Florence Approaching Warmer Waters, Intensification Likely

Hurricane Florence has weakened significantly today thanks to high wind shear. The shear is expected to diminish in the next few days, however. As the storm approaches warmer waters in the western Atlantic, restrengthening is likely.

Florence has been charting a steady west-northwest course since forming a week ago near the Azores. This trajectory will likely continue over the next several days underneath a large mid-ocean ridge. By Tuesday, the storm could be near Bermuda. Most of the model guidance suggests the storm will pass far enough south of Bermuda to limit impacts on the island to some gusty winds and passing rain squalls. However, interests on Bermuda should closely monitor the storm in case a northward deviation occurs.

 

 

Later in the week, models diverge on the future track. Some bring the cyclone close to the U.S. east coast, but some curve the storm well offshore. It’s simply too early to be able to forecast with any accuracy the landfall potential. Regardless of where the storm goes, there will be some big waves and rip currents along the Eastern Seaboard starting late this weekend and persisting through next week.

 

 

Florence may weaken below hurricane status tonight or Friday. However, warmer water and lessening vertical wind shear could allow the cyclone to strengthen again (see potential intensity map above). In fact Florence may be a major hurricane again by the middle of next week! Where and when the storm curves north will determine intensity later in the week.

Powerful Jebi Targets Japan Next Week

Jebi is a powerful cyclone spinning across the West Pacific, and the storm will track steadily northward toward Japan by early next week.

 

Jebi reached Super Typhoon status late this past week, meaning that sustained winds are greater than or equal to 130 knots. Ideal environmental conditions of warm sea-surface temperatures and light wind shear will keep Jebi quite powerful into the first part of next week.

Weather models are fairly consistent in tracking Jebi toward the north over the next few days. Steering winds are expected to take the cyclone into Japan on Tuesday and then into southeast Russia on Thursday.

Impacts to Japan from Jebi could include damaging winds, flooding rain, and a significant storm surge near the area Jebi makes landfall. Major Japanese cities such as Osaka and Tokyo will likely experience some adverse impacts from the cyclone.

Confidence in more specific details regarding impacts to Japan will become clearer this weekend as Jebi inches closer to the island nation.

Tropical Atlantic Basin May Heat Up Soon!

 

It’s been a quiet couple of months over the tropical Atlantic basin. Only two tropical storms have formed over the basin in August, both harmless short-lived cyclones over the open ocean. Indeed, this quiet period has lead to forecasters rolling back the expectations for the remainder of the season. However, there are indications that tropical activity could ramp up as we move towards the traditional peak of hurricane season in early September.

 

 

Thunderstorm activity is building over the Sahel, the region of central Africa that is a breeding ground for Atlantic hurricanes. Although not every storm wave that rolls off the African coast is destined to be a hurricane, conditions are becoming more favorable for development in the next week or so. Models suggest the wave currently approaching the coast will eventually become better organized over the open Atlantic. Other waves nearby are potential candidates as well.

This increasing activity means the odds are better that named storms will form in the next few weeks. That doesn’t mean there’s any immediate threat to the U.S. mainland, but we’ll be monitoring.

UPDATE: Hilo Submerged as Hurricane Lane Draws Closer!

 

Hurricane Lane has weakened further today but remains a dangerous category three hurricane with sustained winds of 130 mph (kph). Outer rain bands have been producing torrential rainfall especially over the Big Island since last night. Rivers have risen well past flood levels, submerging much of the city of Hilo.

 

 

Rainfall totals have exceeded a foot over parts of the Big Island (see table above), including the city of Hilo. Even in a tropical environment, it’s too much rain for the soil and water system to handle. Combine that with elevated tides and surf due to the approaching hurricane and you have a recipe for widespread flooding (see tweets below). Additional rainfall in excess of a foot is likely, leading to additional severe flooding. Mudslides will be a common threat as well.

 

 

 

 

 

The latest model guidance brings the system further north than previously indicated. Although a turn to the west is still anticipated, the potential for a landfall has increased. The center of the storm could move very close to Honolulu by Friday night into Saturday. Eventually the storm should move west and by early next week, Lane will be moving into the open Pacific.

 

 

Lane is being hit by strong southwesterly shear, disrupting the circulation. Additional steady weakening is expected over the next few days. However, Lane could still be a hurricane as it closes in on the central Hawaiian Islands like O’ahu and Moloka’i. That means in addition to the ongoing flooding rains, high winds and storm surge will be increasing dangers. Wind gusts of 70-90 mph (110-140 kph) will lead to trees and roofs coming down with widespread power outages. A storm surge as much as 4-5 feet will inundate prone coastal areas.