Fierce HURRICANE FLORENCE is bearing down on the North Carolina coast, where it is forecast to stall. After that the track becomes foggy, but a bizarre scenario of meandering that will prolong the misery now appears likely. The new forecast indicates that much of South Carolina and perhaps part of Georgia will eventually be impacted by the storm as well.
There are three systems of concern:
• HURRICANE FLORENCE is on track to be an historic disaster in the Carolinas extending over several days, into next week.
• TROPICAL STORM ISAAC has significantly weakened. Still, it will move through the eastern Caribbean islands tomorrow, likely as a tropical storm.
• DISTURBANCE 95L – using the National Weather Service numbering system – is somewhat less organized today. It may still develop into an organized system in the western Gulf and threated Texas.
HURRICANE FLORENCE has top winds estimated at 130 mph this morning – Category 4. Hurricane Hunters have found that the diameter of the storm is increasing, meaning that more of the coast will be affected. This was expected.
The track through tomorrow is unchanged. It is expected to approach the North Carolina coast late tomorrow night as a powerful and destructive hurricane. At that point the storm is expected to slow to a crawl, extending the amount of time the coastal communities will be battered.
Whether Florence stalls tomorrow night with its center over the ocean, or just ashore, is an open question. It is too close to call. The farther inland it goes, the more flooding it will produce over already saturated ground. If the center says over the water, the hurricane will stay stronger longer, prolonging the hammering on the coastline.
After Florence reaches the North Carolina coast, the consensus of the computer forecast models indicates that the center of Florence will drift down the South Carolina coast, spreading misery into that state, perhaps significantly affecting Charleston and even Savannah. This is going to be a slow process extending through the weekend, so it’s too early to be precise.
Hurricane Warnings and Storm Surge Warnings are in effect for most of the South Carolina and all of the North Carolina coast. Storm surge will be life-threatening over the part of that coastline that ends up north of the storm center. The National Hurricane Center is forecasting the ocean water to be pushed 9-13 feet over the land on the Outer Banks of North Carolina, with lesser but still life-threatening surge over most of the Carolina coast and up into the various bays, rivers, and inlets.
In addition, the rainfall forecast has now increased to 20 to 30 inches for the coastal areas of the Carolinas, with some spots receiving 40 inches. Inland areas will receive less, but still 5-10 inches with some areas receiving 20 inches of rain. All that water will try to run out the rivers, streams, and inlets, while the storm surge is pushing in from the ocean. It is a recipe for a disastrous flood, on top of the damage from the wind.
A hurricane that stalls and meanders just offshore is one of the most destructive scenarios.
Here are the Key Messages from the National Hurricane Center concerning Hurricane Florence:
1. A life-threatening storm surge is now highly likely along portions of the coastlines of South Carolina and North Carolina, and a Storm Surge Warning is in effect for a portion of this area. All interests in these areas should complete preparations and follow any
advice given by local officials.
2. Life-threatening, catastrophic flash flooding and significant river flooding is likely over portions of the Carolinas late this week into early next week, as Florence is expected to slow down as it approaches the coast and moves inland.
3. Damaging hurricane-force winds are likely along portions of the coasts of South Carolina and North Carolina, and a Hurricane Warning is in effect. Strong winds could also spread inland into portions of the Carolinas.
4. Large swells affecting Bermuda and portions of the U.S. East Coast will continue this week, resulting in life-threatening surf and rip currents.
TROPICAL STORM ISAAC is struggling with hostile upper-level winds, which are keeping it from strengthening. The peak winds are still estimated at: 60 mph. The official forecast keeps it below hurricane strength as it passes through the eastern Caribbean islands tomorrow.
The threat of some strong winds and heavy rainfall still exists for the affected islands, especially: Martinique, Dominica, and Guadeloupe.
Isaac is forecast to move into the central Caribbean Sea over the weekend and weaken. The eventual track of what’s left of Isaac may have something to do with the way Florence tracks and how strong it remains, which is, of course, doubly uncertain. So we’ll have to watch it. The remnants of Isaac could get pulled north toward South Florida, but it would likely be a minor disturbance or just excess tropical moisture by that time.
Here are Key Messages from the National Hurricane Center concerning Isaac:
1. Isaac is expected to remain at tropical storm intensity when it moves across the Lesser Antilles on Thursday, and tropical storm warnings are in effect for Martinique, Dominica, and Guadeloupe. Tropical storm watches are in effect for Montserrat, St. Kitts and
Nevis, Antigua, and Saba and St. Eustatius. Interests on those islands should follow any advice given by their local officials.
2. Life-threatening flash flooding is possible with Isaac. The storm is expected to produce total rainfall accumulations of 2 to 4 inches with isolated amounts up 8 inches across Martinique,
Dominica and Guadeloupe. Rainfall amounts of 1 to 2 inches with isolated amounts to 4 inches are expected across Puerto Rico and the southern United States Virgin Islands.
DISTURBANCE 95L, using the NHC number, was showing signs of organization, but less so today. It will move across the Yucatan Peninsula of Mexico and into the southern and western Gulf where it might organize into a Tropical Depression or Tropical Storm over the next couple days. These systems can spin up quickly, so residents in northern Mexico and Texas should stay informed.
HURRICANE HELENE, DISTURBANCE #1, and POTENTIAL DISTURANCES #2 are not expected to affect land over the next several days, if ever.
TROPICAL STORM OLIVIA is approaching the Hawaiian Islands. The biggest threat is from heavy rain over the mountainous islands.