Attachments
1 INTRODUCTION
This event briefing describes the impact of rainfall on Saint Lucia, which was associated with a Covered Area Rainfall Event (CARE) starting on 1 July and ending on 3 July 2024. The Rainfall Index Loss (RIL) for the Covered Area Rainfall Event was below the attachment point of Saint Lucia’s Excess Rainfall policy, and therefore no payout is due to the Government of Saint Lucia.
2 EVENT DESCRIPTION
On 29 June at 0300UTC, the US National Hurricane Center (NHC) reported that a tropical storm formed in the central tropical Atlantic Ocean, and it was named Beryl. The system proceeded westward with estimated forward velocity of 18 mph (30 km/h), along the southern periphery of a strong subtropical ridge. In the next 30 hours, the tropical storm rapidly intensified due to the low wind shear, the high moisture content and the warm surface temperature over the tropical Atlantic. Thus, on 29 June at 2100UTC it became a hurricane and on 30 June at 1530UTC, it evolved into a Category 4 hurricane, as reported by NHC. At this time, the centre of Beryl was sited near latitude 10.8° North, longitude 54.9° West, about 350 mi (565 km) ESE of Barbados, and it proceeded towards the Windward Islands with almost unvaried forward velocity and direction. The maximum sustained winds were estimated at 130 mph (215 km/h) and the minimum central pressure at 962 mb.
During the final hours of 30 June and the first hours of 1 July, despite the environmental conditions that were still supportive for the intensification of the hurricane, an eyewall replacement cycle hindered the further strengthening of the system. Indeed, a new outer eye formed outside the small inner core, weakening the latter and gradually becoming dominant. For this reason, when Beryl started to affect the Windward Islands with tropical-storm conditions, during the first hours of 1 July, it had weakened to a Category 3 hurricane, with maximum sustained winds estimated at 120 mph (195 km/h). During these hours, Beryl passed over the waters between Barbados and Tobago, spreading tropical-storm conditions over these islands, and headed towards Grenada (Figure 1).
At 1200UTC, Hurricane Beryl strengthened again, due to the completion of the eye replacement cycle and it became a Category 4 hurricane again. The satellite imagery showed the solid ring of deep convection surrounding the warming, well-defined eye of the hurricane (Figure 2). Three hours later, at about 1500UTC, the NHC reported that Beryl made landfall over Carriacou (Grenada). Between 1200UTC and 2100 UTC, while Grenada, the Grenadines and to a minor extent Saint Vincent were affected by the heavy precipitation associated with the hurricane core, Saint Lucia experienced the passage of a sequence of outer rainbands (Figure 3). As visible from the radar maps, during these 9 hours, several outer rainbands passed rapidly over Saint Lucia, bringing intermittently moderate to locally intense rainfall over the country (Figure 3).
At 2100UTC, Beryl moved away from the southern Windward Islands, and the associated rainfall ceased over these countries. The hurricane continued to proceed west-northwestwards at almost 20 mph (31km/h), towards the central Caribbean Sea.