Category Archives: Tropical Cyclones

Information about tropical cyclones

Tropical Cyclone Pam Still Intensifying

Tropical Cyclone Pam continued to intensify on Wednesday and it is now the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Pam was located at latitude 12.6°S and longitude 170.2°E which put it about 200 miles northeast of Espiritu Santo and about 670 miles northwest of Fiji.  Pam was moving toward the south-southeast at 6 m.p.h.  The maximum sustained wind speed was 130 m.p.h. and there were gusts to 160 m.p.h.  The minimum surface pressure was 937 mb.

A large eye formed in the center of Pam and the strongest winds are occurring in the ring of thunderstorms surrounding the eye.  Pam is moving over warm Sea Surface Temperatures and the upper level winds are fairly light.  As a result, it has developed strong upper level outflow in most directions.  The environment is favorable for further intensification, but strong tropical cyclones often go through eyewall replacement cycles which produce fluctuations in the intensity

Pam is being steered southward by an subtropical ridge to the east of the tropical cyclone.  This general steering pattern is expected to continue during the next several days.  The projected path of Pam takes the center east of Vanuatu and New Caledonia and west of Fiji.  However, a slight deviation to the west could bring strong winds to some of the islands of Vanuatu.

Tropical Cyclone Olwyn Organizing Quickly Near Western Australia

A low level circulation is organizing quickly in an area of thunderstorms northwest of Western Australia and the system has been classified as Tropical Cyclone Olwyn.  At 8:00 a.m. EDT on Wednesday the center of Olwyn was located at latitude16.6°S and longitude 116.1°E which put it about 280 miles north of Karratha and about 390 miles north-northeast of Exmouth, Australia.  The maximum sustained wind speed was 45 m.p.h. and there were gusts to 60 m.p.h.  The minimum surface pressure was 996 mb.

Olwyn is over warm Sea Surface Temperatures and it is in an area where the upper level winds are very weak.  The favorable environment has allowed thunderstorms to grow rapidly and the circulation has developed upper level outflow which is pumping out mass and allowing the pressure to decrease.  Owlyn is expected to remain in a favorable environment until it makes landfall in Western Australia.  It should continue to intensify and a period of rapid intensification is possible.

Olwyn is moving around the western end of a subtropical ridge which is steering it toward the south.  That general steering pattern is expected to continue for the next several days.  On its projected track, Olwyn could approach the coast of Western Australia between Onslow and Exmouth in a about 36 hours.

Olwyn has the potential to cause significant wind damage and generate a storm surge near where the center makes landfall.  In addition, it could produce locally heavy rainfall and the potential for floods as it moves inland.

Tropical Cyclone Nathan Forms Over the Coral Sea

Another tropical cyclone formed in an elongated trough of low pressure over the southwestern Pacific Ocean.  At 10:00 p.m. EDT on Tuesday the center of Tropical Storm Nathan was located at latitude 13.8°S and longitude 146.8°E which put it about 150 miles northeast of Cooktown, Australia and about 250 miles south of Port Moresby, Papua New Guinea.  It was moving toward the west-southwest at 9 m.p.h.  The maximum sustained wind speed was 60 m.p.h. and there were wind gusts to 80 m.p.h.  The minimum surface pressure was 989 mb.

Nathan is over warm Sea Surface Temperatures, but it is being partly influenced by some of the upper level outflow from large Tropical Cyclone Pam which is located farther east.  The wind shear is reducing the rate of intensification, but the environment is favorable enough that continued intensification is likely during the next day or two.

The track forecast for Nathan has a high degree of uncertainty.  It is currently being steered to the west-southwest by a subtropical ridge that is north of the circulation center.  That ridge is predicted to weaken and westerly winds are expected to turn the tropical cyclone back toward the east.  However, the timing of that turn is important.  The center of Nathan could come very close to the coast of Queensland.  If the turn does not occur, Nathan could bring high winds and heavy rain to portions of northern Queensland.

 

Tropical Cyclone Pam Intensifying Quickly

Tropical Cyclone Pam continued to intensify quickly on Tuesday.  At 10:00 p.m. EDT on Tuesday the center of Tropical Cyclone Pam was located at latitude 11.0°S and longitude 169.8°E which put it about 710 miles northwest of Fiji and about 220 miles north-northeast of Espiritu Santo.  Pam was moving toward the southwest at 5 m.p.h.  The maximum sustained wind speed was 115 m.p.h. and there were wind gusts to 135 m.p.h.  The minimum surface pressure was 948 mb.

Pam remains in a very favorable environment.  It is over warm Sea Surface Temperatures and it is in a region of light upper level winds.  The strong core of the tropical cyclone has generated well developed upper level outflow that is pumping out mass in all directions.  Unless it is interrupted by an eyewall replacement cycle, the intensification is likely to continue.

Pam is being steering toward the south by a subtropical ridge located to its east.  The ridge strengthened slightly on Tuesday and pushed the tropical cyclone slightly to the west of the projected track.  The ridge is expected to continue to steer Pam toward the south during the next few days.  The projected track continues to predict that Pam will move east of Vanuatu and New Caledonia and west of Fiji.  However, a further deviation to the west could bring the circulation closer to Vanuatu.  Because of the intensify and large size of the circulation, impacts could be serious if Pam moves over any islands.

 

Tropical Cyclone Pam Intensifying Rapidly Northwest of Fiji

A circulation core developed rapidly in a large area of thunderstorms east of the Solomon Islands and the system was classified as Tropical Cyclone Pam on Monday.  At 10:00 p.m. EDT on Monday the center of Tropical Cyclone Pam was located at latitude 9.8° and longitude 170.4°E which put it about 790 miles northwest of Fiji.  Pam was moving toward the south-southeast at 7 m.p.h.  The maximum sustained wind speed was 75 m.p.h. and there were gusts to 90 m.p.h.  The minimum surface pressure was 974 mb.

Pam intensified rapidly on Monday and reached hurricane intensity within 24 hours of being classified as a tropical cyclone.  It is over Sea Surface Temperatures warmer than 30°C and it has moved into an area where the upper level winds are relatively light.  It normally takes the circulation in a large tropical disturbance a long time to consolidate around an inner core.  However, Pam has well developed upper level outflow, which has pumped out mass and enabled the system to intensify rapidly.  Pam is expected to remain in a very favorable environment and continued rapid intensification is likely.  It could become a very powerful tropical cyclone during the next several days.

Pam is moving around the western end of a subtropical ridge with is steering it in a south-southeasterly direction.  That generally steering pattern is expected to continue for the next several days.  The projected path of Pam carries it west of Fiji and east of Vanuatu and New Caledonia.  Given the large size and intensity of the tropical cyclone, any deviation from the projected path could increase the risk posed by Tropical Cyclone Pam.

 

Tropical Cyclone 15S Forms Over the Mozambique Channel

A low level circulation developed enough organization on the eastern side of a cluster of thunderstorms over the Mozambique Channel to be classified as a tropical cyclone on Thursday.  At 11:00 p.m. EST on Thursday the center of Tropical Cyclone 15S was located at latitude 16.6°S and longitude 42.3° which put it about 110 miles east-southeast of Mogincual, Mozambique and about 200 miles northwest of Maintirano, Madagascar.  It was moving toward the south-southeast at 5 m.p.h.  The maximum sustained wind speed was 40 m.p.h. and there were wind gusts to 50 m.p.h.  The minimum surface pressure was 996 mb.

Southeasterly winds in the upper levels are creating vertical wind shear and most of the stronger thunderstorms are on the western side of the center of circulation.  However, the tropical cyclone is over warm Sea Surface Temperatures and some intensification is possible.  If the upper level winds decrease, the more rapid intensification could occur.  A gradual intensification seems more likely over the short term.

A subtropical ridge of high pressure to the east of the tropical cyclone is steering it slowly to the south.  It is likely to move into a region of weak steering winds  between that ridge of high pressure and another ridge farther to the west.  As a result, the tropical cyclone could move slowly and erratically and even become stationary at times during the next day or two.  Eventually, a third ridge of high pressure is expected to develop to the north of the system and push it westward toward Madagascar.

The tropical cyclone could be a strong tropical storm or near hurricane intensity when it reaches Madagascar.  Some wind damage is possible, but the biggest threat appears to be from locally heavy rainfall and flooding.

 

Tropical Cyclone Glenda Forms South of Diego Garcia

A low level circulation consolidated quickly in a large area of thunderstorms over the south central Indian Ocean and the system was classified as Tropical Cyclone Glenda.  At 11:00 p.m. EST on Tuesday the center of Tropical Cyclone Glenda was located at latitude 17.3°S and longitude 69.8°E which put it about 670 miles south of Diego Garcia and about 1040 miles east-northeast of La Reunion.  Glenda was moving toward the west-southwest at 10 m.p.h.  The maximum sustained wind speed was 65 m.p.h. and there were gusts to 75 m.p.h.  The minimum surface pressure was 982 mb.

Glenda is over warm Sea Surface Temperatures and it has well developed upper level outflow.  The outflow is pumping out mass and the pressure has been decreasing steadily.  Glenda is like to remain in a favorable environment for another 48 hours.  It will likely reach hurricane intensity on Wednesday and it could become the equivalent of a major hurricane on Thursday.

Glenda is being steered to the west-southwest by a subtropical ridge located southeast of it.  This motion is likely to continue for another 24 to 36 hours.  When it approaches the western end of the ridge, it will turn more toward the south.  The projected track keeps Glenda well south of Diego Garcia and has it turning southward well to the east of La Reunion.  As a result, Glenda poses no current threat to any land area.

 

Strong Tropical Cyclone Marcia Moving Over Eastern Queensland

Strong Tropical Cyclone Marcia made landfall a few hours ago on the east coast of Australia northwest of Yeppoon in Queensland.  Marcia is moving roughly parallel to the coast about 25 miles inland from the Pacific Ocean.  At 9:00 p.m. EST on Thursday the center of Tropical Cyclone Marcia was located at latitude 22.9°S and longitude 150.5°E which put it about 25 miles northwest of Yeppoon, about 85 miles northwest of Gladstone and about 340 miles north-northwest of Brisbane, Australia.  Marcia was moving toward the south at 12 m.p.h.  The maximum sustained wind speed was 110 m.p.h. and there were gusts to 150 m.p.h.  The minimum surface pressure was 948 mb.

Marcia is beginning to weaken.  It will initially weaken slowly because it is still near the ocean and the circulation has well developed upper level outflow.  As Marcia moves farther south, it will encounter more vertical wind shear.  Increased wind shear and more time over land, will speed up the rate of weakening in 12 to 24 hours.

Marcia is still strong enough to contain damaging winds.  The center of circulation will pass near Rockhampton in a few hours.  It could produce a significant storm surge on the portion of the coast where the winds are blowing toward the coastline.  Marcia could also generate locally heavy rainfall and the potential for flooding.

 

Tropical Cyclone Lam Moving Farther Inland and Weakening

Tropical Cyclone Lam made landfall earlier today just to the southwest of Elcho Island on the north coast of Australia.  Lam is continuing to move farther inland in the Northern Territory.  At 9:00 p.m. EST on Thursday the center of Lam was located at latitude 13.1°S and longitude 134.4°S which put it 40 miles north of Bulman and about 75 miles south-southwest of Milingimbi, Australia.  It was moving toward the southwest at 10 m.p.h.  The maximum sustained wind speed was 65 m.p.h. and there were gusts to 90 m.p.h.  The minimum surface pressure was 985 mb.

Lam will continue to weaken as it moves farther into the interior of Australia.  The weakening will occur slowly because the circulation is moving over relatively flat terrain.  Lam could produce locally heavy rainfall and the potential for flooding along its path.  The winds and waves along the coast should continue to lessen and the water levels should decrease.

Lam and Marcia Equivalent of Major Hurricanes As They Affect Australia

Both Severe Cyclone Lam and Severe Tropical Cyclone Marcia intensified rapidly during the past few hours and both storms are now the equivalent of major hurricanes.  Lam is making landfall on the north coast of Australia just to the southwest of Elcho Island.  The motion of Marcia has slowed, but it is approaching the coast of Queensland.

At 8:00 a.m. EST on Thursday the center of Lam was located at latitude 12.0°S and longitude 135.4°E which put it about 12 miles west-northwest of Galiwinku and about 35 miles east-northeast of Milingimbi, Australia.  Lam was moving toward the southwest at 5 m.p.h.  The maximum sustained wind speed was 115 m.p.h., which makes Lam the equivalent of a Category 3 hurricane on the Saffir-Simpson Scale.  It was estimate that there were wind gusts to 160 m.p.h. and the minimum surface pressure was 963 mb.

At 8:00 a.m. EST on Thursday the center of Marcia was located at latitude 20.8°S and longitude 150.6°S which put it about 150 miles east of Mackay and about 160 miles north of Yeppoon, Australia.  Lam was moving toward the west-southwest at 7 m.p.h.  The maximum sustained wind speed was 120 m.p.h., which makes Marcia the equivalent of a Category 3 hurricane on the Saffir-Simpson Scale.  It was estimated that there were wind gusts to 165 m.p.h. and the minimum surface pressure was 956 mb.

Both tropical cyclones are capable of causing significant wind damage.  They are also capable of generating a significant storm surge near where the center makes landfall.  Locally heavy rainfall and the potential for flooding exists, as the storms move inland.