“The Hurricane Season Forecast in its Proper Place”

June 10, 2013

I don’t read Communist publications very often, but when I do, I read about hurricanes.

While putting together last year’s hurricane season forecast compilation, I spent some time hunting for the primary source for the Cuban forecast. While I did not succeed in doing so, I did manage to find a gem of a column in Granma, the daily newspaper of the Communist Party of Cuba.  Written by the head forecaster of Cuba’s weather service, Doctor Jose Rubiera, the article reminds its readers of the limitations of hurricane season forecasts. While I’ve seen National Hurricane Center directors and other such officials make some of the same points when they are quoted in articles reporting the release of a new season forecast, I’ve never seen anyone explain the matter in a direct manner as was done in this piece. Because of that, I found it worth the time to translate the column (a copy of which can be found in the original Spanish, here); any awkwardness is the product of my rusty translation skills.

The Hurricane Season Forecast in its Proper Place

When each new hurricane season draws near, and with it a new “Weather Exercise” *,  everyone wants to know the forecast of hurricane activity that is expected for the season. In the National Forecasts Center of the Institute of Meteorology of our county, forecasts of hurricane activity in the Atlantic started to come out in 1996, the end product of a research project led by the  researcher Doctor Maritza Ballester.

 In the United States, the University of Colorado (sic)  also puts one out as does the official weather service of that country, the National Oceanic and Atmospheric Administration (NOAA). The foreign media promotes these forecasts in a sensationalist manner, especially when the forecast calls for a high level of activity in the Atlantic.

It is precisely the massive disclosure of these seasonal forecasts, very different in essence from daily weather forecasts, along with very little explanation regarding what it’s really meant to say and its practical value, that promotes skepticism and frequent criticism of these forecasts.

It is easy for one to notice in a season that was forecast to be active, not a single hurricane affects land and thus  think that the forecast was erroneous, when its actual meaning is different. Thus, with this article I wish to demystify a bit and also put in the place it belongs, the seasonal forecasts of hurricanes, for the purpose of better understanding.

The true value of the studies for the forecast of hurricane season lies in the science contained within, that is, the cognitive value of the study and unlocking the secrets of the oceanic-atmospheric conditions that are favorable or not to the appearance and development of tropical cyclones, and with that, an idea of the probability of hurricane activity.

Nonetheless, the practical value of the seasonal forecasts for the common person, their interests as such, is very limited, as they cannot say so many months beforehand (and nobody on earth can do it), where a storm’s path will be, nor of what force it will strike, how much rain it will bring, etc.

So, in practice, no one should use this type for forecast for themselves. It is only possible to know if there will be more or less tropical cyclones or hurricanes in all of the Atlantic, only this is attempted. Notice that in the large Atlantic basin, which includes the Caribbean Sea and the Gulf of Mexico, there is a vast area that covers Cuba a thousand times over and a city or a specific point, perhaps millions of times.

In the practical sense, having an active, normal, or inactive season means little while the science cannot say exactly months in advance where, when, and at what force. I am going to give the example of the hurricane season forecast for 2012, put out a few days ago:

“The hurricane season will have normal to below normal activity. The formation of 10 tropical cyclones (tropical storms and hurricanes) is forecast, in all of the North Atlantic., 5 of which will reach hurricane strength. In the Atlantic Ocean region, eight tropical cyclones should develop, one would be in the Caribbean, and another in the Gulf of Mexico. The probability of a hurricane forming or intensifying in the Caribbean is low (15%) while that of a pre-existing one from the Atlantic entering the Caribbean (55%) is moderate.”

This assessment is based on the matter of fact that the existence and development of an El Niño in the summer months was forecast and these events produce strong winds at heights of 10-12 kilometers that cuts any incipient cyclone circulation and for this reason, inhibits formation of tropical cyclones in the Atlantic, though some manage to form. **

Moreover, the waters of the eastern Atlantic are colder than normal, another factor that is unfavorable for hurricane activity. Research has shown these links, equal with others, whereas a statistical relationship and analogy with other seasons, produces the numbers released.

Nonetheless, see that just one hurricane, only one, passing through whatever location is enough for its residents to think the season is very active (and for them it is, in reality). examples abound, but I’m going to give only two. The hurricane season of 1930 was very inactive such that there was just one hurricane in the Caribbean… But that was of such great strength that it completely destroyed Santo Domingo, the capital of the Dominican Republic. Another example. The 1992 season was also inactive, only four hurricanes, but one was Andrew, a category 5 that devastated south Florida, United States.

There can also be the case of very active hurricane seasons, like those of 2010 and 2011 with 18 and 19 tropical cyclones respectively (the average or normal for a season is 10) or even better the very active season of 1995, which equaled the 20th century record with 21 cyclones, but in none of these seasons did Cuba have a hurricane.

To summarize, the Atlantic Hurricane Season Forecast indisputably has scientific value, to study the general conditions for formation and development of tropical cyclones, while supplying a probabilistic tool for certain activity; but it does not have a practical value for the general public as it cannot show with such advance notice the details that appear in the short-term forecasts that we always offer in the Early Alerts and the Tropical Cyclone Advisories.

The recommendation is that if you want to know the season forecast, there’s nothing wrong with that, just always interpret it for what it is, a measure of general hurricane activity, but when there is a tropical storm or hurricane already out there, everyone should be up-to-date on its path, evolution, and development via the radio and television and follow the guidance of our Civil Defense. This is the practical information that is truly valuable for effectively dealing with the threat of a hurricane.

* A annual  two day hurricane readiness exercise conducted in Cuba prior to the start of the hurricane season. Spanish speakers can read the government’s description of the “Ejercicio Meteoro” here

** As one can see from reading the ENSO section of the verification of Colorado State’s 2012 hurricane season forecast, or any other season review, the Cubans were far from the only ones to think that an El Niño was going to develop. However, they did seem to put more weight on the probability of its formation than other forecasters did, hence the near 100% under-forecast of storm numbers.

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