source: The Guanacaste Journal

Transition period toward dry season begins

(Infocom) — Following an inclement rainy season that has battered the province of Guanacaste, the National Meteorological Institute (IMN) has indicated in a report that Costa Rica is finally entering a period of transition from wet to dry season.

Costa Rica’s dry season, or summer, typically runs from December to April, which coincides with the country’s “high” tourism season.

This change in climatic conditions is caused by the incursion of cold fronts through the Caribbean Sea, coming from North America — which are typical of the boreal autumn and which generate moderate-to-strong cool north winds that cause periods of dry and decreased rain in the Central Valley and the Pacific, while they lead to strong rain in the Caribbean region and the Northern Zone.

In the Central Valley in particular, wind during this transition time becomes strong, generating rain in the mountains. Alternating dry and wet days is one of the main characteristics of this transition period.

According to the IMN, the 3-4 week transition period toward the dry season already began last week along the Pacific coast and in the mountainous Central Valley.

However, weather experts warn, the hurricane and tropical storm season doesn’t end until Nov. 30, so up until then there’s a chance of tropical cyclones developing in the Caribbean Sea — which could affect the climate throughout the country, especially on the Pacific side, where period of heavy rain are still a possibility.

This season of climate changes will also bring about a rainy period in the Caribbean watershed, which could extend from November 2008 until February 2009.

Costa Rica’s Caribbean region behaves different weather-wise from the rest of the country due to cold fronts that sweep through the area, sometimes even causing periods of constant downpours there for days at a time.

Last week, IMN experts explained, an increase in atmospheric pressure over Central America caused by a cold front generated windy conditions in Costa Rica. The strongest wind gusts were felt in the North Pacific area between Tuesday and Thursday, beginning to let up by Friday.

Meanwhile, this same phenomenon dumped rain on the Caribbean coast and the Northern Zone. These parts of the country saw isolated, moderate-to-strong rains that peaked on Wednesday and Thursday. Additionally, the front brought cloudiness, cool temperatures and drizzle to the northern and eastern parts of the Central Valley. In the Central and South Pacific, atmospheric conditions were stable, with little rain reported.

The “summer” that begins arriving in Guanacaste in late October to early November this year followed a tough winter in the province. As a result of multiple and strong precipitations, many communities were hit by flooding that left hundred of people stranded or in shelters.

It wasn’t until Oct. 20 when the last emergency alert in the region was lifted, after many people who live on the banks of the Tempisque River had to be evacuated and taken to provisional shelters.