Hurricane Dorian – A Catastrophic, Life-Threatening Situation for the NW Bahamas

As of 9:30 AM, Hurricane Dorian shows no signs of weakening, with frequent lightning ongoing in its eyewall, indicative of strengthening. Over the last hour, Dorian’s peak winds from 260 KM/H to 280 KM/H and its pressure dropped a significant 5 millibars between 8:00 AM and 9:30 AM.

Air force reconnaissance planes, i.e. Hurricane Hunters, continue to find lower pressures within the eye of Dorian, as it bears down on Abaco Islands, northwestern Bahamas.

The eyewall of catastrophic Hurricane Dorian is currently reaching the Abaco Islands. This is a life-threatening situation. Residents there should take immediate shelter. Do not venture into the eye if it passes over your location.

Hazards:

  • Wind Gusts over 200 mph (320 KM/H)
  • Storm Surge 15 to 20 feet (4.5-6 meters) above normal tide levels with higher destructive waves.

These hazards will cause extreme destruction in the affected areas.
and will continue for several hours.

A hurricane warning remains in effect Northwestern Bahamas excluding Andros Island. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. Preparations to protect life and property should be rushed to completion.

A hurricane watch remains in effect for Andros Island. A Hurricane Watch means that hurricane conditions are possible within the watch area.

A tropical storm warning is in effect for North of Deerfield Beach to Sebastian Inlet, Florida. A Tropical Storm Warning means that tropical storm conditions are expected within the warning area within 36 hours.

A tropical storm watch is in effect for North of Golden Beach to Deerfield Beach, Florida. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours.

Hazards Affecting Land

Wind: Devastating hurricane conditions are expected in the Abacos Islands very soon and these conditions will spread across Grand Bahama Island later today. Tropical storm conditions are expected within the tropical storm warning area on Monday. Tropical storm conditions are possible within the tropical storm watch area by Monday night.

Storm Surge: A life-threatening storm surge will raise water levels by as much as 15 to 20 feet above normal tide levels in areas of onshore winds on the Abaco Islands and Grand Bahama Island. Near the coast, the surge will be accompanied by large and destructive waves.

Rainfall: Dorian is expected to produce the following rainfall totals through late this week:

Northwestern Bahamas – 12 to 24 inches (300-600 mm), isolated 30 inches (750 mm).
Coastal Carolinas – 5 to 10 inches (125-250 mm), isolated 15 inches (375 mm).
Central Bahamas and the Atlantic Coast from the Florida peninsula through Georgia – 2 to 4 inches (50-100 mm), isolated 6 inches (150 mm).

This rainfall may cause life-threatening flash floods.

Seas: Large swells will affect the east-facing shores of the Bahamas, the Florida east coast, and the southeastern United States coast during the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

Hurricane Dorian’s Strength

These are the highest sustained winds in any Atlantic hurricane since Maria (2017).

Of the 1,869 Atlantic storms recorded over the last 169 years, only 18 have recorded winds as strong or stronger than Hurricane Dorian right now (175 mph).

At Category 5 strength, with winds in excess of 157 MPH (252 KM/H), catastrophic damage is expected.

Category 5 is the highest category of the Saffir–Simpson scale. These storms cause complete roof failure on many residences and industrial buildings and some complete building failures with small utility buildings blown over or away. The collapse of many wide-span roofs and walls, especially those with no interior supports, is common. Very heavy and irreparable damage to many wood frame structures and total destruction to mobile/manufactured homes is prevalent.

Only a few types of structures are capable of surviving intact, and only if located at least 3 to 5 miles (5 to 8 km) inland. They include office, condominium, and apartment buildings and hotels that are of solid concrete or steel frame construction, multi-story concrete parking garages, and residences that are made of either reinforced brick or concrete/cement block and have hipped roofs with slopes of no less than 35 degrees from horizontal and no overhangs of any kind, and if the windows are either made of hurricane-resistant safety glass or covered with shutters. Unless all of these requirements are met, the absolute destruction of a structure is certain.

The storm’s flooding causes major damage to the lower floors of all structures near the shoreline, and many coastal structures can be completely flattened or washed away by the storm surge. Virtually all trees are uprooted or snapped and some may be debarked, isolating most affected communities. Massive evacuation of residential areas may be required if the hurricane threatens populated areas. Total and extremely long-lived power outages and water losses are to be expected, possibly for up to several months.

Dorian’s Forecast Intensity & Track

Dorian continues to exhibit a well-defined eye surrounded by very cold cloud tops on satellite images. The hurricane will remain in a fairly low-shear environment for the next few days, however since it is forecast to move quite slowly over the shallow waters of the northwesternmost Bahamas through Monday, this would likely result in less available oceanic heat content. Therefore, a very slow weakening is anticipated to commence after 12 hours or so. The official intensity forecast is near the high end of the numerical guidance suite.

The hurricane continues moving westward, or about 280/7 kt. A high-pressure ridge to the north of Hurricane Dorian should maintain this westward movement through today. By tonight, the global models show the ridge weakening, and this evolution should result in a slowing of the forward speed, with the hurricane becoming nearly stationary around 48 hours. In comparison to its earlier runs, the new ECMWF track forecast takes the system farther to the west during the next couple of days and is the southwesternmost model through 48 hours.

As a result, the official track forecast has been shifted a little west during that time frame. In 2 to 4 days, Dorian should turn northward in response to a trough over the eastern United States. By the end of the period, the flow on the south side of the trough should cause the cyclone to move northeastward near the Carolinas.

Based on present modeling, Hurricane Dorian is forecast to move along the Eastern Florida Coast as a major Category 4 Hurricane, bringing life-threatening surge and surf to the coastlines, gradually weakening as it heads northward towards Georgia, South Carolina, and North Carolina. This system is forecast to remain a powerful hurricane throughout the forecast period.

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