Category Archives: Atlantic, Caribbean, and Gulf of Mexico

Atlantic TCs

Gabrielle Prompts Hurricane Watch for the Azores

The risk posed by Hurricane Gabrielle prompted the issuance of a Hurricane Watch for the Azores on Tuesday.  At 2:00 p.m. EDT on Tuesday the center of Hurricane Gabrielle was located at latitude 34.3°N and longitude 57.5°W which put the center about 1710 miles (2755 km) west of the Azores.  Gabrielle was moving toward the east-northeast at 20 m.p.h. (32 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 952 mb.

A Hurricane Watch is in effect for all of the Azores.

A circular eye with a diameter of 20 miles (32 km) was at the center of Gabrielle’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Gabrielle’s circulation.  Storms near the center of Gabrielle generated upper level divergence that pumped mass away from the hurricane.  The removal of mass in the upper level was slightly less than the inflow of mass in the lower levels of the atmosphere.  The strong inflow of mass in the lower levels caused the surface pressure to increase gradually.

The size of the circulation around Hurricane Gabrielle did not change much during the past 24 hours.  Winds to hurricane force extended out 40 miles (65 km) from the center of Gabrielle’s circulation.  Winds to tropical storm force extended out 140 miles (225 km) in the western side of Hurricane Gabrielle.  Winds to tropical storm force extended out 70 miles (110 km) in the eastern side of Gabrielle’s circulation.

The Hurricane Intensity Index (HII) for Hurricane Gabrielle was 25.1.  The Hurricane Size Index (HSI) was 12.9 and the Hurricane Wind Intensity Size Index (HWISI) was 38.0.  Hurricane Gabrielle was similar in size and intensity to Hurricane Harvey when Harvey hit Texas in 2017.

Hurricane Gabrielle will move through an environment that will become more unfavorable for intensification during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the southern extent of the upper level westerly winds in the middle latitudes.  Those upper level westerly winds will cause the vertical wind shear to increase.  Hurricane Gabrielle will continue to weaken gradually during the next 24 hours.

The upper level westerly winds in the middle latitudes will steer Hurricane Gabrielle toward the east during the next 24 hours.  On its anticipated track, Hurricane Gabrielle will reach the Azores on Thursday.

Hurricane Gabrielle will bring strong winds and heavy rain to the Azores on Thursday night and Friday.

Hurricane Gabrielle Strengthens to Cat. 4

Hurricane Gabrielle strengthened to Category 4 on the Saffir-Simpson Scale east of Bermuda on Monday afternoon.  At 5:00 p.m. EDT on Monday the center of Hurricane Gabrielle was located at latitude 31.7°N and longitude 61.8°W which put the center about 180 miles (290 km) east-southeast of Bermuda.  Gabrielle was moving toward the north-northeast at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there were wind gusts to 165 m.p.h. (265 km/h).  The minimum surface pressure was 948 mb.

Hurricane Gabrielle strengthened to Category 4 on the Saffir-Simpson Scale east of Bermuda on Monday afternoon.  A circular eye with a diameter of 20 miles (32 km was at the center of Gabrielle’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Gabrielle’s circulation.  Storms near the center of Gabrielle generated upper level divergence that pumped mass away from the hurricane.  The removal of mass caused the surface pressure to decrease.

The size of the circulation around Hurricane Gabrielle increased on Monday.  Winds to hurricane force extended out 40 miles (65 km) from the center of Gabrielle’s circulation.  Winds to tropical storm force extended out 140 miles (225 km) in the western side of Hurricane Gabrielle.  Winds to tropical storm force extended out 70 miles (110 km) in the eastern side of Gabrielle’s circulation.

The Hurricane Intensity Index (HII) for Hurricane Gabrielle was 28.6.  The Hurricane Size Index (HSI) was 13.1 and the Hurricane Wind Intensity Size Index (HWISI) was 41.7.

Hurricane Gabrielle will move through an environment that will become unfavorable for intensification during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the southern extent of the upper level westerly winds in the middle latitudes.  Those upper level westerly winds will cause the vertical wind shear to increase.  Hurricane Gabrielle will start to weaken when the wind shear increases.

The upper level westerly winds in the middle latitudes will steer Hurricane Gabrielle toward the east during the next 24 hours.  On its anticipated track, Hurricane Gabrielle will move away from Bermuda on Tuesday.  Gabrielle will approach the Azores on Thursday.

 

Gabrielle Rapidly Intensifies to Major Hurricane

Hurricane Gabrielle rapidly intensified to a major hurricane southeast of Bermuda on Monday morning.  At 9:00 a.m. EDT on Monday the center of Hurricane Gabrielle was located at latitude 30.6°N and longitude 62.2°W which put the center about 195 miles (310 km) southeast of Bermuda.  Gabrielle was moving toward the north at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 145 m.p.h. (235 km/h).  The minimum surface pressure was 957 mb.

Hurricane Gabrielle rapidly intensified to a major hurricane southeast of Bermuda on Monday morning.  A small circular eye formed at the center of Gabrielle’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Gabrielle’s circulation.  Storms near the center of Gabrielle generated strong upper level divergence that pumped mass away from the hurricane.  The removal of large quantities of mass caused the surface pressure to decrease rapidly.

The circulation around Hurricane Gabrielle became more symmetrical on Monday morning.  Winds to hurricane force extended out 30 miles (50 km) from the center of Gabrielle’s circulation.  Winds to tropical storm force extended out 140 miles (220 km) from the center of Hurricane Gabrielle.

The Hurricane Intensity Index (HII) for Hurricane Gabrielle was 22.1.  The Hurricane Size Index (HSI) was 9.9 and the Hurricane Wind Intensity Size Index (HWISI) was 32.0.  Hurricane Gabrielle was similar in size and intensity to Hurricane Dennis when Dennie hit Northwest Florida in 2005.

Hurricane Gabrielle will move through an environment favorable for intensification during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 29°C.  It will move in the region between an upper level low south of Bermuda and an upper level trough near the east coast of the U.S.  The upper level winds are weak between the upper level low and the upper level trough.  So, there will be little vertical wind shear. Hurricane Gabrielle will intensify during the next 24 hours.  Gabrielle could continue to intensify rapidly during the next few hours .

Hurricane Gabrielle will move around the western end of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Gabrielle toward the north during the next 24 hours.  On its anticipated track, Hurricane Gabrielle will pass east of Bermuda later on Monday.  Gabrielle could approach the Azores by Thursday evening.

Gabrielle Intensifies to a Hurricane

Former Tropical Storm Gabrielle intensified to a hurricane southeast of Bermuda on Sunday.  At 5:00 p.m. EDT on Sunday the center of Hurricane Gabrielle was located at latitude 28.5°N and longitude 61.7°W which put the center about 320 miles (515 km) southeast of Bermuda.  Gabrielle was moving toward the north-northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 992 mb.

NOAA hurricane hunter aircraft conducting research flights into former Tropical Storm Gabrielle found that Gabrielle had intensified to a hurricane on Sunday afternoon.

The inner end of a rainband wrapped around the center of Hurricane Gabrielle.  A small eye appeared on microwave satellite imagery at the center of Gabrielle’s circulation.  Bands of showers and thunderstorms were revolving around the center of Hurricane Gabrielle.  Storms near the center of Gabrielle generated more upper level divergence that pumped mass away to the north and east of the tropical storm.  The removal of mass caused the surface pressure to decrease.

The strongest winds were occurring in the northeastern part of Hurricane Gabrielle.  Winds to hurricane force extended out 25 miles (40 km) in the northeastern quadrant of Gabrielle’s circulation.  Winds to tropical storm force extended out 175 miles (280 km) in the eastern side of Hurricane Gabrielle.  Winds to tropical storm force extended out 70 miles (110 km) in the western half of Gabrielle’s circulation.

Hurricane Gabrielle will move through an environment favorable for intensification during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 29°C.  It will move in the region between an upper level low south of Bermuda and an upper level trough near the east coast of the U.S.  The upper level winds are weak between the upper level low and the upper level trough.  So, there will be little vertical wind shear.  Hurricane Gabrielle will intensify during the next 24 hours.  Gabrielle could intensify rapidly at times.

Hurricane Gabrielle will move around the western end of a subtropical high pressure system over the Atlantic Ocean.  The high pressure system will steer Gabrielle toward the north during the next 24 hours.  On its anticipated track, Hurricane Gabrielle will pass east of Bermuda on Monday.  Gabrielle could approach the Azores by late next week.

Tropical Storm Gabrielle Strengthens

Tropical Storm Gabrielle strengthened on Saturday as it moved over the Atlantic Ocean southeast of Bermuda.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Gabrielle was located at latitude 25.6°N and longitude 59.0°W which put the center about 580 miles (935 km) southeast of Bermuda.  Gabrielle was moving toward the northwest at 10 m.p.h. (16 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 996 mb.

Tropical Storm Gabrielle strengthened on Saturday.  The inner end of a rainband wrapped around the center of Gabrielle’s circulation.  A small eye was visible intermittently at the center of Gabrielle’s circulation.  Thunderstorms were occurring in bands in the northern and eastern parts of Tropical Storm Gabrielle.  Bands in the southern and western parts of Gabrielle’s circulation consisted primarily of showers and lower clouds.  Storms near the center of Gabrielle generated upper level divergence that pumped mass away to the north of the tropical storm.

The distribution of wind speeds in Tropical Storm Gabrielle continued to be asymmetrical.  Winds to tropical storm force extended out 140 miles (220 km) in the eastern side of Gabrielle’s circulation.  Winds to tropical storm force extended out 60 miles in the western side of Tropical Storm Gabrielle.

Tropical Storm Gabrielle will move through an environment that will be favorable for intensification during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the eastern side of an upper level low that is south of Bermuda.  The upper level low will produce southerly winds that will blow toward the top of Gabrielle’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Tropical Storm Gabrielle will intensify during the next 24 hours. Gabrielle is likely to strengthen to a hurricane on Sunday.

Tropical Storm Gabrielle will move around the southwestern part of a subtropical high pressure system over the eastern Atlantic Ocean.  The high pressure system will steer Gabrielle toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Gabrielle will pass east of Bermuda on Monday.  Gabrielle could approach the Azores by late next week.

Tropical Storm Gabrielle Moves Southeast of Bermuda

Tropical Storm Gabrielle moved southeast of Bermuda on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Gabrielle was located at latitude 22.4°N and longitude 56.6°W which put the center about 850 miles (1360 km) southeast of Bermuda.  Gabrielle was moving toward the west-northwest at 12 m.p.h. (19 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 1004 mb.

Tropical Storm Gabrielle started to exhibit more organization on Friday afternoon.  More thunderstorms formed near the center of Gabrielle’s circulation.  More thunderstorms also developed in bands in the eastern side of Tropical Storm Gabrielle.  Bands in the western side of Gabrielle still consisted primarily of showers and lower clouds.

The distribution of wind speeds in Tropical Storm Gabrielle continued to be asymmetrical.  Winds to tropical storm force extended out 150 miles (240 km) in the eastern side of Gabrielle’s circulation.  Winds to tropical storm force extended out 80 miles (130 km) in the western half of Gabrielle’s circulation.

Tropical Storm Gabrielle will move into an environment that will become more favorable for intensification during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the eastern side of an upper level low that is south of Bermuda.  The upper level low will produce southerly winds that will blow toward the top of Gabrielle’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Tropical Storm Gabrielle will intensify during the next 24 hours.  Gabrielle is likely to strengthen to a hurricane during the weekend.

Tropical Storm Gabrielle will move around the southwestern part of a subtropical high pressure system over the eastern Atlantic Ocean.  The high pressure system will steer Gabrielle toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Gabrielle will make its closest approach to Bermuda on Monday.

Tropical Storm Gabrielle Spins over the Central Atlantic

Tropical Storm Gabrielle was spinning over the Central Atlantic Ocean on Thursday.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Gabrielle was located at latitude 20.8°N and longitude 52.7°W which put the center about 700 miles (1125 km) east-northeast of the Northern Leeward Islands.  Gabrielle was moving toward the west-northwest at 13 m.p.h. (21 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 1004 mb.

The appearance of Tropical Storm Gabrielle did not change much on Thursday.  Gabrielle consisted of bands of showers and low clouds revolving around the center of circulation for much of Thursday.  New thunderstorms began to develop late Thursday afternoon in bands northeast of the center of Gabrielle’s circulation.  The bands in the other parts of Tropical Storm Gabrielle still consisted primarily of showers and lower clouds.

The distribution of wind speeds in Tropical Storm Gabrielle was very asymmetrical.  Winds to tropical storm force extended out 290 miles (465 km) in the northeastern quadrant of Gabrielle’s circulation.  Winds to tropical storm force extended out 175 miles (280 km) in the southeastern and northwestern quadrants of Gabrielle.  The winds in the southwestern quadrant of Tropical Storm Gabrielle were blowing at less than tropical storm force.

Tropical Storm Gabrielle will move through an environment that will be only marginally favorable for intensification during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 28°C.  However, an upper level low that is northeast of the Northern Leeward Islands will produce strong southwesterly winds that will blow toward the top of Gabrielle’s circulation.  Those winds will cause strong vertical wind shear.  The strong vertical wind shear will prevent significant intensification during the next 24 hours.  The wind shear is forecast to decrease during the weekend and Tropical Storm Gabrielle is likely to intensify when the shear decreases.

Tropical Storm Gabrielle will move around the southwestern part of a subtropical high pressure system over the eastern Atlantic Ocean.  The high pressure system will steer Gabrielle toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Gabrielle will pass northeast of the Leeward Islands on Friday night.

Tropical Storm Gabrielle Forms East of Leeward Islands

Tropical Storm Gabrielle formed over the Atlantic Ocean east of the Leeward Islands on Wednesday morning.  At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Gabrielle was located at latitude 17.5°N and longitude 46.6°W which put the center about 1085 miles (1745 km) east of the Northern Leeward Islands.  Gabrielle was moving toward the north-northwest at 22 m.p.h. (35 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 1006 mb.

A low pressure system over the Atlantic Ocean east of the Northern Leeward Islands strengthened on Tuesday morning and the U.S. National Hurricane Center designated the system as Tropical Storm Gabrielle.

The circulation around Tropical Storm Gabrielle was poorly organized on Thursday morning.  Thunderstorms were occurring in bands east of the center of Gabrielle’s circulation.  Bands in the western part of Tropical Storm Gabrielle consisted primarily of showers and lower clouds.  An upper level low northeast of the Leeward Islands was producing strong southwesterly winds that were blowing toward the top of Gabrielle’s circulation.  Those winds were causing strong vertical wind shear.  The strong vertical wind shear was causing the asymmetrical distribution of thunderstorms in Tropical Storm Gabrielle.

The distribution of wind speeds in Tropical Storm Gabrielle was also asymmetrical.  Winds to tropical storm force extended out 175 miles (280 km) in the eastern side of Gabrielle’s circulation.  The winds in the western side of Tropical Storm Gabrielle were blowing at less than tropical storm force.

Tropical Storm Gabrielle will move through an environment that will be only marginally favorable for intensification during the next 24 hours.  Gabrielle will move over water where the Sea Surface Temperatures are near 28°C.   However, the upper level low that is northeast of the Northern Leeward Islands will continue to cause strong vertical wind shear.  The strong vertical wind shear will prevent significant intensification during the next 24 hours.

Tropical Storm Gabrielle will move around the southwestern part of a subtropical high pressure system over the eastern Atlantic Ocean.  The high pressure system will steer Gabrielle toward the northwest during the next 24 hours.  On its anticipated track, Tropical Storm Gabrielle will pass northeast of the Leeward Islands later this week.

 

Tropical Storm Fernand Moves East

Tropical Storm Fernand moved east over the North Atlantic Ocean on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Fernand was located at latitude 39.3°N and longitude 47.4°W which put the center about 585 miles (945 km) south-southeast of Cape Race, Newfoundland.  Fernand was moving toward the east-northeast at 15 m.p.h. (24 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 1006 mb.

Many of the thunderstorms in Tropical Storm Fernand dissipated on Wednesday as Fernand moved over cooler water.  The circulation around Fernand consisted primarily of bands of showers and lower clouds.

Winds to tropical storm force extended out 115 miles (185 km) from the center of Tropical Storm Fernand.

Tropical Storm Fernand will move through an environment that will be unfavorable for intensification of a tropical storm during the next 24 hours.  Fernand will move over water where the Sea Surface Temperatures are near 22°C.  An upper level wind trough east of Canada will produce southwesterly winds that will blow across the top of Fernand’s circulation.  Those winds will cause strong vertical wind shear.  The combination of cool water and strong vertical wind shear will cause Tropical Storm Fernand to weaken during the next 24 hours.

Tropical Storm Fernand will move around the northern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Fernand toward the east-northeast during the next 24 hours.  On its anticipated track, Tropical Storm Fernand will move southeast of Newfoundland on Thursday.

Tropical Storm Fernand Passes Far South of Newfoundland

Tropical Storm Fernand passed far to the south of Newfoundland on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Fernand was located at latitude 38.1°N and longitude 53.4°W which put the center about 595 miles (955 km) south of Cape Race, Newfoundland.  Fernand was moving toward the northeast at 12 m.p.h. (19 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 1007 mb.

Tropical Storm Fernand weakened on Tuesday as it passed far to the south of Newfoundland.  Fernand continued to move under the southeastern side of an upper level ridge over the North Atlantic.  The upper level ridge produced northerly winds that blew across the top of Fernand’s circulation.  Those winds caused moderate vertical wind shear.  The vertical wind shear caused the distribution of thunderstorms in Tropical Storm Fernand to remain asymmetrical.  Thunderstorms were occurring in bands in the southern part of Fernand’s circulation.  Bands in the northern part of Tropical Storm Fernand consisted primarily of showers and lower clouds.

The distribution of wind speeds around Tropical Storm Fernand was asymmetrical.   Winds to tropical storm force extended out 90 miles (145 km) in the eastern side of Fernand’s circulation.  The winds in the western side of Tropical Storm Fernand were blowing at less than tropical storm force.

Tropical Storm Fernand will move through an environment that will be unfavorable for intensification of a tropical storm during the next 24 hours.  Fernand will move over water where the Sea Surface Temperatures are near 25°C.  The upper level wind ridge over the North Atlantic will continue to cause moderate vertical wind shear.  The combination of cooler water and vertical wind shear will prevent Tropical Storm Fernand from intensifying during the next 24 hours.

Tropical Storm Fernand will move around the northern side of a high pressure system over the Atlantic Ocean.  The high pressure system will steer Fernand toward the east-northeast during the next 24 hours.  On its anticipated track, Tropical Storm Fernand will remain far to the southeast of Newfoundland on Wednesday.