As we watch one of the smallest hurricanes that we can remember churning in the Atlantic I'm sure that the question "why do we see hurricanes vary in size so much?" or "what causes a storm to be a certain size" comes to mind. I for one have seen some answers to the question but I remain unsatisfied. It seems as though tropical systems take on a personality that is usually carried with them for their entire existence. Hurricane Andrew remained a compact storm system despite intensifying to a category 5 hurricane and despite being disrupted by the Florida peninsula. Hurricane Ike was always a medium to large sized tropical system even as it grew to a category 4 hurricane but after its core was disrupted by Cuba and it entered the GOM it seemed to grow more in size than in intensity. So, what causes a tropical system to start out with a compact or large circulation and what causes it to change? Why is Hurricane Danny a midget.
SKYSUMMIT President | Director of OperationsAdministrator
I believe one reason to be is that he was surrounded by dry air from the beginning...not much moisture to pull from. The moisture he did get came from the ITCZ. Other than that, the basin was pretty dry.
Hammond, LA NWS COOP ID: 16-7425-08 CoCoRaHs ID: LA-TG-23
I believe one reason to be is that he was surrounded by dry air from the beginning...not much moisture to pull from. The moisture he did get came from the ITCZ. Other than that, the basin was pretty dry.
Yes, moisture envelope is a factor, but I also know that there are other factors. Danny has had decent moisture to its south and East, so I'm wondering what the other factors are. I can't remember a storm going from really small and compact like Danny or Charlie to large like Katrina or Ike and I know that there have been storms that have dealt with dry to moist environments.
SKYSUMMIT President | Director of OperationsAdministrator
The strength of the upper air environment comes into factor as well. For instance, if there's a strong, well developed, area of high pressure aloft, and perfectly positioned directly above the storm, the storm's outflow will be perfect aiding in the exhaust of heat in all quadrants.
Last Edit: Aug 21, 2015 16:25:23 GMT -6 by SKYSUMMIT
Hammond, LA NWS COOP ID: 16-7425-08 CoCoRaHs ID: LA-TG-23
mrjamie Vice President | Chief ConsultantGCWX Supporter
From what I have seen the size of a storm is dependent on several factors: environment, initial size, time, and landfalls. I have noticed that storms in good environment over time get larger (Gilbert is a good example). Also in many cases a storm that hits a decent size landmass (Cuba, Hispanola, Florida Peninsular, etc) and survives they tend to grow larger (Andrew, Ike, Katrina). Finally if a storm starts off with a large circulation though slower to develop tend to be larger in size once they strengthen.