Tag Archives: the Azores

Hurricane Lorenzo Prompts Watches for the Azores

The risk posed by Hurricane Lorenzo prompted the issuance of watches for the Azores.  At 11:00 p.m. EDT on Sunday the center of Hurricane Lorenzo was located at latitude 27.6°N and longitude 43.5°W which put it about 1195 miles (1920 km) west-southwest of the Azores.  Lorenzo was moving toward the north-northeast at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (210 km/h).  The minimum surface pressure was 952 mb.

Hurricane Watches were issued for the western and central Azores including Flores, Corvo, Faial, Pico, Sao Jorge, Graciosa, Terceira.  Tropical Storm Watches were issued for the eastern Azores including Sao Miguel and Santa Maria.

Hurricane Lorenzo weakened on Sunday when it moved into a less favorable environment.  Lorenzo moved over water where the Sea Surface Temperature was a little cooler.  In addition, an upper level trough west of Hurricane Lorenzo was producing southwesterly winds which were blowing toward the top of the circulation.  Those upper level winds were causing more vertical wind shear.  The combination of cooler water and more shear was responsible for weakening Hurricane Lorenzo.

Even though Hurricane Lorenzo weakened on Sunday it remained a large and powerful hurricane.  Winds to hurricane force extended out about 90 miles (145 km) from the center of circulation.  Winds to tropical storm force extended out about 250 miles (400 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Lorenzo was 19.2.  The Hurricane Size Index (HSI) 32.6 was and the Hurricane Wind Intensity Size Index (HWISI) was 51.8.  Hurricane Lorenzo was capable of causing widespread serious damage.

Hurricane Lorenzo is likely to continue to weaken slowly during the next several days because of the less favorable environment consisting of cooler water and more vertical wind shear.  Since the circulation around Lorenzo is so large, the hurricane will weaken slowly.

The upper level trough will steer Hurricane Lorenzo toward the northeast during the next two or three days.  On its anticipated track Hurricane Lorenzo could reach the Azores by Tuesday night.  Lorenzo could be a large hurricane capable of causing widespread serious damage when it reaches the Azores.

Hurricane Lorenzo Strengthens to Cat. 5 Southwest of the Azores

Hurricane Lorenzo strengthened to Category 5 on the Saffir-Simpson Scale on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Hurricane Lorenzo was located at latitude 24.2°N and longitude 44.9°W which put it about 1420 miles (2285 km) southwest of the Azores.  Lorenzo was moving toward the north at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 925 mb.

Hurricane Lorenzo strengthened to Category 5 farther east in the Atlantic Ocean than other hurricane on record.  Lorenzo appeared to complete an eyewall replacement cycle earlier on Saturday and then it start to strengthen quickly.  A circular eye with a diameter of 35 miles (55 km) became evident at the center of circulation.  A ring of very strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Hurricane Lorenzo.

The circulation around Hurricane Lorenzo was large.  Wins to hurricane force extended out about 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out about 275 miles (445 km) from the center.  The Hurricane Intensity Index (HII) was 35.0.  The Hurricane Size Index (HSI) was 21.2 and the Hurricane Wind intensity Size Index (HWISI) was 56.2.

Hurricane Lorenzo will remain in a very favorable environment for another 12 to 24 hours.  It will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough will approach Lorenzo from the west later on Sunday.  The trough will produce southwesterly winds which will create more wind shear.  Hurricane Lorenzo will start to weaken when the wind shear increases.  Lorenzo will also move over cooler water on Monday, which will cause more weakening.

The upper level trough will steer Hurricane Lorenzo toward the northeast during the next few days.  On its anticipated track Hurricane Lorenzo could approach the Azores on Tuesday night.  Lorenzo is likely to be a hurricane when it reaches the Azores.  Hurricane Lorenzo will eventually make a transition to a strong extratropical cyclone.  It could be near Ireland in four or five days.

Powerful Hurricane Lorenzo Churns Southwest of the Azores

Powerful Hurricane Lorenzo churned southwest of the Azores on Friday.  At 5:00 p.m. EDT on Friday the center of Hurricane Lorenzo was located at latitude 20.3°N and longitude 43.6°W which put it about 1575 miles (2535 km) southwest of the Azores.  Lorenzo was moving toward the north-northeast at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 948 mb.

Hurricane Lorenzo weakened slowly on Friday, but it remained a large and powerful hurricane.  Winds to hurricane force extended out 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out about 250 miles (400 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Lorenzo was 23.6.  The Hurricane Size Index (HSI) was 20.7 and the Hurricane Wind Intensity Size Index (HWISI) was 44.3.  Hurricane Lorenzo was capable of causing major damage.

Hurricane Lorenzo weakened on Friday because it moved into a less favorable environment.  Lorenzo continued to move over water where the Sea Surface Temperature was near 27°C.  However, an upper level trough west of Lorenzo was producing southwesterly winds which were causing moderate vertical wind shear.  in addition, Hurricane Lorenzo appeared to be drawing drier air into the western half of the circulation.  The effects of increased vertical wind shear and drier air caused Lorenzo to weaken.

Hurricane Lorenzo will continue to move through a less favorable environment and weaken.  Since Lorenzo is a large hurricane, it will weaken more slowly than a smaller hurricane would.  As a result, Lorenzo will likely remain a hurricane for several more days.

The upper level trough will steer Hurricane Lorenzo toward the northeast during the next few days.  On its anticipated track Hurricane Lorenzo will likely approach the Azores on Tuesday.  Lorenzo is likely to still be a hurricane at that time.

Elsewhere over the Atlantic Ocean, Tropical Depression Karen weakened to a trough southeast of Bermuda on Friday afternoon.  At 5:00 p.m. EDT on Friday the center of former Tropical Depression Karen was located at latitude 29.3°N and longitude 58.5°W which put it about 425 miles (685 km) south-southeast of Bermuda.  Karen was moving toward the northeast at 6 m.p.h. (10 km/h).  The maximum sustained wind sped was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1007 mb.

Major Hurricane Dorian Moves Toward the Carolinas

Major Hurricane Dorian moved toward the Carolinas on Wednesday night.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Dorian was located at latitude 31.3°N and longitude 79.6°W which put it about 105 miles (170 km) south of Charleston, South Carolina.  Dorian was moving toward the north at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 115 m.p.h. (195 km/h) and there were wind gusts to 140 m.p.h. (220 km/h).  The minimum surface pressure was 955 mb.

A Hurricane Warning was in effect for the portion of the coast from Savannah River, Georgia to the North Carolina/Virginia border including Albemarle and Pamlico Sounds.  A Hurricane Watch was in effect for the portion of the coast from the mouth of the St. Mary’s River, Florida to Savannah River, Georgia.  Tropical Storm Warnings were in effect for the portions of the coast from the mouth of the St. Mary’s River to Savannah River, Georgia and from the North Carolina/Virginia border to Chincoteague, Virginia.  A Tropical Storm Warning was also in effect for Chesapeak Bay south of Smith Point.  Tropical Storm Watches were in effect for the portion of the coast from Chincoteague, Virginia to Fenwick Island, Delaware, for Chesapeake Bay from Smith Point to Drum Point and for the Tidal Potomac south of Cobb Island.

Hurricane Dorian strengthened back into a major hurricane on Wednesday night as it moved over the warm water in the Gulf Stream.  A large eye with a diameter of 45 miles (75 km) became more circular and symmetrical.  The ring of thunderstorms surrounding the eye became continuous and a little thicker.  The strongest winds were occurring in that ring of storms.  Other bands of showers and thunderstorms revolving around the core of Hurricane Dorian also got stronger.  Storms around the core of Dorian generated upper level divergence which pumped mass away from the hurricane and the surface pressure decreased.

The circulation around Hurricane Dorian increased in size on Wednesday.  Winds to hurricane force extended out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out about 200 miles (320 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Dorian was 20.6.  The Hurricane Size Index (HSI) was 22.6 and the Hurricane Wind Intensity Size Index (HWISI) was 43.2.  Hurricane Dorian was capable of causing widespread major damage.

Hurricane Dorian will move through an environment favorable for intensification during the next 12 hours.  Dorian will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there is little vertical wind shear.  Hurricane Dorian could get a little stronger during the night.  An upper level trough over the central U.S. will move toward Hurricane Dorian on Thursday.  The upper level trough will produce southwesterly winds which will blow toward the top of the hurricane.  Those winds will cause the vertical wind shear to increase, which will cause Dorian to start to weaken.

Hurricane Dorian will move around the western end of a subtropical ridge over the western Atlantic Ocean.  The ridge will steer Dorian toward the north on Wednesday night.  The upper level trough will turn Hurricane Dorian toward the northeast on Thursday.  On its anticipated track Hurricane Dorian could approach the coast of South Carolina on Thursday morning.  Dorian will move along the coast of North Carolina on Thursday afternoon and Thursday night.

Even if the center of Hurricane Dorian stays just south of the coast of South Carolina and North Carolina, the large circulation means that locations near the coast are likely to get hurricane force winds.  Winds blowing water toward the coast could cause storm surges of 5 to 8 feet (1.5 to 2.5 meters) in some locations.  Dorian could also drop locally heavy rain and cause flash flooding  near the coast.

Elsewhere, Tropical Storm Fernand made landfall north of La Pesca, Mexico on Wednesday and Tropical Storm Gabrielle developed south of the Azores.  Ar 11:00 p.m. EDT on Wednesday the center of Tropical Depression Fernand was located at latitude 25.0°N and longitude 99.0°W which put it about 100 miles (160 km) west-northwest of La Pesca, Mexico.  Dorian was moving toward the west-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1007 mb.

At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Gabrielle was located at latitude 21.5°N and longitude 34.4°W which put it about 1220 miles (1965 km) south-southwest of the Azores.  Gabrielle was moving toward the northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 m/h).  The minimum surface pressure was 1002 mb.

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.

Tropical Depression Nineteen Forms East of Bermuda

Tropical Depression Nineteen formed east of Bermuda on Monday.  At 10:00 a.m. EST on Monday the center of Tropical Depression Nineteen was located at latitude 29.5°N and longitude 50.4°W which put it about 875 miles east of Bermuda.  It was moving toward the north-northeast at 3 m.p.h. (5 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1013 mb.

A small low pressure system has been meandering over the Atlantic Ocean between Bermuda and the Azores.  More showers and thunderstorms formed near the center of the the low and the circulation became more circular.  Because the low pressure system developed the characteristics of a tropical cyclone, the National Hurricane Center designated the system as Tropical Depression Nineteen on Monday morning.

The circulation of Tropical Depression Nineteen is being affected by vertical wind shear.  An upper level low located to the northwest of the system is producing easterly winds which are blowing across the top of the depression.  Those winds are producing moderate vertical wind shear shear which is tilting the upper portion of the circulation to the east.  The surface center of circulation was exposed on visible satellite images.  Most of the showers and thunderstorms were occurring to the east of the center.

Tropical Depression Nineteen is forecast to intensify into a tropical storm.  The depression will move over water where the Sea Surface Temperature is near 25.5°C, which is marginally warm enough to support intensification.  The upper level low will continue to produce vertical wind shear which will inhibit intensification during the next 12 to 24 hours.  The shear is forecast to decrease on Tuesday and Tropical Depression Nineteen could strengthen into a tropical storm before it moves over colder water.

Tropical Depression Nineteen is currently in an area where the steering currents are weak.  The circulation around the upper level low to the northwest of the Tropical Depression is being deflected around an upper level ridge to the east of the depression.  Some of the flow is turning northward and the rest of the flow is turning toward the south.  The orientation of the upper low and ridge is forecast to change and the two systems are forecast to steer the depression toward the northeast later this week.  However, if the wind shear stays strong enough to prevent the circulation of the depression from growing vertically, then the winds in the lower level could steer the depression more toward the west.

Ophelia Strengthens to Major Hurricane South of the Azores

Hurricane Ophelia strengthened into a Category 3 hurricane on the Saffir-Simpson Scale on Saturday morning as it moved south of the Azores.  That made Ophelia a major hurricane.  At 11:00 a.m. EDT on Saturday the center of Hurricane Ophelia was located at latitude 34.8°N and longitude 26.6°W which put it about 220 miles (355 km) south of the Azores.  Ophelia was moving toward the northeast at 25 m.p.h. (40 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 135 m.p.h. (220 km/h).  The minimum surface pressure was 960 mb.

It is very unusual to have such a strong hurricane near the Azores, but Ophelia contains all of the elements of a major hurricane.  There is a circular eye at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in that ring of storms.  Well formed rainbands exists in the outer portions of the circulation.  Storms in the core of Ophelia are generating upper level divergence which is pumping mass away to the northeast of the hurricane.  Winds to hurricane force extend out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extend out about 125 miles (205 km) from the center.

Hurricane Ophelia is moving over water where the Sea Surface Temperature is near 25°C.  Normally, water at that temperature would be considered to be too cool to support the development of a major hurricane.  However, the temperature of the air in the upper troposphere is also cool and so the atmosphere is unstable enough to allow for the development of deep convection.  An upper level trough west of Ophelia is producing southwesterly winds which are blowing toward the top of the circulation.  There are also southwesterly winds in the lower and middle levels of the atmosphere and so the vertical wind shear is not strong enough to inhibit intensification

Hurricane Ophelia will be moving over cooler water and it is likely to weaken gradually during the next several days.  When Ophelia moves over the cooler water it will make a transition to an extratropical cyclone.  The size of the circulation will increase during the transition.  Hurricane Ophelia will evolve into a large very powerful extratropical cyclone during the next several days.

The trough west of Ophelia is steering the hurricane toward the northeast.  Hurricane Ophelia is expected to turn more toward the north during the next two or three days.  On its anticipated track Hurricane Ophelia will pass east of the Azores later today.  The strong extratropical cyclone that Ophelia will transition into could approach Ireland and the United Kingdom by Monday morning.  That cyclone will bring very strong winds and heavy rain to that region.

Hurricane Ophelia Moves Closer to the Azores

Hurricane Ophelia moved closer to the Azores on Friday.  At 5:00 p.m. EDT on Friday the center of Hurricane Ophelia was located at latitude 32.3°N and longitude 31.8°W which put it about 480 miles (770 km) southwest of the Azores.  Ophelia was moving toward the east-northeast at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 971 mb.

Despite moving over slightly cooler water, Hurricane Ophelia maintained its structure and intensity on Friday.  There was a small circular eye at the center of circulation, although there appeared to be a break on the northwest side of the ring of thunderstorms around the eye.  Thunderstorms in the core of Ophelia were generating upper level divergence which was pumping away mass.  Bands of showers and thunderstorms were revolving around the core of Hurricane Ophelia.  The stronger rainbands were in the eastern half of the circulation.  Winds to hurricane force extended out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out about 100 miles (160 km) from the center.

Hurricane Ophelia will move through an environment that is capable of supporting a strong cyclone.  Ophelia will move over water where the Sea Surface Temperature is near 25°C.  Normally, that water would be too cool to support a strong hurricane.  However, the temperature in the upper levels of the atmosphere is also cool and that is keeping the atmosphere unstable enough to allow for thunderstorms to develop.  The speed of the winds in Hurricane Ophelia is likely to decrease gradually during the next several days.

When Hurricane Ophelia moves farther north, it will move into a cooler environment with stronger westerly winds in the upper levels.  A cooler environment with more vertical wind shear will cause the structure of Hurricane Ophelia change into the structure of an extratropical cyclone.  The area of stronger winds will expand and the cyclone will become much larger.

Hurricane Ophelia is being steered toward the east-northeast by westerly winds in the middle levels.  A trough will approach Hurricane Ophelia from the west.  Southwesterly winds ahead of the trough will carry Ophelia more toward the north in about 36 hours.  On its anticipated track the center of Hurricane Ophelia will move south of the Azores on Saturday.  Ophelia could bring gusty winds and rain to the Azores when it moves by those islands.  The strong extratropical cyclone that evolves from Hurricane Ophelia could approach Ireland and the United Kingdom on Monday.  That cyclone could bring very strong winds and heavy rain to that region.

Ophelia Strengthens Into a Hurricane Southwest of the Azores

Tropical Storm Ophelia strengthened into a hurricane southwest of the Azores on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Ophelia was located at latitude 30.0°N and longitude 35.7°W which put it about 745 miles (1195 km) southwest of the Azores.  Ophelia was moving toward the northeast at 3 m.p.h.  The maximum sustained wind speed was 85 m.p.h. (140 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 986 mb.

The circulation of Hurricane Ophelia became more circular and symmetrical on Wednesday.  A circular eye developed at the center of circulation.  Thunderstorms in the ring around the eye became taller.  Additional bands of showers and thunderstorms were revolving around the core of Hurricane Ophelia.  Thunderstorms in the core were producing upper level divergence which was pumping mass away to the east of the hurricane.  Winds to hurricane force extended out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out about 70 miles (110 km) from the center.

Hurricane Ophelia will be moving through an environment that could support further intensification on Thursday.  Ophelia will move over water where the Sea Surface Temperature is near 26.5°C.  Ophelia is in an area of weaker upper level winds.  It is north of the subtropical jet stream and it is south of the stronger westerly winds in the middle latitudes.  As a result the vertical wind shear is minimal.  The combination of warm water and little shear allowed Ophelia to intensify into a hurricane and it could strengthen further on Thursday.

Hurricane Ophelia is in an area of weak westerly winds which are steering the hurricane slowly toward the east.  An upper level trough will approach Ophelia from the west and the trough will start to pull the hurricane toward the northeast more quickly later this week.  On its anticipated track Hurricane Ophelia could approach the Azores in two or three days.

Tropical Storm Ophelia Forms Over Eastern Atlantic

The busy 2017 Atlantic hurricane season continued when Tropical Storm Ophelia formed over the eastern Atlantic Ocean on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Ophelia was located at latitude 31.5°N and longitude 39.6°W which put it about 845 miles (1355 km) west-southwest of the Azores.  Ophelia was moving toward the northeast at 3 m.p.h. (5 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 1005 mb.

Thunderstorms formed on Monday near the center of a low pressure system which had been lingering over the eastern Atlantic Ocean and the National Hurricane Center designated the system as Tropical Storm Ophelia.  The thunderstorms formed near the eastern side of the center and several bands of showers and thunderstorms formed in the rest of the eastern half of the circulation.  There were fewer thunderstorms in the western half of Ophelia.  The thunderstorms near the center of circulation were generating upper level divergence which was pumping mass away to the east of the tropical storm.

Tropical Storm Ophelia is an environment that is somewhat favorable to intensification.  Ophelia is moving over water where the Sea Surface Temperature (SST) is near 27°C.  It is near the axis of an upper level trough which is oriented east to west over the Atlantic Ocean.  The trough is producing westerly winds which are blowing toward the top of the circulation and those winds are causing some vertical wind shear.  However, since Ophelia is over water where the SST is 27°C, the clouds are not rising as far into the atmosphere as they would if the water was warmer and some of the upper level winds are blowing completely over the top of the circulation of the tropical storm.  So, the vertical wind shear is not as significant as it could be if the top of Ophelia was higher in the atmosphere.  Tropical Storm Ophelia is likely to strengthen during the next several days and it could eventually become a hurricane.

Since Tropical Storm Ophelia is near the axis of the upper level trough, the steering winds are weaker.  The westerly flow is pushing Ophelia slowly toward the northeast.  The orientation of the trough is forecast to change during the next day or two and Ophelia is expected to move more toward the east-southeast.  On its anticipated track Tropical Storm Ophelia is expected to meander over the eastern Atlantic Ocean for several more days.