(Bloomberg) -- Joaquin is forecast to become a major hurricaneby Saturday as it churns in the Atlantic, triggering hurricanewarnings and watches for the Bahamas. Its course after crossing theisland chain is still uncertain, the National Hurricane Centersaid.

Joaquin, now a Category 1 storm with winds of 80 miles(130 kilometers) per hour, was forecast to begin raking the centralBahamas with hurricane-force winds Thursday. The storm isabout 215 miles east-northeast of those islands and is movingsouthwest at 6 mph, the Miami-based center said in an 11 a.m.advisory.

“Winds are expected to first reachtropical storm strength in the warning area tonight,making outside preparations difficult or dangerous,”Jack Beven, asenior hurricane specialist, said in the advisory. “Preparations toprotect life and property should be rushed to completion.”

Where Joaquin will go after it crosses through the Bahamas isstill uncertain and a direct strike on the U.S. East Coast can’t beruled out, Beven said in a forecast analysis. There is also achance the stormwill harmlessly pass out to sea and miss theU.S.

“Confidence in the details of the track forecast late in theperiod remains low, since the environmental steering currents arecomplex and the model guidance is inconsistent,” Beven said. “It istherefore way too soon to talk about specific wind, rain, or surgeimpacts from Joaquin in the U.S.”

U.S. coastline

There is a 30 percent chance thattropical storm-strength winds will reach the coastlinefrom North Carolina to Delaware in the next five days and a morethan 10 percent chance the storm-strengthwinds of 39 mph ormore will strike anywhere from Massachusetts to South Carolina inthe same time frame.

Some models suggest the storm will hit somewhere inNorth Carolina in four days, while the European Centre for Medium-Range Weather Forecasts model takes it off to the northeast towardBermuda, said Phil Klotzbach, lead author of the Colorado StateUniversity seasonal hurricane forecast.

‘Tough call’

“Since the ECMWF is generally considered to be the best trackmodel, it’s a really tough call,” Klotzbach said. “I’ll be curiousto see what the updated model guidance shows in a couple ofhours.”

The other problem facing forecasters is that the storm’s forwardspeed will probably increase should it become a threat to theU.S., resulting in “impacts along the coast occurring sooner thancurrently forecast,” Beven said. If that happens, “a hurricanewatch could be required for portions of the U.S. coast as early asThursday evening,” he said.

The current forecast shows Joaquin’s top winds reaching 115 mphby Saturday, which would make it a Category 3 storm, or majorhurricane, on the five-step Saffir-Simpson scale.

The U.S. hasn’t been hit by a major hurricane since 2005.

Even without a strike by Joaquin, the U.S. East Coast has beendrenched by heavy downpours. More than 10 inches of rain isforecast to fall throughout parts of southern New Jersey, Delaware,Maryland, Virginia and North Carolina in the next seven days,according to the U.S. Weather Prediction Center in College Park,Maryland.

Flood watch

Flood warnings and watches currently cover most of New Englandand much of New York, the National Weather Service said.

As of noon New York time, 78 flights in the U.S. were cancelledand 794 more delayed, according to FlightAware, a Houston-basedairline tracking service.

In the Central Bahamas, Joaquin, the 10th storm of thesix- month Atlantic hurricane season, could drop as much as 5inches (13 centimeters) of rain. Rum Cay and San Salvador may get10. In addition, Joaquin’s storm surge is expected toraise water levels 2 to 4 feet above normal. The surge “will beaccompanied by large and dangerous waves,” the advisory said.

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

--With assistance from Ladka Bauerova in Prague.

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