Category Archives: Tropical Cyclones

Information about tropical cyclones

Tropical Storm Dexter Passes North of Bermuda

Tropical Storm Dexter passed north of Bermuda on Monday evening.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Dexter was located at latitude 36.8°N and longitude 65.6°W which put the center about 315 miles (415 km) north of Bermuda.  Dexter was moving toward the northeast at 13 m.p.h. (21 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 1002 mb.

An upper level trough near the east coast of the U.S. was producing strong westerly winds that were blowing toward the top of Tropical Storm Dexter.  Those winds were causing strong vertical wind shear.  The wind shear was affecting the structure of Dexter’s circulation.  Thunderstorms were occurring in bands in the eastern side of Tropical Storm Dexter.  Bands in the western side of Dexter’s circulation consisted primarily of showers and lower clouds.

The strong vertical wind shear and the asymmetrical distribution of thunderstorms were also affecting the distribution of wind speeds in Tropical Storm Dexter.  Winds to tropical storm force extended out 90 miles (145 km) in the eastern side of Dexter’s circulation.  The winds in the western side of Tropical Storm Dexter were blowing at less than tropical storm force.

Tropical Storm Dexter will move through an environment unfavorable for intensification of a tropical cyclone during the next 24 hours.  Dexter will move over water where the Sea Surface Temperatures are near 27°C.  The upper level trough near the east coast of the U.S. will continue to cause strong vertical wind shear.  The strong wind shear will prevent Tropical Storm Dexter from intensifying.  Dexter could get stronger when it starts to make a transition to an extratropical cyclone.

The upper level trough near the east coast of the U.S. will steer Tropical Storm Dexter toward the east-northeast during the next 24 hours.  On its anticipated track, Tropical Storm Dexter will move farther away from Bermuda.

Tropical Storm Henriette Forms Southwest of Baja California

Tropical Storm Henriette formed over the Eastern North Pacific Ocean southwest of Baja California on Monday afternoon.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Henriette was located at latitude 14.8°N and longitude 120.6°W which put the center about 895 miles (1440 km) southwest of the southern tip of Baja California.  Henriette was moving toward the west-northwest at 15 m.p.h. (24 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 1004 mb.

A low pressure system over the Eastern North Pacific Ocean southwest of Baja California strengthened on Monday afternoon and the U.S. National Hurricane Center designated the system as Tropical Storm Henriette.

The distribution of thunderstorms in Tropical Storm Henriette was asymmetrical.  Thunderstorms were occurring in bands in the western side of Henriette’s circulation.  Bands in the eastern side of Tropical Storm Henriette consisted primarily of showers and lower clouds.  Storms near the center of Henriette generated upper level divergence that pumped mass away to the west of the tropical storm.  The removal of mass caused the surface pressure to decrease.

The circulation around Tropical Storm Henriette was small.  Winds to tropical storm force extended out 45 miles (75 km) from the center of Henriette’s circulation.

Tropical Storm Henriette will move through an environment somewhat favorable for intensification during the next 24 hours.  Henriette will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the southern side of an upper level ridge over the Eastern North Pacific Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Henriette’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 Henriette will intensify during the next 24 hours.

Tropical Storm Henriette will move around the southern side of a high pressure system over the Eastern North Pacific Ocean.  The high pressure system will steer Henriette toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Henriette will move farther away from Baja California.

 

Tropical Storm Dexter Forms East of North Carolina

Tropical Storm Dexter formed over the Atlantic Ocean east of North Carolina on Sunday evening.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Dexter was located at latitude 34.3°N and longitude 69.4°W which put the center about 300 miles (480km) west-northwest of Bermuda.  Dexter was moving toward the east-northeast at 12 m.p.h. (19 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 1002 mb.

A low pressure system over the Atlantic Ocean east of North Carolina strengthened on Sunday evening and the U.S. National Hurricane Center designated the system as Tropical Storm Dexter.

The appearance of the low pressure system that became Tropical Storm Dexter began to look much more like a tropical storm on Sunday evening.  More thunderstorms formed near the center of Dexter’s circulation.  There was also a well developed band of thunderstorms in the eastern side of Tropical Storm Dexter.  Bands in the western side of Dexter’s circulation still consisted primarily of showers and lower clouds.  Storms near the center of Dexter began to generate upper level divergence that pumped mass away to the east of the tropical storm.  The removal of mass caused the surface pressure to decrease.

Most of the stronger winds were occurring in the eastern side of Tropical Storm Dexter.  Winds to tropical storm force extended out 140 miles (225 km) in the eastern side of Dexter’s circulation.  Winds to tropical storm force extended out 35 miles (55 km) in the western side of Tropical Storm Dexter.

Tropical Storm Dexter will move through an environment somewhat favorable for intensification during the next 24 hours.  Dexter will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the eastern side of an upper level trough over the eastern U.S.  The upper level trough will produce southwesterly winds that will blow toward the top of Dexter’s circulation.  Those winds will cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification.  Tropical Storm Dexter is likely to intensify on Monday.

Tropical Storm Dexter will move around the northwestern part of a subtropical high pressure over the Atlantic Ocean.  The high pressure system will steer Dexter toward the east-northeast during the next 24 hours.  On its anticipated track, Tropical Storm Dexter will pass north of Bermuda during Monday night.

Gil Weakens Back to a Tropical Storm

Former Hurricane Gil weakened back to a tropical storm on Saturday over the Eastern North Pacific Ocean east of Hawaii.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Gil was located at latitude 19.5°N and longitude 132.0°W which put the center about 1500 miles (2415 km) east of Hilo, Hawaii.  Gil was moving toward the west-northwest at 21 m.p.h. (33 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.

Former Hurricane Gil weakened back to a tropical storm on Saturday when it moved over cooler water.  Many of the thunderstorms in the western side of Gil’s circulation weakened when it moved over cooler water.  Thunderstorms were still occurring in bands in the eastern side of Tropical Storm Gil.  The thunderstorms in the eastern side of Gil’s circulation still generated upper level divergence that pumped mass away from the tropical storm.  The removal of mass meant that Tropical Storm Gil weakened slowly.

The distribution of wind speeds in Tropical Storm Gil was relatively symmetrical.  Winds to tropical storm force extended out 140 miles (225 km) from the center of Gil’s circulation.

Tropical Storm Gil will move through an environment mostly unfavorable for intensification during the next 24 hours.  Gil will move over water where the Sea Surface Temperatures are near 24°C.  It will move through a region where there will be little vertical wind shear.  Even though Tropical Storm Gil will move through a region where there will be little vertical wind shear, Gil is likely to continue to weaken because of the cooler water.

Tropical Storm Gil will move around the southern side of a high pressure system over the Eastern North Pacific Ocean.  The high pressure system will steer Gil toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Gil will move toward Hawaii as it weakens.

Tropical Storm Bailu Forms South of Japan

Tropical Storm Bailu formed over the Western North Pacific Ocean south of Japan on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Bailu was located at latitude 33.9°N and longitude 142.6°E which put the center about 185 miles (295 km) south of Tokyo, Japan.  Bailu was moving toward the north-northeast at 29 m.p.h. (46 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 998 mb.

A low pressure system over the Western North Pacific Ocean strengthened on Saturday and the Japan Meteorological Agency designated the system as Tropical Storm Bailu.

The distribution of thunderstorms in Tropical Storm Bailu was asymmetrical.  Thunderstorms were occurring in bands in the northern part of Bailu’s circulation.  Thunderstorms were also occurring in bands in the southwestern part of Tropical Storm Bailu.  Bands in the other parts of Bailu’s circulation consisted primarily of showers and lower clouds.

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

Tropical Storm Bailu will move through an environment marginally favorable for intensification during the next 24 hours.  Bailu will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the eastern side of an upper level trough that is north of Japan.  The upper level trough will produce southwesterly winds that will blow toward the top of Bailu’s circulation.  Those winds will cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification.  Tropical Storm Bailu could intensify during the next 24 hours, if the vertical wind shear does not increase.

The upper level trough north of Japan will steer Tropical Storm Bailu quickly toward the east-northeast during the next 24 hours.  On its anticipated track, Tropical Storm Bailu will move quickly away from Honshu on Sunday.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Krosa was moving rapidly away from Japan.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Krosa was located at latitude 40.2°N and longitude 152.2°E which put the center about 505 miles (820 km) east of Misawa, Japan.  Krosa was moving toward the east-northeast at 28 m.p.h. (45 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 977 mb.

Gil Strengthens to a Hurricane

Former Tropical Storm Gil strengthened to a hurricane over the Eastern North Pacific Ocean southwest of Baja California on Friday.  At 11:00 p.m. EDT on Friday the center of Hurricane Gil was located at latitude 16.5°N and longitude 125.1°W which put the center about 1080 miles (1740 km) west-southwest of the southern tip of Baja California.  Gil was moving toward the west-northwest at 20 m.p.h. (32 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 991 mb.

Former Tropical Storm Gil strengthened to a hurricane on Friday.  The inner end of a rainband wrapped around the western and southern sides of the center of Gil’s circulation.  Bands of showers and thunderstorms were revolving around the center of Hurricane Gil.  Storms near the center of Gil generated upper level divergence that pumped mass away from the hurricane.  The removal of mass caused the surface pressure to decrease.

The strongest winds were occurring in the northeastern part of Hurricane Gil.  Winds to hurricane force extended out 25 miles (40 km) in the northeastern quadrant of Gil’s circulation.  Winds to tropical storm force extended out 125 miles (200 km) from the center of Hurricane Gil.

Hurricane Gil will move through an environment somewhat favorable for intensification during the next 24 hours.  Gil will move over water where the Sea Surface Temperatures are near 27°C.  It will move through a region where there will be little vertical wind shear.  However, Gil will move into a region where there is very dry air.  The dry air will inhibit intensification.  Hurricane Gil could intensify during the next 24 hours if the dry air does not penetrate to the core of Gil’s circulation.

Hurricane Gil will move around the southern side of a high pressure system over the Eastern North Pacific Ocean.  The high pressure system will steer Gil toward the west-northwest during the next 24 hours.  On its anticipated track, Hurricane Gil will continue to move farther away from Baja California.

Elsewhere, former Tropical Storm Iona weakened to a tropical depression as it approached the International Date Line.  At 11:00 p.m. EDT on Friday the center of Tropical Depression Iona was located at latitude 15.8°N and longitude 179.5°W which put the center about 1465 miles (2355 km) west of Honolulu, Hawaii.  Iona was moving toward the west-northwest at 17 m.p.h. (28 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.

Tropical Storm Krosa Passes East of Japan

Tropical Storm Krosa passed east of Japan on Friday.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Krosa was located at latitude 36.8°N and longitude 143.4°E which put the center about 130 miles (210 km) east-northeast of Tokyo, Japan.  Krosa was moving toward the north-northeast 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 972 mb.

Tropical Storm Krosa passed east of Japan on Friday.  Even though Krosa was a tropical storm, there was a clear area at the center of its circulation.  The clear area was surrounded by a broken ring of thunderstorms.  The strongest winds were occurring in that broken ring of storms.  Thunderstorms were occurring in bands in the eastern side of Tropical Storm Krosa. Bands in the western side of Krosa’s circulation consisted primarily of showers and lower clouds.

The distribution of wind speeds in Tropical Storm Krosa was more symmetrical on Friday.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Krosa’s circulation.

Tropical Storm Krosa will move through an environment unfavorable for the intensification of a tropical cyclone during the next 24 hours.  Krosa will move over water where the Sea Surface Temperatures are near 26°C.  It will move under the eastern side of an upper level trough that is north of Japan.  The upper level trough will produce southwesterly winds that will cause moderate vertical wind shear.  Cooler Sea Surface Temperatures and moderate vertical wind shear will cause Tropical Storm Krosa to start a transition to an extratropical cyclone during the next 24 hours.

The upper level trough north of Japan will steer Tropical Storm Krosa toward the east-northeast during the next 24 hours.  On its anticipated track, Tropical Storm Krosa will move away from Japan.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 13W formed south of Japan.  At 11:00 p.m. EDT on Friday the center of Tropical Depression 13W was located at latitude 28.1°N and longitude 137.5°E which put the center about 325 miles (520 km) west-northwest of Iwo To.  Tropical Depression 13W was moving toward the northeast at 7 m.p.h. (11 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 998 mb.

Tropical Storm Krosa Spins Southeast of Japan

Tropical Storm Krosa was still spinning over the Western North Pacific Ocean southeast of Japan on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Krosa was located at latitude 32.0°N and longitude 141.9°E which put the center about 290 miles (465 km) south-southeast of Tokyo, Japan.  Krosa was moving toward the north-northwest at 9 m.p.h. (15 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 980 mb.

The structure of Tropical Storm Krosa started to change on Thursday as it continued to spin over the Western North Pacific Ocean southeast of Japan.  The inner end of a rainband wrapped around the eastern and northern sides of the center of Krosa’s circulation.  A large circular eye appeared to be forming at the center of Krosa, even through Krosa was just a tropical storm.  Bands of showers and thunderstorms were revolving around the center of Tropical Storm Krosa.

The circulation around Tropical Storm Krosa was relatively small for a tropical storm southeast of Japan.  Winds to tropical storm force extended out 110 miles (175 km) from the center of Krosa’s circulation.

Tropical Storm Krosa will move through an environment somewhat favorable for intensification during the next 24 hours.  Krosa will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the middle of an upper level low that is southeast of Japan.  The upper level winds are weak near the center of the upper level low and there will be little vertical wind shear.  However, the upper level low will inhibit upper level divergence.  In addition, Krosa’s circulation is surrounded by drier air.  Tropical Storm Krosa could intensify during the next 24 hours in spite of the effects of the upper level low and the drier air.

Tropical Storm Krosa will move around the western end of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Krosa toward the north during the next 24 hours.  On its anticipated track, the center of Tropical Storm Krosa could pass to the east of Tokyo on Friday.

Tropical Storm Gil Forms South of Baja California

Tropical Storm Gil formed over the Eastern North Pacific Ocean south of Baja California on Wednesday night.  At 5:00 a.m. EDT on Thursday the center of Tropical Storm Gil was located at latitude 12.7°N and longitude 115.1°W which put the center about 785 miles (1260 km) south-southwest of the southern tip of Baja California.  Gil was moving toward the west at 15 m.p.h. (24 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 1004 mb.

A low pressure system over the Eastern North Pacific Ocean south of Baja California strengthened on Wednesday night and the U.S. National Hurricane Center designated the system as Tropical Storm Gil.

The circulation around Tropical Storm Gil was organizing quickly on Thursday morning.  Numerous thunderstorms formed near the center of Gil’s circulation.  Thunderstorms also developed in bands revolving around the center of Tropical Storm Gil.  Storms near the center of Gil generated upper level divergence that pumped mass away from the tropical storm.  The removal of mass caused the surface pressure to decrease.

The distribution of wind speed in Tropical Storm Gil was asymmetrical.  Winds to tropical storm force extended out 160 miles (260 km) in the eastern side of Gil’s circulation.  Winds to tropical storm force extended out 60 miles (95 km) in the western side of Tropical Storm Gil.

Tropical Storm Gil will move through an environment very favorable for intensification during the next 24 hours.  Gil will move over water where the Sea Surface Temperatures are near 28°C.   It will move under the southern side of an upper level ridge over the Eastern North Pacific Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Gil’s circulation.  However, the winds in the lower atmosphere will also blow from the east.  So, there will be little vertical wind shear.  Tropical Storm Gil will intensify during the next 24 hours.  Gil could intensify rapidly,  Tropical Storm Gil could strengthen to a hurricane by Friday.

Tropical Storm Gil will move around the southern side of a high pressure system over the Eastern North Pacific Ocean.  The high pressure system will steer Gil toward the west-northwest during the next 24 hours.  On its anticipated track, Tropical Storm Gil will move away from Baja California.

Elsewhere, Tropical Storm Iona moved quickly away from Hawaii.  At 5:00 a.m. EDT on Thursday the center of Tropical Storm Iona was located at latitude 12.3°N and longitude 166.9°W which put the center about 860 miles (1385 km) southwest of Honolulu, Hawaii.  Iona was moving toward the west at 23 m.p.h. (37 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.

Iona Rapidly Weakens to a Tropical Storm

Former Hurricane Iona rapidly weakened to a tropical storm over the Central Pacific Ocean southwest of Hawaii on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Iona was located at latitude 11.7°N and longitude 162.6°W which put the center about 730 miles (1180 km) south-southwest of Honolulu, Hawaii.  Iona was moving toward the west at 22 m.p.h. (35 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 994 mb.

Former Hurricane Iona rapidly weakened to a tropical storm southwest of Hawaii on Wednesday.  Iona moved into a region of drier air.  The drier air caused many of the thunderstorms in Iona’s circulation to dissipate.  A few thunderstorms were still occurring in bands in the southern and eastern periphery of Tropical Storm Iona.  An upper level trough southwest of Hawaii was producing southwesterly winds that were blowing toward the top of Iona’s circulation.  Those winds were causing moderate vertical wind shear.  The vertical wind shear was also contributing to the weakening of Tropical Storm Iona.

The circulation around Tropical Storm Iona was small.  Winds to tropical storm force extended out 80 miles (130 km) from the center of Iona’s circulation.

Tropical Storm Iona will move through an environment that will be mostly unfavorable for intensification during the next 24 hours.  Iona will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the southeastern part of the upper level trough southwest of Hawaii.  The upper level trough will continue to produce southwesterly winds that will blow toward the top of Iona’s circulation.  Those winds will continue to cause moderate vertical wind shear.  In addition, Iona will also continue to move through the region of drier air that is located southwest of Hawaii.  The combination of moderate vertical wind shear and drier air will cause Tropical Storm Iona to start to continue to weaken during the next 24 hours.

Tropical Storm Iona will move around the southern side of a high pressure system over the Central Pacific Ocean.  The high pressure system will steer Iona toward the west during the next 24 hours.  On its anticipated track, Hurricane Iona will move farther away from of Hawaii on Thursday.

Elsewhere over the Central Pacific Ocean, the upper level trough southwest of Hawaii caused former Tropical Storm Keli to weaken to a tropical depression.  At 5:00 p.m. EDT on Wednesday the center of Tropical Depression Keli was located at latitude 13.9°N and longitude 156.6°W which put the center about 520 miles (835 km) south of Honolulu, Hawaii.  Keli was moving toward the west at 17 m.p.h. (28 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.