Tag Archives: AL13

Tropical Depression 13 Forms, Watch Issued for Saba and St. Eustatius

Tropical Depression Thirteen formed about 1000 miles (1600 km) east of the Lesser Antilles on Wednesday night.  At 11:00 p.m. EDT on Wednesday the center of Tropical Depression Thirteen was located at latitude 14.6°N and longitude 47.9°W which put it about 1035 miles (1670 km) east-southeast of the northern Leeward Islands.  The depression was moving toward the west-northwest at 20 m.p.h. (32 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 1008 mb.

A Tropical Storm Watch was issued for Saba and St. Eustatius.

A distinct center of circulation developed within a tropical wave east of the Lesser Antilles on Wednesday night and the National Hurricane Center designated the system as Tropical Depression Thirteen.  The circulation around the depression was still organizing.  Thunderstorms were building near the newly formed center of circulation.  Bands of showers and thunderstorms were developing.  The stronger thunderstorms were in bands in the northern half of the circulation.  Storms near the center began to generate upper level divergence which was pumping mass away from the depression.

Tropical Depression Thirteen will move through an environment favorable for intensification during the next few days.  The depression will move over water where the Sea Surface Temperature is near 28°C.  It will move a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Depression Thirteen will likely strengthen gradually at first while the circulation is organizing.  If an inner core develops, then the rate of intensification could increase.

Tropical Depression Thirteen will move south of the subtropical high pressure system over the North Atlantic Ocean.  The high will steer the depression toward the west-northwest during the next few days.  On its anticipated track Tropical Depression Thirteen could approach the northern Leeward Islands on Friday.

Hurricane Lorenzo Brings Wind and Rain to the Azores

Hurricane Lorenzo brought wind and rain to the Azores on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Lorenzo was located at latitude 39.1°N and longitude 32.7°W which put it about 85 miles (135 km) west-southwest of Flores Island, Azores.  Lorenzo was moving toward the northeast at 40 m.p.h. (65 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 960 mb.

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

Although Hurricane Lorenzo moved into a more extratropical environment, it remained a large and powerful hurricane.  Winds to hurricane force extended out 150 miles (240 km) from the center of circulation.  Winds to tropical storm force extended out 390 miles (630 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Lorenzo was 16.5.  The Hurricane Size Index (HSI) was 50.2 and the Hurricane Wind Intensity Size Index (HWISI) was 66.7.  The radius of hurricane force winds was larger in Hurricane Lorenzo than it was in Hurricane Sandy in 2012.  The overall size of Hurricane Lorenzo was similar to the size of Hurricane Sandy.

Hurricane Lorenzo will move into an extratropical environment during the next several days.  Lorenzo will move over water where the Sea Surface Temperature is colder than 24°C.  An upper level trough over the north Atlantic Ocean will produce southwesterly winds which will blow toward the top of the circulation.  Those winds will cause strong vertical wind shear.  The colder water and strong shear will cause Hurricane Lorenzo to weaken gradually.  The cooler, more strongly sheared environment will also cause Hurricane Lorenzo to make a transition into a strong extratropical cyclone during the next 48 hours.

The upper level trough will steer Hurricane Lorenzo rapidly toward the northeast during the next 24 to 36 hours.  Lorenzo will turn more toward the east later on Thursday.  On its anticipated track Hurricane Lorenzo will bring strong winds, large waves and heavy rain to the Azores on Wednesday.  Lorenzo will be capable of causing extensive serious damage.  The extratropically transitioned Hurricane Lorenzo could approach Ireland and the United Kingdom on Thursday night and Friday.

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.

Lorenzo Rapidly Strengthens Into a Major Hurricane

Hurricane Lorenzo rapidly strengthened into a major hurricane west of the Cabo Verde Islands on Thursday.  At 6:00 a.m. EDT on Thursday the center of Hurricane Lorenzo was located at latitude 15.2°N and longitude 39.3°W which put it about 995 miles (1600 km) west of the Cabo Verde Islands.  Lorenzo was moving toward the west-northwest at 15 m.p.h. (24 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 955 mb.

Lorenzo was a large well organized a hurricane.  There was a circular eye at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Hurricane Lorenzo.  Storms around the core were generating strong upper level divergence which was pumping mass away from the hurricane.  Winds to hurricane force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out about 210 miles (335 km) from the center.

Hurricane Lorenzo will move through an environment favorable for intensification during the next day or so.  Lorenzo will move over water where the Sea Surface Temperature is near 27°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Lorenzo is likely to strengthen to Category 4 on the Saffir-Simpson Scale during the next 24 hours.  Lorenzo will move over cooler water during the weekend, which will cause the hurricane to weaken.

Hurricane Lorenzo will move around the western end of a ridge of high pressure over North Africa and the eastern Atlantic Ocean.  The ridge will steer Lorenzo toward the north during the weekend.  On its anticipated track Hurricane Lorenzo could approach the Azores next week.

Elsewhere over the Atlantic Ocean Tropical Storm Karen moved farther away from Puerto Rico.  At 5:00 a.m. EDT in Thursday the center of Tropical Storm Karen was located at latitude 25.5°N and longitude 63.5°W which put it about 520 miles (835 km) north-northeast of San Juan Puerto Rico.  Karen was moving toward the north-northeast at 15 m.p.h. (24 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 1004 mb.

Tropical Storm Karen Drops Heavy Rain on Puerto Rico and the Virgin Islands

Tropical Storm Karen dropped heavy rain on parts of Puerto Rico and the Virgin Islands on Tuesday.  At 2:00 p.m. EDT on Tuesday the center of Tropical Storm Karen was located at latitude 17.5°N and longitude 66.0°W which put it about 65 miles (105 km) south of San Juan Puerto Rico.  Karen was moving toward the north at 8 m.p.h. (13 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.

Tropical Storm Warnings were in effect for Puerto Rico including Vieques and Culebra, the U.S. Virgin Islands and the British Virgin Islands.

The circulation around Tropical Storm Karen exhibited more organization on Tuesday afternoon.  A new low level center of circulation formed a little farther to the west near a cluster of stronger thunderstorms.  The minimum surface pressure decreased by several millibars.  More thunderstorms formed near the center of circulation and in bands revolving around the center.  Storms near the newly reformed center of circulation were generating more upper level divergence which was pumping mass away from the tropical storm.  The removal of mass was what allowed the surface pressure to decrease.  Winds to tropical storm force extended out about 80 miles (130 km) from the center of circulation.

Tropical Storm Karen will move through an environment favorable for intensification during the next 24 to 48 hours.  Karen will move over water where the Sea Surface Temperature is near 29°C.  Karen has moved under the middle of an upper level ridge over the eastern Caribbean Sea where the upper level winds are weaker.  There will be less vertical wind shear during the next day or two.  The environment around Tropical Storm Karen will support intensification.  However, the center of Karen will pass over Puerto Rico during the next 24 hours.  The mountains in Puerto Rico will disrupt the circulation in the lower levels and Tropical Storm Karen will weaken when it passes over those mountains.  Karen will likely strengthen again when it moves north of Puerto Rico.

Tropical Storm Karen will move around the western end of a subtropical high pressure system over the Atlantic Ocean.  The high will steer Karen toward the north during the next day or two.  On its anticipated track Tropical Storm Karen will move across Puerto Rico during the next 24 hours.  Karen will drop heavy rain on parts of Puerto Rico, the U.S. Virgin Islands and the British Virgin Islands.  Prolonged heavy rain will create a high risk for flash floods in those areas.

Elsewhere over the Atlantic Ocean, Tropical Storm Jerry was moving slowly toward Bermuda and Tropical Storm Lorenzo was strengthening west of the Cabo Verde Islands.  At 2:00 p.m. EDT the center of Tropical Storm Jerry was located at latitude 30.9°N and longitude 69.1°W which put it about 270 miles (435 km) west-southwest of Bermuda.  Jerry was moving toward the north-northeast 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 km/h).  The minimum surface pressure was 992 mb.  A Tropical Storm Warning was in effect for Bermuda.

At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Lorenzo was located at latitude 12.4°N and longitude 29.3°W which put it about 270 miles (435 km) west-southwest of the Cabo Verde Islands.  Lorenzo was moving toward the west-northwest at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 997 mb

Hurricane Leslie Speeds Toward Portugal and Spain

After spending almost three weeks meandering around the Central Atlantic Ocean, Hurricane Leslie sped toward Portugal and Spain on Friday afternoon.  At 2:00 p.m. EDT on Friday the center of Hurricane Leslie was located at latitude 33.3°N and longitude 26.1°W which put it about 515 miles (830 km) west of Madeira, Island.  Leslie was moving toward the east-northeast at 33 m.p.h. (54 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 971 mb.

A Tropical Storm Warning was in effect for Madeira Island.

The circulation around Hurricane Leslie remained well organized.  A small circular eye was at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  The ring of storms was thinner west of the eye.  Several bands of showers and thunderstorms north and east of the eye were revolving around the core of Hurricane Leslie.  Bands south and west of the center of circulation consisted mostly of showers and lower clouds.  Winds to hurricane force extended out about 70 miles (110 km) from the center of Hurricane Leslie.  Winds to tropical storm force extended out about 230 miles (370 km) from the center of circulation.  Much of the stronger winds were occurring in the southern half of the circulation.

Hurricane Leslie will be moving through an environment unfavorable for a hurricane.  Leslie is currently over water where the Sea Surface Temperature is near 25°C, but it will move over cooler water during the next 24 to 36 hours.  An upper level trough south of Iceland is producing strong westerly winds which are blowing toward the top of Hurricane Leslie.  Those winds will cause significant vertical wind shear, but Hurricane Leslie will move south of the strongest winds.  A combination of cooler water and strong vertical wind shear will cause Hurricane Leslie to make a transition to a strong extratropical cyclone during the next day or so.

The upper level trough south of Iceland will steer Hurricane Leslie quickly toward the east-northeast.  On its anticipated track Hurricane Leslie will approach southern Portugal on Sunday morning.  Leslie will likely be a strong extratropical cyclone at that time.  Leslie will bring strong winds and heavy rain to parts of Portugal and Spain during the weekend.  Heavy rain could cause flash floods in some locations.

Possible Tropical Development Near Yucatan Peninsula

A tropical cyclone could develop near the Yucatan peninsula during the next few days.  At 2:00 p.m. EDT on Friday the center of Invest 91L was located at latitude 16.0°N and longitude 84.3°W which put it about 400 miles (640 km) southeast of Cancun, Mexico.  It was moving toward the northwest at 6 m.p.h. (10 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.

A broad area of low pressure is over the western Caribbean Sea, Central America and the adjacent waters of the Eastern North Pacific Ocean.  Several smaller, mesoscale centers of rotation appear to be revolving around the larger low pressure system.  One of the mesoscale centers is over the Eastern North Pacific Ocean just west of the coast of Central America.  One or two other mesoscale centers appear to be over the western Caribbean Sea near Honduras.  The low level circulation is not currently well organized.  It is broad and diffuse.  Thunderstorms are clustered around the mesoscale centers, but large scale rainbands have not formed.

Westerly winds in the upper levels are are blowing over the top of the system.  Those winds are creating moderate vertical wind shear which is inhibiting the development of the low pressure system.  The upper level winds are forecast to weaken during the next few days and the wind shear will diminish.  The Sea Surface Temperature of the water in the northwestern Caribbean Sea and Gulf of Mexico is near 30°C.  The broad low pressure system could slowly organize during the next two to three days.  The National Hurricane Center is indicating that there is a 70% probability of formation of a tropical cyclone near the Yucatan peninsula or over the southern Gulf of Mexico during the next five days.  A reconnaissance plane is scheduled to investigate the low pressure system on Sunday, if necessary.

The broad low is southwest of a subtropical high pressure system over the Atlantic Ocean.  The high is expected to steer the low toward the northwest during the weekend.  On its anticipated track the low will move over the northwestern Caribbean Sea during the next several days.  it could move into the Gulf of Mexico on Monday.

Elsewhere over the Atlantic Ocean, Tropical Storm Leslie continued to meander northeast of Bermuda.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Leslie was located at latitude 36.2°N and longitude 58.4°W which put it about 455 miles (730 km) northeast of Bermuda.  Leslie was moving toward the north-northwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 986 mb.

Leslie Strengthens Into a Hurricane East of Bermuda

Former Tropical Storm Leslie strengthened into a hurricane east of Bermuda on Wednesday morning.  At 11:00 a.m. EDT on Wednesday the center of Hurricane Leslie was located at latitude 29.5°N and longitude 56.8°W which put it about 510 miles (825 km) east-southeast of Bermuda.  Leslie was nearly stationary.  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (155 km/h).  The minimum surface pressure was 975 mb.

After being designated as a subtropical storm, Hurricane Leslie made a transition to an extratropical cyclone and then back to a subtropical storm.  Leslie eventually moved over warmer water and the structure changed to that of a tropical storm, which intensified slowly until it reached hurricane intensity earlier this morning.  It is gradually exhibiting the classical appearance and structure of a hurricane.

There is a circular eye at the center of circulation.  A nearly complete ring of thunderstorms surrounds the eye and the strongest winds are occurring in that ring of storms.  Several bands of showers and thunderstorms are revolving around the core of Hurricane Leslie.  Storms near the core are generating upper level divergence which is pumping mass away from the hurricane, which is causing the surface pressure to decrease.  Winds to hurricane force extend out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extend out about 230 miles (370 km) from the center.

Hurricane Leslie will remain in an environment favorable for intensification for another day or two.  Leslie will remain over water where the Sea Surface Temperature is near 27.5°C.  it will be in a region where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Leslie is likely to get a little stronger during the next day or so.  Leslie will move over cooler water later this week and it will start to weaken when that happens.

Hurricane Leslie has been in an area where the steering winds were weak which is why it has meandered east of Bermuda during the past few days.  A subtropical ridge southeast of Leslie will strengthen during the next day or two and the ridge will start to steer the hurricane toward the north.  On its anticipated track Hurricane Leslie will move farther away from Bermuda later this week.