Category Archives: Tropical Cyclones

Information about tropical cyclones

Tropical Cyclone Marcia Intensifying Quickly as It Nears Australia

The circulation around Tropical Cyclone Marcia is organizing rapidly as it moves toward eastern Australia.  An eye is apparent on visible satellite imagery and Marcia rapidly intensified to hurricane intensity.  At 1:00 a.m. EST on Thursday the center of Marcia was located at latitude 20.5°S and longitude 151.0°E which put it about 125 miles east-northeast of Mackay and about 180 miles north-northeast of Yeppoon, Australia.  Marcia was moving toward the west-southwest at 16 m.p.h.  The maximum sustained wind speed was 95 m.p.h. and there were gusts to 135 m.p.h.  The minimum surface pressure was 956 mb.

Marcia has developed an eye and thunderstorms completely surround it.  The core of Marcia is symmetrical which indicates a well organized storm.  As Marcia moved toward the southwest, it moved west of the strongest upper level winds, which reduced the vertical wind shear.  Marcia was over warm Sea Surface Temperatures and the more favorable environment allowed it to intensify quickly.  It will remain in a favorable environment until it makes landfall and further intensification is possible.

Marcia is near the western end of a subtropical ridge which is steering it to the southwest.  Once the system moves inland, it is likely to move in more of a southerly direction, but it should be weaker by that time.

Marcia could make landfall in around 12 hours near the Northumberland Isles between Mackay and Yeppoon.  The rapid organization of the circulation increased the destructive potential of Marcia.  It is strong enough to cause wind damage and it could cause a storm surge near where the center makes landfall.  The stronger circulation could also produce locally heavy rainfall and the potential for flooding as it moves inland.

 

Severe Cyclone Lam Approaching North Coast of Australia

Severe Cyclone Lam is located just to the west of the Wessel Islands.  It is moving slowly southwestward toward the north coast of Australia.  At 10:00 p.m. EST on Wednesday the center of Severe Cyclone Lam was located at latitude 11.5°S and longitude 135.9°E which put it about 40 miles north-northeast of Elcho Island and about 75 miles northwest of Nhulunbuy, Australia.  Lam was moving toward the southwest at 5 m.p.h.  The maximum sustained wind speed was 85 m.p.h. and there were gusts to 120 m.p.h.  The minimum surface pressure was 967 mb.

Lam is moving over Sea Surface Temperatures that are warmer than 30°C.  The upper level winds are relatively light and there is little vertical wind shear.  Since the environment is favorable, some further intensification is possible before Lam makes landfall in about 12 hours.

Lam is expected to make landfall on the north coast of Australia just to the southwest of Elcho Island.  It is a strong tropical cyclone capable of causing wind damage.  A weather station near Cape Wessel measured a sustained wind speed of 80 m.p.h. and wind gusts to 100 m.p.h. when the eyewall passed over the station.  The intensity and slow movement of Lam are also creating the potential for a significant storm surge near where the center makes landfall.  The slow motion will also create the potential for locally heavy rainfall and flooding as Lam moves inland.

 

Severe Cyclone Lam Reaches Hurricane Intensity Near Wessel Islands

Tropical Cyclone Lam reached hurricane intensity near the northern coast of Australia and was upgraded to Severe Cyclone status.  At 10:00 p.m. EST on Tuesday the center of Severe Cyclone Lam was located at latitude 11.1°S and longitude 137.0°E which put it near the Wessel Islands, about 80 miles north of Nhulunbuy and about 110 miles northeast of Elcho Island, Australia.  Lam was moving toward the west at 8 m.p.h.  The maximum sustained wind speed was 75 m.p.h. and there were gusts to 100 m.p.h.  The minimum surface pressure was 976 mb.

Lam remains over very warm Sea Surface Temperatures and the vertical wind shear is modest.  So, it has the potential to intensify further as long as the center remains over water.  A subtropical ridge is steering Lam westward and that motion is expect to continue for another 8 to 16 hours.  When it reaches the western edge of the ridge, Lam is expected to turn toward the southwest and it could make a landfall west of Elcho Island in 24 to 36 hours.  Lam is strong enough to pose a risk of a significant storm surge and it could also produce locally heavy rainfall and flooding as it moves inland.

 

Tropical Cyclone 13P Forms Northeast of Australia

A second tropical cyclone formed near the coast of Australia when a center of circulation developed in a cluster of thunderstorms northeast of Queensland.  At 10:00 p.m. EST on Tuesday the center of Tropical Cyclone 13P was located at latitude 16.5°S and longitude 155.9°E which put it 385 miles east of Willis Island and about 800 miles north of Brisbane, Australia.  It was moving toward the south at 7 m.p.h.  The maximum sustained wind speed was 40 m.p.h. and there were gusts to 50 m.p.h.  The minimum surface pressure was 996 mb.

Tropical Cyclone 13P is near the western end of a subtropical ridge and moderately strong northerly winds are blowing over the top of the circulation, especially over the eastern half of it.  As a result, more thunderstorms are forming in the western half of the circulation.  The tropical cyclone is over Sea Surface Temperatures that are warm enough to support intensification.  The upper level northerly winds are enhancing outflow to the south of the circulation and so some intensification is possible.

The subtropical ridge is expected to steer Tropical Cyclone 13P in a generally southwesterly direction, which will move it toward the east coast of Australia.  A landfall near Gladstone could occur in 36 to 48 hours.

 

Cyclone Lam Developed Rapidly Over the Northern Gulf of Carpentaria

A well defined center of circulation developed rapidly on Monday in an area of thunderstorms over the northern Gulf of Carpentaria and the system was classified as Cyclone Lam.  At 10:00 p.m. EST on Monday the center of Lam was located at latitude 11.6°S and longitude 139.4°E which put it about 180 miles east-northeast of Nhulunbuy, Australia and about 260 miles northeast of Alyangula.  Lam was moving toward the west at 5 m.p.h.  The maximum sustained wind speed was 60 m.p.h. and there were gusts to 80 m.p.h.  The minimum surface pressure was 989 mb.

Lam is an environment that favors intensification.  The Sea Surface Temperatures (SSTs) in the northern Gulf of Carpentaria are near 30°C.  There are light east-southeasterly winds in the upper levels, which are creating some vertical wind shear, but there is well-developed upper level outflow on the western side of the circulation.  The upper level divergence is pumping out mass and the surface pressure is decreasing.  The circulation is tightening up around the core and further intensification is likely.  Given the warm SSTs, rapid intensification is possible if the magnitude of the wind shear remains at a modest level.

A subtropical ridge to the south of Lam is steering it slowly toward the west.  Lam is expected to continue moving westward for another 18 to 24 hours until it reaches the western end of the subtropical ridge.  When Lam reaches the western edge of the ridge, it is expected to move toward the southwest.  The timing of that turn is very important.  If the turn occurs a few hours later than expected, Lam could make landfall in northern Australia near Nhulunbuy.  If Lam turns southwestward sooner, it could remain over the Gulf of Carpentaria longer and make landfall closer to Groote Eylandt.  Lam has the potential to create dangerous storm surges when it makes landfall.  There is also the potential for wind damage, locally heavy rainfall and flooding.

 

Higos Weakening Rapidly East of Saipan

After intensifying rapidly into a strong but small typhoon on Monday, vertical wind shear caused Higos to begin a rapid weakening trend on Tuesday.  At 11:00 p.m. EST on Tuesday the center of Typhoon Higos was located at latitude 15.3°N and longitude 152.9°E which put it about 450 miles east of Saipan and about 880 miles west-southwest of Wake Island.  Higos was moving toward the west-northwest at 7 m.p.h.  The maximum sustained wind speed was 80 m.p.h. and there were gusts to 90 m.p.h.  The minimum surface pressure was estimated to be 974 mb.

Strong southwesterly winds in the upper levels are blowing over the top of Higos.  Those strong winds have blown the upper half of the circulation off to the northeast of the lower half of the circulation.  The lower portion of the circulation consists of a tight center with spiral bands of shallower clouds rotating around the center.  The wind shear is preventing deep thunderstorms from forming near the center and it is causing Higos to weaken rapidly.  Unless the shear lets up, which is unlikely, the lack of deep convection to remove mass will cause the surface pressure to increase and the circulation to spin down.

Since Higos consists primarily of a lower level circulation it is likely to be steered by winds in the lower portion of the atmosphere.  A subtropical ridge to the east of Higos is likely to steer it to the north-northwest until the wind shear causes it to spin down.

 

Typhoon Higos Maintaining Intensity Well East of Guam

The organization of Typhoon Higos improved on Monday.  At 11:00 p.m. EST on Monday the center of Typhoon Higos was located at latitude 13.7°N and longitude 154.7°E which put it about 710 miles east of Guam and about 870 miles west-southwest of Wake Island.  Higos was moving toward the northwest at 9 m.p.h.  The maximum sustained wind speed was 95 m.p.h. and there were gusts to 115 m.p.h.  The minimum surface pressure was 967 mb.

The circulation around Higos remains in an area where the upper level winds are not too strong and the wind shear is in the light to moderate range.  An eye has developed at the center of circulation which is evident on both infrared and visible satellite imagery.  The eye is surrounding by a tight symmetrical ring of thunderstorms.  It has the appearance of a well organized circulation.  Upper level outflow continues and it is especially strong on the northeast side of Higos.  The typhoon also remains over warm Sea Surface Temperatures and so the environment could support some further intensification on Tuesday.  As Higos moves farther north, it will begin to be affected by stronger upper level westerly winds.  The stronger winds will create more wind shear and weaken Higos.

Higos is moving around the western end of a subtropical ridge, which is steering it toward the northwest.  As it gets farther north, the upper level westerly winds will being to push it toward the northeast.  Higos is expected to weaken as it moves northwest of Wake Island.

 

Higos Intensfies Into a Typhoon

Tropical Storm Higos intensified into a typhoon on Sunday.  At 11:00 p.m. EST on Sunday the center of Typhoon Higos was located at latitude 12.3°N and longitude 156.4°E which put it about 780 miles east of Guam.  It was moving toward the west-northwest at 3 m.p.h.  The maximum sustained wind speed was 85 m.p.h. and there were gusts to 100 m.p.h.  The minimum surface pressure was 967 mb.

Higos has been moving slowly through an area where the vertical wind shear was not too strong.  Thunderstorms around the center of circulation supported strong upper level divergence, which pumped out large quantities of mass.  A well developed upper level outflow channel to the northeast enhanced the flow of mass away from the system.  Those processes allowed the surface pressure to decrease and the wind speeds to increase on Sunday.  Higos remains over warm Sea Surface Temperatures and further intensification is possible on Monday.  Eventually, when it moves farther north, Higos will move into an area of stronger wind shear and weaken.

Higos is moving near the western end of a subtropical ridge.  It is in an area of weak steering winds, and Higos is moving slowly.  The increased intensity and vertical height of the circulation make it more likely that Higos will move toward the north as it reaches the western end of the subtropical ridge.  The guidance from numerical models has increased the probability of this track.

 

Tropical Storm Higos Forms East of Guam

A center of circulation consolidated within a large area of thunderstorms centered about 900 miles east of Guam and the system was designated as Tropical Storm Higos.  At 10:00 p.m. EST on Saturday the center of Tropical Storm Higos was located at latitude 12.1°N and longitude 157.4°E which put it about 480 miles northeast of Fananu and about 850 miles east of Guam.  Higos was moving toward the north-northwest at 7 m.p.h.  The maximum sustained wind speed was 45 m.p.h. and there were wind gusts to 60 m.p.h.  The minimum surface pressure was 993 mb.

Higos was moving over warm Sea Surface Temperatures.  Satellite imagery indicated that upper level divergence was well developed and there appeared to be an outflow channel to the northeast.  As the divergence pumped out mass, the surface pressure decreased and the wind speeds increased.  A spiral band of thunderstorms wrapped around the center of circulation and the system displayed increased organization.  Higos has the potential to intensify during the next 24 to 48 hours and it could possible become a typhoon.  Later in the week stronger upper level winds are expected to increase the vertical wind shear and weaken Higos.

Higos was near the western end of a subtropical ridge of high pressure which was steering it toward the northwest.  The subtropical ridge is expected to continue to steer the storm toward the northwest in the short term.  Over the longer term the track of Higos will depend to some extent on how strong it becomes.  If it intensifies more, Higos will be affected more strongly by upper level westerly winds located farther north.  Those winds would cause Higos to take a more northerly track.  If Higos remains weaker, then it could be less affected by the upper level westerlies and it might take a track farther south.  Guidance from numerical models is split between a more northerly and a more westerly track.

 

Tropical Cyclone Fundi Forms Near the Southwest Coast of Madagascar

A well defined center of circulation developed in the lower levels of an area of thunderstorms near the southwest coast of Madagascar and the system was designated as Tropical Cyclone Fundi.  At 5:00 p.m. EST on Friday the center of Tropical Cyclone Fundi was located at latitude 22.8°N and longitude 42.9°E which put it about 60 miles west of Toliara, Madagascar.  Fundi was moving toward the southeast at 8 m.p.h.  The maximum sustained wind speed was 40 m.p.h. and there were gusts to 50 m.p.h.  The minimum surface pressure was 999 mb.

The environment around Fundi contains some factors that would support intensification and other factors that would inhibit intensification.  It is over warm Sea Surface Temperatures and there is well developed outflow in the upper levels.  Those factors would favor intensification.  However, the center of circulation is very close to the coast of Madagascar and part of the circulation is over land.  Interaction with land will inhibit future intensification.  If the center of circulation remains over the water, then some intensification is possible during the next day or two.  If the center of circulation moves over southern Madagascar, then it will weaken.  Eventually, Fundi will move poleward and encounter colder Sea Surface Temperatures and more vertical wind shear.

 

A subtropical ridge located east of Fundi is steering the tropical cyclone toward the southeast.  The ridge is expected to continue to steer it toward the southeast or south in the short term.  As Fundi moves farther south, it will begin to encounter upper level westerly winds which will turn it more toward the east.