Rare Late Season Tropical Cyclone Forms over South Indian Ocean

A rare late season tropical cyclone formed over the South Indian Ocean on Thursday. At 5:00 p.m. EDT on Thursday the center of Tropical Cyclone 01S was located at latitude 10.7°S and longitude 95.0°E which put it about 170 miles (275 km) west-northwest of Cocos Island. Tropical Cyclone 01S was moving toward the southeast at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1002 mb.

The circulation around a low pressure system over the South Indian Ocean west-northwest of Cocos Island strengthened on Thursday and the Joint Typhoon Warning Center and the Australian Bureau of Meteorology both designated the system as a tropical cyclone. It is unusual for a tropical cyclone to form this late in the season in the southern hemisphere. It is the equivalent of a tropical cyclone forming in late January in the northern hemisphere.

The distribution of thunderstorms around Tropical Cyclone 01S was asymmetrical. The strongest thunderstorms were occurring in bands in the southern half of the tropical cyclone. Bands in the northern half of Tropical Cyclone 01S consisted primarily of showers and lower clouds. Tropical Cyclone 01S was under the southwestern part of an upper level ridge centered northwest of Australia. The upper level ridge was producing northerly winds that were blowing toward the top of the tropical cyclone’s circulation. Those winds were causing moderate vertical wind shear. The wind shear was causing the asymmetrical distribution of thunderstorms. Winds to tropical storm force extended out 170 miles (275 km) in the southeastern quadrant of Tropical Cyclone 01S. Winds in the other parts of the tropical cyclone were blowing at less than tropical storm force.

Tropical Cyclone 01S will move through an environment somewhat favorable for intensification during the next 24 hours. The tropical cyclone will move over water where the Sea Surface Temperatures are near 28˚C. However, the upper level ridge northwest of Australia will continue to cause moderate vertical wind shear. Tropical Cyclone 01S could strengthen a little more during the next 24 hours, but the moderate vertical wind shear will limit intensification.

Tropical Cyclone 01S will move north of a high pressure system over the South Indian Ocean during the next several days. The high pressure system will steer the tropical cyclone toward the west. On its anticipated track Tropical Cyclone 01S will begin to move farther away from Cocos Island.

Tropical Storm Songda Develops East of Okinawa

Tropical Storm Songda developed east of Okinawa on Thursday afternoon. At 5:00 p.m. EDT on Thursday the center of Tropical Storm Songda was located at latitude 26.4°N and longitude 136.6°E which put it about 600 miles (970 km) east of Okinawa. Songda was moving toward the north-northwest at 29 m.p.h. (45 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1002 mb.

An area of low pressure strengthened east of Okinawa on Thursday afternoon and the Japan Meteorological Agency designated the system as Tropical Storm Songda. Tropical Storm Songda was revolving around the northeastern part of a much larger low pressure system (sometimes called a monsoon gyre) centered northeast of the Philippines. The interaction of Songda’s circulation with the larger low pressure system was producing an asymmetrical distribution of thunderstorms. Thunderstorms were occurring in bands in the northeastern half of Tropical Storm Songda. Bands in the southwestern half of Songda consisted primarily of showers and lower clouds. Storms near the center of Songda generated upper level divergence that pumped mass away to the northeast of the tropical storm.

Tropical Storm Songda will move through an environment marginally favorable for intensification during the next 24 hours. Songda will move over water where the Sea Surface Temperatures are near 30˚C. The circulation around the larger low pressure system will produce upper level winds from the southeast that will blow toward the top of Songda’s circulation. The winds in the lower levels of the atmosphere will also be blowing from the southeast and so there will be less vertical wind shear. The wind shear could still be strong enough to inhibit intensification. Songda could also move into a region where the air is drier. Tropical Storm Songda could strengthen a little during the next 24 hours, but wind shear and drier air are likely to limit intensification.

The large low pressure system northeast of the Philippines will steer Tropical Storm Songda toward the northwest during the next 24 hours. On its anticipated track Tropical Storm Sondga could approach the northern Ryukyu Islands within 24 hours. Songda could bring gusty winds and locally heavy rain to the northern Ryukyu Islands.

Tropical Storm Georgette Forms Southwest of Baja California

Tropical Storm Georgette formed southwest over the Eastern North Pacific Ocean southwest of Baja California on Wednesday afternoon. At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Georgette was located at latitude 16.5°N and longitude 115.9°W which put it about 590 miles (950 km) southwest of the southern tip of Baja California. Georgette was moving toward the west at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1005 mb.

The circulation around a small low pressure system southwest of Baja California strengthened on Wednesday afternoon and the National Hurricane Center designated the system as Tropical Storm Georgette. The circulation around Tropical Storm Georgette was very small. Winds to tropical storm force extended out 25 miles (40 km) in the northeastern quadrant of Georgette’s circulation. The winds in the other parts of Georgette were blowing at less than tropical storm force. More thunderstorms developed near the center of Tropical Storm Georgette on Wednesday afternoon. Thunderstorms were also occurring in bands in the western side of Georgette. Bands in the eastern side of the circulation consisted primarily of showers and lower clouds. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical storm.

Tropical Storm Georgette will move through an environment somewhat favorable for intensification during the next 24 hours. Georgette will move over water where the Sea Surface Temperatures are near 28˚C. Georgette will move under the southern part of an upper level ridge over the Eastern North Pacific. The ridge will produce easterly winds that will blow toward the top of Georgette’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification. Tropical Storm Georgette could strengthen during the next 24 hours, if the vertical wind shear does not increase. The larger circulation around Tropical Storm Frank, which is located east-southeast of Georgette could begin to affect the intensity of Tropical Storm Georgette in a day or so.

Tropical Storm Georgette will move south of a high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Georgette toward the west during the next 24 hours. If Tropical Storm Frank moves closer to Georgette, then the larger circulation around Frank could start to pull Georgette toward the southwest. On its anticipated track Tropical Storm Georgette will move farther away from Baja California during the next 24 hours.

Elsewhere over the Eastern North Pacific Ocean, Tropical Storm Fanrk slowly strengthened on Wednesday. At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Frank was located at latitude 12.5°N and longitude 106.8°W which put it about 745 miles (1200 km) south-southeast of the southern tip of Baja California. Frank was moving toward the west at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 1002 mb.

Tropical Storm Frank Forms South of Mexico

Tropical Storm Frank formed over the Eastern North Pacific Ocean south of Mexico on Tuesday morning. At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Frank was located at latitude 11.6°N and longitude 102.4°W which put it about 525 miles (845 km) south-southeast of Manzanillo, Mexico. Frank was moving toward the west at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1004 mb.

The circulation around a low pressure system over the Eastern North Pacific Ocean south of Mexico strengthened on Tuesday morning and the National Hurricane Center designated the system as Tropical Storm Frank. The distribution of thunderstorms around Tropical Storm Frank was asymmetrical. Many of the thunderstorms were occurring in bands in the western half of Frank’s circulation. Bands in the eastern half of the tropical storm consisted primarily of showers and lower clouds. An upper level ridge over Mexico and the Eastern North Pacific was producing easterly winds that were blowing toward the top of Frank’s circulation. Those winds were causing moderate vertical wind shear and they were the main reason for the asymmetrical distribution of thunderstorms. Winds to tropical storm force extended out 35 miles (55 km) in the northern side of Tropical Storm Frank. The winds in the southern half of Frank were blowing at less than tropical storm force.

Tropical Storm Frank will move through an environment somewhat favorable for intensification during the next 36 hours. Frank will move over water where the Sea Surface Temperatures are near 29˚C. However, the upper level ridge will continue to produce easterly winds that will cause moderate vertical wind shear. The wind shear will inhibit intensification. Tropical Storm Frank could strengthen gradually during the next 36 hours, if the vertical wind shear does not increase.

Tropical Storm Frank will move south of a high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Frank toward the west during the next 36 hours. On its anticipated track Tropical Storm Frank will move farther away from the west coast of Mexico. Frank will pass south of Baja California later this week.

Estelle Weakens to a Tropical Storm

Former Hurricane Estelle weakened to a tropical storm over the Eastern North Pacific Ocean southwest of Baja California on Tuesday morning. At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Estelle was located at latitude 19.0°N and longitude 115.5°W which put it about 450 miles (725 km) southwest of the southern tip of Baja California. Estelle was moving toward the west-northwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 993 mb.

Drier air in the western half of former Hurricane Estelle reached the center of circulation on Tuesday morning and Estelle weakened to a tropical storm. The strongest winds in Tropical Storm Estelle were occurring in bands of thunderstorms in the eastern side of the circulation. Bands in the western half of the circulation consisted primarily of showers and lower clouds. More thunderstorms developed again east of the center of Estelle later on Tuesday morning. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 115 miles (185 km) from the center of Estelle’s circulation.

Tropical Storm Estelle will move through an environment only marginally favorable for intensification during the next 24 hours. Estelle will move over water where the Sea Surface Temperatures are near 25˚C. It will move under an upper level ridge over the Eastern North Pacific Ocean west of Mexico. The upper level winds are weak in the ridge and there will be little vertical wind shear. However, the drier air in the western half of Tropical Storm Estelle is likely to continue to inhibit the formation of thunderstorms in that part of the circulation. Estelle could intensify during the next 24 hours, if thunderstorms continue to develop near the center of circulation. However, the drier air is likely to limit any intensification. Tropical Storm Estelle will move over cooler water during the next several days, which is likely to cause it to weaken.

Tropical Storm Estelle will move around the southern side of a high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Estelle toward the west during the next 24 hours. On its anticipated track Tropical Storm Estelle will move farther to the southwest of Baja California.

Hurricane Estelle Passes South of Baja California

Hurricane Estelle passed south of the southern tip of Baja California on Monday afternoon. At 5:00 p.m. EDT on Monday the center of Hurricane Estelle was located at latitude 18.2°N and longitude 112.5°W which put it about 365 miles (590 km) south-southwest of the southern tip of Baja California. Estelle was moving toward the west-northwest at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 80 m.p.h. (130 km/h) and and there were wind gusts to 95 m.p.h. (150 km/h). The minimum surface pressure was 986 mb.

Hurricane Estelle appeared to pull drier air into the western side of its circulation on Monday. Bands in the western half of Estelle consisted primarily of showers and lower clouds. The strongest thunderstorms were occurring in bands in the eastern half of Hurricane Estelle. The strongest winds were also occurring in the eastern part of Estelle. Winds to hurricane force extended out 25 miles (40 km) in the eastern half of Estelle’s circulation. Winds to tropical storm force extended out 100 miles (160 km) from the center of circulation. Storms near the center were still generating upper level divergence that pumped mass away from the hurricane.

Hurricane Estelle will move through an environment somewhat favorable for intensification during the next 24 hours. Estelle will move over water where the Sea Surface Temperatures are near 28˚C. It will move under an upper level ridge over the Eastern North Pacific Ocean west of Mexico. The upper level winds are weak in the ridge and there will be little vertical wind shear. However, the drier air in the western half of Hurricane Estelle will continue to inhibit the formation of thunderstorms in that part of the circulation. Estelle could intensify during the next 24 hours, but the drier air is likely to limit any intensification. Hurricane Estelle will start to move over cooler water later on Tuesday.

Hurricane Estelle will move around the southern side of a high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Estelle toward the west-northwest during the next 24 hours. On its anticipated track Hurricane Estelle will remain well to the south of Baja California.

Estelle Rapidly Intensifies to a Hurricane

Former Tropical Storm Estelle rapidly intensified to a hurricane over the Eastern North Pacific Ocean south of Manzanillo, Mexico on Saturday. At 11:00 p.m. EDT on Saturday the center of Hurricane Estelle was located at latitude 14.7°N and longitude 105.0°W which put it about 300 miles (485 km) south of Manzanillo, Mexico. Estelle was moving toward the west-northwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 80 m.p.h. (130 km/h) and and there were wind gusts to 95 m.p.h. (150 km/h). The minimum surface pressure was 988 mb.

Former Tropical Storm Estelle rapidly intensified to a hurricane on Saturday. A circular eye was developing at the center of Hurricane Estelle’s circulation. The developing 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 Estelle. Storms near the core generated upper level divergence that pumped mass away from the hurricane in all directions. Winds to hurricane force extended out 15 miles (25 km) from the center of Estelle. Winds to tropical storm force extended out 70 miles (110 km) from the center of circulation.

Hurricane Estelle will move through an environment favorable for intensification during the next 36 hours. Estelle will move over water where the Sea Surface Temperatures are near 29˚C. It will move under an upper level ridge near the west coast of Mexico. The upper level winds are weak in the ridge and there will be little vertical wind shear. Hurricane Estelle will intensify during the next 36 hours. Estelle could continue to intensify rapidly and it could strengthen to a major hurricane.

Hurricane Estelle will move around the southern side of a high pressure system over Mexico. The high pressure system will steer Estelle toward the west-northwest during the next 36 hours. On its anticipated track Hurricane Estelle could be south of Baja California on Monday.

Elsewhere, Tropical Storm Darby weakened south of Hawaii. At 11:00 p.m. EDT on Saturday the center of Tropical Storm Darby was located at latitude 17.7°N and longitude 157.5°W which put it about 250 miles (400 km) south of Honolulu, Hawaii. Darby was moving toward the west at 22 m.p.h. (32 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1007 mb.

Tropical Storm Estelle Forms South of Mexico

Tropical Storm Estelle formed over the Eastern North Pacific Ocean south of Mexico on Friday night. At 11:00 p.m. EDT on Friday the center of Tropical Storm Estelle was located at latitude 13.2°N and longitude 102.0°W which put it about 290 miles (470 km) south-southwest of Acapulco, Mexico. Estelle was moving toward the northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1006 mb.

An area of low pressure over the Eastern North Pacific Ocean south of Mexico strengthened on Friday night and the National Hurricane Center designated the system as Tropical Storm Estelle. The circulation around Estelle exhibited more organization. More thunderstorms developed near the center of Tropical Storm Estelle. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical storm. Bands of showers and thunderstorms were revolving around the center of Estelle’s circulation. Winds to tropical storm force extended out 45 miles (75 km) in the northeastern quadrant of Tropical Storm Estelle. The wind in the other parts of Estelle’s circulation were blowing at less than tropical storm force.

Tropical Storm Estelle will move through an environment favorable for intensification during the next 36 hours. Estelle will move over water where the Sea Surface Temperatures are near 28˚C. It will move under an upper level ridge near the west coast of Mexico. The upper level winds are weak in the ridge and there will be little vertical wind shear. Tropical Storm Estelle will intensify during the next 36 hours and it could strengthen to a hurricane.

Tropical Storm Estelle will move around the southern side of a high pressure system over Mexico. The high pressure system will steer Estelle toward the west-northwest during the next 36 hours. On its anticipated track Tropical Storm Estelle will move away from the west coast of Mexico.

Elsewhere, Tropical Storm Darby weakened east-southeast of Hawaii. At 11:00 p.m. EDT on Friday the center of Tropical Storm Darby was located at latitude 17.7°N and longitude 149.4°W which put it about 400 miles (640 km) east-southeast of Hilo, Hawaii. Darby was moving toward the west at 20 m.p.h. (32 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 1006 mb.

Hurricane Darby Moves over the Central Pacific

Hurricane Darby moved over the Central Pacific Ocean on Thursday morning. At 11:00 a.m. EDT on Thursday the center of Hurricane Darby was located at latitude 16.6°N and longitude 140.9°W which put it about 955 miles (1540 km) east of Hilo, Hawaii. Darby was moving toward the west-northwest at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 105 m.p.h. (165 km/h) and and there were wind gusts to 125 m.p.h. (200 km/h). The minimum surface pressure was 977 mb.

Hurricane Darby moved west of longitude 140°W west on Thursday morning which meant that it crossed from the Eastern North Pacific basin to the Central Pacific. A small eye persisted at the center of Darby’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Storms near the center of circulation generated upper level divergence that pumped mass away from the hurricane. The circulation around Hurricane Darby was small. Winds to hurricane force extended out 20 miles (30 km) from the center of Darby. Winds to tropical storm force extended out 45 miles (75 km) from the center of circulation.

Hurricane Darby will move into an environment unfavorable for intensification during the next 36 hours. Darby will move over water where the Sea Surface Temperatures are near 26˚C. An upper level trough located to the northwest of Hurricane Darby will produce southwesterly winds that will blow toward the top of Darby’s circulation. Those winds will cause the vertical wind shear to increase. More wind shear will cause Hurricane Darby to weaken. Since the circulation around Hurricane Darby is so small, the vertical wind shear could cause Darby to weaken quickly.

Hurricane Darby will move around the southern side of a high pressure system over the Central Pacific Ocean. The high pressure system will steer Darby toward the west during the next 36 hours. On its anticipated track Hurricane Darby could be southeast of Hawaii by Saturday. Darby is forecast to be much weaker by that time.

Major Hurricane Darby Churns Toward the Central Pacific

Major Hurricane Darby churned toward the Central Pacific Ocean on Tuesday. At 11:00 a.m. EDT on Tuesday the center of Hurricane Darby was located at latitude 14.7°N and longitude 129.7°W which put it about 1410 miles (2270 km) west-southwest of the southern tip of Baja California. Darby was moving toward the west at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and and there were wind gusts to 150 m.p.h. (240 km/h). The minimum surface pressure was 959 mb.

Hurricane Darby had a small, but very symmetrical, circulation on Tuesday. A circular eye with a diameter of 12 miles (19 km) was at the center of Hurricane Darby. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Several bands of showers and thunderstorms were revolving around the small core of Hurricane Darby. Storms near the core generated strong upper level divergence that pumped mass away from the hurricane. Winds to hurricane force extended out 15 miles (25 km) from the center of Darby’s circulation. Winds to tropical storm force extended out 50 miles (80 km) from the center of circulation.

Darby continued to exhibit the appearance of a small, annular hurricane. The Hurricane Intensity Index (HII) for Hurricane Darby was 23.6. The Hurricane Size Index (HSI) was 5.2 and the Hurricane Wind Intensity Size Index (HWISI) was 28.8.

Hurricane Darby will move into an environment unfavorable for intensification during the next 36 hours. Darby will move over water where the Sea Surface Temperatures are near 27˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Hurricane Darby will move over cooler water during the next several days as it moves toward the west. Darby is likely to weaken gradually as it moves over the cooler water.

Hurricane Darby will move around the southern side of a high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Darby toward the west during the next 36 hours. On its anticipated track Hurricane Darby will cross into the Central Pacific Ocean on Wednesday night.