A rapidly advancing tropical disturbance, identified as Invest 98L, swept through the Windward Islands on Sunday and has now entered the Caribbean, where it is poised to deliver substantial rainfall over several days. The likelihood of 98L strengthening into a tropical storm later this week is increasing, with the possibility of reaching hurricane status if the system lingers over the exceptionally warm waters of the central Caribbean.
Even if 98L stays offshore, communities along the southern coasts of the Greater Antilles, particularly the Dominican Republic, should brace for possible torrential rain and flooding in the coming days as the storm’s northern periphery impacts the region. Parts of northern Honduras and Nicaragua also face potential risks. Fortunately, due to strong wind shear caused by the subtropical jet stream extending from Florida to the Bahamas, 98L is not expected to threaten the continental U.S. for at least the next week.
The National Hurricane Center updated its Tropical Weather outlook on Monday morning, raising the chances of 98L becoming a tropical depression by Wednesday to 50%—up from 30% noted in the previous advisory—and an 80% chance in the following week. The next name in the Atlantic storm list is Melissa.
As 98L passed over the Windward Islands, it moved as an open tropical wave, lacking the distinct closed surface circulation that defines a tropical cyclone. Maximum wind gusts recorded included 45 mph at Barbados’ Grantley Adams International Airport during heavy squalls, with other notable gusts reaching 32 mph in St. Lucia and 37 mph in Martinique.
By midday Monday, the system was traveling west at speeds of 15 to 20 mph. It is forecast to deliver heavy rains to the ABC islands and the northern coast of South America through Wednesday.
The pace of 98L is anticipated to slow down by Tuesday, leading to a clearer understanding of its potential tracks according to different weather models. For much of the weekend, the GFS model suggested a northward turn by Wednesday, directing the storm toward the Dominican Republic before it moves into the Atlantic. Conversely, the European model indicated a continued westward trajectory with a later north-northeast turn, potentially affecting Honduras, Jamaica, Cuba, and the Bahamas. The Google DeepMind model presents a mix of both scenarios.
Despite current high wind shear inhibiting the system’s growth, conditions are expected to improve by midweek, favoring 98L’s development. The mid-level humidity is projected to rise significantly, along with warm sea surface temperatures nearly reaching 30.5 degrees Celsius, which could fuel the storm’s intensification.
Depending on 98L’s path, two primary scenarios are emerging. If it takes the quicker path northward, it might not have adequate time to strengthen before significant rainfall occurs, potentially impacting the Dominican Republic and causing flash floods. Alternatively, if it remains over the central Caribbean longer, the chance of it strengthening into a storm or hurricane increases, posing risks to multiple Caribbean nations.
Further insights into the storm’s intensity and trajectory are expected as it potentially forms a closed low-level circulation in the following days. Meanwhile, residents in impacted areas—especially Haiti and the Dominican Republic—are advised to prepare for possible severe weather conditions, as trends indicate an impending impact as soon as Thursday.