The Subtropical Storm Ernesto became Tropical Storm Ernesto yesterday afternoon over the North Atlantic. As of 3 PM EDT, Ernesto was located midway between far eastern Canada and the Azores, about 650 miles SE of Cape Race, Newfoundland. It is heading towards northeast at 18 mph across the open waters of North Atlantic.

Ernesto developed a more symmetric field of convection and more defined convective banding near its center, which prompted the National Hurricane Center (NHC) to upgrade the system into a Tropical Storm. Ernesto remained a large, but relatively weak system on Thursday afternoon: the highest sustained winds were up to only 45 mph with winds of 40 mph extended out as far as 160 miles across the southeast quadrant.

Ernesto is traveling over waters with temperature of around 25 °C, which is just below the traditional 26 °C threshold for tropical development. The storm will encounter much cooler sea-surface temperatures as it continues northeast today, so Ernesto will become a post-tropical cyclone soon as it also begins to merge with a frontal zone. It could remain a potent gale-producer, when it accelerates toward the western Europe. Ernesto’s remnants will sweep across Ireland and Great Britain over the weekend, bringing some heavy rain and gusty winds.

Latest satellite image of Ernesto while still far over open waters of Atlantic ocean.

Latest NHC (National Hurricane Center) tracks Ernesto towards Ireland while weakening towards the Great Britain later tomorrow. The second map is showing a various models simulations of Ernesto’s track.

Winds will be the main threat with this storm. Various models suggesting gale force winds with gusts up to 100 km/h are locally possible, as well as high waves along the coastal areas of Ireland and SW England.

Here is a precipitation swath map across the Isles, locally 30-50mm seem possible from N Ireland into N England and S Scotland according to the latest model guidance.