Hurricane Erin has continued its trajectory in the North Atlantic, well southeast of New England, producing rip currents along parts of the U.S. East Coast, Bermuda, and Atlantic Canada as it moves forward into the weekend.
As of 8 a.m. EDT on Friday, Erin was located between Bermuda and Halifax, Nova Scotia, approximately 400 miles from both locations.
With sustained winds reaching up to 90 mph (150 km/h), the storm was on a northeast path at 22 mph (35 km/h), and despite its transformation into a mid-latitude cyclone, Erin is expected to maintain hurricane-strength winds over the weekend.
The storm is forecasted to become a weakening post-tropical cyclone by Monday, located south of Iceland.
Erin was officially deemed post-tropical on Friday evening at 5 p.m. EDT.
Having transitioned through its life cycle without making landfall, Erin’s impact has nonetheless been felt, particularly in terms of flash flooding, which claimed nine lives in the Cabo Verde Islands on August 10-11 from the disturbance that preceded Erin.
Moreover, one fatality was reported in the Dominican Republic, while numerous rescues from Erin-related rip currents occurred along the East Coast.
Remarkably, Erin ranks among the largest hurricanes in the Atlantic, with only a handful of storms in the past 60 years matching its size, placing it in the top 4% of hurricanes based on dimensions.
According to Michael Lowry, since the satellite era began in 1966, only Superstorm Sandy in 2012 has approached Erin’s size and tracked so closely to the U.S. east coast.
Erin’s coastal flooding peaked on Thursday night during high tide, with significant flooding reported at three NOAA tide gauges in Duck, North Carolina; Virginia City, Virginia; and Kiptopeke, Virginia, located within Chesapeake Bay.
Moderate flooding was also experienced across nine other states: Maryland, Delaware, New Jersey, New York, Connecticut, Rhode Island, Massachusetts, New Hampshire, and Maine.
In the forecast for future tropical systems, Invest 90L has emerged as a primary candidate for development in the Atlantic.
Designated on Thursday by the National Hurricane Center (NHC), 90L has remained somewhat disorganized but is expected to strengthen as it moves toward a weakness in steering flow created by Erin.
As of Friday, the system was located several hundred miles northeast of the northern Leeward Islands and was showing some signs of organization despite scattered showers and thunderstorms.
Ensemble forecast models indicate a strong likelihood of 90L developing into a tropical storm, with NOAA intensity models predicting it will reach at least tropical storm strength by early next week.
On Saturday morning, NHC raised the two-day formation odds for 90L to nearly 100%, forecasting it to become a tropical depression later that day and a tropical storm by Sunday.
A scheduled Air Force hurricane-hunter flight aimed to investigate 90L on Saturday afternoon.
The primary area of concern with 90L is Bermuda, with projections indicating a sharply recurving path that could take the storm near the island on Monday.
With sea surface temperatures between 28 to 29 degrees Celsius (82-84 degrees Fahrenheit) and light to moderate wind shear anticipated through Sunday, 90L could capitalize on its favorable environment.
Some cooler waters upwelled by Erin may affect 90L, but it is expected to remain far enough east to mitigate potential impacts from the upwelling.
Another system, identified as Invest 99L, has also become a topic of interest as it traverses the Main Development Region of the tropical Atlantic.
Originating on Tuesday, 99L exhibited a broad but organized circulation as it moved between Africa and the Lesser Antilles on Friday.
Despite warm sea surface temperatures of around 28 degrees Celsius (82°F), the system faces challenges due to dry air and moderate wind shear, which is currently around 10-20 knots.
Forecasts indicate that while wind shear may increase initially, it is expected to decrease over the weekend, potentially aiding in 99L’s organization.
However, persistent dry air may still impede significant development.
The NHC provided formation odds of 40% and 50% for 99L over the next two and seven days, respectively.
By Saturday morning, those odds were lowered to 10% and 20%, revealing the uncertainty surrounding 99L’s potential.
Currently, 99L is moving westward at a relatively low latitude, prompting attention from residents of the Windward Islands and southern Leeward Islands, with the disturbance anticipated to reach the area by Tuesday.
There remains limited support among ensemble forecast models for significant development at this time.
As the situation unfolds, residents should remain vigilant while keeping track of updates on both 90L and 99L, as well as staying aware of the residual impacts from Hurricane Erin.
image source from：yaleclimateconnections
