Tag Archives: Ernesto

Ernesto Makes Transition to Tropical Storm

Former Subtropical Storm Ernesto made a transition to a tropical storm on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Ernesto was located at latitude 43.0°N and longitude 41.0°W which put it about 645 miles (1035 km) east-southeast of Cape Race, Newfoundland.  Ernesto was moving toward the northeast at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1007 mb.

Even though now Tropical Storm Ernesto moved over water where the Sea Surface Temperature was between 24°C and 25°C, there was enough energy in the upper ocean to cause more thunderstorms to develop.  In addition, many of the thunderstorms developed close to the center of circulation.  The inner bands of showers and thunderstorms became stronger and the bands in the outer parts of the circulation weakened.  Ernesto exhibited a structure like a tropical cyclone and the National Hurricane Center classified the system as a tropical storm in the 5:00 p.m. EDT advisory.

Tropical Storm Ernesto will move over much cooler water during the next 24 hours.  It is likely to make a transition to an extratropical cyclone when it moves over the cooler water.  Ernesto could strengthen when colder air is pulled into the western half of the circulation and a cold front forms south of the center.  The development of the cold front and upper level divergence could strengthen the pressure gradient force which would give the air a stronger push.  An upper level trough east of the U.S. is forecast to steer Ernesto in the general direction of Ireland and the United Kingdom.

Subtropical Storm Ernesto Forms West of the Azores

Subtropical Storm Ernesto formed west of the Azores on Wednesday morning.  At 11:00 a.m. EDT on Wednesday the center of Subtropical Storm Ernesto was located at latitude 38.1°N and longitude 46.0°W which put it about 695 miles (1120 km) southeast of Cape Race, Newfoundland.  Ernesto was moving toward the north at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1008 mb.

More thunderstorms formed closer to the center of a low pressure system west of the Azores on Wednesday morning and the National Hurricane Center designated the system as Subtropical Storm Ernesto.  Several bands of showers and thunderstorms wrapped around the eastern and northern portions of the circulation.  Bands northwest of the center of Ernesto consisted primarily of showers and lower clouds.  The circulation may have been transporting some cooler, drier, more stable air into that part of the circulation.  Showers and thunderstorms around the center of Ernesto were generating upper level divergence which was pumping mass away to the northeast of the subtropical storm.

Subtropical Storm Ernesto will move through an environment that could support some intensification during the next day or so.  Ernesto will move over water where the Sea Surface Temperature is near 26°C.  It will move through a region where the upper level winds are not too strong and there will not be much vertical wind shear.  Subtropical Storm Ernesto could strengthen during the next 12 to 24 hours.  Ernesto will move over cooler water later on Thursday and it will start to weaken.  An upper level trough east of the U.S. will approach Subtropical Storm Ernesto from the west.  Southwesterly winds ahead of the trough will cause more vertical wind shear and Ernesto could make a transition to an extratropical cyclone.

The southwesterly winds ahead of the upper level trough will steer Subtropical Storm Ernesto in a general northeasterly direction.  On its anticipated track Subtropical Ernesto will pass between the Azores and Greenland.