-does not need to make landfall as a category 5
-i will not bet in this market
For this market I get <1%.
For much of below I consider the probability of a single cat 5 hurricane and condition on location in the Gulf of Mexico:
Based on my climatology notebook there are only historically two Cat. 5 hurricanes, after September 7, that fit recently (1991-2023)... Ian (2022) and Rita (2005) (this excludes Katrina). You have to go back to 1967 to find the only other one (AL131967 - Beluah) -- This gives a prior of about 6% using a 1991-2023 baseline.
For reference, these are the other storms I find if you don't condition on date, and only condition on intensity and location: ['AL051977', 'AL091969', 'AL092022', 'AL122005', 'AL131967', 'AL182005']. It doesn't increase the probabilities if you go so far back. If you don't condition on after September 7 ( and consider the whole year ) then it is about 9% (when you include Katrina) using 1991-2023 baseline.
There are no other examples per IBtracks that I could find in my notebook.
For reference I used the shapefile here to filter out the rows by location: https://www.marineregions.org/gazetteer.php?p=details&id=4288).
Given 6-9% for a single hurricane, the probablity of two events meeting the question critiera is going to be significantly less than this. I don't have the expertise but I would hazard a guess that taking the two events as independent and multiplying them would actually result in a probability that is actually higher than you would get from some dynamical model. Given that, and taking the high end (for the whole year of 9%) I get 0.09 * 0.09 ~= 0.0081, which is less than 1%.
@parhizj i have a more long-winded response but for the sake of just replying for now, tldw is: from what I've read (as am amateur) in climatology reports I don't think that extrapolation on previous seasons is as reliable today as it might have been 20-30 years ago. The burgeoning amount of heat in the Atlantic Ocean lends to greater and greater unpredictability of weather events and more anomalies. Additionally this year the NOAA predicted an 85% chance of an above-normal season.
That was longer than I thought it was going to be aha
@SoundsNentindo Agree with everything you said. Not sure if we will still have an above normal season though myself. However it will take a lot of “track luck” to get two cat 5s again in the same area in the same year. It’s possible there will actually be less tropical cyclones in the future, hotter, wetter climatology but more intense. The numbers game of this ratio though to increase the odds of the track luck needed seems implausible but I also am just guessing based on some simple statistics. If you asked a question like by 2050 will this happen .. where there more rolls of the dice I would have to set a completely different probability, but we are only talking about 1.5 hurricane seasons left not 20 or 30
Can you clarify the resolution criteria for this market? Only 1–3 tropical cyclones typically form in the Gulf of Mexico each year and I don't believe any has ever become category 5. Katrina (pictured), for example, formed in the Atlantic ocean, near the Bahamas before moving into the Gulf of Mexico, where it became a category 5.
Do you intend to resolve this based on where the storm forms (originates) or where it is when it reaches category 5 or by some other criteria?
