Hurricane Isaac

[mezzacyclone]

Their did look some displacement earlier but it really looks to be coming together now!

WOW, 995.5mb 15.867N 57.400W,,,,

[Coast]

[Iceberg]

Just seen the recon. sub 100mb now and it seems as though the llcc has pushed under the stronger northern mid/high centre, still not perfectly aligned but enough to start to cause moer significant pressure drops under the cdo.

[summer blizzard]

Wierdly the NHC still have this at 1004mb however its presentation is epic and pretty big. I still lean west of Florida but either way i don't see such a big circulation being killed.

[mezzacyclone]

Holding on but looking out of sorts with 43kn winds despite dry air drawn in recently and lightly moderate shear but multiple circulations appear evident with south and north (weaker) vortices?,

likely the (T)UTT had decoupled the main LLC but current mission 3 may find more strength surrounding the strengthening southern vortex? One noticeable point is visible outflow bands particularly over Venezuela/Guyana coastal areas?

http://rammb.cira.co.../rmtcnhvis8.gif

USAF Recon is headed SW over Dominica (21:18 bst) and over the fading NWern circulation with a lowest ESP of 1004mb and NOAA (mission 4) is just leaving Barbados base.

I`d say we are at a point where Isaac is getting himself slowly better organised despite the re-occurring dry westerly air and shear barriers and it should not be such a surprise that he will look most impressive by tomorrow`s end?

Upper Trough caveat upheld

[AderynCoch]

Still far too early to tell where it's going to make its turn, or how strong it will be by that point. It seems to me that the forecast track has been gradually shifting eastwards - if this keeps up it may miss Florida altogether.

In the short term Isaac will pass over or very close to the mountainous terrain of Hispaniola, so a lot will depend on how much weaker and more disorganised the storm ends up afterwards.

[Coast]

In the short term Isaac will pass over or very close to the mountainous terrain of Hispaniola, so a lot will depend on how much weaker and more disorganised the storm ends up afterwards.

ROSEAU, Dominica (AP) — Tropical Storm Isaac took aim at the Dominican Republic and Haiti early Thursday, expected to gain strength after drenching tiny islands in its whirl over the eastern entrance to the Caribbean.

No major damage was reported, but authorities in Puerto Rico said an elderly woman had died in an accident while preparing for the storm. U.S. forecasters said Isaac was likely to approach Hispaniola, the island shared by the Dominican Republic and Haiti, as a hurricane late Thursday or early Friday after intensifying over the warm waters of the Caribbean Sea. It was predicted to move on to Cuba as a tropical storm and perhaps eventually menace Florida as a hurricane later in the week.

In the eastern Caribbean, many seafront bars and restaurants remained open Wednesday night as lightning and thunder crackled and choppy surf slapped against piers and seawalls. The storm was 270 miles (440 kilometers) southeast of San Juan, Puerto Rico, late Wednesday, with maximum sustained winds of 45 mph (75 kph). Isaac was moving west at 20 mph (32 kph), the U.S. National Hurricane Center said. At the bar of the Fort Young Hotel in Dominica's coastal capital of Roseau, a few tourists and locals drank cold beer and chatted over the sound of white-crested waves outside. "The skies were very black and cloudy most of the day, but it's been pretty quiet so far. Some rain, very little wind," bartender Raymond Reynolds said Wednesday at the 71-room hotel on the jagged, densely forested island. "We've been through this before."

In the foothills of Dominica's Morne Aux Diables volcano, Tess Hunneybell, owner of Manico River Eco Resort, said most of Wednesday was "weirdly quiet" after she and others wrapped the resort's signature treehouses in tarpaulin and nailed shut louvre doors. As a precaution, Prime Minister Roosevelt Skerrit urged people to stay home from work. "I don't want lives to lost," he said. As the storm approached, military authorities at the U.S. base in Guantanamo Bay, Cuba, canceled several days of pretrial hearings in the case of five prisoners charged in the Sept. 11 attacks. They also planned to evacuate about 200 people, including legal teams and relatives of Sept. 11 victims.

Isaac posed a potential threat to Florida during next week's Republican National Convention in Tampa, according to forecasters, though the storm's track was uncertain. In the U.S. Virgin Islands, along the harbor in St. Croix's historic town of Christiansted, piers normally lined with pleasure boats were empty Wednesday. Business owners stacked sandbags around the doorways of pastel-colored buildings. Schools and government offices in St. Croix were ordered to remain closed Thursday. St. Kitts had announced similar closures Wednesday.

With the storm expected to pass just south of Puerto Rico on Thursday, Gov. Luis Fortuno declared a state of emergency for the U.S. territory and activated the National Guard. He also canceled classes and closed government agencies. Federal officials closed the popular San Felipe del Morro castle in Old San Juan. Authorities in Puerto Rico reported that a 75-year-old woman died Wednesday in the northern city of Bayamon when she fell from a second-floor balcony while filling a barrel with water in preparation for the storm. The U.S. Coast Guard closed all ports in Puerto Rico and the U.S. Virgin Islands to incoming commercial ships and warned that all commercial vessels bigger than 200 gross tons must leave or obtain permission to remain in port.

Downpours drenched the French island of Guadeloupe on Wednesday, said local chief meteorologist Norbert Aouizerats. Officials warned of swollen rivers and flooding in Martinique, where authorities urged people in low-lying areas to evacuate. In the Dominican Republic, authorities banned boats from entering its waters and warned of heavy rains from Thursday through Saturday. Liat airline and American Eagle canceled flights to islands including Dominica, the U.S. Virgin Islands, Guadeloupe and Martinique. On the island of Vieques, just east of Puerto Rico, people prepared for the government to temporarily shut off power.

Glenn Curry, an owner of Bananas Guesthouse, said he closed the restaurant and would move guests to a higher floor. "I don't think this is going to be a major storm, but it's going to be noisy and unpleasant for a few hours," he said.

http://www.chron.com...ola-3808725.php

[Chris D]

Is it me or is this storm moving due W much longer than predicted? I think it's because it's stayed much weaker than forecasted resulting in it not following the upper air pattern as much?

I suspect this has big ramifications later down the line because now it looks certain to enter the Gulf.

[Iceberg]

Agree Chris ECM has been best with so far by a large margin, it might yet still miss cuba and travel south of the island...The storm has no easy to see centre atm though but is due to slow down now. Also a massive relocation of the centre over the last 24 hrs.

[Coast]

Agree Chris ECM has been best with so far by a large margin, it might yet still miss cuba and travel south of the island.

'Spaghetti' mode tracks for various organisations (no ECM!):

All pretty tight really.

[Chris D]

'Spaghetti' mode tracks for various organisations (no ECM!):

All pretty tight really.

Yes but they all expect it to get stronger in the shorter term, thus following the upper level ridge more and responding to the trough.

However, if it stays this weak for much longer then a more westerly course looks on the cards. Remains to be seen yet!

Personally I don't take too much attention to the exact model tracks this far out. They chop and change so much you are prone to a heart attack sooner or later. Lol.

Edited August 23, 2012 by Chris D

[Gray-Wolf]

Did I not see ECM operational run putting a strong Isaac into N.Orleans? Anything that lingers in the G.O.M., and avoids contact with Florida, is gonna be big!

I think over the Florida Keys and into the G.O.M.. From there either panhandle or a nasty wobble along the oil rigs toward N.O. Having a pessimistic week/month/year....

[geoffw]

i am pretty sure N.O will be safe

[geoffw]

it wont even be a cat 2 by the time it hits the USA

[Coast]

[Somerset Squall]

it wont even be a cat 2 by the time it hits the USA

Id love to have your crystal ball Geoff LOL. Truth is, no-one knows for sure this far out. I expect westwards tweaks to the track forecast as Isaac has weakened to a minimal 35kt intensity now and is not being steered by the upper levels. It's very difficult to know how long Isaac will spend over the islands of the Caribbean and this obviously will have big effects on the intensity of Isaac prior to potentially entering the Gulf. IMO, it is now looking likely Isaac will enter the Gulf.

RECON is finding the centre of Isaac is again reforming further south.

Edited August 23, 2012 by Somerset Squall

[Chris D]

http://www.wtsp.com/news/local/article/269554/8/Latest-on-Tropical-Storm-Isaac-

Latest on models etc, good animations.

[summer blizzard]

Recon had to turn back but did find the centre further south.

Only 100-200 miles further west than predicted and we see him miss Haiti altogether, 400-500 and we see him thread the needle between Jamaica and Cuba in which case he would seriously go bang (shallow, hot water).

At any rate it looks like i was right about him missing Florida so hopefully he misses Haiti and has longer over water.

[summer blizzard]

A couple of notes also..

ECWMF is very insistent that this will stay NW/WNW and the 12z had a sub 950mb hurricane destroying Texas, the other and perhaps more important note is that this storm is already huge as hurricanes go and as such the storm surge on the Gulf coast will be massive, i would expect some pretty bad destruction along the coast no matter what the strength.

[summer blizzard]

JTWC's new warning has it at 110 kt-- a strong Cat 3 on the Gulf coast.

Edited August 23, 2012 by summer blizzard

[Iceberg]

Recon in ATM but it can't find any west winds, lowest pressure Around 15.5 70 which is considerably south of the last Nhc estimate.

Recon flew around the last Nhc estimate but found no centre.

My best guess is that the centre is reforming under the deeper convection again but whether it actually happens and sticks is unknown.

Without the west winds it shouldn't be Isaac but somehow I don't see the Nhc dropping it.

Final thing ECM did forecast this to be an open wave at this point so is doing quite well.

[Coast]

Looks to be heading to the west of Florida:

Tropical Storm ISAAC: Storm-centered zoom at 93 hours lead

[mezzacyclone]

Recon in ATM but it can't find any west winds, lowest pressure Around 15.5 70 which is considerably south of the last Nhc estimate.

Recon flew around the last Nhc estimate but found no centre.

My best guess is that the centre is reforming under the deeper convection again but whether it actually happens and sticks is unknown.

Without the west winds it shouldn't be Isaac but somehow I don't see the Nhc dropping it.

Final thing ECM did forecast this to be an open wave at this point so is doing quite well.

Mission 10`s picking up some westerly SMFR 10s peaks of 52kn (59.8mph) now lat15.01 long70.98 with a circulation earlier @ 15 69.6 where the dropsonde went down with a 1000mb MSLP,,,,

So a shift south (by something in the region of 100 miles?) is clearly troublesome as the Haitian/DR mountains could have severely pegged it back but more open high SST seas look in the path with Jamaica and the Grand Caymans awaiting but will strengthening introduce a tighter turn?

Their really scrutinising this one?

11:33bst update: 58kn (66.7mph) peak 10sec FLW @ lat16.11 lon -69.43 on AF300 mission 10 NE > SW sweep over suspect centre, Strengthening signs? Increasingly dangerous signs if it don`t start to veer NWards asap with an increased chance of `cane status sooner rather than later and poss 2 status in the GOM?

Edited August 24, 2012 by mezzacyclone

[Somerset Squall]

Unless Isaac strengthens soon, I cannot see it being pulled as far north as currently forecast. Then again I am no expert. Will be interesting to see what happens.

[Coast]

UPDATE 2-Tropical Storm Isaac heads for Haiti, Dominican Republic

• "Poorly organized" Isaac moving westward across Caribbean
  
• Many forecasts show it eventually tracking west of Florida
  
• Hundreds of thousands in Haiti tent camps brace for storm
  

MIAMI, Aug 24 (Reuters) - Tropical Storm Isaac headed towards the Dominican Republic and Haiti on Friday, rumbling slowly west across the Caribbean after unleashing heavy rain on parts of Puerto Rico.

In Haiti, Isaac was threatening thousands of people still living in tents after a devastating earthquake more than two years ago. The storm also posed a threat to Florida, where it could pass near the state's Gulf Coast on Monday as the U.S. Republican National Convention starts in Tampa. Authorities have not ruled out the possibility of postponing or relocating the Republican convention if the storm takes direct aim at Tampa. But Craig Fugate, director of the Federal Emergency Management Agency, said the convention was not his biggest concern, at least for now.

"People are spending a lot of time talking about that. I wish they'd be talking about making sure people in the (Florida) Keys are getting ready and that people in southwest Florida are getting ready," he told CNN. The storm could also affect U.S. energy interests in the Gulf of Mexico, with analysts at Weather Insight, a Thomson Reuters company, giving it a 50 percent probability of moving into the heart of the oil and gas production region. Isaac was forecast to remain a tropical storm after crossing the Dominican Republic and Haiti and then passing over Cuba into the Florida Straits. Many forecast models show it eventually advancing into the Gulf of Mexico, strengthening into a hurricane and possibly making landfall near Alabama, the Florida Panhandle, Louisiana or Mississippi on Tuesday.

"Isaac will likely restrengthen when it moves over the Florida Straits and the eastern Gulf of Mexico," the U.S. National Hurricane Center (NHC) said. But the center warned it was "important not to focus on the exact track because of forecast uncertainties and the fact that Isaac has a large area of tropical storm force winds." It said Isaac was centered about 165 miles (265 km) south of the Dominican Republic's capital, Santo Domingo, and about 230 miles (370 km) southeast of Port-au-Prince, the Haitian capital, as of Friday morning. "Poorly organized Isaac jogs westward," it said in its latest advisory, putting its speed at 15 mph (24 kph) and forecasting a turn towards the west-northwest later in the day.

"The center of Isaac will move near or over Hispaniola today ... and move near or over southeastern Cuba on Saturday."

RISK OF HURRICANE

The storm had top sustained winds of 45 mph (75 km per hour) but the Miami-based hurricane center said Isaac could swell into a hurricane later on Friday as it nears Hispaniola, the island shared by the Dominican Republic and Haiti, but weaken as it moves over land. Isaac was expected to dump between 8 and 12 inches (20 to 30.5 cm) of rain over parts of Hispaniola, with total accumulations up to 20 inches (51 cm) in some areas, the NHC said, posing a significant threat to Haiti, which is highly prone to flooding and mudslides because of its near-total deforestation. "These rains could cause life-threatening flash floods and mud slides," the center said in its advisory.

Haiti, the poorest country in the Americas, still has about 350,000 people living in tents or makeshift shelters more than 2-1/2 years after a devastating earthquake that took more than a quarter of a million lives. Red Cross workers toured crowded tent camps of Haitians left homeless by the 2010 quake to warn about Isaac. Text messages were sent out to tens of thousands of people urging them to stay away from rivers and evacuate tent camps in case the storm hits. Authorities in the Dominican Republic began evacuating people living on the banks of rivers, streams and areas vulnerable to landslides in preparation for the approach of Isaac, whose effects were beginning to be felt with showers in the south of the country. In the U.S. commonwealth of Puerto Rico, officials also braced for flooding after Isaac passed south of the island.

NOT ENOUGH SHELTERS IN HAITI

Republican convention planners said they would continue to monitor the storm closely while staying in close contact with the National Weather Service, Governor Rick Scott, local emergency officials and the campaign of presumptive Republican presidential nominee Mitt Romney. "Any slight westward versus eastward deviation makes a huge difference for Florida," said Phil Klotzbach, a research scientist who heads the respected hurricane forecast team at Colorado State University.

Some forecast models predicted a final landfall in the Florida Panhandle, in the northwest corner of the state, and several showed the storm passing near Florida's Gulf Coast where Tampa is located. Florida has not been hit by a major hurricane since 2005 and forecasts showed Isaac was not expected to strengthen beyond a weak Category 1, with top sustained wind speeds of about 80 mph (129 kph).

In Haiti, Red Cross teams, equipped with shelter and sanitation kits, deployed to distribute emergency supplies, including cooking equipment, water chlorination kits, and plastic sheeting and wood for temporary shelters, said Florent Del Pinto, Haiti head of operations for the International Federation of the Red Cross and Red Crescent Societies. Some camp residents will likely move to government-designated shelters. "But there are not enough shelters for them all," said Del Pinto, adding that the shelters - schools, churches and other concrete buildings - could only handle about 50 percent of the camp residents.

In 2004, Tropical Storm Jeanne killed hundreds of people and flooded the port city of Gonaives with 7 feet (2 meters) of water in places, destroying roads and bridges and virtually cutting it off from the rest of the country. Over the open Atlantic, Tropical Storm Joyce remained a weak tropical depression on Friday. It was expected to regain tropical storm strength on Monday while on a path that may take it close to Bermuda.

http://uk.reuters.co...E8JO15B20120824