A Purely Mathematical Atlantic Season 2009 Prediction
2009 Atlantic Hurricane Season
Climatology merely tells us how weather has reacted to certain situations in the past, but it will not necessarily tell us what will happen in every instance, though. However, we can get a good idea of how tropical systems form under certain conditions. With this in mind, here is how I have come up with my 2009 season prediction.
This is a purely mathematical system I have come up with which focuses mainly on ENSO conditions during the past 30 seasons. It also flips the normal predictive reasoning on its head, by focusing primarily on major hurricanes and using that to determine total number of hurricanes for the current season. Most predictions involve determining the total number of tropical storms developing, and then using that as baseline reasoning to determine hurricane and major hurricane numbers. In my research I have found very little correlation between total tropical system number and major hurricane number. I have, however, found a very tight correlation between total hurricane and major hurricane number. Therefore, I am disregarding all non-hurricane strength development in this forecast.
What I have done is assigned each of the past 30 seasons one of four labels: La Nina, Neutral, Emerging/Weak El Nino, and Deep El Nino. I have determined these by referring to consensus on past ENSO events and EPac temperatures. Then I determined the percentage of hurricanes which were major hurricanes for each season.
Here is a breakdown of what I found:
- In the past 30 years only 2 seasons had no major hurricanes, one year was in the midst of a deep El Nino (1994), one year was surprisingly under neutral conditions (1986).
-Overall, 38.03% of all Atlantic hurricanes were major hurricanes
*- % of Atlantic hurricanes which were major hurricanes -*
-La Nina years- 42.15%
-Neutral years- 37.47%
-Light/Emerging El Nino years- 36.02%
-Deep El Nino years- 36.9%
*- Average # of major hurricanes per season -*
-La Nina years- 3.0 majors
-Neutral years- 3.17 majors
-Light/Emerging El Nino years- 2.0 majors
-Deep El Nino years- 1.7 majors
Results-Update- After a reanalysis of past ENSO phases, I have fixed the numbers to more accurately reflect the best data available.
What does this mean for this year? As we are currently going through a transition period, it is hard to say if this will be categorized as a ENSO neutral year or an Emerging Nino event. I must split the difference between both major #'s and will assign a value of 2.56 major hurricanes for the season. Due to the fact that we are in an active period of Atlantic tropical formation, I will round that to 3 major storms. Using the same 50/50 method with major hurricane % for the season, I believe approximately 36.75% of this year's hurricanes will reach major status. That works out to approximately 7 total hurricanes for the season.
Got all that?
So to sum up, my final prediction for the 2009 Atlantic hurricane season is:
7 hurricanes, 3 major hurricanes
Reader Comments
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I originally planned to include total system #, but as I went along I found out that the number of total tropical systems for a season didn't fit a tight pattern with the # of hurricanes or major hurricanes. There would be one year with a baker's dozen worth of tropical storms, but only a few would develop into hurricanes. Then other years would have only 6 or 7 tropical systems, and a majority would make it to hurricane status. I never could make a neat connection between ENSO phase and total tropical system number. I just found the correlation between the number of major hurricanes and total hurricanes fit a fairly predictable pattern.
If I keep crunching the numbers I may find a better pattern that will give me a good way to predict total system number, but for now I'm leaving it at just hurricanes.
NWS Lake Charles,La. 1997
Possible Effects of ENSO (El Niño/Southern Oscillation)
Years of moderate to strong warm ENSO events were checked for any possible relationship with tropical cyclones affecting Louisiana and southeast Texas. These warm events seemed to have no significant correlation to an increase or decrease in tropical storms and hurricanes entering the area; it has been recently discovered though that it does make a difference further down the Texas coast.
Unexpectedly, ENSO events seemed to have a strong correlation to major hurricanes in this area. Five of the eight major hurricanes struck the region during the middle of moderate to strong El Niño events. If one expands the criteria to within one year of a moderate ENSO seven of eight become included. Further study is needed to totally resolve this issue.
Link
Although for a specific area their findings gelled with yours. I'd love to know if there are any other studies like this out there. Interesting stuff.
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