6pm Tropical Update

I am going to repost most of what I wrote at 1:30, because not much has changed:

It is not time to let down our guard, but I have nothing but good news today. Yesterday I was amazed that a hurricane could form with the strength of the wind shear that was in place over Hanna. Last night and this morning that wind shear has finally taken it’s toll. This morning thunderstorms were blown away from the north side of the storm, and the eye had been exposed. This has severely disrupted the storm’s circulation, and it will likely take a while before the storm gets organized again. Hanna has also been meandering southward. This is great news, because it is getting close to Haiti and it’s 10,000 foot tall mountains. If Hanna gets too close to Haiti, it will weaken further. Also, the farther south it is when it begins the eventual turn to the northwest, the farther west the eventual track will be. Finally, the computer models have all shifted west with the forecast tracks. Some of them bring Hanna into Florida, which will weaken it before it heads toward us. Other models bring it into Georgia or far southern South Carolina.

This afternoon there was been a flare up of thunderstorms near the center of Hanna. This may be the storm fighting back against the wind shear, but I think the damage has been done, and the storm will continue to struggle until the wind shear relaxes.

The general forecast for Hanna has not changed. I have mentioned that we will not know the details until it starts moving northwest, and that is still the case. The wind shear will start to weaken tonight and tomorrow, allowing for the storm to intensify again. We will find out how much damage has been done to the storm’s circulation overnight as the wind shear slackens. If it starts to strengthen right away, it could regain hurricane status fairly quickly. If it struggles tonight, it will be a slow go before it gets it’s act together.

Hanna will start the move to the northwest tomorrow. Exactly when it starts NW, and how much farther south or SW it gets tonight will determine where it makes landfall. Also consider that it will be moving along coast of the Southeast US, so a small change in the storms direction of movement can mean a large error in where is actually makes landfall.

Here is my forecast:

Tonight, Hanna will continue to meander in the Bahamas, likely remaining a tropical storm.

Tomorrow, Hanna will start the move to the NW and will pick up speed. It may also strengthen back into a hurricane, depending on how weak it gets this afternoon.

Thursday, Hanna will threaten Florida, or even make a landfall as a tropical storm or cat 1 hurricane. We will notice an increase in wind late in the day. Clouds will roll in at night, and we may see the first spiral bands of rain late at night.

Friday, This will be our stormy day. A lot may change between now and Friday. Here are the worst and best cases:

* At most we may see a cat 1 or cat 2 hurricane making landfall to our south. We will see heavy rain of 4-8 inches and the threat for tornadoes. Winds could be stronger in the Pee Dee than along the coast, however there will be a risk for coastal flooding and a storm surge along the Grand Strand. Highs tides at Springmaid Pier are 11:34pm Thursday, 12:19pm Friday, and 12:24am Saturday. The Friday noon tide will be the critical one.

* If Hanna hits Florida first, or never recovers from today’s weakening, we will still have a stormy day. Heavy rain of 4-8 inches and the threat for tornadoes will remain. Winds will not be as much of an issue, and although there may still be some erosion and coastal flooding at the time of high tide, the storm surge will not be as high.

The hurricane hunters found an unorganized storm with no thunderstorms on the northwest side of the eyewall. Winds are still strong and pressures are low, so as soon as the wind shear calms down a bit, it should start to strengthen. The hurricane center’s forecast track is actually a bit farther east. This is because the storm has drifted southeast today…. Not south or southwest, so the starting point for the eventual NW movement is a bit farther east. The computer models are still mostly to our west.



Elsewhere in the tropics:

Gustav has pretty much stalled over land. It will no longer be a wind threat, but will dump a lot of rain across Louisiana, Mississippi, and Arkansas.

Ike is getting stronger and will become a hurricane soon. The ridge of high pressure that is one of the factors in the movement of Hanna is building westward, and should be in place over the East Coast before Ike gets here. That will keep Ike on a westward track, and keep it to our south.



Josephine is way out there, but looks good on satellite. This may be a hurricane in the next couple of days, but may stay out to sea. It is still a long way off, so I have not spent much time looking at this one.

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