Tropical Cyclone Vayu Weakens South of Pakistan

Tropical Cyclone Vayu weakened over the Arabian Sea south of Pakistan on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Cyclone Vayu was located at latitude 24.2°N and longitude 65.3°E which put it about 275 miles (445 km) south-southwest of Karachi, Pakistan.  Vayu was moving toward the northwest 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.

The low level circulation around Tropical Cyclone Vayu remained well organized on Saturday, but the distribution of thunderstorms was asymmetrical.  The stronger thunderstorms were occurring in the southern half of the former eyewall and in several rainbands in the southern half of the circulation.  The strongest winds were occurring in the remaining portion of the eyewall.  Bands in the northern half of the circulation consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out about 150 miles (240 km) from the center of circulation.

The circulation around Tropical Cyclone Vayu continued to draw drier air into the northern half of the tropical cyclone on Saturday.  An upper level ridge north of Vayu was producing strong northeasterly winds which were blowing toward the top of the circulation.  Those winds were causing moderate vertical wind shear.  The drier air and wind shear were the primary factors causing the asymmetrical distribution of thunderstorms.

Tropical Cyclone Vayu will move through an environment unfavorable for intensification during the next 24 hours.  Even though Vayu will move over water where the Sea Surface Temperature is near 30°C, the combined effects of the drier air and the wind shear are likely to cause the tropical cyclone to continue to weaken on Sunday.  If the upper level winds get stronger, they could blow the upper half of the circulation southwest of the lower part of Tropical Cyclone Vayu.  In that case Vayu will weaken more quickly.

The future track of Tropical Cyclone Vayu will also depend on the vertical wind shear.  If the wind shear is not too strong and the circulation remains vertically intact, then the ridge north of Vayu will steer the tropical cyclone slowly toward the northwest on Sunday.  If the upper level winds blow the upper half of the circulation away from the lower portion of Tropical Cyclone Vayu, then southwesterly winds in the lower atmosphere will blow the shallower system toward the northeast.  Guidance from numerical models suggest this second scenario is more likely and the anticipated track takes Tropical Cyclone Vayu toward the northeast.

Tropical Cyclone Vayu Stalls, Weakens Southwest of Gujarat

Tropical Storm Vayu stalled and weakened southwest of Gujarat on Friday.  At 11:00 p.m. EDT on Friday the center of Tropical Cyclone Vayu was located at latitude 20.6°N and longitude 67.4°E which put it about 170 miles (275 km) southwest of Dwarka, India.  Vayu was moving toward the west at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 90 m.p.h. (150 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 969 mb.

The structure of the inner core of Tropical Cyclone Vayu changed significantly on Friday.  The previous small eye disappeared and a large new eye with a diameter of 50 miles (80 km) developed at the center of Vayu.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  The strongest rainbands were located in the southern half of the circulation.  Bands in the northern half of the circulation consisted primarily of showers and lower clouds.  Winds to hurricane/typhoon force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm extended out about 150 miles (240 km) from the center.

The environment around Tropical Cyclone Vayu will become less favorable for a tropical cyclone on Saturday.  An upper level ridge north of Vayu will strengthen.  The ridge will produce stronger northeasterly winds which will blow toward the top of the circulation.  Those winds will cause more vertical wind shear.  Tropical Cyclone Vayu will also continue to pull drier air into the northern half of the circulation.  Vayu will move over water where the Sea Surface Temperature is near 30°C.  Even though Tropical Cyclone Vayu will be over very warm water, the combined effects of stronger wind shear and drier air are likely to cause it to weaken on Saturday.

The ridge north of Vayu will block the tropical cyclone from moving toward the north on Saturday.  The ridge is likely to continue to steer Tropical Cyclone Vayu slowly toward the west over the northeastern Arabian Sea during the next 24 hours.  On its anticipated track Vayu will move farther away from Gujarat and Pakistan on Saturday.

Tropical Cyclone Vayu Turns West Over Northeast Arabian Sea

Tropical Cyclone Vayu turned west over the northeastern Arabian Sea on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Vayu was located at latitude 20.9°N and longitude 68.4°E which put it about 80 miles (130 km) southwest of Porbandar, India.  Vayu was moving toward the west-northwest at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 960 mb.

Tropical Cyclone Vayu maintained its intensity on Thursday, but the circulation exhibited slightly less organization.  A small eye continued to mark the center of circulation.  A ring of strong thunderstorms surrounded the eye, but there was a break in the northeastern portion of the ring.  The circulation continued to pull drier air into the northern part of the tropical cyclone.  Many of the stronger thunderstorms were occurring in bands in the southern half of the circulation.  Rainbands in the northern half of the circulation were weaker.  Winds to hurricane/typhoon force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 125 miles (200 km) from the center.

Tropical Cyclone Vayu will continue to move through an environment capable of sustaining a tropical cyclone on Friday.  Vayu will move under the axis of an upper level ridge where the winds are weaker and there will be little vertical wind shear.  The Sea Surface Temperature in the northeastern Arabian Sea is near 30°C.  However, Tropical Cyclone Vayu moved slowly on Thursday and it may have stirred some cooler water to the surface.  In addition, the circulation around Vayu will continue to draw in drier air from over south Asia.  Tropical Cyclone Vayu could start to weaken slowly on Friday, although it could maintain its intensity if it moves away from the upwelled cooler water.

Tropical Cyclone Vayu will be south of a strengthening ridge of high pressure over south Asia.  The ridge will block Vayu and prevent it from moving farther toward the north.  The ridge will steer Vayu slowly toward the west during the next 24 to 48 hours.  On its anticipated track Tropical Cyclone Vayu will remain southwest of Gujarat and south of Pakistan during the next two days.

Tropical Cyclone Vayu Slows Near Gujarat Coast

Tropical Cyclone Vayu slowed near the coast of Gujarat on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Vayu was located at latitude 20.4°N and longitude 69.1°E which put it about 85 miles (135 km) south-southwest of Porbandar, India.  Vayu was moving toward the north-northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 962 mb.

The circulation around Tropical Cyclone Vayu weakened slightly on Wednesday, although the inner core appeared to remain mostly intact.  The circulation seemed to pull some drier air over India into the eastern and northern portions of Vayu.  Outer rainbands weakened in those parts of the tropical cyclone.  The drier air did not appear to have penetrated the inner core of the circulation.  A tiny eye remained at the center of circulation.  A ring of showers and thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Bands of strong thunderstorms in the southern half of the circulation were revolving around the core of Tropical Cyclone Vayu.  Winds to hurricane/typhoon force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extended out about 120 miles (195 km) from the center.

Tropical Cyclone Vayu will move through an environment that will be mainly favorable for a tropical cyclone during the next 24 to 48 hours.  Vayu will move over water where the Sea Surface Temperature is near 30°C.  It will move near the axis of an upper level ridge where winds are weaker and there will be less vertical wind shear.  The drier air being pulled into the circulation from over India will be a factor that could inhibit any additional strengthening of Tropical Cyclone Vayu.  Vayu could strengthen during the next 24 hours, but it is more likely to maintain its intensity or weaken slightly.  If drier air mixes into the inner core of the circulation, then Tropical Cyclone Vayu could weaken more quickly.

Tropical Cyclone Vayu will move around the western end of a ridge over India during the next 12 to 24 hours.  The ridge will steer Vayu toward the north-northwest on Thursday.  A second ridge will develop north of Tropical Cyclone Vayu.  The second ridge will block the northward movement of Vayu and force the tropical cyclone to move more toward the west.  On its anticipated track the core of Tropical Cyclone Vayu will remain west of the coast of Gujarat.  Bands on the eastern side of the circulation could drop rain over Gujarat but the strongest part of the circulation is likely to remain offshore.

Tropical Cyclone Vayu Strengthens to Equivalent of Hurricane/Typhoon

Tropical Cyclone Vayu strengthened into the equivalent of a hurricane/typhoon over the eastern Arabian Sea on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Tropical Cyclone Vayu was located at latitude 16.4°N and longitude 70.8°E which put it about 200 miles (320 km) southwest of Mumbai, India.  Vayu was moving toward the north at 10 m.p.h. (16 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. (150 km/h).  The minimum surface pressure was 974 mb.

Microwave satellite imagery indicated that an inner rainband had wrapped completely around the center of circulation and a small eye had formed at the center of Tropical Cyclone Vayu.  The core of Vayu was relatively small.  Winds to hurricane/typhoon force only extended out about 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extended out about 100 miles (160 km) from the center.  Storms around the core of Tropical Cyclone Vayu were generating upper level divergence which was pumping mass to the west of the tropical cyclone.  Additional bands of showers and thunderstorms were revolving around the core of Vayu.

Tropical Cyclone Vayu will move through an environment favorable for intensification during the next 24 to 36 hours.  Vayu will move over water where the Sea Surface Temperature is near 30°C.  Tropical Cyclone Vayu will move near the southwestern portion of an upper level ridge.  The ridge will produce southeasterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification.  Tropical Cyclone Vayu will intensify during the next 24 to 36 hours.  It could intensify rapidly once the eye and eyewall are fully formed.  Vayu could strengthen into the equivalent of a major hurricane.

Tropical Cyclone Vayu will move around the western end of a ridge over India.  The ridge will steer Vayu toward the north.  On its anticipated track Tropical Cyclone Vayu could approach the coast of Gujarat within 36 hours.  Vayu could be the equivalent of a major hurricane by that time.  It could bring strong winds and locally heavy rain to Gujarat.  Heavy rain could cause flash floods.  Tropical Cyclone Vayu could also generate a significant storm surge along the coast of Gujarat.

Tropical Cyclone Forms Over Eastern Arabian Sea

A tropical cyclone formed over the eastern Arabian Sea on Monday.  At 11:00 a.m. EDT on Monday the center of Tropical Cyclone 02A was located at latitude 13.7°N and longitude 70.8°E which put it about 400 miles (645 km) south-southwest of Mumbai, India.  It was moving toward the north-northwest at 10 m.p.h. (16 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 996 mb.

More thunderstorms formed near the center of a low pressure system over the eastern Arabian Sea on Monday and the system exhibited sufficient organization to be designated a tropical cyclone.  The distribution of thunderstorms around the tropical cyclone was asymmetrical.  Most of the stronger thunderstorms were located in bands developing in the western half of the circulation.  The inner portions of a rainband was wrapping around the southern side of the center of circulation.  Bands in the eastern half of the circulation consisted primarily of lower clouds and showers.  Winds to tropical storm force extended out about 60 miles (95 km) from the center of circulation.

Tropical Cyclone 02A developed southwest of an upper level ridge.  The ridge was producing easterly winds which were blowing toward the top of the circulation.  Those winds were causing moderate vertical wind shear and they were the primary cause for the asymmetrical distribution of thunderstorms.  The tropical cyclone will move over water where the Sea Surface Temperature is near 30°C.   Wind shear will inhibit intensification, but it will not be strong enough to prevent Tropical Cyclone 02A from strengthening.  The tropical cyclone will gradually intensify and it could strengthen to the equivalent of a hurricane/typhoon.  If an eye and eyewall form as part of an inner core and the wind shear decreases, then a period of rapid intensification could occur.

Tropical Cyclone 02A will move around the western end of the upper level ridge.  The ridge will steer the tropical cyclone toward the north-northwest during the next several days.  On its anticipated track Tropical Cyclone 02A could approach the coast of Gujarat within 72 hours.  it could be the equivalent of a hurricane/typhoon by that time.

Subtropical Storm Andrea Develops Southwest of Bermuda

Subtropical Storm Andrea developed southwest of Bermuda on Monday afternoon.  An Air Force Reserve Hurricane Hunter aircraft investigated an area of low pressure southwest of Bermuda on Monday afternoon.  The aircraft determined that there was a well defined center of circulation at the surface and the National Hurricane Center designated the system as Subtropical Storm Andrea.  At 11:00 p.m. EDT on Monday the center of Subtropical Storm Andrea was located at latitude 29.5°N and longitude 68.7°W which put it about 300 miles (485 km) southwest of Bermuda.  Andrea was moving toward the north at 12 m.p.h. (19 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 1006 mb.

The circulation around Subtropical Storm Andrea was asymmetrical.  Most of the thunderstorms and the strongest winds were occurring northeast of the center of circulation.  Bands in other parts of the circulation consisted primarily of lower clouds and showers and the winds were weaker in those parts of Andrea.  An upper low northeast of the Bahamas was producing southerly winds which were blowing toward the top of the circulation.  Those winds were creating moderate vertical wind shear and the shear was the primary cause of the asymmetrical structure of Subtropical Storm Andrea.  The asymmetrical structure was the reason why Andrea was classified as a subtropical storm.  Winds to tropical storm force extended out about 65 miles (105 km) from the center of Andrea in the northeastern quadrant of the circulation.

Subtropical Storm Andrea will move through an environment marginally favorable for intensification on Tuesday.  Andrea will move over water where the Sea Surface Temperature is near 25°C.  The upper low will continue to cause moderate vertical wind shear, but the low could weaken slightly on Tuesday.  If the upper level winds weaken, then Andrea could get stronger.  Stronger upper level westerly winds could affect Subtropical Storm Andrea on Wednesday.  Those winds will cause stronger vertical wind shear which will weaken Andrea.

The upper level low northeast of the Bahamas will steer Subtropical Storm Andrea toward the north during the next 12-18 hours.  After that time the upper level westerly winds are likely to steer Andrea more toward the east.  On its anticipated track Subtropical Storm Andrea could be near Bermuda in about 36 hours.  Andrea could bring gusty winds and rain showers to Bermuda on Wednesday.

Weaker Tropical Cyclone Ann Nears Northern Queensland

A weaker Tropical Cyclone Ann neared northern Queensland on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Cyclone Ann was located at latitude 14.4°S and longitude 148.4°E which put it about 230 miles (370 km) east-northeast of Cooktown, Australia.  Ann was moving toward the west-northwest at 14 m.p.h. (22km/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 996 mb.  The Australian Bureau of Meteorology issued a Tropical Cyclone Warning that extended from Lockhart River to Cooktown including Coen and Lizard Island.

The circulation around Tropical Cyclone Ann weakened on Monday because of a drier, more stable environment and more vertical wind shear.  Low level convergence pulled drier, more stable air closer to the center of Tropical Cyclone Ann.  The drier, more stable air caused many of the stronger thunderstorms to weaken.  Despite the drier, more stable environment stronger thunderstorms redeveloped south of the center of circulation late on Monday.  Tropical Cyclone Ann was moving near the northwestern portion of an upper level ridge.  The ridge produced easterly winds which caused moderate vertical wind shear.  The wind shear also contributed to the weakening of storms in the northern half of the circulation.

Tropical Cyclone Ann continued to have a distinct low level center of circulation despite the less favorable environment.  However, the wind field exhibited a more asymmetric structure.  The strongest winds were occurring in an area of thunderstorms south of the center of circulation.  Winds to tropical storm force extended out about 100 miles (160 km) from the center in the southern half of the circulation.  Winds to tropical storm force only extended out about 50 miles (80 km) from the center in the northern half of the circulation.

Tropical Cyclone Ann will continue to move through a less favorable environment during the next 24 hours.  Ann will move over water in the Coral Sea where the Sea Surface Temperature is near 27.5°C.  It will continue to move through a region where there is drier, more stable air and the upper level ridge will continue to cause moderate vertical wind shear.  The drier, more stable air and moderate vertical wind shear will prevent significant intensification.  Tropical Cyclone Ann could maintain its intensity during the next 12 hours, but it may weaken when it approaches the coast of the Cape York Peninsula.

Tropical Cyclone Ann will move north of a ridge which will steer Ann toward the west-northwest.  On its anticipated track Tropical Cyclone Ann will make landfall on the Cape York Peninsula in northern Queensland in about 24 hours.  Ann will bring some gusty winds, but the greatest risk will be locally heavy rain.

Tropical Cyclone Ann Strengthens Over Coral Sea

Tropical Cyclone Ann strengthened over the Coral Sea on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Ann was located at latitude 15.4°S and longitude 153.6°E which put it about 565 miles (910 km) east of Cairns, Australia.  Ann was moving toward the west-northwest at 15 m.p.h. (24 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 987 mb.

The circulation around Tropical Cyclone Ann exhibited greater organization on Sunday.  There were indications on satellite images that a cloud filled eye might be trying to form at the center of circulation.  A broken ring of thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Ann.  Storms near the core were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to tropical storm force extended out about 100 miles (160 km) from the center of circulation.

Tropical Cyclone Ann will be moving through an environment that contains factors favorable for intensification and a factor that will inhibit potential intensification.  Ann will move over water where the Sea Surface Temperature is near 28°C.  So, there will be sufficient energy in the upper ocean to support intensification.  Tropical Cyclone Ann will move north of an upper level ridge.  The ridge will produce easterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification.  Tropical Cyclone Ann is surrounded by drier more stable air and the drier air is the factor that will inhibit intensification.  So far, the circulation around Ann has kept the drier air outside the tropical cyclone.  If the drier air remains outside the circulation, then Tropical Cyclone Ann would have a chance to strengthen.  However, if the drier air gets pulled into the circulation, then Ann will weaken.  The higher probability is that Tropical Cyclone Ann could maintain its intensity or weaken slowly during the next day or two depending on what happens to the drier air.

Tropical Cyclone Ann will move north of an area of high pressure, which will steer the tropical cyclone toward the west-northwest.  On its anticipated track Ann will approach the Cape York Peninsula north of Coen in less than 48 hours.  Tropical Cyclone Ann could bring gusty winds and locally heavy rain to northern Queensland.

Tropical Cyclone Ann Forms Over Coral Sea

Tropical Cyclone Ann formed over the Coral Sea on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Ann was located at latitude 16.3°S and longitude 158.7°E which put it about 875 miles (1410 km) east of Cairns, Australia.  Ann was moving toward the west at 5 m.p.h. (8 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 999 mb.

A distinct low level center of circulation became more evident in satellite images of a low pressure system over the eastern Coral Sea on Saturday and the system was designated as Tropical Cyclone Ann.  A rainband wrapped around the southern and western sides of the center of circulation.  A microwave satellite image indicated that the band may have wrapped completely around the center in the middle levels of the circulation.  Storms near the center of circulation began to generate upper level divergence which was pumping mass away from the tropical cyclone.  The circulation around Tropical Cyclone Ann was relatively small.  Winds to tropical storm force extended out about 85 miles (135 km) from the center of circulation in the southern half of Ann.

Tropical Cyclone Ann will move through an environment somewhat favorable for intensification during the next day or two.  Ann will move over water where the Sea Surface Temperature is near 28.5°C.  It will move south of an upper level ridge.  The ridge will produce easterly winds which will cause some vertical wind shear.  The shear will inhibit intensification, but it is not likely to be strong enough to prevent intensification.  Tropical Cyclone Ann is likely to intensify during the next 24 hours.

The ridge will steer Tropical Cyclone Ann toward the west-northwest during the next two to three days.  On its anticipated track Tropical Cyclone Ann will approach the Cape York Peninsula in northern Queensland in about 72 hours.  Ann could bring gusty winds and locally heavy rain.

Elsewhere around the tropics in the southern hemisphere, Tropical Cyclone Lili was weakening near the coast of East Timor.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Lili was located at latitude 9.1°S and longitude 126.8°E which put it about 120 miles (195 km) east-northeast of Suai, East Timor.  Lili was moving toward the west at 4 m.p.h. (6 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 1000 mb.