After a quiet start to the hurricane season, the Atlantic has reawakened and is full of storms and systems to watch for, and at least one could pose a serious threat to the United States.
There is great concern about a group of rains in northern Venezuela called “Invest 98L”, which crossed the Windward Islands with strong winds and gusts of rain. This one will remain tame until the weekend, when it’s about to move into a bracelet atmosphere.
It could enter the Gulf of Mexico next week, although its exact path is not yet known. Assuming it becomes at least a tropical storm, it will be named Hermine. The National Hurricane Center gives it a 90 percent chance of doing so.
For now, anyone residing along the Gulf Coast and Florida should pay close attention to this as the forecast evolves over the next few days.
Fiona will hit parts of Canada as the region’s strongest storm on record
Currently, it is poorly organized. The reason it’s not doing much yet is because of perturbing shear, or a change in wind speed and/or direction with height, that it’s struggling with. Too much shear can bring down an incipient storm, as if it were subjected to a game of atmospheric tug and drag. This shear comes from the high-altitude outflow, or escape, of Fiona far to the northeast.
Invest 98L will move westward over the next few days, and will remain hindered by shear until Sunday. Things are going to ramp up a lot quickly from Sunday evening to Monday.
That’s when the shear will relax as 98L moves over some of the warmer waters in the Atlantic. The northwestern Caribbean is full of ocean heat content, or thermal energy contained in bath-like marine waters, which will support accelerated consolidation and strengthening of the nascent storm.
Simultaneously, 98L, likely a named storm, will move under an upper-level high pressure system. This will work in the 98L’s favor in two ways:
- divergence High pressure means that the air is separated. This divergence in the upper atmosphere will have a vacuum-like effect, creating a vacuum and facilitating the ascent of surface air. This enhancement of the storm’s updrafts will speed up how quickly the warm, moist “inflow” can rush into the storm.
- Way out. The maxima rotate clockwise. This is the direction of tropical cyclone exit in the Northern Hemisphere. This high pressure will work with 98L to evacuate high altitude “spent” air away from the storm, allowing it to ingest more juice air from below. Imagine placing an extractor fan at the top of a chimney. The air would be pulled up and out, meaning more air would come in from the bottom and the fire at the base would grow. This storm will do the same.
There is a chance of a very strong storm somewhere in the northwestern Caribbean on Monday. It may escalate quickly at this point.
However, it could track anywhere from Mexico’s Yucatan Peninsula to central Cuba. But the storm could also move between those regions, entering the Gulf of Mexico on Monday or Tuesday afternoon.
There are only two escape routes that could allow the storm to avoid the gulf. There is an outside chance that, if it remains weak, it will continue westward in the Caribbean toward Central America. If it strengthens quickly, it could turn north over central Cuba and drift into the Atlantic. But only a minority of model simulations present these atypical scenarios.
Most model simulations project that the system will end up in the Gulf, while subtleties in the direction of atmospheric currents will determine where the storm eventually makes landfall.
A little bit of good news is that if the storm makes landfall to the north or west of the Gulf of Mexico, the dry air from the north can weaken it slightly. That’s not much comfort, however, when virtually the entire Gulf region is running warmer than average at the most active time of the year for hurricanes.
If the storm continues further east, it could escape dry air. That would be a concern if any potential track brings him closer to Florida.