Tropical System Likely to Form, Threaten Central America Later this Week

Newly designated Invest 97L expected to develop and bring the threat for heavy rain and flooding to Central America for the weekend

We continue to monitor an area of low pressure moving through the eastern Caribbean – designated Invest 97L – which could threaten Central America as an organized tropical system by week’s end.

It’s still too early to say definitively whether the system will continue westward over Central America or bend northward during the upcoming weekend, but forecasts have trended toward a southern scenario that keeps the potential tropical cyclone safely south of Florida into next week.

As we discussed in Monday’s newsletter, the disturbance will be traversing Caribbean waters that are topping 90°F in spots, about as warm as you’d expect to find any water during hurricane season. The western Caribbean has been at record warmth since the hurricane season began. Even as November approaches, waters in the region are running about as warm as any previous time of year prior to 2023. Despite being a full month and a half past the typical peak in Caribbean water temperatures, the waters today still feel as hot as any September on record.

Moderate wind shear is expected to stifle development over the next few days, but by Thursday into Friday, models show wind shear relaxing, which may give 97L or what forms from it an opportunity to organize as it approaches Central America.

High pressure steering in command to the north of 97L will keep the system on a westward trajectory through the Caribbean for most of the week. Models are in good agreement with moving what could become Tropical Depression 22 or Vince inland into Central America between Costa Rica and Honduras by Saturday.

Forecast tracks for 97L from the European model ensemble system into next week. The European model for now keeps the system on a westward trajectory into Central America. Credit: Weathernerds.org

The trend since early yesterday has been for stronger high pressure steering to persist that may not only block a turn north but could even push the organizing storm system southwestward toward the eastern Pacific. Though the forecast consensus for now favors the system staying to our south into next week, some credible scenarios do curl it northward by late weekend, so we’ll want to monitor the trends in the days ahead for any changes.

In the meantime, those from Costa Rica to Nicaragua to Honduras should be ready for a possible tropical threat – including the risk for heavy rain, widespread flooding, and dangerous mudslides – by week’s end.

The first Hurricane Hunter mission into 97L is scheduled for Wednesday afternoon.

Elsewhere across the Atlantic

Invest 96L near the Bahamas petered out yesterday and behind it the rest of the Atlantic outside the Caribbean looks to stay quiet into next week.