Tag Archives: SH27

Tropical Cyclone Courtney Equivalent of Cat. 4 Hurricane

Tropical Cyclone Courtney was the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale over the South Indian Ocean on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Courtney was located at latitude 19.9°S and longitude 89.1°E which put the center about 715 miles (1150 km) southwest of the Cocos Islands.  Courtney was moving toward the southwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 939 mb.

Tropical Cyclone Courtney strengthened on Saturday.  Courtney was the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.  A small circular eye was present at the center of Courtney’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 Courtney’s circulation.  Storms near the center generated upper level divergence that pumped mass away from the tropical cyclone.  The removal of mass caused the surface pressure to decrease.

The circulation around Tropical Cyclone Courtney was small.  Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Courtney’s circulation.  Winds to tropical storm force extended out 105 miles (165 km) from the center of Tropical Cyclone Courtney.

The Hurricane Intensity Index (HII) for Tropical Cyclone Courtney was 29.9.  The Hurricane Size Index (HSI) was 10.7 and the Hurricane Wind Intensity Size Index (HWISI) was 40.6.

Tropical Cyclone Courtney will move through an environment that will become unfavorable for intensification during the next 24 hours.  Courtney will move over water where where the Sea Surface Temperatures are near 26°C.  It will move under the eastern side of an upper level trough over the South Indian Ocean.  The upper level trough will produce northwesterly winds that will blow toward the top of Courtney’s circulation.  Those winds will cause the vertical wind shear to increase.  Tropical Cyclone Courtney will weaken when the vertical wind shear increases.

Tropical Cyclone Courtney will move around the western end of a high pressure system over the South Indian Ocean.  The high pressure system will steer Courtney toward the south during the next 24 hours.  On its anticipated track, Tropical Cyclone Courtney will move farther away from the Cocos Islands.

Tropical Cyclone Dianne Brings Wind and Rain to Western Australia

Tropical Cyclone Dianne brought wind and rain to Western Australia on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Dianne was located at latitude 16.6°S and longitude 123.8°E which put the center about 75 miles (120 km) north-northeast of the Derby, Australia.  Dianne was moving toward the south at 8 m.p.h. (13 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 991 mb.

A Warning is in effect for the portion of the coast between Kuri Bay and Derby.

The center of Tropical Cyclone Dianne made landfall on the coast of Western Australia north-northeast of Derby.  Dianne was the equivalent of a tropical storm at the time of landfall.  The circulation around Tropical Cyclone Dianne was small.  Winds to tropical storm force only extended out 65 miles (105 km) from the center of Dianne’s circulation.

Tropical Cyclone Dianne will move around the western end of a high pressure system over northern Australia.  The high pressure system will steer Dianne toward the south during the next 24 hours.  On its anticipated track, Tropical Cyclone Dianne will move inland over Western Australia during the next 24 hours.

Tropical Cyclone Dianne will bring strong winds and locally heavy rain to parts of Western Australia.  Heavy rain could cause flash floods in some locations.

Flood Watches are in effect for the Tanami Desert, the Western Desert and the Sandy Desert.

Elsewhere over the South Indian Ocean, Tropical Cyclone Courtney intensified to the equivalent of a major hurricane southwest of the Cocos Islands.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Courtney was located at latitude 17.6°S and longitude 92.5°E which put the center about 445 miles (715 km) southwest of the Cocos Islands.  Courtney was moving toward the west-southwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 948 mb.

Tropical Cyclone Dianne Nears Western Australia

Tropical Cyclone Dianne neared the coast of Western Australia on Friday morning.  At 5:00 a.m. EDT on Friday the center of Tropical Cyclone Dianne was located at latitude 15.3°S and longitude 123.6°E which put the center about 140 miles (225 km) north of the Derby, Australia.  Dianne was moving toward the south-southeast at 10 m.p.h. (16 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 991 mb.

A Warning is in effect for the area between Kuri Bay and Derby.

A Tropical Low strengthened to Tropical Cyclone Dianne near the coast of Western Australia during Thursday night.  More thunderstorms formed near the center of Tropical Cyclone Dianne.  More thunderstorms also formed in bands revolving around the center of Dianne’s circulation.  Storms near the center of Dianne generated more upper level divergence that pumped mass away from the tropical cyclone.  The removal of more mass caused the surface pressure to decrease.

The circulation around Tropical Cyclone Dianne was small.  Winds to tropical storm force extended out 90 miles (145 km) from the center of Dianne’s circulation.

Tropical Cyclone Dianne will move through an environment somewhat favorable for intensification during the next few hours.  Dianne will move over water where where the Sea Surface Temperatures are near 29°C.  It will move under the northern part of an upper level ridge that extends from over Australia to the South Indian Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of the Tropical Low.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification.  Dianne could intensify during the next few hours.

Tropical Cyclone Dianne will move around the western end of a high pressure system over northern Australia.  The high pressure system will steer Dianne toward the southeast during the next 24 hours.  On its anticipated track, Tropical Cyclone Dianne will make landfall on the coast of Western Australia northeast of Derby in a few hours.

Tropical Cyclone Dianne will bring strong winds and locally heavy rain to parts of Western Australia.  Heavy rain could cause flash floods in some locations.

Flood Watches are in effect for the Tanami Desert, the Western Desert and the Sandy Desert.

Elsewhere over the South Indian Ocean, Tropical Cyclone Courtney passed south of the Cocos Islands.  At 5:00 a.m. EDT on Friday the center of Tropical Cyclone Courtney was located at latitude 16.9°S and longitude 94.9°E which put the center about 330 miles (530 km) south-southwest of the Cocos Islands.  Courtney was moving toward the west at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 972 mb.

Tropical Low Prompts Watch for Western Australia

A risk posed by a Tropical Low prompted the Australian Bureau of Meteorology to issue a Watch for a portion of the coast of Western Australia on Thursday.  At 5:00 a.m. EDT on Thursday the center of the Tropical Low was located at latitude 13.8°S and longitude 121.8°E which put the center about 215 miles (350 km) west-northwest of the Kuri Bay, Australia.  The Tropical Low was moving toward the east-northeast at 5 m.p.h. (7 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 997 mb.

A Watch is in effect for the portion of the coast of Western Australia from Mitchell Plateau to Beagle Bay.  The Watch includes Derby and Beagle Bay.

A low pressure system over the South Indian Ocean west of Australia exhibited more organization on Thursday morning and the Australian Bureau of Meteorology classified the system as a Tropical Low.  The U.S. Joint Typhoon Warning Center designated the low pressure system as Invest 93S.

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

The Tropical Low will move through an environment somewhat favorable for intensification during the next 24 hours.  The Tropical Low will move over water where where the Sea Surface Temperatures are near 29°C.  It will move under the northern part of an upper level ridge that extends from over Australia to the South Indian Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of the Tropical Low.  Those winds will cause moderate vertical wind shear.  The moderate vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification.  The Tropical Low could intensify during the next 24 hours.

The Tropical Low will move around the western end of a high pressure system over northern Australia.  The high pressure system will steer the Tropical Low toward the southeast during the next 24 hours.  On its anticipated track, the Tropical Low will make landfall on the coast of Western Australia between Kuri Bay and Derby in 36 hours.

The Tropical Low will bring strong winds and locally heavy rain to parts of Western Australia.  Heavy rain could cause flash floods in some locations.

Elsewhere over the South Indian Ocean, Tropical Cyclone Courtney continued to strengthen south-southeast of the Cocos Islands.  At 5:00 a.m. EDT on Thursday the center of Tropical Cyclone Courtney was located at latitude 16.8°S and longitude 99.5°E which put the center about 380 miles (610 km) south-southeast of the Cocos Islands.  Courtney was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 973 mb.

Tropical Cyclone Courtney Strengthens to Equivalent of Hurricane/Typhoon

Tropical Cyclone Courtney strengthened to the equivalent of a hurricane/typhoon over the South Indian Ocean southeast of the Cocos Islands on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Cyclone Courtney was located at latitude 17.3°S and longitude 101.7°E which put the center about 505 miles (815 km) southeast of the Cocos Islands.  Courtney was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 980 mb.

Tropical Cyclone Courtney strengthened steadily on Wednesday.  The inner end of a rainband wrapped around the center of Courtney’s circulation.  Other bands of showers and thunderstorms were revolving around the center of Tropical Storm Courtney.  Storms near the center of Courtney generated upper level divergence that pumped mass away from the tropical cyclone.  The removal of mass caused the surface pressure to decrease.

The size of the circulation around Tropical Cyclone Courtney increased on Wednesday.  Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Courtney’s circulation.  Winds to tropical storm force extended out 150 miles (240 km) from the center of Tropical Cyclone Courtney.

Tropical Cyclone Courtney will move through an environment somewhat favorable for intensification during the next 24 hours. Courtney will move over water where where the Sea Surface Temperatures are near 28°C.  It will move under the northern part of an upper level ridge that is west of Australia.  The upper level ridge will produce easterly winds that will blow toward the top of Courtney’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification.  Tropical Cyclone Courtney is likely to intensify during the next 24 hours.

Tropical Cyclone Courtney will move around the northern side of a high pressure system that is over the South Indian Ocean.  The high pressure system will steer Courtney toward the west during the next 24 hours.  On its anticipated track, Tropical Cyclone Courtney will pass south of the Cocos Islands later this week.

Tropical Cyclone Courtney Develops Northwest of Australia

Tropical Cyclone Courtney developed over the South Indian Ocean northwest of Australia on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Cyclone Courtney was located at latitude 17.4°S and longitude 106.3°E which put the center about 585 miles (945 km) northwest of Exmouth, Australia.  Courtney was moving toward the west-southwest at 17 m.p.h. (28 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 993 mb.

A low pressure system over the South Indian Ocean northwest of Australia strengthened on Tuesday and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Courtney.  More thunderstorms formed near the center of Courtney’s circulation.  More thunderstorms also developed in bands revolving around the center of Tropical Cyclone Courtney.  Storms near the center of Courtney generated upper level divergence that pumped mass away from the tropical cyclone.  The removal of mass caused the surface pressure to decrease.

The circulation around Tropical Cyclone Courtney was small.  Winds to tropical storm force extended out 85 miles (135 km) from the center of Courtney’s circulation.

Tropical Cyclone Courtney will move through an environment somewhat favorable for intensification during the next 24 hours.  Courtney will move over water where where the Sea Surface Temperatures are near 28°C.  It will move under the northern part of an upper level ridge that is west of Australia.  The upper level ridge will produce easterly winds that will blow toward the top of Courtney’s circulation.  Those winds will cause moderate vertical wind shear.  The moderate vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification.  Tropical Cyclone Courtney is likely to intensify during the next 24 hours.

Tropical Cyclone Courtney will move around the northern side of a high pressure system that is over the South Indian Ocean.  The high pressure system will steer Courtney toward the west during the next 24 hours.  On its anticipated track, Tropical Cyclone Courtney will pass far to the south of Christmas Islands.  Courtney will pass south of the Cocos Islands later this week.

Tropical Cyclone Seroja Prompts Watch for Western Australia

A potential threat posed by Tropical Cyclone Seroja prompted the issuance of a Watch for the coast of Western Australia. At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Seroja was located at latitude 19.2°S and longitude 109.8°E which put it about 315 miles (505 km) northwest of Exmouth, Australia. Seroja was moving toward the southwest 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 994 mb.

A Tropical Cyclone Watch was issued for the portion of the coast of Western Australia from Coral Bay to Lancelin. The Watch included Carnarvon, Denham, Kalbarri and Geraldton.

More thunderstorms developed in bands revolving around the center of Tropical Cyclone Seroja on Thursday night. The distribution of thunderstorms was more symmetrical, which indicated that the vertical wind shear was decreasing. Thunderstorms near the center of circulation generated upper level divergence that pumped mass away from the tropical cyclone. Winds to tropical storm force extended out 115 miles (185 km) from the center of Seroja.

Tropical Cyclone Seroja will move through an environment favorable for intensification during the next 36 hours. Seroja will move over water where the Sea Surface Temperatures will be near 30°C. It will move under the axis of an upper level ridge centered northwest of Australia during the next 24 hours. The upper level winds are weaker near the axis of the ridge and the wind shear will decrease. Tropical Cyclone Seroja could strengthen into the equivalent of a hurricane/typhoon during the next 24 hours. Seroja could strengthen more rapidly if the inner end of a rainband wraps around the center and an inner core forms.

Tropical Cyclone Seroja will move around the northwestern part of a high pressure system over Australia during the next day or so. The high will steer Seroja toward the southwest during the next 24 hours. An upper level trough over the South Indian Ocean will approach Tropical Cyclone Seroja from the west during the weekend. The trough will turn Seroja toward the southeast. On its anticipated track Tropical Cyclone Seroja will make landfall on the coast of Western Australia between Denham and Lancelin in 60 hours.

Elsewhere over the South Indian Ocean, Tropical Cyclone Odette was interacting with the northwest side of Tropical Cyclone Seroja. At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Odette was located at latitude 14.5°S and longitude 108.2°E which put it about 675 miles (1090 km) northwest of Exmouth, Australia. Odette was moving toward the east at 9 m.p.h. (15 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 988 mb. Even though the wind speeds are stronger in Tropical Cyclone Odette than they are in Tropical Cyclone Seroja, the circulation around Seroja is larger. The circulation of Odette is forecast to absorbed by the larger circulation of Seroja. In addition, upper level divergence from Seroja will cause vertical wind shear over Odette, which will also cause the circulation around Odette to weaken.

Tropical Cyclone Seroja Spins Northwest of Australia

Tropical Cyclone Seroja was spinning northwest of Australia on Wednesday night. At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Seroja was located at latitude 16.0°S and longitude 113.4°E which put it about 410 miles (665 km) north of Exmouth, Australia. Seroja was moving toward the west-southwest at 8 m.p.h. (13 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 985 mb.

Tropical Cyclone Seroja was exhibiting signs of intensification on Wednesday night, but it was also still being affected by vertical wind shear. More thunderstorms were beginning to form near the center of circulation. However, the distribution of thunderstorms was asymmetrical. Many of the stronger thunderstorms were occurring in bands in the western half of Seroja. Bands in the eastern half of the circulation consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 100 miles (160 km) from the center of circulation.

Tropical Cyclone Seroja will move through an environment more favorable for intensification during the next several days. Seroja will move over water where the Sea Surface Temperatures will be near 30°C. It will move under the northwestern part of an upper level ridge centered over northwestern Australia during the next 24 hours. The ridge will produce northeasterly winds which will blow toward the top of the circulation. Those winds will cause some vertical wind shear. Tropical Cyclone Seroja could intensify gradually during the next 24 hours. Seroja will move closer to the axis of the upper level ridge in a day or so. The winds are weaker near the axis of the ridge and the wind shear will decrease. Tropical Cyclone Seroja could strengthen into the equivalent of a hurricane/typhoon during the next 36 hours. Seroja could strengthen more rapidly when the vertical wind shear decreases and it is forecast to intensify into the equivalent of a major hurricane.

Tropical Cyclone Seroja will move around the northwestern part of a high pressure system over Australia. The high will steer Seroja toward the southwest during the next 48 hours. On its anticipated track Tropical Cyclone Seroja will remain northwest of Western Australia during the next two days. An upper level trough over the South Indian Ocean will approach Seroja during the weekend. The trough will turn Tropical Cyclone Seroja toward the southeast and it could approach the coast of Western Australia south of Denham in 72 hours.

Elsewhere over the South Indian Ocean, Tropical Cyclone 27S was interacting with the western side of Tropical Cyclone Seroja. At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone 27S was located at latitude 15.8°S and longitude 105.9°E which put it about 645 miles (1040 km) northwest of Exmouth, Australia. The tropical cyclone was moving toward the northeast at 4 m.p.h. (6 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 994 mb.

Tropical Cyclone Seroja Moves away from Indonesia

Tropical Cyclone Seroja moved slowly away to the south of Indonesia on Monday. At 11:00 p.m. EDT on Monday the center of Tropical Cyclone Seroja was located at latitude 11.7°S and longitude 119.8°E which put it about 460 miles (740 km) north-northwest of Broome, Australia. Seroja was moving toward the west-southwest at 8 m.p.h. (13 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 985 mb.

After dropping heavy rain over parts of eastern Indonesia and causing flash floods and mudslides, Tropical Cyclone Seroja moved slowly away from the area on Monday. The circulation around Seroja appeared to be a little stronger on Monday night. Bands of showers and thunderstorms were revolving around a well defined low level center of circulation. Storms near the center generated upper level divergence that pumped mass away to the west of the tropical cyclone. Winds to tropical storms force extended out 100 miles (160 km) from the center of circulation.

Tropical Cyclone Seroja will move through an environment somewhat favorable for intensification during the next several days. Seroja will move over water where the Sea Surface Temperatures will be near 30°C. It will move under the northern part of an upper level ridge centered over northwestern Australia. The ridge will produce easterly winds which will blow toward the top of the circulation. Those winds will cause moderate vertical wind shear. Tropical Cyclone Seroja could intensify gradually during the next 48 hours. Seroja could strengthen into the equivalent of a hurricane/typhoon during the next several days. The wind shear will decrease later this week and Tropical Cyclone Seroja could strengthen more rapidly when that occurs.

Tropical Cyclone Seroja will move around the northwestern part of a high pressure system over Australia. The high will Seroja toward the southwest during the next 48 hours. On its anticipated track Tropical Cyclone Seroja will remain northwest of Western Australia during the next two days. An upper level trough over the South Indian Ocean will approach Seroja later this week. The trough could turn Tropical Cyclone Seroja toward the southeast and it could eventually threaten Western Australia.

Elsewhere over the South Indian Ocean, Tropical Cyclone 27S churned south of Christmas Island. At 11:00 p.m. EDT on Monday the center of Tropical Cyclone 27S was located at latitude 16.3°S and longitude 105.5°E which put it about 700 miles (1100 km) northwest of Learmonth, Australia. The tropical cyclone was moving toward the southeast at 4 m.p.h. (6 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 994 mb.

Tropical Cyclone Seroja Intensifies South of Indonesia

Tropical Cyclone Seroja intensified south of Indonesia on Sunday. At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Seroja was located at latitude 10.7°S and longitude 122.3°E which put it about 120 miles (195 km) west-southwest of Kupang, Indonesia. Seroja was moving toward the southwest at 5 m.p.h. (8 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 994 mb.

A tropical low near West Timor intensified into Tropical Cyclone Seroja south of Indonesia on Sunday. Bands of strong thunderstorms were revolving around the center of Seroja. The strongest bands were in the northern and western parts of the circulation. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical cyclone. Winds to tropical storm force extended out 100 miles (160 km) from the center.

Tropical Cyclone Seroja will move through an environment favorable for intensification during the next several days. Seroja will move over water where the Sea Surface Temperatures will be near 30°C. It will move under the axis of an upper level ridge. The winds are weak near the axis of the ridge and there will be little vertical wind shear. Tropical Cyclone Seroja will continue to intensify during the next 48 hours. Seroja could strengthen into the equivalent of a hurricane/typhoon during the next 36 hours.

Tropical Cyclone Seroja will move around the northwestern part of a high pressure system over Australia. The high will Seroja toward the southwest during the next 48 hours. On its anticipated track Tropical Cyclone Seroja will remain northwest of Western Australia during the next two days. An upper level trough over the South Indian Ocean will approach Seroja later this week. The trough could turn Tropical Cyclone Seroja toward the southeast and it could eventually threaten Western Australia.

Elsewhere over the South Indian Ocean, Tropical Cyclone 27S formed south of Christmas Island. At 5:00 p.m. EDT on Sunday the center of Tropical Cyclone 27S was located at latitude 15.0°S and longitude 104.8°E which put it about 330 miles (535 km) south of Christmas Island. The tropical cyclone was moving toward the south at 8 m.p.h. (13 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 997 mb.