Author Archives: jay_hobgood

Leslie Intensifies to a Hurricane

Former Tropical Storm Leslie intensified to a hurricane over the eastern Atlantic Ocean on Friday night.  At 11:00 p.m. EDT on Friday the center of Hurricane Leslie was located at latitude 10.3°N and longitude 33.6°W which put the center about 725 miles (1170 km) west-southwest of the Cabo Verde Islands.  Leslie was moving toward the west-northwest at 7 m.p.h. (11 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 989 mb.

Former Tropical Storm Leslie intensified to a hurricane over the eastern Atlantic Ocean on Friday night.  A circular eye formed at the center of Leslie’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 revolved around the core of Hurricane Leslie.  Storms near the core generated upper level divergence that pumped mass away from the hurricane.  The removal of mass caused the surface pressure to decrease.

The circulation around Hurricane Leslie was relatively small.  Winds to hurricane force extended out 15 miles (25 km) in the northeastern quadrant of Leslie’s circulation.  Winds to tropical storm force extended out 70 miles (110 km) from the center of Hurricane Leslie.

Hurricane Leslie will move through an environment mostly favorable for intensification during the next 24 hours.  Leslie will move over water where the Sea Surface Temperatures are near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Upper level divergence from Hurricane Kirk is currently just missing Hurricane Leslie.  If Leslie moves under the divergence from Hurricane Kirk, then the wind shear will increase.  Hurricane Leslie is likely to stay just outside the upper level divergence from Hurricane Kirk on Saturday, which will allow Leslie to intensify.

Hurricane Leslie will move around the southwestern side of a high pressure system over the eastern Atlantic Ocean.  The high pressure system will steer Leslie toward the northwest during the next 24 hours.  On its anticipated track, Hurricane Leslie will move farther away from the Cabo Verde Islands.

Elsewhere over the Atlantic Ocean, powerful Hurricane Kirk was in the middle of an eyewall replacement cycle.  At 11:00 p.m. EDT on Friday the center of Hurricane Kirk was located at latitude 25.0°N and longitude 49.8°W which put the center about 1610 miles (2585 km) southwest of the Azores.  Kirk was moving toward the north-northwest at 13 m.p.h. (20 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 943 mb.

Hurricane Kirk Strengthens to Cat. 4

Hurricane Kirk strengthened to Category 4 on the Saffir-Simpson Scale over the Tropical Atlantic Ocean on Thursday.  At 11:00 p.m. EDT on Thursday the center of Hurricane Kirk was located at latitude 21.5°N and longitude 47.5°W which put the center about 1670 miles (2685 km) southwest of the Azores.  Kirk was moving toward the northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 170 m.p.h. (275 km/h).  The minimum surface pressure was 935 mb.

Hurricane Kirk rapidly continued to intensify on Thursday.  Kirk reached Category 4 on the Saffir-Simpson Scale.  A circular eye with a diameter of 17 miles (28 km) was at the center of Kirk’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 revolved around the center of Hurricane Kirk.  Storms near the center of Kirk generated strong upper level divergence that pumped large quantities of mass away from the hurricane.  The removal of large amounts of mass caused the pressure to continue to decrease.

The core of Hurricane Kirk contracted as Kirk intensified on Thursday.  Winds to hurricane force extended out 35 miles (55 km) from the center of Kirk’s circulation.  Winds to tropical storm force extended out 185 miles (295 km) from the center of Hurricane Kirk.

The Hurricane Intensity Index (HII) was 29.9.  The Hurricane Size Index (HSI) was 13.0 and the Hurricane Wind Intensity Size Index (HWISI) was 42.9.

Hurricane Kirk will move through an environment favorable for intensification during the next 24 hours.  Kirk will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the middle of an upper level ridge over the central Atlantic Ocean.  The winds are weak near the middle of the upper level ridge and there will be little vertical wind shear.  Hurricane Kirk is likely to intensify during the next 24 hours unless the inner end of a rainband wraps around the existing eye and eyewall.  If concentric eyewalls form, then an eyewall replacement cycle would cause Kirk to weaken.  If an eyewall replacement cycle does not occur, then Hurricane Kirk could strengthen to a Category 5 hurricane.

Hurricane Kirk will move around the western part of a subtropical high pressure system over the Atlantic Ocean.  The high pressure system will steer Kirk toward the north-northwest during the next 24 hours.  On its anticipated track, Hurricane Kirk will remain far from any land area.

Elsewhere over the Atlantic Ocean, the upper level divergence from Hurricane Kirk was inhibiting the intensification of Tropical Storm Leslie.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Leslie was located at latitude 10.0°N and longitude 32.0°W which put the center about 610 miles (980 km) west-southwest of the Cabo Verde Islands.  Leslie was moving toward the west at 6 m.p.h. (10 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 1001 mb.

Typhoon Krathon Brings Wind and Rain to Taiwan

Typhoon Krathon brought strong winds and heavy rain to Taiwan on Wednesday night.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Krathon was located at latitude 22.6°N and longitude 120.1°E which put the center about 25 miles (40 km) southwest of Kaohsiung, Taiwan.  Krathon was moving toward the northeast at 3 m.p.h. (5 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 965 mb.

Typhoon Krathon was causing strong winds and dropping heavy rain over Taiwan on Wednesday night.  The center of Krathon was just off the coast of southwest Taiwan near Kaohsiung.  Typhoon Krathon was moving very slowly toward Taiwan.  The slow forward motion of Krathon’s circulation meant it was causing prolonged periods of strong winds and heavy rain.

Typhoon Krathon was weakening gradually as it slowly approached Taiwan, but Krathon was still a powerful typhoon.  Winds to typhoon force extended out 40 miles (65 km) from the center of Krathon’s circulation.  Winds to tropical storm force extended out 155 miles (250 km) from the center of Typhoon Krathon.

The Hurricane Intensity Index (HII) for Typhoon Krathon was 12.7.  The Hurricane Size Index (HSI) was 12.1 and the Hurricane Wind Intensity Size Index (HWISI) was 24.8.  Typhoon Krathon was similar in size and intensity to Hurricane Dolly when Dolly hit south Texas in 2008.

An upper level trough over China will steer Typhoon Krathon slowly to the northwest during the next 24 hours.  On its anticipated track, the center of Typhoon Krathon will move inland over southwestern Taiwan.  Krathon will continue to produce strong winds and heavy rain during the next 24 hours.  Very heavy rainfall will cause widespread flash floods.

Kirk Rapidly Intensifies to a Major Hurricane

Hurricane Kirk rapidly intensified to a major hurricane over the tropical Atlantic Ocean on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Kirk was located at latitude 19.5°N and longitude 44.5°W which put the center about 1140 miles (1835 km) east-northeast of the Lesser Antilles.  Kirk was moving toward the northwest at 10 m.p.h. (16 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 952 mb.

Hurricane Kirk rapidly intensified to a major hurricane on Wednesday.  A circular eye with a diameter of 35 miles (55 km) formed at the center of Kirk’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 revolved around the center of Hurricane Kirk.  Storms near the center of Kirk generated upper level divergence that pumped large quantities of mass away from the hurricane.  The removal of large amounts of mass caused the pressure to decrease rapidly.

The size of the circulation around Hurricane Kirk increased when Kirk intensified on Wednesday.  Winds to hurricane force extended out 35 miles (55 km) from the center of Kirk’s circulation.  Winds to tropical storm force extended out 220 miles (355 km) from the center of Hurricane Kirk.

The Hurricane Intensity Index (HII) was 23.6.  The Hurricane Size Index (HSI) was 13.4 and the Hurricane Wind Intensity Size Index (HWISI) was 37.0.

Hurricane Kirk will move through an environment favorable for intensification during the next 24 hours.  Kirk will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the middle of an upper level ridge over the central Atlantic Ocean.  The winds are weak near the middle of the upper level ridge and there will be little vertical wind shear.  Hurricane Kirk will intensify during the next 24 hours.  Kirk could strengthen to a Category 5 hurricane.

Hurricane Kirk will move around the southwestern part of a subtropical high pressure system over the Atlantic Ocean.  The high pressure system will steer Kirk toward the northwest during the next 24 hours.  On its anticipated track, Hurricane Kirk will remain far from any land area.

Elsewhere over the Atlantic Ocean, Tropical Storm Leslie formed southwest of the Cabo Verde Islands.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Leslie was located at latitude 10.4°N and longitude 30.1°W which put the center about 490 miles (790 km) southwest of the Cabo Verde Islands.  Leslie was moving toward the west at 6 m.p.h. (10 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 1005 mb.

Tropical Cyclone Ancha Forms Southeast of Diego Garcia

Tropical Cyclone Ancha formed over the South Indian Ocean southeast of Diego Garcia on Tuesday night.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Ancha was located at latitude 11.7°S and longitude 74.2°E which put the center about 335 miles (540 km) south-southeast of Diego Garcia.  Ancha was moving toward the south-southwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 994 mb.

A low pressure system over the South Indian Ocean southeast of Diego Garcia intensified on Tuesday night and Meteo France la Reunion designated the system as Tropical Cyclone Ancha.  The circulation around Tropical Cyclone Ancha exhibited more organization on Wednesday morning.  The inner end of a rainband wrapped around the southern side of the center of Ancha’s circulation.  Even though the circulation around Tropical Cyclone Ancha exhibited more organization, the distribution of thunderstorms was still asymmetrical.  Thunderstorms were occurring in bands in the eastern and southern parts of Ancha’s circulation.  Bands in the northern and western parts of the circulation consisted primarily of showers and lower clouds.  Storms near the center of Ancha generated upper level divergence that pumped mass away to the east of the tropical cyclone.

The circulation around Tropical Cyclone Ancha was small.  Winds to tropical storm force only extended out 50 miles (80 km) from the center of Ancha’s circulation.

Tropical Cyclone Ancha will move through an environment unfavorable for intensification during the next 24 hours.  Ancha will move over water where the Sea Surface Temperatures are near 24°C.  It will move under the northern part of an upper level trough over the South Indian Ocean.  The upper level trough will produce southwesterly winds that will blow toward the top of Ancha’s circulation.  Those winds will cause moderate vertical wind shear.  The combination of cooler water and moderate vertical wind shear will cause Tropical Cyclone Ancha to weaken during the next 24 hours.

Tropical Cyclone Ancha will move around the western end of high pressure system over the South Indian Ocean.  The high pressure system will steer Ancha toward the southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Ancha will pass well to the south of Diego Garcia.

Typhoon Krathon Stalls Southwest of Taiwan

Typhoon Krathon stalled just to the southwest of Taiwan on Tuesday evening.  At 11:00 p.m. EDT on Tuesday the center of Typhoon Krathon was located at latitude 21.7°N and longitude 119.4°E which put the center about 100 miles (160 km) southwest of Kaohsiung, Taiwan.  Krathon was moving toward the east at 2 m.p.h. (3 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (235 km/h).  The minimum surface pressure was 956 mb.

Typhoon Krathon stalled just southwest of Taiwan on Tuesday.  As Krathon’s circulation remained nearly stationary, strong winds mixed cooler water to the surface of the ocean.  The cooler water reduced the energy available to be transferred to the atmosphere and Typhoon Krathon gradually weakened.

Even though Typhoon Krathon weakened on Tuesday, Krathon was still the equivalent of a major hurricane.  A circular eye with a diameter of 25 miles (40 km) was at the center of Typhoon Krathon.  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 revolved around the core of Krathon’s circulation.  Storms near the core of Krathon generated upper level divergence that pumped mass away from the typhoon.

The circulation around Typhoon Krathon was very symmetrical.  Winds to typhoon force extended out 60 miles (95 km) from the center of Krathon’s circulation.  Winds to tropical storm force extended out 160 miles (260 km) from the center of Typhoon Krathon.

The Hurricane Intensity Index (HII) for Typhoon Krathon was 20.6.  The Hurricane Size Index (HSI) was 18.6 and the Hurricane Wind Intensity Size Index (HWISI) was 39.2.  Typhoon Krathon was similar in intensity to Hurricane Rita when Rita hit Louisiana in 2005.  Krathon was not quite as big as Rita was.

Typhoon Krathon will move through an environment mostly favorable for intensification during the next 24 hours.  Krathon will be over water where the Sea Surface Temperatures are near 27°C.  It will be under the axis of an upper level ridge over eastern China.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  However, as long as the core of Typhoon Krathon remains over the cooler water it is mixing to the surface of the ocean, Krathon will continue to gradually weaken.

Typhoon Krathon will be in an area where the steering currents are weak during the next few hours.  An upper level trough over southern China will start to steer Krathon toward the slowly northeast on Wednesday.  The center of Krathon could make landfall on the coast of Taiwan northwest Kaohsiung in 24 hours.

Bands in the northeastern part of Typhoon Krathon are already dropping heavy rain on parts Taiwan.  Krathon will bring strong winds and heavier rain to the southwestern part of Taiwan when it moves closer to the coast.  Heavy rain will cause flash floods.  Typhoon Krathon could also cause a storm surge of up to 10 feet (3 meters) on the coast of southwestern Taiwan.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Jebi sped rapidly northeast of Japan.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Jebi was located at latitude 43.1°N and longitude 150.5°E which put the center about 300 miles (485 km) east of Kushiro, Japan.  Jebi was moving toward the northeast at 41 m.p.h. (67 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 976 mb.

Tropical Depression Forms South of Mexico

Tropical Depression Eleven-E formed over the Eastern North Pacific Ocean south of Mexico on Tuesday afternoon.  A Tropical Storm Warning and a Tropical Storm Watch were issued for portions of the coast of Mexico.  At 5:00 p.m. EDT on Tuesday the center of Tropical Depression Eleven-E was located at latitude 15.1°N and longitude 94.6°W which put the center about 85 miles (135 km) south-southeast of Salina Cruz, Mexoco.  The tropical depression was moving toward the north at 5 m.p.h. (8 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 1006 mb.

A Tropical Storm Warning is in effect for the portion of the coast from Puerto Angel to Boca de Pijijiapan, Mexico.

A Tropical Storm Watch is in effect for the portion of the coast from Boca de Pijijiapan to the Mexico/Guatemala border.

A low pressure system over the Gulf of Tehuantepec strengthened on Tuesday afternoon and the U.S. National Hurricane Center designated the system as Tropical Depression Eleven-E.  A distinct low level center of circulation was evident on visible satellite images.  The strongest thunderstorms were occurring in bands in the western side of the tropical depression.  There were also thunderstorms in bands in the eastern periphery of the circulation around Tropical Depression Eleven-E.  Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical depression.

Tropical Depression Eleven-E will move through an environment somewhat favorable for intensification during the next 24 hours.  The tropical depression will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the southern side of an upper level ridge over Mexico.  The upper level ridge will produce easterly winds that will blow toward the top of the tropical depression.  Those winds will cause moderate vertical wind shear.  The wind shear will inhibit intensification, but the shear will not be enough to prevent some intensification.  Tropical Depression Eleven-E is likely to intensify to a tropical storm during the next 24 hours.

Tropical Depression Eleven-E will move around the eastern side of a trough of low pressure that extended from central Mexico to the Eastern North Pacific Ocean.  The trough of low pressure will steer the tropical depression slowly toward the north during the next 24 hours.  On its anticipated track, the center of Tropical Depression Eleven-E will make landfall on the coast of Mexico near Salina Cruz in about 24 hours.

Tropical Depression Eleven-E is likely to be a tropical storm when it makes landfall on the south coast of Mexico.  It will bring strong winds and locally heavy rain to Oaxaca and Chiapas.  Heavy rain is likely to cause floods in some locations.

Kirk Intensifies to a Hurricane

Former Tropical Storm Kirk intensified to a hurricane over the Atlantic Ocean west of the Cabo Verde Islands on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Hurricane Kirk was located at latitude 16.2°N and longitude 40.1°W which put the center about 1070 miles (1720 km) west of the Cabo Verde Islands.  Kirk was moving toward the northwest at 12 m.p.h. (19 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 986 mb.

Former Tropical Storm Kirk intensified to a hurricane on Tuesday.  The inner end of a rainband wrapped around the center of KIrk’s circulation and an eye appeared to be forming at the center of Hurricane Kirk.  Bands of showers and thunderstorms were revolving around the core of Hurricane Kirk.  Storm near the center of Kirk’s circulation generated upper level divergence that pumped mass away from the hurricane.

The size of the circulation around Hurricane Kirk increased on Tuesday.  Winds to hurricane force extended out 30 miles (50 km) in the northeastern quadrant of Kirk’s circulation.  Winds to tropical storm force extended out 200 miles (320 km) from the center of Hurricane Kirk.

Hurricane Kirk will move through an environment favorable for intensification during the next 24 hours.  Kirk will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the middle of an upper level ridge over the eastern Atlantic Ocean.  The winds are weak near the middle of the upper level ridge and there will be little vertical wind shear. Hurricane Kirk will intensify during the next 24 hours.  Kirk is likely to strengthen to a major hurricane later this week.

Hurricane Kirk will move around the southwestern part of a subtropical high pressure system over the Atlantic Ocean.  The high pressure system will steer Kirk toward the northwest during the next 24 hours.  On its anticipated track, Hurricane Kirk will move farther away from the Cabo Verde Islands.

Typhoon Krathon Intensifies to Equivalent of Cat. 4 Hurricane

Typhoon Krathon intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Monday as it passed just south of Taiwan.  At 5:00 p.m. EDT on Monday the center of Typhoon Krathon was located at latitude 20.7°N and longitude 119.9°E which put the center about 135 miles (220 km) south-southwest of Kaohsiung, Taiwan.  Krathon was moving toward the west at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h).  The minimum surface pressure was 927 mb.

Typhoon Krathon continued to intensify Monday.  It is now the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.  A circular eye with a diameter of 30 miles (50 km) is present at the center of Krathon’s circulation.  The eye is surrounded by a ring of thunderstorms and the strongest winds are occurring in that ring of storms.  Numerous bands of showers and thunderstorms are revolving around the core of Typhoon Krathon.  Storms near the core generated strong upper level divergence that pumped mass away from the typhoon.

The circulation around Typhoon Krathon is symmetrical.  Winds to typhoon force extend out 80 miles (130 km) from the center of Krathon’s circulation.  Winds to tropical storm force extend out 200 miles (320 km) from the center of Typhoon Krathon.

The Hurricane Intensity Index (HII) for Typhoon Krathon is 31.6.  The Hurricane Size Index (HSI) is 24.1 and the Hurricane Wind Intensity Size Index (HWISI) is 55.7.  Typhoon Krathon is similar in intensity to Hurricane Laura when Jeanne hit Louisiana in 2020.  Krathon is bigger than Laura was.

Typhoon Krathon will move through an environment favorable for intensification during the next 24 hours.  Krathon will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the axis of an upper level ridge south of Japan.  The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear.  Even though Typhoon Krathon will be in an environment favorable for intensification, Krathon may not intensify.  Images from the Taiwan Central Weather Agency’s radar indicate that concentric eyewalls may be forming at the center of Krathon’s circulation.  If concentric eyewalls do form, then an eyewall replacement cycle would cause Typhoon Krathon to weaken during the next 24 hours.

Typhoon Krathon will move around the southwestern part of a high pressure system south of Japan.  The high pressure system will steer Krathon slowly toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Krathon will move southwest of Taiwan.  An upper level trough over southern China will start to steer Krathon toward the northeast on Wednesday.  The center of Krathon could make landfall on Taiwan near Kaohsiung.

Typhoon Krathon will be a large, powerful storm when it hits Taiwan.  Krathon will bring strong winds and heavy rain to Taiwan.  Heavy rain will cause flash floods in some locations.  Typhoon Krathon could also cause a storm surge of up to 13 feet (4 meters) on the coast of southwestern Taiwan.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Jebi strengthened south of Japan.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Jebi was located at latitude 31.7°N and longitude 141.3°E which put the center about 320 miles (520 km) south-southeast of Tokyo, Japan.  Jebi was moving toward the north at 17 m.p.h. (28 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.

Tropical Storm Kirk Forms Over the Eastern Atlantic

Tropical Storm Kirk formed over the eastern Atlantic Ocean west of the Cabo Verde Islands on Monday morning.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Kirk was located at latitude 13.5°N and longitude 34.8°W which put the center about 740 miles (1195 km) west of the Cabo Verde Islands.  Kirk was moving toward the west 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 1001 mb.

A low pressure system over the eastern Atlantic Ocean west of the Cabo Verde Islands strengthened on Monday morning and the U.S. National Hurricane Center designated the system as Tropical Storm Kirk.  The circulation around Tropical Storm Kirk exhibited more organization on Monday.  The inner end of a rainband wrapped around the center of Kirk’s circulation.  Storms near the center of KIrk’s circulation generated upper level divergence that pumped mass away from the tropical storm.  Even though Tropical Storm Kirk exhibited more organization, the distribution of thunderstorms was asymmetrical.  Thunderstorms were occurring in bands in southern and eastern parts of Kirk’s circulation.  Bands in the northern parts of Tropical Storm Kirk consisted primarily of showers and lower clouds.

The distribution of winds speeds around Tropical Storm Kirk was fairly symmetrical.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Kirk’s circulation.

Tropical Storm Kirk will move through an environment favorable for intensification during the next 24 hours.  Kirk will move over water where the Sea Surface Temperatures are near 29°C. It will move under the middle of an upper level ridge over the eastern Atlantic Ocean.  The winds are weak near the middle of the upper level ridge and there will be little vertical wind shear.  Tropical Storm Kirk will intensify during the next 24 hours.  Kirk is likely to strengthen to a hurricane on Tuesday.

Tropical Storm Kirk will move around of a subtropical high pressure system over the Atlantic Ocean.  The high pressure system will steer Kirk toward the west during the next 24 hours.  On its anticipated track, Tropical Storm Kirk will move farther away from the Cabo Verde Islands.

Elsewhere over the Atlantic Ocean, Tropical Storm Isaac was making a transition to an extratropical cyclone north-northwest of the Azores and Tropical Depression Joyce was spinning east-northeast of the northern Leeward Islands.

At 11:00 a.m. EDT on Monday the center of Tropical Storm Isaac was located at latitude 44.8°N and longitude 29.1°W which put the center about 480 miles (775 km) north-northwest of the Azores.  Isaac was moving toward the east-northeast at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 983 mb.

At 11:00 a.m. EDT on Monday the center of Tropical Depression Joyce was located at latitude 22.4°N and longitude 49.3°W which put the center about 940 miles (1510 km) east-northeast of the Northern Leeward Islands.  Joyce was moving toward the north at 2 m.p.h. (3 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 1006 mb.