Where Tropical Storm Erin is headed and when it will become a hurricane

Washington Post

a day ago

Tropical Storm Erin sputtered in the open waters of the eastern Atlantic when it was wrapped in a veil of dry, dusty air from the Sahara Desert, which limited the storm's ability to strengthen. But it's still set to become a hurricane by the weekend — likely a major one of at least Category 3 strength.
The storm is now expected to become a hurricane on Friday, about a day later than originally forecast.
A weaker Erin is taking a slightly more southerly track, wrote the National Hurricane Center. The storm's forecast cone passes just north of Saint Martin, the British Virgin Islands and Puerto Rico – islands where rough seas, gusty winds and locally heavy showers and thunderstorms are possible this weekend.
After that, an intensifying Erin will probably take a turn to the north, skirting around the western edge of the Bermuda high, a storm-steering high-pressure belt in the central Atlantic — probably taking a path that misses the Bahamas and United States but potentially threatens Bermuda and the Canadian Maritimes next week.
The long-term forecast will feature subtle shifts in the days ahead, but there is a growing consensus that a direct hit in the United States is unlikely — with the storm shoved offshore by a disturbance in the upper atmosphere.
Early Wednesday, Erin was located midway between Africa and the Lesser Antilles. It was moving west around 20 mph and had winds of 45 mph.
On infrared satellite, more convection, or thunderstorm and shower activity, was visible — albeit mostly west of the center. That's in stark contrast to Tuesday, when Erin's dry, naked circulation was largely devoid of rain, drifting southwestward.
This southerly shift slightly increases the risk of impacts to the northern Leeward and Puerto Rico.
'However, the magnitude of those impacts is still not known,' wrote the National Hurricane Center.
Erin will make a close approach to the northern Leeward Islands and Puerto Rico, where some impacts are possible this weekend.
In the Caribbean, the most likely scenario is a sideswipe. Erin probably won't directly strike any land, but instead pass close enough for secondary effects — like blustery winds, squally showers and storms, rip currents and ocean swells.
Similarly, the Bahamas are unlikely to experience direct impacts from Erin, at least according to current forecasts. The storm may graze the islands, but largely stay east. If Erin's anticipated turn to the north is delayed, then more direct impacts from the system's outer rain bands could brush the eastern Bahamas over the weekend into early next week.
Beginning Thursday, Erin should start to strengthen more steadily. Here's why:
Erin may reach at least Category 3 strength over the weekend, with the National Hurricane Center predicting maximum sustained winds of 115 mph. The storm may near Bermuda around the middle of next week.
Although Erin will probably be hundreds of miles offshore, the storm will generate big waves, choppy seas and elevate the risk for rip currents along the Eastern Seaboard next week.
Several more waves of energy will follow behind Erin this week, each having some chance of strengthening.
These storm seedlings — called African Easterly Waves — emerge from Africa's Sahel region from June to October and are key factors in the development of hurricanes.
People living in or visiting the Caribbean Islands should remain especially vigilant, as additional storm activity is possible next week.
The National Hurricane Center was also monitoring a disturbance crossing the Yucatán Peninsula on Wednesday, which will cross the sultry waters of the Bay of Campeche and southern Gulf of Mexico from Thursday into Friday, enhancing downpours in eastern Mexico and Texas.
The next storm names after Erin are Fernand, Gabrielle and Humberto.