Hurricane Delta is re-strengthening in the central Gulf after its encounter with Mexico’s Yucatán Peninsula. The then-tiny central core of the hurricane was disrupted by its trek over land, which knocked down the winds dramatically. But the atmospheric conditions over the Gulf are supportive for strengthening.
The question is, how much can Delta intensify today? Tomorrow, as the storm approaches the Louisiana coast, it will encounter cooler water over the near-shore shelf where the Gulf is very shallow. Early season cold fronts have already cooled that water. That should start the weakening process before the center comes ashore.
As often happens during a storm’s reorganization, Delta has grown in size over the last two days. At its peak intensity, Hurricane Hunters measured the storm’s eye at 5 miles wide. The latest measurements showed it has grown to about 40 miles across. Like a figure skater spins slower when she spreads her arms in a twirl, the storm’s winds slow down as the energy spreads out over more of the Gulf.
Broader storms are also slower to strengthen, so Delta is not expected to become as strong as it was when it was in the Caribbean – it reached 145 mph, Category 4 hurricane at that time. But after today’s increase, it is forecast to reach Category 3 strength, and be a larger and very dangerous storm at landfall.
Delta is heading for, essentially, the same part of Louisiana that Hurricane Laura hit in August. It’s not wildly unusual for two hurricanes to make landfall in the same place in the same year. It happened in Florida in 2004 when Hurricanes Frances and Jeanne both targeted Stuart, just north of Palm Beach, Florida. And a similar thing happened near Fort Lauderdale in 1947 when two hurricanes went over the area in 1947, though they came from different directions.
So if Delta comes ashore as a Category 3, that will be very usual – two Cat 3+ storms in the same year. The odds favor Delta weakening some in the last few hours before landfall, so a Category 3 isn’t likely, but residents need to be ready for that possibility.
The Gulf water is forecast to be pushed 7 to 11 feet above the normal high tide level at the coast in the same area and just to the east of where Hurricane Laura surged the water 17 feet over normally dry land. Obviously, neither scenario is survivable for people that remain at ground level.
The storm surge will affect the entire Louisiana coast, and water will be elevated in Mississippi, as well.
In addition, heavy rain will spread inland and flooding is a concern in a corridor from Louisiana into the Midwest. This is essentially the same area where Laura caused local flooding. Up to 15 inches of rain with widespread 5 to 10 inches is forecast in the South.
The remnants of Delta will pass through the Mid-Atlantic states and the Northeast late in the weekend into early next week bringing heavy rain as well, though the moisture will be spread out by that time, so the flood threat is lower.
Long-range computer forecast models don’t show anything suspicious developing in the tropics for the next week, at least. Though, as we’ve seen, systems in the Caribbean can sometimes suddenly develop out of nothing. The winter weather pattern hasn’t settled in yet.