Two tropical systems could develop in Caribbean, Gulf of Mexico

The second system has the potential to be even more menacing as it passes through the Caribbean but may not begin to develop substantially for another five days or so, if it does so.

The dual tropical threat comes as multiple factors may align for above-average activity during a month that has featured some of the most destructive hurricanes in Atlantic history.

The rambunctious 2020 hurricane season has been spitting out tropical cyclones like a factory, already having cranked out 23. That’s exhausted the entire list of conventional hurricane names the National Hurricane Center had available, sweeping us into the Greek alphabet for only the second time on record.

The season seems far from done displaying its tempestuous power.

The first of two tropical waves that bear watching was located in the western Caribbean on Thursday morning.

A zone of low pressure appears to be developing east of Honduras and Nicaragua, the nascent system primed to become a tropical depression or storm over the weekend or into next week. If it receives a name, Gamma — the third letter in the Greek alphabet — is up next.

The National Hurricane Center estimates it has a 70 percent likelihood of development in the days ahead. By early Saturday, the system is likely to consolidate and meander toward the Yucatán Peninsula. Heavy rain, with localized totals exceeding a foot, may accompany the tropical system’s passage.

From there, the system’s track is uncertain. It could erode over Quintana Roo and Yucatán states in Mexico, dumping its copious moisture in the process before dissipating. A farther southward track would favor this outcome.

If whatever core develops by then only clips or sidesteps the Yucatán Peninsula to the north, the system could evade the pernicious effects of land interaction, and remain over the ocean. That would allow for a slightly stronger system somewhere between Punta Cana and the western tip of Cuba.

Regardless of what occurs, the future system is unlikely to become overly intense, and probably won’t make it beyond tropical storm strength. That’s because wind shear, a disruptive change of wind speed and/or direction with height, will be increasing ahead of a cold front parked over the central Gulf of Mexico. As much as the system tries to get its act together, the atmosphere will be playing tug of war and working to dismantle it.

However, the system’s remnants, intact or not, could bring heavy rainfall to the eastern Gulf of Mexico or parts of Florida early next week. Predicting timing and precipitation amounts for a storm that has yet to form, however, is not yet possible.

Following this initial Caribbean disturbance, a second system will try to get going next week as a tropical wave, presently east of the Lesser Antilles, slowly meanders southwest over the Caribbean.

It has many hoops to jump through, but it could tighten into a concentrated area of spin and work toward becoming a tropical storm or hurricane somewhere in the western Caribbean or Gulf of Mexico by the end of next week. If a system were to form, the environment may become more conducive to intensification, compared with the initial Caribbean disturbance, but uncertainty is high so far into the future.

The National Hurricane Center indicates a 20 percent chance of development in the next five days but that development prospects will increase at longer time frames.

Beyond these two systems, it appears hurricane activity will become more favored beginning in about a week’s time. That’s when a broad area of rising motion over the Pacific will pivot east and envelop the western Atlantic. That will help boost thunderstorm updrafts and make it easier for tropical systems to form.

At the same time, a chain reaction of atmospheric mechanisms beginning with happenings in the Indian and Pacific Oceans will work to reduce the amount of wind shear over the Atlantic. Calmer winds aloft will prove more hospitable for tropical development.

In addition, the Gulf of Mexico remains anomalously warm, save for where draining rainwater and upwelled subsurface ocean waters by Sally cooled the oceans a bit near the continental shelf in the northern gulf. That increases the ability of tropical systems to sustain themselves in the gulf should one arrive.