Comparing Dean to Ivan
August 19, 2007
UPDATE at 4:30 PM: Based on the satellite imagery, it looks like Dean’s CPA to Kingston is going to come out very nearly identical to that of Ivan’s, about 40-45 nautical miles, which keeps Kingston out of the strongest winds.
The one stretch of Jamaica still in danger of getting the very worst wind-wise is the stretch that sticks out: the southern coast from Portland Point to Treasure Beach (Jamaica map). That will depend on which way the next couple of unpredictable wobbles go.
The other benefit of Dean’s faster motion that I neglected to point out is that it reduces the cumulative wind effects (i.e. the total amount of time the area is exposed to hurricane force winds). That serves to enhance building survivability.
Looking at the forecast and the satellite loop, it looks like Dean’s closest point of approach to Kingston is going to be comparable to that of Ivan back in 2004. It may come slightly closer to the southwestern-most point of Jamaica, however.
The wind speed is comparable to what it Ivan’s was when it passed by Jamaica, however, the radius of hurricane force winds is a little bit larger (60 miles vice 45 miles).
A significant plus relative to Ivan is that Dean is moving much quicker (18 mph vice 8). Because rainfall accumulation is inversely related to forward speed (i.e. slower storm = more rain), Dean shouldn’t put nearly as much rain on Jamaica as did Ivan (25+ inches in many places).
Not to say that there won’t be widespread damage, but owing to the distance that it appears to be to keeping from land and its forward speed, Dean will give Jamaica a fairly significant break from the worst case scenario.