It’s been an exceptionally slow start to the 2019 Atlantic hurricane season, but the quiet period is about to change.
Three systems are meandering over the Atlantic right now, all in varying stages of development. The most notable, swirling just offshore of Florida near the Bahamas, will invigorate the Sunshine State’s afternoon downpours this weekend. While nearly all of the system’s thunderstorm activity can be found east of the system’s center, the center of circulation itself was actually just 40 miles offshore of Miami on Friday morning.
“It’s the right time of year to have something poking around South Florida,” said Brian McNoldy, Capital Weather Gang’s tropical expert. “While people here have been watching it closely, I don’t think anyone feels threatened by it.”
The storm’s center is forecast to remain offshore, allowing it to slowly intensify, though coastal areas will be fringed by its moisture. The National Hurricane Center estimates this system — dubbed “Invest 98L” — has a 90 percent chance of developing into a tropical depression within the next five days.
From there, there’s a chance the fledgling thunderstorm cluster becomes a tropical storm. In fact, it could even intensify into a low-end hurricane as it recurves out to sea off the East Coast. Though it will not be all that far offshore, it’s not likely to pose much of a threat to land, with most computer models forecasting that the system will pass uneventfully out to sea.
The storm could spur rainfall along the coastal Carolinas on Monday and Tuesday, as well as an increased risk of rip currents for area beaches. New England’s beaches could see some choppy wave action, just in time for Labor Day weekend, particularly on Cape Cod and the islands.
As with any tropical storm or hurricane, it requires close monitoring, and there are some indications that a weather system over the northern Great Plains could influence the downstream weather pattern in such a way that the tropical weather system would come closer to the East Coast than forecast.
The next system to develop in the Atlantic will be named Dorian. But 98L has competition.
A second system to watch
Meanwhile, there is one more system to talk about.
Born from an African easterly wave that swept off the continent earlier this week, the disorganized tropical wave looks fairly innocuous for the time being. The National Hurricane Center is estimating a 50 percent chance of further development within the next five days. This morning, the system was designated as an “invest” — Invest 99L.
By late morning Friday, satellite passes over the system revealed an internal structure that may lend itself to strengthening more quickly than originally forecast. Even if it does, though, its longevity is questionable.
“99L is very isolated and it could easily ingest dry air and get choked off,” according to McNoldy, who isn’t expecting much out of it. However, it could precondition the Atlantic’s hurricane breeding ground for the next system by saturating the mid and upper atmosphere with more moisture. In any case, 99L is one to closely watch.
Computer model projections differ on 99L’s ultimate fate, with the main U.S. model showing a stronger storm than the European model.
Where have the storms been?
We are overdue for more Atlantic tropical cyclones. Storm activity has been barely a fifth of what is typically observed by this time of year.
“We are at just 21 percent of average [Accumulated Cyclone Energy] for the date,” McNoldy said. Accumulated Cyclone Energy, or ACE, is a measure of how much energy has been expended by tropical cyclones.
The Atlantic has been shut down by a combination of dust blown off the Sahara Desert, which can inhibit tropical cyclone development, as well as widespread sinking air. This discourages the formation of thunderstorms.
With just a trickle of storms so far this year, many have been anxiously holding their breath for when — or if — activity inevitably picks back up.
You probably remember Hurricane Barry, which breezed into Louisiana in mid-July as a borderline hurricane with drenching rainfall. But not many people heard of the “C” storm this year. Tropical Storm Chantal was a sneaky little fluke, named at 11 p.m. Eastern time on Tuesday night. The patch of merry-go-round thunderstorms lasted only 24 hours as a tropical storm before dissipating into a depression, its maximum sustained winds never exceeding 40 mph.
But its remnant circulation, whimsically traced by low and mid-level clouds, could make for an interesting sight outside airplane windows on some trans-Atlantic flights.
What lays ahead for September remains to be seen.