The National Hurricane Center raised the odds Monday that a trough of low pressure in the central subtropical Atlantic could become the next tropical depression or storm, lifting the system’s seven-day development chance to 40% from 20% a day earlier. Forecasters said the disturbance, about 1,000 miles east-southeast of Bermuda at 2 p.m. EDT, still had disorganized showers and thunderstorms.
The update matters because it came as the Atlantic hurricane forecast enters the most active stretch of the season. The hurricane season runs from June 1 through Nov. 30, and the height of activity is usually mid-August through mid-October. NOAA has already trimmed expectations for the year, saying last month it now sees seven to 13 named storms, two to six hurricanes and possibly no major hurricanes at all, or at most two.
The National Hurricane Center said conditions over the system were expected to become more conducive for development by the middle of the week. It added that a tropical depression could form late this week if the disturbance continues moving slowly west-northwest over the subtropical Atlantic. That is the simple reason forecasters are watching it now: a weak system with more favorable surroundings can organize quickly enough to matter, even when the tropics have been quiet since Edouard.
The quiet stretch is part of what makes the higher odds stand out. The season has produced tropical storms Arthur, Bertha, Cristobal, Dolly and Edouard, but no hurricane so far. Edouard’s last advisory came on Sept. 3 as it moved inland over Texas after making landfall in Louisiana, and the next name on the list is Fay. A season with named storms but no hurricane is possible because storms can stay weak, remain short-lived, or never find the conditions needed to strengthen further.
That leaves the forecast with one clear answer and one open question. The National Hurricane Center sees a better chance of development this week, but whether the system actually becomes a tropical depression or tropical storm late in the week will depend on how quickly the atmosphere changes overhead.
