Aug 22, 2011

DAY 82

Irene is a hurricane in the making. Tropical Storm Irene has all the characteristics of a storm that is on the verge of strengthening to hurricane status. The convective bands are forming on all sides and are being pulled into Irene's center of circulation.

(Tropical Storm Irene Visible Satellite)

On the zoomed out shot, you can see a beautiful anti-cyclone has been established over top of Irene, spinning out those cirrus clouds clockwise. All the circulation, and ventilation has been set properly. Now the next step will be the formation of an eye-wall around the center.

(TS Irene Infrared)

It may not be able to set up that eye-wall and become a hurricane just yet though. It is just about to make landfall in Puerto Rico, and with the center of circulation over land, Irene's progress will be disrupted temporarily. The National Weather Service in eastern Puerto Rico is reporting heavy rain with 25 mph winds, gusting to 50 mph tonight at 11pm eastern. That Island should have no major problems with a weak storm like this, inland flooding and mudslides are the greatest threat. That threat will be far greater if Irene impacts Hispaniola.

(TS Irene Nearing Landfall in Puerto Rico)

Irene is headed slightly WNW at 15 mph. Her maximum sustained winds are 70 mph, and her pressure has fallen to 993 mb. She is not forecast to become a hurricane over the next 48 hours as she impacts Puerto Rico and the Dominican Republic. Although it is very possible for Irene to still strengthen as she moves through Puerto Rico. She has been gathering so much energy and momentum, that could push her over the threshold before the land interaction shuts off some of her fuel source.

After Irene's direct hit on Puerto Rico, she is expected to graze the northern coast of the Dominican Republic and Haiti tomorrow. Once she clears that, Irene will be free to strengthen into a hurricane before hitting Andros Island in the Bahamas and then into Florida. The NHC track has Irene as a hurricane off the coast of Port St. Lucie Thursday evening. And then making landfall as a Cat 1 hurricane in North Florida.

The computer forecast models show a completely different scenario. 3 models shown in the image above take Irene through the Bahamas and then into Charleston, South Carolina on Saturday. While the 2 other models keep Irene moving west after impact with Hispaniola. Given the fact that we don't know what impact the land interaction is going to have on Irene over the next 48 hours, I would say we can afford to wait and see with this one. For one, she won't be able to become bad hurricane over the next 2 days. And two, we will still have 48 hours to prepare after she is clear of  Hispaniola. The steering layer below does show a path up the eastern seaboard.

Elsewhere in the tropics, Tropical Depression Harvey is trying to make a comeback. He made landfall in Belize yesterday, cross the Mexican Yucatan and entered the Bay of Campeche. You can't quite make out the center of circulation in the visible satellite image from earlier today, but it is in the very south end of the bay, not under that cluster of convection over land. The National Hurricane Center is actually forecasting Harvey to regain his status as a tropical storm tomorrow morning just before making landfall again and then dissipating over Mexico.

Tropical Depression Harvey)

Also, Invest 98L is still listed with a 10% chance of development in NHC two day tropical outlook. Things are not looking so good for this Invest right now. It could still become one of those storms that get named out in the middle of nowhere and then quickly vanish. But it is more likely just to disappear straight away.

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