As anticipated in its latest forecast, the Climate Prediction Center of the National Oceanic and Atmospheric Administration (NOAA, in English) revealed today, Thursday, that it increased to 61% the probability that the La Nina phenomenon dominate for the rest of the current year.
If that happens, it would be the third time since 1950 (when weather records began) that such an atmospheric event would prevail for three consecutive winters, according to the weather agency. At the moment, the northern hemisphere remains under a La Niña warning, which means that atmospheric conditions related to this event are occurring.
The two previous times that La Niña dominated for three consecutive winters were 1973-1976 and 1998-2001.
The La Niña phenomenon occurs in the Pacific Ocean when temperatures along the equator turn cold. This scenario limits the development of hurricanes, while reducing the chances of extensive rain events.
Nevertheless, La Niña effects in the Atlantic Ocean are opposite to what the Pacific experiences. On this side of the planet, equatorial temperatures warm up and cutting winds decrease, which favors the development and formation of cyclones.
In Puerto Rico, for example, more rain events are recorded during this climatic event. If the prevailing phenomenon were El Niño, the island would be more likely to experience prolonged periods of drought, he explained to The new day climatologist Rafael Mendez Tejeda.
“It is important to point out that temperatures are cold in the Pacific, in the Atlantic they are not cold. Here they are hot and the hurricanes where they are generated are in the Atlantic. What La Niña does is it doesn’t reduce heat and it doesn’t reduce shear to limit hurricanes.”specified the expert in a telephone interview.
The also professor stressed that this new report should not create hysteria or despair among the population, but, on the contrary, should serve to review emergency plans in the face of any eventuality.
“The population must prepare, as always. They have to understand that they have to prepare even if no system comes. What I always say is that this is like life insurance that you buy, but you don’t want to use it,” he said.
At the moment, the projection for this year’s hurricane season in consideration of the La Niña phenomenon is unknown. NOAA’s official forecast for the hurricane season, which begins in June, will be released on May 24.
Through an update on the conditions of the El Niño/Southern Oscillation (ENSO, in English), the Center explained that the temperatures of the surface of the Pacific Ocean persisted during the past month below the average, which translates into a reduction in the values of the El Niño phenomenon and, therefore, a continuation of the girl.
“Subsurface temperature anomalies remained negative, reflecting a large area of below-average temperatures from the surface to approximately 100 meters depth throughout the central and eastern equatorial Pacific Ocean. […] In general, the coupled ocean-atmosphere system reflected the continuation of La Niña”, reads the report.
However, the agency explained that La Niña could see a slight decrease in its conditions during the summer, just before strengthening for the beginning of the fall, at the end of October.
Given this scenario, the probability that the atmospheric event will continue until August had a reduction of one percentage point compared to last month, so the percentage now stands at 58%.
While, the probability that La Niña will continue through the fall increased to 61%, which implies five percentage points more than the previous one. Last month the percentage was limited to the range of 50 to 55 percent.
The probability that ENSO-Neutral or El Niño will dominate during the fall/winter is 34 and five percent, respectively.
ENSO probability forecasting is developed through a multi-stakeholder analysis between NOAA, its National Weather Service, the Climate Prediction Center, and other agencies.
The report takes into account weather model visualizations, real-time observations of atmospheric conditions, and human judgment.