The “La Niña” Phenomenon is responsible for causing the conditions for the formation of tropical cyclones, three of these phenomena could affect Costa Rica; according to the seasonal forecast of the National Meteorological Institute (IMN).
“During the seasonal forecast, a certain number of tropical cyclones are expected in that period from June to November. “What we are predicting is that there will be around three more tropical cyclones in the Caribbean Sea region,” explained Daniel Poleo, an IMN expert.
What favors the formation of these cyclones?
“The La Niña phenomenon is an influence that is causing the Pacific to be colder and the Caribbean Sea to be warmer, which favors the formation of more tropical storms. “We identified what influenced the fact that June will close with an increase in the passage of tropical waves through Costa Rican soil,” Poleo said.
According to IMN data, the normal for June is an average of 10 storms, while this year the month closed with the influence of 12 storms. Rains will continue until November, in that period the influence of three cyclones is expected.
Tropical Cyclone Stages
Depending on the atmospheric and oceanic conditions in which it develops, the World Meteorological Organization (WMO, 1999) established that they are classified as follows:
Tropical Depression: A tropical cyclone in which the maximum mean wind at sea surface level (average speed in one minute) is 62 km/h or less.
Tropical Storm: A well-organized, hot-core tropical cyclone in which the maximum average sea-surface wind (average minute speed) is 63 to 117 km/h.
Hurricane: A hot-core tropical cyclone in which the maximum average sea-level wind (average speed in one minute) is 118 km/h or greater. It is a fully organized system throughout the troposphere with well-defined rain bands around the center of the low-pressure system.
“It is important, as we have already seen with tropical storm Bonnie, that these are forecasts based on what we see at the Institute and that they can change as they pass,” concluded the IMN expert.