Greater Antilles: Adverse weather forecast across Cuba, the Dominican Republic, Haiti, Jamaica, Puerto Rico, and the US Virgin Islands through at least May 7

Adverse weather conditions are forecast across much of the Greater Antilles region of the Caribbean through at least May 7. A series of troughs over the region is expected to bring heavy rainfall and thunderstorms over much of Cuba, the Dominican Republic, Haiti, Jamaica, Puerto Rico, and the US Virgin Islands over the coming days. Strong winds, lightning, and possible hail may accompany storms. Heavy downpours may trigger flooding in low-lying areas and landslides on unstable slopes. Strong winds may generate rough seas in coastal areas.

Cuba's Institute of Meteorology has forecast showers across much of the country May 1, with thunderstorms and heavy downpours developing over eastern regions. Further showers are forecast across central and eastern regions through at least May 5, with thunderstorms possible in the east.

The Dominican Republic's National Office of Meteorology (ONAMET) has warned of heavy rainfall, thunderstorms, and strong winds across much of the country May 1-3. Due to the possibility of flooding and landslides, weather alerts (the lowest level on a two-tier scale) have been issued for Duarte, El Seibo, Espaillat, Hato Mayor, Hermanas Mirabal, La Altagracia, La Vega, Maria Trinidad Sanchez, Monsenor Nouel, Monte Plata, Puerto Plata, Sanchez Ramirez, Santiago, and Santo Domingo provinces.

The Haiti Hydrometeorological Unit (UHM) has forecast showers and strong winds across much of the country May 1-2. The heaviest rainfall is likely in parts of Artibonite, Centre, Grand'Anse, Nippes, Nord, Nord-Est, Ouest, and Sud departments.

The Jamaica Meteorological Service has forecast showers and thunderstorms across most parishes May 1-3 and across hilly areas and southern parishes May 4. Red thunderstorm warnings (the highest level on a three-tier scale) have been issued across Jamaica May 1-2.

The US National Weather Service (NWS) has forecast isolated thunderstorms, possible excessive rainfall, strong winds, and rough seas across Puerto Rico and the US Virgin Islands May 1. The wet and unstable weather pattern is expected to persist through May 7, with further thunderstorms and heavy rainfall likely. Heavy downpours may trigger flooding in low-lying areas, and strong winds are expected to continue to generate rough seas.

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rainfall has saturated the soil.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are possible where significant flooding or landslides impact utility networks.

Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger flight delays and cancellations at regional airports. If strong winds trigger hazardous sea conditions, authorities may temporarily suspend port operations or close beach fronts. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation.

Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.