Hurricane Joaquin Keeps Forecasters Guessing on Its Path

Tropical Storm Joaquin jumped in strength and is forecast to become a Category 1 hurricane by Wednesday, even as computer models disagree on where it will end up.

Joaquin’s top winds reached 65 miles (105 kilometers) per hour, up from 45 mph earlier Tuesday, the Miami-based National Hurricane Center said in a 5 p.m. advisory. The system was moving west-southwest at 5 mph and was about 405 miles east of the northwestern Bahamas.

“Additional strengthening is forecast during the next 48 hours,” according to the 5 p.m. Tuesday advisory written by senior hurricane specialist Richard Pasch. “Joaquin could become a hurricane on Wednesday.”

Joaquin, the 10th storm of the six-month Atlantic hurricane season that ends on Nov. 30, is forecast to reach sustained winds of 90 mph by Friday, making it a strong Category 1 system on the five-step Saffir-Simpson scale.

Warm Waters

Wind shear, which had been tearing at its structure, is expected to drop off, and the storm will pass across water that is about 86 degrees Fahrenheit (30 Celsius), the warmest ever in that part of the Atlantic in records going back to 1880, Jeff Masters, Weather Underground co-founder, wrote on his blog Tuesday.

“It looks like the bottom may fall out of this one,” said Phil Klotzbach, lead author of the Colorado State University seasonal hurricane forecast. The warm water runs deep and that can allow the storm to intensify rapidly.

While the storm’s strength is coming into clearer focus, its path has remained hard to determine.

The forecast is complicated by the number of moving parts on the weather map right now, said Tom Downs, a meteorologist with WeatherBell LLC in New York.

“Meteorologically, the interesting thing is the number of players on the field,” Downs said, citing a cold front, a system that was in the western Gulf of Mexico, another that moved over Florida from the eastern Gulf of Mexico and the remnants of Tropical Storm Ida, farther east in the Atlantic. “This is one of the reasons the forecast is so challenging and the wide range of potential solutions.”

Models Disagree

Two computer models disagreed on the storm’s five-day track by 1,000 miles, Klotzbach said.

Two runs of the European Centre for Medium Range Weather Forecasting model came back with different locations as to where the storm would be on Sunday, Masters said in an e-mail interview.

“So the forecast situation is unusual and complex,” he said.

The situation should clear up as reconnaissance aircraft flying into Joaquin get better data to feed into the computer models, Masters said. The National Oceanic and Atmospheric Administration will leave a dropsonde instrument package in the storm.

Track Uncertain

“Anyone who says they have any confidence in where it is going to go is lying to you,” said Rob Carolan, a meteorologist at Hometown Forecast Services Inc. in Nashua, New Hampshire.

On top of the threat from the storm itself, the U.S. Northeast, including New York, will get drenched from “fire-hose precipitation,” Carolan said. This will be in addition to heavy rain falling on the area from other weather systems through Wednesday.

Through the next week, nearly 9 inches (23 centimeters) of rain is forecast to fall across New England, and about 8 inches in southern New York and northern New Jersey, the U.S. Weather Prediction Centersaid.

All that water will be flowing into urban rivers and heavily populated areas, which could make the flooding worse, Carolan said.

Joaquin Update: Wed., Sept. 30, 8 a.m.

Joaquin Becomes a Hurricane as Winds, Rain Approach Bahamas

Storm Joaquin grew into a Category 1 hurricane as it bore down on the Bahamas, where warnings and watches are posted for the central and northwestern islands in the chain.

The storm’s top winds now reach 75 miles (120 kilometers) per hour, just above the threshold for a hurricane, the U.S. National Hurricane Center said. It was about 245 miles east- northeast of the central Bahamas, moving southwest at 6 mph, according to an 8 a.m. advisory from the Miami-based center.

“Hurricane conditions are expected to reach portions of the Central Bahamas by Thursday,” Jack Beven, a senior hurricane specialist., said in the advisory. “Preparations to protect life and property should be rushed to completion.”

Joaquin, the 10th storm of the six-month Atlantic hurricane season, could drop as much as 5 inches (13 centimeters) of rain across much of the Central Bahamas, with Rum Cay and San Salvador possibly receiving 10. In addition, Joaquin’s storm surge is expected to raise water levels 2 to 4 feet above normal. The surge “will be accompanied by large and dangerous waves,” the advisory said.

Islands Threatened

Cat Island, the Exumas, Long Island, Rum Cay and San Salvador can expect to experience hurricane-force winds within the next 36 hours. The storm may later hit the northwestern Bahamas, including Abacos, Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence.

Forecasters are also trying to gauge the threat to the U.S. While there is little confidence in the long-term track, hurricane center maps show the storm off the Virginia coast by Monday.

The problem facing meteorologists is that computer forecast models cannot agree on where the storm will go. The U.S. is currently being raked by a number of large weather patterns that are bringing soaking rains to the Northeast.

“Given that a wide range of outcomes is possible, it is too soon to say what the impacts, if any, Joaquin will have on the United States,” senior hurricane specialist Michael Brennan wrote in an analysis at 5 a.m.