Hurricane Ernesto barreled through the United States and British Virgin Islands as a severe tropical storm on Tuesday night, bringing heavy rains and near-hurricane-force wind gusts to much of the Leeward Islands, Virgin Islands and eastern Puerto Rico. A tool released today by the non-profit research group Climate Central shows that record warm waters caused by man-made climate change made the storm more than 50 times more likely.
Ernesto was upgraded to a Category 1 hurricane at 11 a.m. ET on Wednesday, with winds of 75 mph and a central pressure of 991 MB, making it the third hurricane of the season after Beryl and Debbie. From 1991 to 2020, the average formation date for a third Atlantic hurricane was September 7.
Early Wednesday morning, the National Hurricane Center (NHC) said the WeatherFlow station in Culebra, Puerto Rico, reported sustained winds of 68 mph with gusts to 86 mph. Naval Station Roosevelt Roads in eastern Puerto Rico reported sustained winds of 48 mph with gusts to 74 mph. NOAA Saildrone, located about 65 miles northeast of San Juan, Puerto Rico, reported sustained winds of 61 mph with gusts of 76 mph.
As of 10 a.m. ET Wednesday, 5 to 7 inches of rain had fallen across much of the United States and the British Virgin Islands, with up to 9 inches falling in eastern Puerto Rico. An additional four to six inches is expected in southeastern Puerto Rico (see tweet below).
At 11 a.m. ET Wednesday, Ernesto was moving northwest at 16 mph, about 175 miles northwest of San Juan, Puerto Rico. Tropical storm warnings cover Puerto Rico, the United States and the British Virgin Islands. Satellite imagery shows a stable storm with widespread and growing showers and thunderstorms (convection). The dry air on the west side of the hurricane is injected by westerly upper-level winds, causing moderate wind shear of 10-20 knots, keeping the convection on this side weak.
Ernesto's Big Wave
Ernesto was a major storm with tropical storm-force winds extending as far as 230 miles from the center and hurricane-force winds as far as 35 miles from the center. By Friday, the NHC predicts the hurricane-force wind field will expand, extending 115 miles outward from the center. This strong wind field will produce some large waves, resulting in hazardous swimming conditions at most beaches along the U.S. and Atlantic Canadian coasts later this week and early next week (Figure 1).
Ernesto's intensity forecast: Likely Cat 2, maybe Cat 3
Ernesto will continue to track near-record warm sea surface temperatures of about 29 degrees Celsius (84 degrees Fahrenheit), about 1 degree Celsius (1.8°F) above the mid-August average. According to Climate Central's Ocean Temperature Climate Change Tool, there is a more than 50-fold likelihood that the record warm ocean temperatures Ernesto experienced as he approached the Lesser Antilles were caused by human-caused climate change (Figure 2 ).
Wind shear is expected to be mostly moderate (10-20 knots) over the next few days. Ernesto will be in an environment with dry air, so shear may cause problems for the storm at times. The National Hurricane Center predicts Ernesto will peak as a low-end Category 3 hurricane on Friday with winds of 115 mph before gradually weakening.
Ernesto's trajectory forecast: Bermuda and Newfoundland at risk
Ernesto will pass near Bermuda on Saturday, and the major storm is likely to bring at least tropical storm force winds. Whether Bermuda will take a damaging hit from Ernesto's eyewall will depend on subtle deviations in its northward orbit, which will be determined by upper-level features that have not yet solidified in forecast models.
A trough of low pressure moving north of Ernesto is expected to shift the hurricane more to the northeast early next week, with the storm potentially threatening eastern Nova Scotia and Newfoundland, Canada.
typhoon Ampil may become a major typhoon very close to Tokyo
The world's largest city – Tokyo, Japan, with a population of 39 million – could be hit by a dangerous typhoon later this week. Tropical Storm Apil will rapidly intensify as it moves north toward Japan, and is expected to turn sharply near or east of Tokyo on Friday local time. In Wednesday's early morning (6Z) run, the HWRF model brought Ampil to Category 2-3 equivalent strength during the sharp turn, while the HAFS-A model brought Ampil to Category 4 strength before the turn.
Overall models agree that Ampil will turn offshore, which will subject Tokyo to heavy rains and strong winds, but the metropolitan area will remain on the typhoon's weaker left (west) side. But some members were tracking Ampil directly over Tokyo, so the typhoon deserves close attention. Typhoons “Fasai” and “Hagabis” struck only one month apart in 2019, affecting the Tokyo area after reaching peak intensity levels of Category 4 and Category 5 respectively, causing an estimated US$27 billion in damage across Japan ( 2019 U.S. dollars).
Forecast updates for Ernesto and Ampil will be published in this article on Thursday, At that time we will publish our monthly weather/climate summary for July 2024.
We help millions of people understand climate change and what to do about it. Help us reach more people like you.
