Today is the meteorological peak of the Atlantic hurricane season, and Mother Nature is living up to expectations, with 3 active hurricanes in the Atlantic Ocean along with 2 areas to watch. In the Pacific Ocean, there are 4 tropical cyclones, including Olivia, which may impact Hawaii.
So, our 5 Things to Watch has been amended a bit for this week. This is your 5 Hurricanes to Watch.
How unusual is this amount of activity in the Atlantic? According to Philip Klotzbach, a meteorologist who specializes in hurricanes at Colorado State University, the record for most simultaneous Atlantic hurricanes is 4, set on August 22, 1893 and on September 25-26, 1998. The last time there were 3 simultaneous hurricanes before now was last year, from September 6-9. Currently, we have the chance for 5 tropical cyclones to be active at the same time in the Atlantic later this week. The record for active simultaneous Atlantic named storms is 4 (set on several occasions), and the record for tropical cyclones, including tropical depressions, is 6 set in September 1971. These next fews days and possibly weeks have the chance to break several of these records.
Obviously Florence is the storm we have been watching the closest as it continues to look more and more likely to impact land and cause catastrophic damage later this week across parts of the Southeast and Mid-Atlantic of the US (check out our long form Sunday Storm special piece all about Florence here). Florence is currently a major hurricane over a thousand miles off the East Coast as it continues to rapidly intensify. Midday Sunday the storm was only a tropical storm, and by Monday morning it has transitioned into a major hurricane (category 3 or higher), indicating a very favorable environment. Wind shear will remain low while sea surface temperatures will increase, meaning that Florence will only intensify further. That’s a scary senario.
The storm will likely make landfall as a major hurricane — currently forecast as a category 4 — Thursday night on either the coast of North Carolina or South Carolina. The exact track of Florence remains a bit uncertain, but the odds currently favor a landfall near the border of these two states. Since the east track is uncertain, the specific impacts are as well. Coastal residents, especially north of the center of the storm, will face the worst of it, with life-threatening storm surge and damaging winds expected. There will also be issues inland as the storm will stall for several days over this coming weekend. Flash flooding is a significant concern across parts of the Carolinas and Virginia and possibly surrounding states. Where the heaviest of rain falls is still unclear, but some towns will receive over 2 feet of rain in a relatively short period of time. 2 feet!
The word of advice right now is to prepare for the storm if you are even remotely in its path. All preparations along the coast should be rushed to completion by Wednesday evening. According to the National Hurricane Center,
There is an increasing risk of life-threatening impacts from Florence: storm surge at the coast, freshwater flooding from a prolonged and exceptionally heavy rainfall event inland, and damaging hurricane-force winds. While it is too soon to determine the exact timing, location, and magnitude of these impacts, interests at the coast and inland from South Carolina into the mid-Atlantic region should closely monitor the progress of Florence, ensure they have their hurricane plan in place, and follow any advice given by local officials.
Again, for a more in-depth analysis on Florence, check out last night’s Sunday Storm by our head meteorologist Joshua Feldman.
Just 1-2 days before Florence makes landfall on the mainland US, Hurricane Olivia over the central Pacific Ocean will likely make landfall on at least one of the Hawaiian islands between Tuesday night and Wednesday as a strong tropical storm. Hawaii has been an unlikely target by tropical cyclones already this year, despite consisting of a few small islands in the middle of a very large ocean. They most recently experienced Hurricane Lane a couple weeks ago.
Olivia will not have the strength of Lane, but will actually likely make landfall, unlike Lane. Olivia will be faster-moving though, leaving the islands by Wednesday night. The main risk that Olivia will bring to most of the islands is strong winds, which may lead to scattered power outages. Tropical Storm Warnings are currently in effect for Oahu, Maui County (including the islands of Maui, Molokai, Lanai, and Kahoolawe), and Hawaii County. There will also be heavy rain, with the volcanic peaks receiving potentially over 2 feet of rainfall while several inches falls in the lower elevations. Last but not least, large surf and rip currents will be a big hazard in the waters through much of this week.
Isaac intensified from a tropical storm into a hurricane Sunday evening as it tracks west across the Main Development Region of the Atlantic Ocean. He will threaten the Lesser Antilles as a hurricane on Thursday as he crosses into the Caribbean Sea. The good news is that recent satellite imagery suggests Isaac is weakening. Nonetheless, a strong tropical storm or weak hurricane is forecast for the Lesser Antilles later this week. By the weekend, islands like Puerto Rico and Hispaniola may become targeted by the storm, but they are currently on the northern edge of the forecast cone from the National Hurricane Center. Environmental conditions will also become non-conducive, allowing for Isaac to weaken once it reaches the Caribbean Sea.
Surprise, surprise, there’s yet another hurricane in the Atlantic: Helene. This cyclone impacted the Cabo Verde islands this past weekend, bringing hurricane conditions to some of the islands. Thankfully, Helene has since tracked south and west enough for conditions to improve across the islands. Unlike Isaac, which is tracking west toward the Caribbean Sea, Helene will take a sharp turn to the north by Thursday, gradually weakening by this weekend as it moves over the cooler waters of the North Atlantic Ocean. No impacts are expected.
There are two areas to watch in the Atlantic basin at this time: one over the North Atlantic Ocean and a second much closer to home in the western Gulf of Mexico. The second area to watch currently consists of disorganized thunderstorms over the northwestern Caribbean Sea, and has been designated as Invest 95L with a 50-50 chance of development within the next 5 days. These storms will track over the Gulf of Mexico as the week progresses, and may become organized enough to become a tropical depression late-week. This comes as upper-level winds weaken, allowing for these storms to spin around each other while over very warm sea surface temperatures. Storms can spin up quickly in the Gulf, so while a weak tropical cyclone is currently possible at this time, this area to watch will definitely need to be tracked very closely this week for potential strengthening into a tropical storm or hurricane. Texas and surrounding areas will need to monitor the progress of this disturbance.