Weather Warning

Tropical wave #8 over Costa Rica

June 24th, 2025

10:15 a.m.

Diagnosis: The axis of Tropical Wave #8 entered the country in the early hours of Tuesday. This system has caused cloud incursions toward the northern Caribbean border regions with Nicaragua. During the morning, isolated light to moderate rainfall was recorded in the Northern Caribbean and Northern Zone, with accumulations of less than 10 mm.

Forecast: For the remainder of the morning, isolated light to moderate rain will persist in the Northern Caribbean and Northern Zone, with accumulations of less than 5 mm over the next 1 to 2 hours.

In the afternoon, heavy showers with thunderstorms are expected, especially in the northern part of the country such as the Northern Zone, Northern Caribbean, and Northern Pacific. There is a high probability that these rains will continue into the early night hours, gradually decreasing in intensity. Rainfall totals are estimated between 20 mm and 50 mm, with maximums between 50 mm and 90 mm over 6 to 12-hour periods. In the mountainous areas of the Central Pacific, Southern Pacific, and Southern Caribbean, showers and thunderstorms are expected, with the possibility of rain moving toward the coasts by late afternoon and early evening. Estimated amounts range from 20 mm to 40 mm, with maximums up to 70 mm over 6 to 12 hours. In the Central Valley, scattered rain is expected, with showers and thunderstorms mainly in the western part of the region. Totals are estimated between 10 mm and 30 mm, with maximums up to 60 mm over 6 to 12 hours.

Tropical Wave #9 is expected to enter the country between Wednesday night and Thursday. The continued passage of tropical waves, combined with low-pressure systems associated with the Intertropical Convergence Zone, maintains a highly unstable atmosphere, favoring the formation of deep convective clouds and significant rainfall across various regions of the country.

Warning: Special attention is advised for the Nicoya Peninsula, the entire Northern Zone, and the Caribbean in general, as well as the Central and Southern Pacific regions, due to very high soil saturation levels (between 90–100%), which increase the risk of related incidents.

The IMN recommends:

• Exercise caution in areas prone to flooding due to possible storm drain overflows caused by water accumulation.
• Take precautions during thunderstorms: if you see or hear strong wind gusts near storm clouds, seek shelter in a safe place, as falling tree branches, power lines, or other objects could occur. These gusts may reach up to   80 km/h in isolated cases.
•     Stay informed through official channels: Twitter: @IMNCR, Facebook: Instituto Meteorológico Nacional CR, and Website: www.imn.ac.cr

Paulo J. Solano S. | Meteorologist DMSA-IMN

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