Hurricane Joaquin strengthens and track shifts east

Tracking through the warm ocean waters of the Bahamas Thursday, Hurricane Joaquin has exploded in intensity and is now a dangerous Category 4 storm. Forecast uncertainty continues to be high, and the track has shifted east since Wednesday. While the storm may remain offshore, the East Coast remains at risk for widespread flooding and, perhaps, damaging winds.

With peak winds of 130 mph, Hurricane Joaquin is the second major hurricane - Category 3 or stronger - of the season and the strongest. Joaquin is expected to strengthen even more over the next day. The National Hurricane Center predicts it may achieve sustained winds of 140 mph.

In its 11 a.m. update, the official forecast track from the hurricane center remained just off of the East Coast, with areas from North Carolina to New York City in the cone of uncertainty and at risk for landfall. Though key details on the final track of the powerful hurricane remain in question, one thing does look certain: extreme rainfall totals are likely for large parts of the Eastern Seaboard, if the storm tracks close to the coast or inland.

Since Wednesday, a few of the trusted computer models, including the American GFS model, have shifted their tracks farther east, suggesting a lower chance of landfall for the East Coast. This is more in line with what the European model has been suggesting, which in 2012 nailed the track of Hurricane Sandy many days before other models caught on.

Despite the eastward trend on Thursday, the National Hurricane Center notes that landfall is still a possibility and that coastal residents should be making preparations and watching the forecast carefully. "Confidence in the details of the forecast after 72 hours remains low, as there have been some large changes in the model guidance overnight," the center writes. "The range of possible outcomes is still large, and the possibility of a hurricane landfall in the Carolinas still cannot be ruled out."

Though the exact path of Joaquin will determine where the heaviest rain will fall, and how much, the biggest potential impact from this storm remains widespread flooding. The rain that will wash over the East Coast isn't just from Joaquin - there's also a lingering cold front and trough of low pressure 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 catastrophic flooding.

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.

Storm surge is the rise of water caused by strong winds plowing water up onto land, into bays and up rivers. Sometimes it happens gradually, sometimes dramatically, but it's always a very destructive force.

It's still too soon to say anything specific about storm surge impacts in the United States from Hurricane Joaquin, but if the storm tracks north along the coast as recent forecasts have suggested it will, storm surge will be a problem. Onshore winds can cause significant surge flooding very far from the storm's center.

The location and intensity of strong wind is highly dependent on the exact track that Hurricane Joaquin takes. But a major hurricane landfall is certainly not out of the question anywhere from South Carolina up into New England, depending on if and when a turn to the west will occur.

Though the track forecast has shifted east, residents in the Eastern Seaboard states should be preparing for these impacts, which will begin for many on Thursday and Friday.