Joaquin, Becomes a Major Hurricane, Impacting Bahamas; U.S. East Coast Landfall Remains Possible

September 30,2015
Hurricane Joaquin strengthened to major hurricane status as a Category 3 storm Wednesday night, as it moves dangerously close to the Bahamas, and prospects are looking increasingly worrisome for the U.S. mainland as the official forecast raises the odds of the East Coast seeing its first landfalling hurricane in 15 months.
Joaquin will pass dangerously close to Samana Cays island through Thursday morning, moving toward Rum Cay and San Salvador islands later Thursday. With the Category 3 hurricane passing close to the islands at a relatively slow speed, and perhaps even intensifying to Category 4 status, a catastrophic situation may unfold there with a prolonged period of intense hurricane conditions.
Hurricane warnings have been expanded to include more of the Bahamas as Hurricane Joaquin churns toward the nation of islands east of Florida.
(MORE: Expert Analysis | Hurricane Central)
An Air Force Reserve Hurricane Hunter reconnaissance aircraft flying through Hurricane Joaquin Wednesday night found winds near the center had become much stronger, prompting the agency to raise the wind figure to 105 mph in the 8 p.m. advisory and 115 mph at 11 p.m. The latter makes Joaquin a Category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale.
Equipment on the plane measured surface winds as high as 130 mph in gusts within powerful thunderstorms in the developing eyewall in the still-growing tropical cyclone.
With Joaquin strengthening 30 mph within a 24-hour period on Wednesday, rapid intensification criteria has been met. Further strengthening is expected in the coming days.

Hurricane Joaquin Information

Hurricane Joaquin continues to intensify as wind shear – harmful to the intensification of tropical cyclones – lessens, and a complicated atmospheric pattern makes its future track – including any potential landfall on the U.S. East Coast – extremely difficult to forecast.
Residents along the East Coast of the U.S. should pay close attention to the forecast now through this weekend. It's a particularly difficult forecast that hinges on the behavior of several different atmospheric features over North America and the North Atlantic Ocean.

Aware Threat Index

Computer forecast models – and the meteorologists who rely on them for guidance – are grappling with a complex interaction between Joaquin, a cold front near the East Coast, the remnants of Tropical Storm Ida, a strong bubble of high pressure aloft over the North Atlantic Ocean, and a potentially strong area of low pressure aloft digging into the southeastern U.S. later this week.

Ensemble Forecast Model Tracks

Joaquin's future depends critically on the position and relative strength of those players – not to mention its own strength. Strong wind shear had kept most of Joaquin's thunderstorm activity (convection) south or east of its center of circulation, but that changed Tuesday afternoon and evening as thunderstorms developed closer to its circulation center.
(MORE: Expert Analysis | Hurricane Central)

Visible Satellite

Because Joaquin is strengthening and drifting ever closer to the Bahamas, the government of that country has issued warnings and watches for much of its territory. Here are the details as of 8 p.m. EDT:

• A hurricane warning is now in effect for the northwestern Bahamas including the Abacos, Berry Islands, Eleuthera, Grand Bahama Island, and New Providence, but excluding Andros Island and Bimini.
• A hurricane warning remain in effect for the central Bahamas, including Cat Island, the Exumas, Long Island, Rum Cay and San Salvador.
• A hurricane watch is now in effect for Bimini.
• A tropical storm warning is now in effect for the southeastern Bahamas including the Acklins, Crooked Island, Long Cay, the Inaguas, Mayaguana, and the Ragged Islands, but excluding the Turks and Caicos Islands.

Hurricane Joaquin: Watches and Warnings

Hurricane preparations should be rushed to completion in the hurricane warning area.
(MORE: Bahamians Prepare for Hurricane Joaquin)
Joaquin is expected to slowly churn toward the Bahamas through Thursday. The extent of the effects on those islands will depend heavily on how close it gets and how much time it spends nearby before making the anticipated northward turn.
At this time, we expect some of the worst impacts in the Bahamas to occur on San Salvador and Rum Cay, the islands closest to Joaquin's current position. On San Salvador, rainfall totals could exceed 2 feet. Sustained tropical-storm force winds of 39 mph or greater may develop Wednesday night and continue unabated for 48 hours or more.

Track Forecast: Still Extremely Challenging

Although computer model simulations have had the advantage of ingesting high-resolution real-world data from the Air Force reconnaissance flight earlier in the day, it doesn't seem to have brought them any closer to a consensus.
The American GFS model forecast continues to show Joaquin making an alarming northwestward turn, slamming it right into Virginia, Maryland or North Carolina this weekend. Meanwhile, the European ECMWF model suggests Joaquin has a chance of staying away from the U.S. East Coast.
It is simply too soon and the uncertainty is too high to determine any impacts from Joaquin itself for the U.S. East Coast at this time.
The National Hurricane Center's official forecast cone is below. The official forecast remains a compromise between the competing scenarios from the computer models.
(MAP: Track Hurricane Joaquin with our New Interactive Storm Tracker)

Projected Path

Note that the official intensity forecast now brings Joaquin to Category 3 strength on Saturday morning, which by definition would make it a major hurricane.
Regardless of the ultimate outcome of Joaquin's path, portions of the East Coast will still see multiple impacts from the evolving large-scale weather pattern, including flooding rainfall, gusty winds, high surf, beach erosion and some coastal flooding. Click the link below for more information on that story.
(MORE: Significant Impacts Likely on East Coast)

Late Week and Weekend Setup

In summary, here's what we know about Joaquin as of Wednesday's 11 p.m. EDT advisory:

• Hurricane Joaquin's center is located about 90 miles east of the central Bahamas.
• Maximum sustained winds are estimated at 115 mph, a Category 3 hurricane on the Saffir-Simpson hurricane wind scale.
• As wind shear over the storm lessens, Joaquin should strengthen further over the next 2 to 3 days.
• This system is moving slowly to the southwest and this is expected to continue through Thursday before turning north Friday into Saturday.
• Hurricane watches and warnings are in effect for parts of the Bahamas.
• Joaquin may directly or indirectly affect the East Coast late this weekend or early next week, and a landfall is possible.
• Moisture and/or energy associated with Joaquin could enhance rainfall along the cold front in the Northeast late this week. Regardless, the East Coast will see significant impacts from the larger scale weather pattern taking shape.

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