Weather Underground – October 3, 2015
Hurricane Joaquin is finally accelerating away from The Bahamas, after clobbering parts of the central Bahamas with 36 hours or more of storm surge flooding, high winds and torrential rainfall. All hurricane and tropical storm watches and warnings have been dropped as of 8 a.m. Saturday.
Hurricane watches have been posted for Bermuda as Joaquin begins what is essentially the second leg of its journey, having made the expected sharp change in direction earlier Friday after drifting southwestward for several days.
Hurricane Joaquin Information
The Category 3 storm will stay away from the Atlantic coasts of the U.S. and Canada, due in part to the influence of an extremely dangerous non-tropical system developing over the southeastern U.S.
(MORE: Dangerous Flash Flooding | Coastal Flood Threat, Too!)
A total blackout was reported on the three hardest-hit islands of the central Bahamas. About 85 percent of the homes in one settlement on Crooked Island were reportedly destroyed.
(MORE: Bahamas Latest News/Impacts | Cargo Ship in Joaquin)
The Latest
- At 8 a.m. EDT Saturday, the eye of Hurricane Joaquin was centered about 165 miles northeast of San Salvador in the central Bahamas.
- Maximum sustained winds remain at 125 mph, making Joaquin a Category 3 hurricane on the Saffir-Simpson Hurricane Wind Scale.
- All warnings have been dropped in The Bahamas.
- Joaquin will continue to accelerate northeastward, with its center likely passing west of Bermuda Sunday.
- A tropical storm warning and hurricane watch are in effect for Bermuda. Any further adjustment east of the forecast could bring stronger winds to Bermuda Sunday.
- Dangerous coastal and rainfall flooding will occur in several states in the eastern U.S. through at least Monday despite Joaquin remaining well out to sea.
Joaquin’s Fury Finally Relenting in the Central Bahamas
After pummeling parts of the central Bahamas for over 36 hours, Joaquin’s eyewall, the ring of extreme winds surrounding the eye itself, has now pulled away from the storm-battered islands.
Satellite imagery indicates some trailing bands of rain, with winds much lower than those in the eyewall, are still soaking parts of the central Bahamas, mainly Rum Cay, San Salvador and Cat Island.
Visible Satellite
Flooding from storm surge and torrential rainfall has been documented on Long Island and Acklins, among other central Bahamas locations. A Weather Underground personal weather station at Pitts Town, Crooked Island, reported winds up to 84 mph before it stopped reporting.
The National Hurricane Center was forecasting storm surge flooding of 6-12 feet above normal tide levels, in addition to rainfall of up to 25 inches. Given the small size of the islands, the electrical grid will likely experience a complete blackout and may be partially or completely destroyed. Recovery could take weeks or months.
Conditions, there, will slowly improve Saturday as Joaquin gains forward speed and moves northeast.
(MORE: Expert Analysis | Hurricane Central)
Forecast Track Clearer
Computer forecast models – and the meteorologists who use them for guidance – grappled earlier with a complex interaction between Joaquin, a cold front near the East Coast, the remnants of Tropical Storm Ida, a strong bubble of high pressure aloft over the North Atlantic Ocean, and a strong area of low pressure aloft digging into the southeastern U.S.
Over the last few days, those computer forecasts put out a bewildering range of future track scenarios, though mostly in two main camps – one favoring a U.S. landfall, and the other favoring a decisive northeastward path over the open waters of the western Atlantic.
On Thursday, computer models moved closer to a consensus, as models formerly bullish on a U.S. landfall began pulling their forecast paths east, favoring tracks closer to the Atlantic seaboard or even entirely offshore. By Friday morning, the overwhelming majority of reliable track models kept the center of Joaquin away from the U.S. East Coast.
Ensemble Forecast Model Tracks
Data from NOAA Gulfstream aircraft surveillance missions and extra balloon soundings launched from National Weather Service offices on the mainland may have contributed to the eastward shift in some of the model guidance.
(MORE: 3 Reasons Hurricane Joaquin Has Been So Difficult to Forecast)
That model consensus is reflected in the forecast track accompanying the latest National Hurricane Center advisory.
(MAP: Track Hurricane Joaquin with our New Interactive Storm Tracker)
Projected Path
Regardless of the ultimate outcome of Joaquin’s path, portions of the East Coast states will still see multiple impacts from the evolving large-scale weather pattern, including flooding rainfall, coastal flooding, high surf, beach erosion, and gusty winds. These threats will extend well inland from the Atlantic coast.
(MORE: Dangerous Flash Flooding | Coastal Flood Threat, Too!)
Next Threat: Bermuda
The most likely path of the center of Hurricane Joaquin is west of Bermuda Sunday.
However, hurricanes are not simply a point on the map, but have impacts well away from the center. With tropical storm-force winds extending up to around 200 miles from the center, it appears at least tropical storm-force conditions will affect Bermuda Sunday.
Hurricane Joaquin: Watches and Warnings
Interests in Bermuda should continue to monitor closely for changes in the forecast track of Joaquin. If Joaquin’s center shifts farther east, that could put shift the eyewall closer to the archipelago. Hence the reason for the hurricane watch.
Rapid Intensification Earlier
An Air Force Reserve Hurricane Hunter reconnaissance aircraft flying through Hurricane Joaquin Thursday morning found estimated surface winds of 117 knots, or roughly 135 mph, in the southwestern eyewall’s deep thunderstorms.
At one point between Wednesday morning and Thursday evening, Joaquin saw a pressure drop of 57 millibars in about 39 hours, going from a strong tropical storm to a Category 4 hurricane in the process.
Colorado State University tropical meteorologist Dr. Phil Klotzbach said Joaquin was the first Category 4 hurricane to track through The Bahamas in October since 1866. Joaquin’s minimum central pressure of 931 millibars Thursday was also the lowest observed in an Atlantic Basin hurricane since September 2010, when Hurricane Igor bottomed out at 924 millibars.
Klotzbach also said Joaquin was only the 20th Category 4 or 5 hurricane to impact The Bahamas in historical records dating to 1851, and the second latest in the season to do so. Only a Nov. 10, 1932 Category 4 hurricane occurred later, Klotzbach says.
Hurricane Joaquin rapidly intensified as wind shear – harmful to the intensification of tropical cyclones – diminished, allowing Joaquin’s core convection to feed off the warm water near the central Bahamas. However, wind shear will increase once again as Joaquin moves north this weekend over cooler water, leading to steady weakening.