Charleston-Huntington, WV I am writing a different narrative every night this week on Ivan. I have asked my webmaster to keep all entries on line in reverse chronological order since I want those who love big storms to not miss a single night's work.
Early Tuesday Posting: Hurricane Flags flying on Gulf Coast
At 11pm last night, (Monday), my colleagues from the National Hurricane Center (NHC) issued the first official US Hurricane Watch for Ivan from Morgan City Louisiana to St Mark's Florida. That's a rather wide 400 mile stretch of real estate and a clear indication that it's still anyone's game as to where landfall occurs.
And startling as it may be, when Ivan does roar onshore, it will be his first direct strike of a land mass. That's because his lethal eye swung between the western tip of Cuba and the Yucatan peninsula late last night. This DODGE OF LAND is part of the worst case scenario for storms that leave the Caribbean and prance into the Gulf. Take Gilbert of 1988 infamy, for example. After thrashing Jamaica and growing to category 5 status, Gilbert ran headfirst into Cancun and Cozumel. By the time he emerged over the Gulf, he had lost some punch and never did regain his awesome cat 5 fury. He struck the NE coast of Mexico with winds near 120mph not 160 thanks to that interaction with land.
Ivan on the other hand maintained his cat 5 status last night. As of midnight, Ivan the Terrible (read Monday's posting about this nickname's origin) packed a sustained 160 mile per hour punch in his eye wall. Turns out without the eye crossing the western tip of Cuba, Ivan still kicked up wind gusts to 160 on that part of the isle of Cuba. That tells me his powerhouse eye wall (the concentric ring of storm clouds that house his fiercest winds) likely is producing winds as high as 190mph in gusts (160 sustained must be for a 10 minute period...160 in gusts is for just a few seconds...quite a difference). That my friends are why the evacuation that goes on tomorrow will be a hasty one.
Now good news for a second consecutive night, the NHC experts are saying the tempest will succumb to sheer and weaken to a 120 mph cat 3 storm on landfall. If realized, that would match Charley's fury and be stronger than Frances' winds. Why the forecasted weakening? And is that weakening assured? Well, to understand why Ivan will weaken, imagine a fan on a table top blowing a stream of air across the kitchen. Now, let’s bring a steaming kettle of Mama Cavalier's delicious Italian wedding soup and put it on the same table. Let the fan sit say 12-24" above the kettle. The steam that comes from the kettle would rise then be whisked or sheered away across the room by the fan's breeze. Same thing happens in a hurricane as tropical air is lifted into the storm's top. That sheering in effect is ripping away at Ivan's 2nd floor and a practical way to weaken the storm.
In nature, that fan is supplied by winds in the upper atmosphere above the storm's eye. So far those winds have been light and not disruptive. By the experts from the NHC say the Gulf has some of these sheering winds ahead of Ivan's path. Hence the forecast of weakening.
But warm ocean waters as high as 85 degrees are ahead of Ivan too. And Ivan is a glutton for warm, humid water that evaporates from the ocean surface. Think of the warm water as a sort of steroid for the storm. The great storms feast on this warm water and maintain their explosive intensity. Time will tell if the winds aloft can overcome the warm water ahead. For now, I will stick with the NHC's forecast as the best. After all, they are the true experts.
With landfall still hard to spatially and temporally (time and place) predict, I still can not say with surety that we will see a flood locally. My gut is we will get several inches of rain over a 3 or 4 day period. The rains should arrive in time for high school football games Friday night, and then continue over the weekend. That in itself is a bit disconcerting.
I will aim for a more specific landfall tomorrow night and update whether Ivan is indeed weakening or still hell-bent on maintaining his lofty cat 5 status.