Weather Warning (Update)

Tropical Wave #5 over Costa Rica this Fraday

June 13, 2025

4:45 p.m.

Diagnosis: Unstable atmospheric conditions this Friday in the country are due to factors such as Tropical Wave #5 (OT#5) passing over the country today, a low-pressure system belonging to the Intertropical Convergence Zone (ITCZ) located off the North Pacific coast of Costa Rica, favoring a humid westerly flow on that slope. During the afternoon, scattered rain and showers with thunderstorms occurred over the central mountain range of the country, these in the Central Volcanic Range (east of the Central Valley), the Tilarán and Guanacaste mountain ranges, the General Valley, and the western South Caribbean. The most significant accumulated rainfall is: 70 mm in Guayabo-Bagaces and Santa Rosa de Guanacaste, 45 mm in San Carlos, 30 mm in Los Chiles, Cutris, and Sarapiquí, 20 mm in Cañas, and between 10 and 25 mm in the Central Valley.

Forecast: For the Central and South Pacific regions, isolated rain and showers with thunderstorms are expected in the mountains and surrounding valleys. Rainfall amounts between 20 and 40 mm are expected. For the North Pacific mountain range and most of the Northern Zone, localized heavy rains with thunderstorms will continue. Estimated amounts are between 40 and 90 mm over 6-hour periods. In the Central Valley, scattered rains are expected, mostly light to moderate, especially in the eastern zone and the eastern mountainous areas. Estimated amounts are between 10 and 45 mm. For the Caribbean, rain with showers and occasional thunderstorms are expected in the lower reaches (30 and 70 mm) and showers in the mountainous areas and along the border with Nicaragua (5 and 40 mm). The rains are expected to continue into the night and early morning, especially in localized coastal areas on both sides. By Saturday, OT#5 will have left the country; however, ITCZ ​​activity will continue through the weekend.

Warning: Special attention should be paid to the Nicoya Peninsula, the Tempisque Valley, the Sarapiquí Basin, and the South and Central Pacific, as these areas have very high soil saturation levels, between 85% and 100%, which increases the risk of incidents.

Due to the above, the IMN recommends:

• Caution due to sewage saturation in areas prone to this type of flooding.

• Prepare for thunderstorms and seek shelter in a safe place if strong wind gusts occur or are perceived near storm clouds, due to the possible fall of tree branches, power lines, among other things. These gusts can reach 80 km/h in some isolated cases.

• Stay informed through social media: Twitter: @IMNCR, Facebook: Instituto Meteorológico Nacional CR and the website:www.imn.ac.cr

Jose Valverde Mora

Meteorologist

DMSA-IMN