30 August 2012

Isaac, Kirk, and TD12 keeping the basin active

This is the time of year when the tropical Atlantic really gets cooking, and this year is no exception.  Isaac was the season's forth hurricane, Kirk is now the fifth, and we'll soon have another to add to the list: TD12 just formed and is primed to strengthen quickly.


The figure below shows the past 5 days of estimated rainfall over the southeast US, along with Isaac's track in black.  The very localized maximum over the Palm Beach FL region can clearly be seen (we had some significant and stagnant raindbands here in southeastern Florida), as well as the much more obvious and widespread huge totals over southern LA, MS, and AL.  There are of course many problems with inland flooding now... in addition to the hundreds of miles of coastline affected by the large storm surge -- from central LA all the way over to the FL panhandle.  This goes to show once again to never focus on the exact centerline of the track.  These are large storms with severe impacts felt very far from the center.

I have a full 50-hour radar loop of Isaac's path over the northern Gulf coast, as well as the rest of the prior radar loops for Isaac.

Isaac is now a 35kt tropical storm, and still centered over Louisiana (with strong winds and rainbands extending out for hundreds of miles).  It's been over land since Tuesday evening, and is still a tropical storm... the hot swampy southern half of LA doesn't provide the usual death blow to a tropical system that other locations do.

Warning: I'm going to go on a little rant now...  I've heard reports of people saying "I didn't think it was going to be this bad", and "I didn't leave because it was only a Category 1".  THE CATEGORY OF A STORM HAS NOTHING TO DO WITH RAINFALL OR STORM SURGE.  Not a thing.  The only thing that distinguishes a tropical storm from a major hurricane is wind speed in the center of the storm.  Forecasts of storm surge and rainfall were quite accurate, evacuation orders were made, we had Katrina as a recent teacher, yet people still perceived the only risk as being the peak winds.  Hopefully after a few more storms like this (since history is forgotten after about a year), perhaps some people in vulnerable areas will begin to realize that they are at risk from other elements besides the peak winds right at the center of the storm.  And another key point: THERE IS NO SUCH THING AS A WEAK HURRICANE.  By definition, even a Category 1 hurricane's winds are destructive.  I realize there are people who do not have the means to evacuate, and for them, I hope better government-sponsored (local or state) programs can be designed to help them.  But for the people who stay just because they feel they're not at risk despite the warnings from hurricane experts and emergency managers... how many destructive storms will it take to convince them?  End rant.


As of yesterday's update, Kirk had just formed.  Today it's a 65kt hurricane!  It is in the process of recurving, and should bend back toward the northeast before reaching 53W.


Finally, the disturbance that I mentioned yesterday that was near 36W is now near 45W, and was just recently upgraded to Tropical Depression 12.  The intensity is estimated to be 30kts and 1007mb; and is forecast to become a hurricane this weekend as it heads WNW... likely recurving north of the Lesser Antilles.  It's presently about 1100 miles east of the Lesser Antilles and moving west at 17kts.  While it appears to be a storm that will never affect land, it's too far out to say for certain, so is worth keeping a close eye on.  This is very close to becoming Tropical Storm Leslie, and interestingly, the average hurricane season never even reaches the "L" storm.

No comments:

Post a Comment