"Erin is predicted to hit Category 3 strength by this weekend."
"Tropical Storm Erin has begun what’s expected to be a week-plus oceanic journey across the North Atlantic. As it looks now, much of that trek will be as a potent hurricane that bears close watching.
Erin was designated a tropical storm on Monday after it barrelled across the Cabo Verde Islands on Sunday as a strong disturbance. As of 11 a.m. EDT Monday, Erin was centered nearly 300 miles west-northwest of the Cabo Verde Islands, heading west at a brisk 20 mph. Erin’s sustained winds were 45 mph.
Over the period 1990-2020, the average formation date of the Atlantic’s fifth tropical storm of the year was August 22, so the Atlantic is running a bit on the high side in terms of named-storm production – but all of the named systems to date have been only weak to moderate tropical storms. The average formation date of the first Atlantic hurricane is August 11, and current forecasts bring Erin to hurricane strength on Wednesday, August 13.
On Monday, Erin had a small but well-defined circulation, as detected by wind data from a satellite-borne scatterometer. Wind shear is light to moderate (around 10 knots), and the atmosphere is on the moist side, with mid-level relative humidity of around 60 percent. Emerging tropical systems often benefit from nighttime processes that help showers and thunderstorms to blossom – the so-called nighttime convective maximum – and this boosted Erin’s development on Sunday night. Also working in Erin’s favor is general rising motion across the eastern tropical Atlantic, the result of multiple large-scale features aligning (see our August 8 post)."
Bob Henson reports for Yale Climate Connections August 11, 2025.
SEE ALSO:
"Where Tropical Storm Erin Is Headed And When It Will Become A Hurricane" (Washington Post)
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