Tropical Cyclone Forms Over Northern Bay of Bengal

A tropical cyclone formed over the northern Bay of Bengal on Thursday.  At 11:00 a.m. EDT on Thursday the center of the tropical cyclone was located at latitude 20.0°N and longitude 86.5°E which put it about 25 miles (40 km) south-southwest of Paradip, India.  The cyclone was moving toward the north-northeast at 18 m.p.h. (30 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 999 mb.

A center of low pressure developed within a broader area of showers and thunderstorms over the northern Bay of Bengal on Thursday.  A wide band of showers and thunderstorms wrapped around the eastern side of the circulation.  The center of circulation was west of that primary rainband.  Additional bands of showers and thunderstorms formed in other parts of the circulation.  The circulation exhibited enough organization and characteristics to be classified as a tropical cyclone.  The Indian Meteorological Department was giving the the system a classification of depression.

The tropical cyclone is being steered north by a ridge of high pressure to its east.  On its anticipated track the tropical cyclone with make landfall on the coast of the northern Bay of Bengal within 12 hours.  Although the tropical cyclone is moving over water where the Sea Surface Temperature is near 31°C and there is not much vertical wind shear, it does not have much time to intensify before the center moves inland.  The tropical cyclone could strenthen a little more prior to landfall.  It will bring a storm surge of several feet (one to two meters) to the coast along the northern Bay of Bengal.  The tropical cyclone will also drop locally heavy rain and flooding could occur in some parts of India and Bangladesh.

Lan Strengthens to a Typhoon East of the Philippines

Tropical Storm Lan strengthened east of the Philippines on Tuesday and the Japan Meteorological Agency designated it a typhoon.  At 5:00 p.m. EDT on Tuesday the center of Typhoon Lan was located at latitude 11.2°N and longitude 132.4°E which put it about 515 miles (830 km) east of the Philippines.  Lan was moving toward the north-northeast at 5 m.p.h. (8 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 976 mb.

The circulation of Typhoon Lan became much more well organized on Tuesday.  Several long rainbands developed in the circulation and other smaller bands formed in the periphery of the typhoon.  The circulation of Typhoon Lan was circular and symmetrical.  Thunderstorms near the core of Lan began to generate strong upper level divergence which was pumping mass away from the typhoon in all directions.  The upper level divergence allowed the surface pressure to decrease and the wind speed to increase.  Lan is a large typhoon.  Winds to tropical storm force extend out about 230 miles (370 km) from the center of circulation.

Typhoon Lan will move through an environment favorable for intensification.  Lan will move over water where the Sea Surface Temperature is near 30°C.  Typhoon Lan will move through an area where the upper level winds will be weak and there will be little vertical wind shear during the next several days.  Typhoon Lan will continue to strengthen and there could be a period of rapid intensification after a well formed eye develops at the center of circulation.

Typhoon Lan was in an area where the steering currents were weak and it moved little on Tuesday.  An upper level ridge north of Lan blocked the typhoon from moving northward.  A weakness is forecast to develop in the ridge and the models are forecasting that Typhoon Lan will move northward during the rest of this week.  On its anticipated track Typhoon Lan will remain east of the Philippines.  Lan could be southeast of Okinawa in three or four days.

Former Hurricane Ophelia Brings Strong Winds to Ireland

Former Hurricane Ophelia brought strong winds to Ireland and parts of the United Kingdom on Monday.  Although former Hurricane Ophelia had made a transition to an extratropical cyclone before it reached Ireland, it was still a very powerful storm when it moved across that region.  There were reports of several fatalities, damage and power outages across Ireland.  Met Eireann (the Irish meteorological agency) reported the following wind gusts during the passage of former Hurricane Ophelia.

At the Fastnet Lighthouse (anemometer at 200 feet [61 meters] ) there was a gust of 191 km/h (118 m.p.h.).  Sherkin Island reported a wind gust of 135 km/h (84 m.p.h.) before the power went out.  Cork airport reported a wind gust of 126 km/h (78 m.p.h.) before the power went out. Shannon airport reported a wind gust of 122 km/h (76 m.p.h.).  Roches Point reported a wind gust of 156 km/h (97 m.p.h.).  The Kinsale Platform reported a wind gust of 141 km/h (87 m.p.h.) and the Dublin airport reported a wind gust of 104 km/h (65 km/h).

Tropical Storm Lan Develops Northwest of Palau

Tropical Storm Lan developed northwest of Palau on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Lan was located at latitude 10.7°N and longitude 132.1°E which put it about 275 miles (445 km) north-northwest of Koror, Palau.  Lan was moving toward the west at 12 m.p.h. (19 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 993 mb.

A more distinct center of circulation developed within Tropical Storm Lan, but the low pressure system was still in the process of organizing.  The low level center of circulation of Lan was at the end of a long rainband that extends from the western periphery around the southern and eastern parts of the tropical storm.  That low level center appeared to be on the northern side of a much larger counterclockwise rotation.  Most of the stronger showers and thunderstorms were occurring in the long rainband.  A few new, thinner bands of showers and thunderstorms seemed to be forming inside the long rainband to west of the center of circulation.

Tropical Storm Lan will be moving through an environment that will be favorable for intensification.  Lan will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of Lan is producing easterly winds which were blowing toward the top of the circulation.  There was some vertical wind shear, but it was not strong enough to prevent the intensification of Tropical Storm Lan.  Tropical Storm Lan is likely to intensify more slowly while the circulation organizes.  Once the center of circulation become tighter, then Lan could intensify more quickly.  A period of rapid intensification could occur, if Lan becomes a typhoon and an eye develops.

The ridge north of Lan and the counterclockwise flow to its south are combining to steer the tropical storm toward the west.  Numerical models are indicating that a weakness will develop in the ridge north of Tropical Storm Lan.  If that happens, then the steering current could weaken for 12 to 24 hours and Tropical Storm Lan might not move much.  If the break in the ridge becomes more pronounced, then Tropical Storm Lan could start to move more toward the north.  On its anticipated track Tropical Storm Lan is expected to remain east of the Philippines, but the tropical storm could move closer to the northern Philippines if the forecast weakness in the ridge does not occur.

Typhoon Khanun Makes Landfall in Southern China

Typhoon Khanun made landfall near Zhanjiang in southern China on Sunday.  At 5:00 p.m. EDT on Sunday the center of Typhoon Khanun was located at latitude 20.9°N and longitude 109.3°E which put it about 50 miles (80 km/h) south-southeast of Beihai, China.  Khanun was moving toward the west at 17 m.p.h. (27 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 969 mb.

Typhoon Khanun brought gusty winds and locally heavy rain over coastal sections of southern China on Sunday.  Khanun has weakened since it made landfall.  An upper level ridge centered over eastern China is producing easterly winds which are blowing over the top of the circulation.  Those winds are causing strong vertical wind shear, which is pushing the upper half of the circulation to the west of low level circulation.  The circulation is pulling drier air from Asia into the western part of Typhoon Khanun and the drier air is wrapping around the southern and eastern sides of the circulation.   Interaction with land and strong vertical wind shear will continue to weaken Khanun on Monday.  Khanun will bring rain to southern China and northern Vietnam as it weakens.

Elsewhere over the western North Pacific Ocean Tropical Depression Twentyfive-W formed west of Yap.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression Twentyfive-W was located at latitude 10.3°N and longitude 136.1°E which put it about 125 miles (200 km) west-northwest of Yap.  It was moving toward the north-northwest at 11 m.p.h. (17 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 999 mb.

The circulation of Tropical Depression Twentyfive-W is still organizing.  Most of the showers and thunderstorms are in a primary rainband that wraps around the eastern side of the circulation.  The depression is moving through an area favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is not much vertical wind shear.  Tropical Depression Twentyfive-W is likely to be become a tropical storm during the next 24 hours and it could become a typhoon in a couple of days.  The depression is forecast to move toward the north-northwest as it moves around the western end of a subtropical ridge over the Pacific Ocean.

Khanun Intensifies Into a Typhoon Southeast of Hong Kong

Tropical Storm Khanun intensified into a typhoon southeast of Hong Kong on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Khanun was located at latitude 20.1°N and longitude 114.2°W which put it about 170 miles (275 km) south-southeast of Hong Kong.  Khanun was moving toward the west-northwest at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 965 mb.

The circulation of Typhoon Khanun became much more well organized on Saturday.  A small circular eye formed at the center of circulation.  A tight ring of strong thunderstorms formed around the eye.  The strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Typhoon Khanun.  There were many more showers and thunderstorms in the western half of the circulation.  The storms in the core of Khanun were generating upper level divergence which was pumping mass away to the west of the typhoon.  Winds to typhoon force extended out about 70 miles (110 km) from the center of circulation.  Winds to tropical storm force extended out about 250 miles (400 km) from the center.

Typhoon Khanun will move through an environment favorable for intensification for about another 12 to 18 hours.  Khanun will move over water where the Sea Surface Temperature is near 29°C.  An upper level ridge north of Typhoon Khanun is producing easterly winds which are blowing toward the top of the circulation.  The easterly winds are causing some vertical wind shear, but the shear is not strong enough to prevent intensification.  The circulation of Typhoon Khanun will interact with land in 12 to 18 hours and that interaction should halt further intensification.

The ridge north of Khanun has been steering the typhoon toward the west-northwest.  The ridge is forecast to strengthen on Sunday and it will steer Typhoon Khanun more toward the west.  On its anticipated track the center of Typhoon Khanun will pass south of Hong Kong and Macao on Sunday.  Khanun will approach the south coast of China near Zhanjiang in 12 to 18 hours.  Typhoon Khanun will bring strong gusty winds and locally heavy rain to southern China west of Hong Kong and Macao.  The heavy rain could cause flooding in some locations.  Typhoon Khanun will be weaker when it moves over the Gulf of Tongking in about 24 hours.

Ophelia Strengthens to Major Hurricane South of the Azores

Hurricane Ophelia strengthened into a Category 3 hurricane on the Saffir-Simpson Scale on Saturday morning as it moved south of the Azores.  That made Ophelia a major hurricane.  At 11:00 a.m. EDT on Saturday the center of Hurricane Ophelia was located at latitude 34.8°N and longitude 26.6°W which put it about 220 miles (355 km) south of the Azores.  Ophelia was moving toward the northeast at 25 m.p.h. (40 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 135 m.p.h. (220 km/h).  The minimum surface pressure was 960 mb.

It is very unusual to have such a strong hurricane near the Azores, but Ophelia contains all of the elements of a major hurricane.  There is a circular eye at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in that ring of storms.  Well formed rainbands exists in the outer portions of the circulation.  Storms in the core of Ophelia are generating upper level divergence which is pumping mass away to the northeast of the hurricane.  Winds to hurricane force extend out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extend out about 125 miles (205 km) from the center.

Hurricane Ophelia is moving over water where the Sea Surface Temperature is near 25°C.  Normally, water at that temperature would be considered to be too cool to support the development of a major hurricane.  However, the temperature of the air in the upper troposphere is also cool and so the atmosphere is unstable enough to allow for the development of deep convection.  An upper level trough west of Ophelia is producing southwesterly winds which are blowing toward the top of the circulation.  There are also southwesterly winds in the lower and middle levels of the atmosphere and so the vertical wind shear is not strong enough to inhibit intensification

Hurricane Ophelia will be moving over cooler water and it is likely to weaken gradually during the next several days.  When Ophelia moves over the cooler water it will make a transition to an extratropical cyclone.  The size of the circulation will increase during the transition.  Hurricane Ophelia will evolve into a large very powerful extratropical cyclone during the next several days.

The trough west of Ophelia is steering the hurricane toward the northeast.  Hurricane Ophelia is expected to turn more toward the north during the next two or three days.  On its anticipated track Hurricane Ophelia will pass east of the Azores later today.  The strong extratropical cyclone that Ophelia will transition into could approach Ireland and the United Kingdom by Monday morning.  That cyclone will bring very strong winds and heavy rain to that region.

Hurricane Ophelia Moves Closer to the Azores

Hurricane Ophelia moved closer to the Azores on Friday.  At 5:00 p.m. EDT on Friday the center of Hurricane Ophelia was located at latitude 32.3°N and longitude 31.8°W which put it about 480 miles (770 km) southwest of the Azores.  Ophelia was moving toward the east-northeast at 13 m.p.h. (20 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 971 mb.

Despite moving over slightly cooler water, Hurricane Ophelia maintained its structure and intensity on Friday.  There was a small circular eye at the center of circulation, although there appeared to be a break on the northwest side of the ring of thunderstorms around the eye.  Thunderstorms in the core of Ophelia were generating upper level divergence which was pumping away mass.  Bands of showers and thunderstorms were revolving around the core of Hurricane Ophelia.  The stronger rainbands were in the eastern half of the circulation.  Winds to hurricane force extended out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out about 100 miles (160 km) from the center.

Hurricane Ophelia will move through an environment that is capable of supporting a strong cyclone.  Ophelia will move over water where the Sea Surface Temperature is near 25°C.  Normally, that water would be too cool to support a strong hurricane.  However, the temperature in the upper levels of the atmosphere is also cool and that is keeping the atmosphere unstable enough to allow for thunderstorms to develop.  The speed of the winds in Hurricane Ophelia is likely to decrease gradually during the next several days.

When Hurricane Ophelia moves farther north, it will move into a cooler environment with stronger westerly winds in the upper levels.  A cooler environment with more vertical wind shear will cause the structure of Hurricane Ophelia change into the structure of an extratropical cyclone.  The area of stronger winds will expand and the cyclone will become much larger.

Hurricane Ophelia is being steered toward the east-northeast by westerly winds in the middle levels.  A trough will approach Hurricane Ophelia from the west.  Southwesterly winds ahead of the trough will carry Ophelia more toward the north in about 36 hours.  On its anticipated track the center of Hurricane Ophelia will move south of the Azores on Saturday.  Ophelia could bring gusty winds and rain to the Azores when it moves by those islands.  The strong extratropical cyclone that evolves from Hurricane Ophelia could approach Ireland and the United Kingdom on Monday.  That cyclone could bring very strong winds and heavy rain to that region.

Tropical Storm Khanun Forms Near Luzon

Tropical Storm Khanun formed near northern Luzon on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Khanun was located near latitude 18.0°N and longitude 121.6°W which put it about 240 miles (390 km) north of Manila, Philippines.  Khanun was moving toward the west at 13 m.p.h. (21 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 994 mb.

A center of circulation developed near the surface in an area of thunderstorms on Thursday and the Japan Meteorological Agency designated the system as Tropical Storm Khanun.  The circulation of Tropical Storm Khanun was still organizing.  The center of Khanun moved across northern Luzon and the passage over land interrupted the development of the circulation.  Despite the passage over land, a primary rainband wrapped around the western side of the circulation.  Additional bands of showers and thunderstorms developed in the western half of the circulation.  The rainbands were weaker in the eastern half of Khanun, especially in the part of the circulation still over northern Luzon.

Tropical Storm Khanun will move through an environment favorable for intensification when it moves over the South China Sea.  Khanun will move over water where the Sea Surface Temperature is near 30°C.  The tropical storm is moving under the western half of an upper level ridge.  The ridge is producing easterly winds which are blowing toward the top of the circulation.  Those winds are causing moderate vertical wind shear.  The shear will slow the rate of intensification, but it should not be strong enough to prevent Tropical Storm Khanun from intensifying.  Khanun should start to strengthen once the center move farther west of Luzon.  Tropical Storm Khanun is forecast to become a typhoon during the weekend.

Tropical Storm Khanun is moving south of a ridge which is steering the tropical storm toward the west.  A generally westward motion is expected to continue during the next several days.  On its anticipated track Tropical Storm Khanun could approach Hainan Island in about 48 hours.  Khanun is likely to be a typhoon at that time.

Ophelia Strengthens Into a Hurricane Southwest of the Azores

Tropical Storm Ophelia strengthened into a hurricane southwest of the Azores on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Ophelia was located at latitude 30.0°N and longitude 35.7°W which put it about 745 miles (1195 km) southwest of the Azores.  Ophelia was moving toward the northeast at 3 m.p.h.  The maximum sustained wind speed was 85 m.p.h. (140 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 986 mb.

The circulation of Hurricane Ophelia became more circular and symmetrical on Wednesday.  A circular eye developed at the center of circulation.  Thunderstorms in the ring around the eye became taller.  Additional bands of showers and thunderstorms were revolving around the core of Hurricane Ophelia.  Thunderstorms in the core were producing upper level divergence which was pumping mass away to the east of the hurricane.  Winds to hurricane force extended out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out about 70 miles (110 km) from the center.

Hurricane Ophelia will be moving through an environment that could support further intensification on Thursday.  Ophelia will move over water where the Sea Surface Temperature is near 26.5°C.  Ophelia is in an area of weaker upper level winds.  It is north of the subtropical jet stream and it is south of the stronger westerly winds in the middle latitudes.  As a result the vertical wind shear is minimal.  The combination of warm water and little shear allowed Ophelia to intensify into a hurricane and it could strengthen further on Thursday.

Hurricane Ophelia is in an area of weak westerly winds which are steering the hurricane slowly toward the east.  An upper level trough will approach Ophelia from the west and the trough will start to pull the hurricane toward the northeast more quickly later this week.  On its anticipated track Hurricane Ophelia could approach the Azores in two or three days.