optimistic about its longer term prospects. We’ll of course continue to monitor the trends.

More heavy rains into Central America and Mexico from 94L

The robust tropical wave we started following early this week is headed to the extreme southern Gulf and Bay of Campeche this weekend. The thunderstorm activity remains disorganized, but forecast models still show the possibility of a brief tropical system spinning up before it moves inland into Mexico on Sunday into Monday.

Regardless, the upshot will be more heavy rains into Central America and Mexico, areas affected by rounds of tropical rains last week.