The waves are those troughs of low pressure that sweep across the Atlantic from Africa and generally bring unstable weather.
The closest has a 60 percent chance of becoming a tropical cyclone within the next 48 hours, said the U.S. National Hurricane Center in Miami, Florida. It is broad, spanning much of the western Caribbean.
The hurricane center said that the system is beginning to show signs of organization and environmental conditions appear ripe for the formation of at least a tropical depression, the center said. The system is moving west at 15 to 20 mph.
The Instituto Meteorológico Nacional in San José said Wednesday that hot morning temperatures and the general humidity that is coming in from the Pacific favors heavy storms and thunderstorms. There was rain in San José during the afternoon. The Caribbean was mostly dry, and the shower activity did not reach a level of major concern, despite the institute’s warning. It said that some rivers might overflow.
However, the same conditions prevail today, and the institute expects more rain and electrical activity. But it also said that the humidity was diminished by the rains Wednesday.
The second tropical wave is still in the mid-atlantic. It is accompanied by showers, said the hurricane center. It is moving west at 15 mph, the center said. The center said that it did not expect much development in the next 48 hours but conditions could be more conducive for development later.
Although hurricanes almost never touch Costa Rica, their indirect effects can cause major damage. Tropical waves are associated with many of the major storms.