Tag Archives: SH15

Tropical Cyclone Oma Strengthens to Equivalent of Hurricane/Typhoon

Tropical Cyclone Oma strengthened to the equivalent of a hurricane/typhoon over the Coral Sea north of New Caledonia on Friday.  At 1:00 p.m. EST on Friday the center of Tropical Cyclone Oma was located at latitude 15.4°S and longitude 164.2°E which put it about 300 miles (485 km) north of New Caledonia.  Oma was moving toward the west-southwest at 4 m.p.h. (6 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 969 mb.

The circulation around Tropical Cyclone Oma continued to become better organized on Friday.  A ring of thunderstorms wrapped around much of the center of circulation and there were indications on satellite images that an eye could be forming.  The strongest thunderstorms were the northwestern part of the ring.  The ring was thinner east of the center and there were several breaks in that portion of the ring.  Storms near the center were generating upper level divergence which was pumping mass away from core of the tropical cyclone.  Bands of showers and thunderstorms were revolving around the center of circulation.  The bands were stronger north and west of the center and the stronger winds were occurring in that part of Tropical Cyclone Oma.

Tropical Cyclone Oma will move through an environment favorable for intensification during the next day or two.  Oma will move over water where the Sea Surface Temperature is near 30°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Oma is likely to strengthen more and there is a chance that it could intensify into the equivalent of a major hurricane.

Tropical Cyclone Oma will move slowly around the western end of a strengthening subtropical ridge.  The ridge will steer Oma slowly toward the southwest during the next 24 hours.  Tropical Cyclone Oma will move toward the southwest more rapidly in a day or so when the subtropical ridge is stronger.  On its anticipated track the core of Tropical Cyclone Oma could pass near the northernmost islands of New Caledonia in 24 to 36 hours.

Tropical Cyclone Oma Spins Northwest of Vanuatu

Tropical Cyclone Oma continued to spin over the Coral Sea northwest of Vanuatu on Thursday.  At 7:00 p.m. EST on Thursday the center of Tropical Cyclone Oma was located at latitude 15.3°N and longitude 165.1°E which put it about 260 miles (420 km) northwest of Port Vila, Vanuatu.  Oma was nearly stationary.  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 979 mb.

Tropical Cyclone Oma exhibited evidence of greater organization on Thursday.  The inner end of a rainband wrapped more tightly around the center of circulation.  Other bands of showers and thunderstorms also exhibited greater organization.   Storms around the center of circulation generated more upper level divergence which pumped mass away from the tropical cyclone.  Winds to tropical storm force extended out about 200 miles (320 km) from the center of circulation.

Once Tropical Cyclone Oma starts to move, it will move through an area favorable for intensification.  Oma will move over water where the Sea Surface Temperature is near 30°C.  It will move into a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Oma will be likely to intensify and it will likely strengthen into the equivalent of a hurricane/typhoon.

Tropical Cyclone Oma has been in an area where the winds at the steering level were weak and it has moved little during the past several days.  An upper level ridge east of Oma is forecast to strengthen during the next few days.  When the ridge strengthens, it will start to steer Tropical Cyclone Oma toward the southwest.  On its anticipated track Oma will move slowly away from Vanuatu and it could be north of New Caledonia in a few days.

Tropical Cyclone Oma Forms Northwest of Vanuatu

Tropical Cyclone Oma formed over the Coral Sea northwest of Vanuatu on Tuesday.  At 10:00 a.m. EST on Tuesday the center of Tropical Cyclone Oma was located at latitude 13.8°S and longitude 165.6°E which put it about 330 miles (535 km) northwest of Port Vila, Vanuatu.  Oma was moving toward the east at 7 m.p.h. (11 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 988 mb.

A distinct low level center of circulation formed within a broader area of low pressure northwest of Vanuatu on Tuesday and the Fiji Meteorological Service designated the system as Tropical Cyclone Oma.  The distribution of thunderstorms around Oma was asymmetrical.  Many of the stronger thunderstorms were occurring in bands northwest of the center of circulation.  Bands southeast of the center consisted primarily of showers and lower clouds.  The thunderstorms northwest of the center were generating upper level divergence which was pumping mass away to the northwest of the tropical cyclone.

An upper level ridge northeast of Vanuatu was producing southeasterly winds which were blowing toward the top of Tropical Cyclone Oma.  Those winds were causing moderate vertical wind shear and they were inhibiting upper level divergence to the southeast of Oma.  The wind shear was the probable cause of the asymmetrical distribution of thunderstorms.

Tropical Cyclone Oma will move through an environment somewhat favorable for intensification during the next several days.  The upper level ridge will continue to cause vertical wind shear.  However, Oma will move over water where the Sea Surface Temperature is near 30°C.  Tropical Cyclone Oma could slowly strengthen during the next day or two.

Tropical Cyclone Oma is currently embedded in a monsoon trough that is steering it toward the east.  A subtropical ridge is forecast to strengthen east of Vanuatu.  Oma will slow down while the ridge builds east of Vanuatu and it could linger northwest of Vanuatu for several days.  The ridge will eventually turn Tropical Cyclone Oma toward the south.  The timing and location of that turn will be important.  If Oma moves farther east before it turns southward, then it could approach northwest Vanuatu in 24 to 36 hours.  If Oma stalls and then turns southward, then the strongest part of the tropical cyclone could pass west of Vanuatu.  Tropical Cyclone Oma could eventually move near New Caledonia in a few days.

Tropical Cyclone Nora Strengthens Over Gulf of Carpentaria

Tropical Cyclone Nora strengthened over the Gulf of Carpentaria on Friday.  At 11:00 p.m EDT on Friday the center of Tropical Cyclone Nora was located at latitude 12.6°S and longitude 140.0°E which put it about 125 miles (205 km) west of Weipa, Australia.  Nora was moving toward the southeast at 9 m.p.h. (14 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (210 km/h).  The minimum surface pressure was 956 mb.  The Australian Bureau of Meteorology had issued a Warning for the portion of the coast from Karumba to Mapoon including Weipa and Mornington Island.  A Watch was in effect for the portion of the coast from Weipa to the border between the Northern Territory and Queensland.

Tropical Cyclone Nora strengthened on Friday as it entered the northern portion of the Gulf of Carpentaria.  An eye appeared intermittently at the center of circulation.  A band of stronger thunderstorms wrapped intermittently around the formative eye and the strongest winds were blowing in the band of thunderstorms.  Bands of showers and thunderstorms were revolving around the center of circulation.  Storms near the core of the circulation were generating upper level divergence which was pumping mass away from the tropical cyclone.

Tropical Cyclone Nora will be moving through an environment favorable for intensification.  Nora will move over water where the Sea Surface Temperature is near 30°C.  It will move under an area where the upper level winds are weak and there is little vertical wind shear.  Tropical Cyclone Nora could strengthen into the equivalent of a major hurricane during the next 24 to 36 hours.

Tropical Cyclone Nora is moving near the western end of a mid-level ridge which is steering Nora toward the south.  A general motion toward the south is expected to continue for another day or two.  On its anticipated track Nora could approach the coast of Queensland between Kowanyama and the mouth of the Gilbert River in 24 to 36 hours.  Nora could bring gusty winds and locally heavy rain to portions of northwestern Queensland.

Elsewhere, Tropical Cyclone Marcus was weakening off the coast of Western Australia.  At 11:00 p.m. EDT on Friday the center of Tropical Cyclone Marcus was located at latitude 25.9°S and longitude 107.5°E, which put it about 770 miles (1045 km) west of Carnarvon, Australia.  Marcus was moving toward the south-southeast at 20 m.p.h. (32 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 984 mb.

Tropical Cyclone Nora Develops Rapidly North of Australia

Tropical Cyclone Nora developed rapidly north of Australia over the Arafura Sea on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Nora was located at latitude 10.0°S and longitude 136.8°E which put it about 160 miles (260 km) north of Nhulunbuy, Australia.  Nora was moving toward the east at 3 m.p.h. (5 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 986 mb.

A center of circulation organized quickly on Thursday in an area of thunderstorms over the Arafura Sea and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Nora.  A primary rainband wrapped around the western and northern side of the center of circulation.  An eye appeared to be forming at the center of Tropical Cyclone Nora.  Bands of showers and thunderstorms were revolving around the core of the circulation.  Storms around the core were generating well developed upper level divergence which was pumping mass away from the tropical cyclone.  The removal of mass was allowing the surface pressure to decrease rapidly and the wind speeds were increasing in response.

The Australian Bureau of Meteorology issued Warnings for the portions of the coast from Elcho Island to Cape Shield including Cape Wessel and from Pormpuraaw to Thursday Island.  A Watch was in effect for the portion of the coast from Pormpuraaw to the border between the Northern Territory and Queensland including Mornington Island.

Tropical Cyclone Nora will move through an environment very favorable for intensification during the next 48 hours.  Nora will move over water where the Sea Surface Temperature is near 30°C.  It will move through an area where the upper level winds are weak and there is little vertical wind shear.  Nora is likely to intensify rapidly and it is likely to become the equivalent of a hurricane/typhoon within 24 hours.  Tropical Cyclone Nora could become the equivalent of a major hurricane within 24 to 48 hours.

Tropical Cyclone Nora was moving through an area where steering winds are weak and it was moving slowly toward the east.  A subtropical ridge east of Australia is expected to strengthen.  The ridge is forecast to steer Nora more toward the south in 12 to 24 hours.  On its anticipated track Tropical Cyclone Nora is expected to move over the Gulf of Carpentaria toward the coast of Queensland.  Nora could strengthen into a dangerous tropical cyclone.

Elsewhere, Tropical Cyclone Marcus continued to churn west of Australia.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Marcus was located at latitude 20.6°S and longitude 106.0°E which put it about 555 miles (895 km) west-northwest of Learmonth, Australia.  Marcus was moving toward the south at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 951 mb.

Tropical Cyclone Marcus Strengthens to Equivalent of Category 5 Hurricane Northwest of Australia

Tropical Cyclone Marcus strengthened into the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale as it churned northwest of Australia on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Tropical Cyclone Marcus was located at latitude 15.8°S and longitude 108.0°E which put it about 600 miles (960 km) northwest of Learmonth, Australia.  Marcus was moving toward the west-southwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h).  The minimum surface pressure was 918 mb.

After completing an eyewall replacement cyclone on Tuesday, Tropical Cyclone Marcus began to intensify quickly again on Wednesday.  Marcus exhibited a circular, symmetrical circulation.  There was a tiny circular eye at the center of circulation.  The strongest winds were occurring in a ring of thunderstorms that surrounded the small inner eye.  Recent satellite images suggested that another eyewall replacement cycle may be beginning.  A larger, outer eyewall appeared to have encircled the small inner eye.  Bands of showers and thunderstorms were revolving around the concentric eyewalls.  Storms in the core of Marcus were generating very well developed upper level divergence which was pumping mass away in all directions from the tropical cyclone.

As frequently happens during eyewall replacement cycles, Tropical Cyclone Marcus increased in size after Tuesday’s eyewall replacement cycle was completed.  Winds to hurricane/typhoon force extended out about 50 miles (85 km) from the center of circulation.  Winds to tropical storm force extended out 180 miles (290 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Marcus was 35.0.  The Hurricane Size Index (HSI) was 18.7 and the Hurricane Wind Intensity Size Index (HWISI) was 53.7.

Tropical Cyclone Marcus is in an environment that is very favorable for strong tropical cyclones.  Marcus is moving over water where the Sea Surface Temperature is near 30°C.  It is moving through an area where the upper level winds are weak and there is little vertical wind shear.  Although Tropical Cyclone Marcus is in a very favorable environment, another eyewall replacement cycle would cause it to weaken.  The wind would begin to converge into the outer eyewall, which would cause the storms in the inner eyewall to weaken.  The wind speeds would decrease as the inner eyewall weakens.  Then the strongest winds would be found in the outer eyewall and the circulation would increase in size.

Tropical Cyclone Marcus is nearing the western end of a subtropical ridge over Australia.  The ridge is steering Marcus toward the west-southwest, but the tropical cyclone will turn more toward the south when it reaches the end of the ridge.  Tropical Cyclone Marcus will make a gradual turn toward the southeast during the next several days.  On its anticipated track Tropical Cyclone Marcus will remain west of Western Australia during the next 36 to 48 hours.

Tropical Cyclone Marcus Strengthens Into Equivalent of Major Hurricane

Tropical Cyclone Marcus strengthened into the equivalent of a major hurricane on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Cyclone Marcus was located at latitude 15.0°S and longitude 117.7°E which put it about 340 miles (550 km) north of Port Hedland, Australia.  Marcus was moving toward the west at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 955 mb.

The circulation of Tropical Cyclone Marcus was symmetrical and very well organized.  A very small circular eye was at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of the circulation.  Storms in the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone.  Winds to hurricane/typhoon force extended out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out about 190 miles (305 km) from the center.

Tropical Storm Marcus will continue to move through an environment very favorable for strong tropical cyclones during the next two days.  Marcus will move over water where the Sea Surface Temperature is near 30°C.  It is moving under an area where the upper level winds are weak and there is little vertical wind shear.  Tropical Cyclone Marcus is likely to intensify and it could reach the equivalent of a Category 5 hurricane.  If a rainband wraps around the core of the circulation, then a second eyewall could form.  That would initiate an eyewall replacement cycle, which would cause Marcus to weaken at least temporarily.

Tropical Cyclone Marcus is moving around the western end of a subtropical ridge, which is steering Marcus toward the west.  A general motion toward the west is expected to occur for anther 24 to 48 hours.  Marcus will reach the western end of the ridge in about two days, and then the tropical cyclone will turn toward the south.  On its anticipated track Tropical Cyclone Marcus will stay north of the coast of Western Australia for the next few days.

Tropical Cyclone Marcus Strengthens Rapidly North of Australia

Tropical Cyclone Marcus moved back over the South Indian Ocean on Sunday and it strengthened rapidly north of Australia.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Marcus was located at latitude 15.0°S and longitude 122.8°E which put it about 215 miles (345 km) north-northeast of Broome, Australia.  Marcus was moving toward the west at 11 m.p.h. (17 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 987 mb.

Tropical Cyclone Marcus weakened when it moved over the northernmost part of Western Australia, but it began to strengthen quickly after the core moved back over water.  An eye rapidly reformed at the center of circulation.  A ring of strong thunderstorms redeveloped around the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of the circulation.  Storms around the core were generating upper level divergence which was pumping mass away from the tropical cyclone.  The circulation of Tropical Cyclone Marcus was relatively compact.  Winds to tropical storm force extended out about 80 miles (130 km) from the center of circulation.

Tropical Cyclone Marcus will be moving through an environment very favorable for intensification during the next two days.  Marcus will move over water where the Sea Surface Temperature is near 30°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Marcus is likely to continue to intensify rapidly and it could become the equivalent of a major hurricane in 24 to 36 hours.

Tropical Cyclone Marcus is moving around the northern side of a subtropical ridge over Australia, which is steering Marcus toward the west.  A general motion toward the west is forecast to continue for several more days.  Tropical Cyclone Marcus will reach the western end of the ridge in two or three days.  Marcus will turn toward the south at that time.  On its anticipated track Tropical Cyclone Marcus will move farther away from the coast of Western Australia during the next two days.

Tropical Cyclone Marcus Makes Landfall on North Coast of Australia

Tropical Cyclone Marcus made landfall on the northern coast of Western Australia east of Kalumburu on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Marcus was located at latitude 14.2°S and longitude 127.7°E which put it about 70 miles (115 km) east of Kalumburu, Australia.  Marcus was moving toward the west-southwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 85 m.p.h. (140 km/h).  The minimum surface pressure was 984 mb.  The Australian Bureau of Meteorology issued a Warning for the portion of the coast between Wyndham and Beagle Bay not including Wyndham or Derby.

Tropical Cyclone Marcus strengthened as it moved over the Timor Sea on Saturday.  There was a small circular eye at the center of circulation.  The 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 the circulation.  Storms in the core were generating upper level divergence which was pumping mass away from the tropical cyclone.

Tropical Cyclone Marcus will weaken on Sunday while the core of the circulation moves over the extreme northern part of Western Australia.  Marcus is likely to strengthen when the center moves west of Kuri Bay and back out over water.  The Sea Surface Temperature of the water west of Kuri Bay is around 30°C.  The upper level winds will be weak and there will be little vertical wind shear.  Marcus will likely intensify into the equivalent of a hurricane/typhoon after the center of circulation moves back over water.

Tropical Cyclone Marcus is moving north of a subtropical ridge over Australia.  The ridge is steering Marcus to the west-southwest and that general motion is expected to continue for several more days.  On its anticipated track Tropical Cyclone Marcus will move over the Mitchell Plateau toward Kuri Bay.  Marcus will move away from the north coast of Western Australia when it moves west of Kuri Bay.

Tropical Cyclone Marcus Brings Wind and Rain to Darwin

Tropical Cyclone Marcus brought wind and rain to Darwin, Australia on Friday night.  A weather station at Darwin Harbor recorded a wind gust to 80 m.p.h. (130 km/h).  At 11:00 p.m. EDT on Friday the center of Tropical Cyclone Marcus was located at latitude 12.7°S and longitude 130.7°E which put it about 20 miles (30 km) southwest of Darwin, Australia.  Marcus was moving toward the southwest at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 982 mb.  The Australian Bureau of Meteorology issued a Warning for the portion of the coast from Cape Hotham to Mitchell Plateau including Darwin and the Tiwi Islands.  A Watch was issued for the portion of the coast from Cockatoo Island to Mitchell Plateau.

Tropical Cyclone Marcus intensified as it approached Darwin.  An eye developed at the center of circulation and a ring of strong thunderstorms surrounded the eye.  The strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of the circulation.  Storms around the core were generating upper level divergence which was pumping away mass from the tropical cyclone.

Tropical Cyclone Marcus will move through an area favorable for intensification during the next 24 hours.  Marcus will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge over Australia is producing easterly winds which are blowing toward the top of the circulation.  Those winds are creating some vertical wind shear, but the shear is not strong enough to prevent intensification.  Tropical Cyclone Marcus could strengthen into the equivalent of a hurricane/typhoon when it moves over the Timor Sea on Saturday.

Tropical Cyclone Marcus was being steered toward the southwest by the ridge over Australia and the southwesterly motion is expected to continue.  On its anticipated path the center of Tropical Cyclone Marcus will move across the Timor Sea on Saturday.  Marcus could approach the north coast of Western Australia east of Kalumburu in about 24 hours.