by Glenn "Hurricane" Schwartz
Nicole is intensifying. Nicole will make a direct hit on Florida's east coast. But Nicole is not Andrew. It is not Ian. It is not Sandy. Every tropical storm and hurricane is unique. But many have characteristics of prior storms. For example:
- Like Andrew, a direct east to west hit makes for maximum storm surge. But Nicole will be MUCH less intense.
- Like Sandy, Nicole covers a HUGE area, and will affect hundreds of miles of coastline.
- Like Ian, Nicole is likely to keep intensifying as it approaches the coast.
Nicole's unique structure is going to lead to another example of the problem with the NHC's "forecast cone", or "cone of uncertainty", or "cone of concern" (among other things it has been called), like with Ian. There will be big problems and damage far beyond the cone. The cone is already too narrow. Lots of coastline north of the cone will get a much worse impact than implied by not being "in the cone".
NHC has addressed this admitted problem by providing warnings and graphics showing "Storm Surge Warnings". Even though hurricane force winds won't be expected, the storm surge flooding will be just as bad as if a hurricane had made a direct hit. DON'T JUST LOOK AT THE CONE!
The Storm Surge Watch and Warning covers more than 570 miles of coastline (plus some of the Florida West Coast as well)! In contrast, Andrew's surge damage covered about 2 percent of that area!
So, Nicole's final landfall point and intensity are much less important than with a typical tropical cyclone. That is, except that areas SOUTH of the landfall point will have MUCH less of a surge, less wind, and less rain.
Next, let's cover the track and intensity. As I've mentioned over the past few days, the upper-air pattern supporting this storm can be considered "extreme". And extreme patterns can lead to extreme results. That is why evacuations are already being ordered. And it's why NHC is predicting a higher landfall intensity than nearly all of their computer models. And it is still predicting a landfall farther south than the computer models would suggest.
As an example, the above forecast issued at 1pm Tuesday was already obsolete just 3 hours later. The 4pm advisory showed 55 knot max winds, while the models only suggested 55 knots by about 1am. That's a pretty big error. Obviously, the computer models are underestimating the intensification. Will that trend continue? How much will the eventual error be?
The other thing to notice in the intensity forecast is the re-intensification after about 84 hours (by Friday evening). This implies Nicole emerging into the Gulf of Mexico and re-intensifying before the re-curve to the northeast.
There is already very little wind shear around the storm, so that shouldn't be an issue.
We've been following the "best of the best" computer models all season-the European Ensemble forecasts. The best model is run 51 times with slightly different initial conditions. The below map shows low pressure centers along with the average pressure pattern, followed by the Thursday and Friday forecasts:
The Wednesday map shows a giant area of high pressure centered near NYC. Those lines between that high and the low pressure in Nicole show the huge pressure difference. That's why Nicole is so much more dangerous than just looking at how low the pressure is. And it's why there will be coastal flooding from Florida to North Carolina.
Once Nicole starts moving northeastward Friday it will spread heavy rain up the entire Eastern U.S. for Friday and Saturday.
Glenn "Hurricane" Schwartz firstname.lastname@example.org