Three tropical waves are roaming the Atlantic, one of which is set to earn the name “Bonnie” and another of which could douse Southeast Texas with heavy flooding rains. The peak of hurricane season is still 2½ months away, but the Atlantic Basin has quickly roared to life.
The same storm could ultimately grow stronger in the Caribbean, with a slight chance that it could turn into the Atlantic’s first hurricane of the season and whirl over warm ocean waters by the end of the week.
On its heels, another tropical wave shows some signs of organization but probably won’t become nearly as noteworthy as its predecessor. Regardless, it bears watching.
A third system, meanwhile, is beginning to materialize in the northwestern Gulf of Mexico. That one, while unlikely to strengthen enough to earn a name, will probably become a tropical rainstorm and is a concern for several major metropolitan areas in Texas, where heavy flooding rains could be in the cards.
Atmospheric scientists and hurricane specialists have already warned that this season could be rough, forecasting it to be anomalously active, or “hyperactive.” The presence of a La Niña pattern, coupled with a repository of exceptionally warm sea-surface temperatures in the Gulf of Mexico and myriad other factors, favors a particularly busy few months ahead.
Invest 94L — the one to watch closely
On Monday morning, Invest 94L was about 300 miles northeast of French Guiana in South America and was drifting west-northwest at 15 to 20 mph. On satellite imagery, it looked considerably healthier than it had 48 or even 24 hours before, roiling with shower and thunderstorm activity and thriving thanks to a reduction in shear. A Hurricane Hunter aircraft from the National Oceanic and Atmospheric Administration is to investigate the system Monday afternoon.
Disruptive wind shear, or a change of wind speed and/or direction with height, can be unfavorable to a developing tropical cyclone, playing a tug-of-war of sorts that can tear it apart. In this case, however, 94L is nestled within a pocket of comparatively tepid shear, which has allowed for organization over the past few days.
Broad low-level circulation exists, but it remains to be seen if a more concentrated, cohesive vortex can form. If a near-surface swirl does materialize, it would need thunderstorm updrafts to vertically stretch it. That’s one of the first steps to forming a tropical depression, the precursor to a tropical storm.
The National Hurricane Center estimates a 90 percent chance that 94L will eventually become a tropical storm, with a 70 percent likelihood of it in the next two days. By late Tuesday or Wednesday, it could be flirting with tropical storm strength as it breezes through the Windward Islands with heavy rain and gusty winds. Some places could see totals of 4 to 8 inches of rain.
Once maximum winds exceed 39 mph around a discernible center, 94L would become Bonnie, the second named storm of the 2022 Atlantic hurricane season. It could make a run at hurricane strength in the Caribbean between Wednesday and the weekend before potentially making landfall somewhere in Costa Rica, Honduras, Nicaragua or Belize, affecting those countries or Guatemala.
Flooding rains and mountain mudslides, along with some degree of damaging wind and coastal surge, remain on the table.
Second ‘Main Development Region’ system
Following 94L is a second tropical wave over the Atlantic’s Main Development Region (MDR). That’s the broad stretch of tropical ocean water between northern South America and northwest Africa where named storms routinely spin up in mid- to late summer. Only three tropical systems on record have been named in the MDR during the month of June.
A tropical wave in the Atlantic is now being given a 60% chance of tropical cyclone formation in next 5 days by National #Hurricane Center. Only 3 storms on record have been named in June in tropical Atlantic (south of 20°N, east of 60°W): Unnamed (1933), Ana (1979), Bret (2017). pic.twitter.com/MM1CZIOohC— Philip Klotzbach (@philklotzbach) June 24, 2022
Weather models are divided in their simulations of the weak wave, but there remains about a 1 in 5 chance of eventual development. Regardless, it’s looking like the Leeward Islands could see some additional rain by the weekend.
Heavy rain at the tip of the Mississippi Delta has been lurking in the northern Gulf of Mexico for the past couple of days, and will linger and fester before gradually shifting west. It may develop a bit of spin thanks to its positioning at the tail end of a cold front.
It won’t become a depression or get a name; the National Hurricane Center awards it only a 20 percent chance of development. But it will contain a lot of moisture.
The jury is still out on where the system will go, but it could bring significant rainfall to coastal Texas somewhere between the Houston-Galveston metro area and Matagorda Bay if and when the mass of downpours moves ashore. Some models simulate hovering over the western gulf and eventual dissipation. How it evolves in the days ahead remains to be seen.