Hurricane Joaquin forecast

Slate has a projection for the 'unknowable' hurricane:

The National Hurricane Center has upgraded Hurricane Joaquin to a Category 4 huricane after a hurricane hunter mission investigating the storm found sustained winds of approximately 130 mph and deepening central pressure, both signs of strengthening.
Looking toward the future, midday weather models continued the trend toward an offshore track for Joaquin. The high-resolution HWRF model joined the larger-scale GFS and European models indicating a future path toward Atlantic Canada or Bermuda. The GFDL and Canadian models, both in the second tier of accuracy, are the only major models remaining to insist on a landfall in the United States, likely in the Carolinas or southern Virginia.
However, this is not to say that the risk to the United States from Joaquin is decreasing. Latest runs of the GFS and European models— which have high levels of historical accuracy— still indicate ten to twenty inches of rainfall is likely in the Carolinas over the weekend, regardless of Joaquin's track. That would be enough to break all-time monthly rainfall records for several cities in as little as three days and create the potential for historic flooding.
North Carolina Governor Pat McCrory has declared a state of emergency for North Carolina. That makes three states— North Carolina, New Jersey, and Virginia— that are bending the rules to prepare for Hurricane Joaquin.
New Jersey Governor Chris Christie has declared a state of emergency for New Jersey in advance of Hurricane Joaquin. Christie, who is currently running for President, has pledged to remain in New Jersey until the storm passes.
Right now, a major hurricane is threatening landfall in the United States within the next three days. Even worse: meteorologists— myself included— don’t really know where it’s headed. Since it’s been nearly ten years since the last storm of Hurricane Joaquin’s strength hit the US, it’s understandable that this situation would make more than a few people nervous.
Here’s what we know at the moment:
Overnight, Hurricane Joaquin— which is currently posing a grave threat to parts of the Bahamas— continued its trend of rapid intensification that saw it grow from tropical storm to high-end Category 3 in less than a day. The latest official forecast from the National Hurricane Center predicts Joaquin will reach Category 4 strength later Thursday, if it hasn’t already. On Twitter, NHC director Rick Knabb emphasized the continued threat to the mainland, saying hurricane watches may be required later Thursday, which would set in motion local preparedness efforts and possible evacuations.
However, overnight weather forecast models have thrown a giant wrench into anything resembling confidence in a likely path for Joaquin over the next few days after it departs the Bahamas.
For most of the day Wednesday, I talked about the worst-case scenario we might be able to reasonably expect from Joaquin and that scenario is pretty terrifying: a Category 3 or 4 hurricane landfall in southern Virginia would be catastrophic to a very vulnerable region and could temporarily turn parts of Washington, DC, into a swamp. It would be like Hurricane Sandy, only for the Chesapeake Bay area.
Thankfully, that scenario is looking a bit less likely Thursday morning. That’s mainly because, over the past twelve hours, the GFS model— America’s flagship weather forecasting tool— for this storm has undergone a dramatic shift from the North Carolina/Southern Virginia region that it’s been targeting for the previous day and a half all the way to Nova Scotia, a shift of more than a thousand miles.
That’s prompted the latest official National Hurricane Center forecast to shift back to the north, toward the New York City metro area, though I don’t think it will remain there for long. That’s because a New York City landfall hasn’t been consistently showing up in any model; it’s merely the NHC’s way of splitting the difference between two very different but roughly equally likely possibilities: a landfall in the Carolinas/Virginia or a track safely out to sea.
Hurricane Joaquin is proving to be an excellent example of the challenges of trying to predict the behavior of a nonlinear system days in advance. Sometimes, that’s just a really, really hard thing to do. There’s a reason chaos theory was invented by a meteorologist. And now, we’re seeing that play out in real time, as possible future paths of a Category 3 or 4 hurricane oscillate wildly over the most densely populated part of the country.
At the risk of becoming overly philosophical, we’re at a moment in our civilization’s history when stupendous recent technological advances can often make us feel as if we are omniscient. In our pockets, we carry devices that can tell us virtually anything we want, instantly. As much as we may want it to, the atmosphere does not work that way.
To accurately understand what the weather will do days in advance, you have to observe it perfectly, and perfectly understand the underlying physics. We actually do the second part better than the first; there is just no way to launch enough weather balloons or satellites to monitor the entire Earth system, down to the millimeter. On days like today when the weather pattern is especially complex, this uncertainty really sucks, but we sort of just have to sit back and wait to see what the atmosphere will do.
In such a situation, it’s best to focus on what we do know:
Minor coastal flooding is already occurring along the East Coast from strong onshore winds being funneled between Joaquin to the south and strong Canadian high pressure to the north. That flooding will likely worsen over the next few days, regardless of the track of Joaquin.
As Joaquin funnels tropical moisture northward, rainfall totals will be enormous across much of the East Coast regardless of whether the hurricane hits land; we’re talking one to two feet of rain for the hardest hit areas. That will produce flash flooding severe enough to float away cars even in areas far from the coast. It isn’t nearly as dramatic as a landfalling major hurricane, but for many areas, it could be just as damaging. Flooding from heavy rain is more than twice as deadly, on average, as the wind from a hurricane.
Given the potential impact— even if the center of Joaquin moves safely out to sea this weekend— it’s really important to start thinking about steps you might take to be sure you and your family remain safe.

Rico says we'll just have to hunker down and hope it goes elsewhere... (Which it did.)

Tracking through the warm ocean waters of the Bahamas, Hurricane Joaquin exploded in intensity, becoming a dangerous Category 4 storm. But, at the same time, the forecast track for Joaquin shifted markedly east, and it is now very likely the storm will remain out to sea rather than slamming into the East Coast.
While Joaquin may remain offshore, parts of the East Coast remain at risk for flooding from a predecessor surge of moisture streaming up the eastern seaboard Friday into Saturday.
With peak winds of 130 mph, Hurricane Joaquin became the strongest hurricane of the season Thursday. Joaquin is expected to strengthen even more into Friday and may attain sustained winds of 140 mph, according to the National Hurricane Center.
In its update, the official forecast track from the hurricane center shifted the path of the storm almost entirely off the East Coast. Only coastal areas of the Mid-Atlantic and southern New England remain inside the cone of uncertainty, signaling areas to the west and south are mostly out of the woods from the storm’s direct effects.
“A strong majority of the forecast models are now in agreement on a track farther away from the East Coast,” the National Hurricane Center wrote. “We are becoming optimistic that the Carolinas and the mid-Atlantic states will avoid the direct effects from Joaquin.”
Despite the shift in the track out to sea, the National Hurricane Center cautions “we cannot yet completely rule out direct impacts along on the east coast, and residents there should continue to follow the progress of Joaquin over the next couple of days.”
Flooding remains a major concern due to rain indirectly linked to Joaquin and its interaction with a lingering cold front that is actively drawing deep, tropical moisture up the East Coast and squeezing it out like a wet rag.
Much of the Eastern United States has already received soaking rains from these two features over the past week, and now many of the same areas can expect a whole lot more. This will result in potentially severe flooding, especially in areas of South Carolina where up to twenty inches of rain is predicted.
Flood watches are already in effect from South Carolina all the way up to Connecticut. The flood threat is a serious one: if you are in a flood-prone area, now is the time to begin to take precautions.

Rico says let's hope it continues out to sea and avoids New England...