Monthly Archives: October 2016

Seymour Strengthens Into a Cat. 4 Hurricane

Hurricane Seymour strengthened into a small but very powerful Category 4 hurricane on the Saffir-Simpson Scale on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Seymour was located at latitude 16.1°N and longitude 117.7°W which put it about 690 miles (1110 km) southwest of the southern tip of Baja California.   Seymour was moving toward the west-northwest at 15 m.p.h.  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 943 mb.

The circulation of Hurricane Seymour is very small, but it is very well organized.  There is a circular eye with a diameter of 10 miles (12 km) which is surrounded by a ring of strong thunderstorms.  Winds to hurricane force only extend out about 18 miles (29 km) from the center of circulation.  Winds to tropical storm force extend out about 80 miles (130 km) from the center.  The Hurricane Intensity Index (HII) is 31.6, but the Hurricane Size Index (HSI) is only 7.1.  The Hurricane Wind Intensity Size Index is 38.7.  Hurricane Seymour is not as strong as Hurricane Patricia was in 2015 and Seymour is smaller than Patricia was.  When Hurricane Patricia had maximum sustained winds of 200 m.p.h. (320 km) its HSI ranged between 11.3 and 13.8.

Hurricane Seymour will remain in a very favorable environment for another 6 to 12 hours.  It will move over water where the Sea Surface Temperature (SST) is near 28°C.  The upper level winds will be light and there will be little vertical wind shear.  Later on Wednesday the upper level winds will increase and Hurricane Seymour will begin to move over cooler SSTs.  The increasingly unfavorable environment will cause Seymour to weaken.  Because of the small size of Seymour’s circulation, wind shear could cause the hurricane to weaken quickly.

Hurricane Seymour is moving around the western end of a ridge that is steering the hurricane toward the west-northwest.  When Seymour reaches the western end of the ridge, the hurricane will begin to move more toward the north.  On its anticipated track Hurricane Seymour will weaken well to the west of Baja California.  An upper level trough moving over the Northern Pacific Ocean could eventually transport some of the moisture from Hurricane Seymour over the western U.S.

Tropical Cyclone Kyant Forms Over Bay of Bengal

Tropical Cyclone Kyant formed over the Bay of Bengal on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Tropical Cyclone Kyant was located at latitude 16.6°N and longitude 90.4°E which put it about 480 miles (770 km) east of Vishakhapatnam, India.  Kyant was moving toward the west 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 994 mb.

A cluster of thunderstorms persisted over the eastern Bay of Bengal during the past few days, but strong upper level easterly winds prevented the development of the system.  The upper level winds began to diminish on Monday and a low level circulation center began to develop on the eastern edge of the area of thunderstorms.  When the upper level winds became weaker, then thunderstorms were able to develop closer to the center of circulation.  The system acquired the structural characteristics associated with a tropical cyclone and the India Meteorological Department named it Kyant.

The circulation of Tropical Cyclone Kyant is still organizing.  Some vertical wind shear continues because of easterly upper level winds being generated by a ridge northeast of the tropical cyclone.  The shear is causing more of the thunderstorms to form in the western half of the circulation.  However, additional thunderstorms have developed closer to the center in recent hours and some spiral rainbands have formed.  The thunderstorms near the center are generating upper level divergence which is starting to pump out mass in all directions.

Tropical Cyclone Kyant will be moving through a favorable environment during the next several days.  It will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds should remain weaker, and the vertical wind shear will not be strong enough to prevent strengthening.  Tropical Cyclone Kyant is likely to intensify and it could undergo a period of rapid intensification.

The upper level ridge is steering Tropical Cyclone Kyant toward the west and that general motion is expected to continue.  On its anticipated track Tropical Cyclone Kyant could approach the east coast of India in about 48 hours.  It could bring strong winds and very heavy rain to portions of eastern India later this week.

Seymour Rapidly Intensifies into a Cat. 2 Hurricane

Tropical Storm Seymour rapidly intensified into a Category 2 hurricane on the Saffir-Simpson Scale on Monday as it moved farther away from Mexico.  At 11:00 p.m. EDT on Monday the center of Hurricane Seymour was located at latitude 15.5°N and longitude 112.6°W which put it about 540 miles (870 km) south-southwest of the southern tip of Baja California.  Seymour was moving toward the west at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 976 mb.

Hurricane Seymour intensified very rapidly on Monday.  The maximum sustained wind speed increased from 50 m.p.h. (80 km/h) to 105 m.p.h. (165 km/h) in a 24 hour period.  The circulation contracted and the primary rainband wrapped tightly around a small eye.  Seymour is a very small hurricane and hurricane force winds only extend out about 12 miles (19 km) from the center of circulation.  Winds to tropical storm force only extend out about 70 miles (130 km) from the center.  Although Seymour is a small hurricane, the circulation is well organized.  The small eye is surrounded by an almost continuous ring of thunderstorms.  Several other spiral bands are rotating around the core of Hurricane Seymour.  Thunderstorms in the core are generating upper level divergence which is pumping out mass in all directions.

Hurricane Seymour will remain in a favorable environment on Tuesday.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are light and there is little vertical wind shear.  Hurricane Seymour is likely to intensify on Tuesday and it could become a major hurricane.  When Seymour moves farther to the west, it will be nearer to an upper level trough which will produce southwesterly winds over the hurricane.  Increased vertical wind shear will begin to weaken Hurricane Seymour.

A ridge over Mexico is steering Hurricane Seymour toward the west and that general motion will occur for another 24 to 36 hours.  Hurricane Seymour will approach the western end of the ridge on Wednesday, and the hurricane will turn more toward the north when that happens.  On its anticipated track this turn will occur well to the west of Baja California.

Tropical Storm Seymour Develops Quickly West of Mexico

Tropical Storm Seymour developed quickly west of Mexico on Sunday and it brought to an end a stretch of three quiet weeks over the Eastern North Pacific Ocean.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Seymour was located at latitude 14.4°N and longitude 107.1°W which put it about 370 miles (590 km) south-southwest of Manzanillo, Mexico.  Seymour was moving toward the west-northwest at 15 m.p.h. (24 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 1002 mb.

The circulation in a cluster of thunderstorms organized quickly on Sunday afternoon.  A primary rainband around the northern and western sides of the circulation wrapped almost entirely around the center and an eye appeared to be forming on microwave satellite images.  Additional bands of thunderstorms were developing.  Thunderstorms in the core of Seymour were beginning to generate upper level divergence.

Tropical Storm Seymour will be moving through a very favorable environment.  It is moving over water where the Sea Surface Temperature is near 31°C.  The upper level winds are relatively weak and there is little vertical wind shear.  Tropical Storm Seymour will continue to intensify and it could intensify rapidly.  Seymour will become a hurricane and it could become a major hurricane.

A ridge over Mexico is steering Tropical Storm Seymour toward the west-northwest and that general motion is expected to continue for several more days.  When Seymour reaches the western end of the ridge, it will turn toward the north.  On its anticipated track Tropical Storm Seymour will make the northward turn well to the southwest of Baja California.

Typhoon Haima Brings Gusty Winds and Rain to China

The large eye of Typhoon Haima neared the coast of China on Thursday and the typhoon was bringing gusty winds and heavy rain to the area near Hong Kong.  At 11:00 p.m. EDT on Thursday the center of Typhoon Haima was located at latitude 22.6°N and longitude 115.6°E which put it about 105 miles (170 km) east of Hong Kong.  Haima was moving toward the northwest at 18 m.p.h.  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 967 mb.

After the center of Typhoon Haima moved northwest of Luzon, a large eye reformed at the center of the typhoon.  The diameter of the eye is about 60 miles (95 km).  The eye is surrounded by a thin ring of thunderstorms and multiple rainbands.  Haima is a large typhoon.  Winds to typhoon force extend out about 70 miles (110 km) from the center and winds to tropical storm force extend out about 240 miles (390 km) from the center.

Typhoon Haima is moving around the western end of a subtropical ridge which is steering it toward the northwest.  Haima is expected to turn more toward the north when it reaches the coast of China.  An upper level trough over eastern Asia will begin to steer Haima toward the northeast on Friday.  On its anticipated track the eye of Typhoon Haima will make landfall on the coast of China near Haifeng and Lufeng.

The Hurricane Intensity Index (HII) for Typhoon Haima is 13.9.  The Hurricane Size Index (HSI) is 27.0 and the Hurricane Wind Intensity Size Index (HWISI) is 40.9.  These indices indicate that Typhoon Haima is capable of causing widespread serious wind damage.  Typhoon Haima will also generate a serious storm surge north of where the eye makes landfall and the wind blows the water toward the coast.  Haima will also bring heavy rain and a threat of floods to Guangdong, Jiangxi and Fujian provinces when it moves inland.

Typhoon Haima Producing Strong Winds and Heavy Rain Over Northern Luzon

Typhoon Haima was producing strong winds and heavy rain as it moved across northern Luzon on Wednesday.  At 5:00 p.m. EDT on Wednesday the center of Typhoon Haima was located at latitude 18.2°N and longitude 120.8°E which put it about 10 miles (15 km) east of Laoag, Philippines.  Haima was moving toward the west-northwest at 20 m.p.h. (32 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (235 km/h).  The minimum surface pressure was 946 mb.

The center of Typhoon Haima moved quickly across northern Luzon on Wednesday.  Haima made landfall on northeastern Luzon east of Tuguegarao.  As it moved toward the west-northwest the center of Typhoon Haima passed near Tuao and Dingras.  The center also passed over the Cordillera Central, where it produced very heavy rain in places where the wind was blowing up the slopes of the mountains.

Movement across the mountain ranges in northern Luzon weakened Typhoon Haima and an eye is no longer evident on satellite images.  However, Haima is still a large, powerful typhoon.  Winds to typhoon force extend out 65 miles (105 km) from the center of circulation.  Winds to tropical storm force extend out about 240 miles (390 km) from the center.  The Hurricane Intensity Index (HII) for Haima is 20.6.  The Hurricane Size Index (HSI) is 25.6 and the Hurricane Wind Intensity Size Index (HWISI) is 46.2.  The indices indicate that Typhoon Haima is capable of causing widespread major wind damage.

The core of Typhoon Haima is not as well organized as it was before the typhoon made landfall in Luzon.   Some reorganization of the core could occur when Typhoon Haima moves over the South China Sea.  Haima will move over water where the Sea Surface Temperature is near 29°C.  The upper level winds are weak and Typhoon Haima is still producing strong upper level divergence which is pumping mass away in all directions.  Typhoon Haima could restrengthen somewhat or maintain its intensity after the center moves northwest of the Philippines.  When Haima nears the coast of China, it will approach an upper level trough and vertical wind shear will increase.  So, Typhoon Haima is likely to be on a weakening trend when it makes landfall in China.

Typhoon Haima is moving around the western end of subtropical ridge which is steering it toward the west-northwest.  Typhoon Haima is likely to move more toward the northwest after it leaves Luzon and reaches the end of the ridge.  When Typhoon Haima nears the coast of China, it will move under southwesterly winds caused by an upper level trough over China.  Those winds will turn Haima more toward the north.  On its anticipated track Typhoon Haima could make a landfall in China northeast of Hong Kong in about 36 hours.

Typhoon Haima will continue to produce strong winds and heavy rains over parts of northern Luzon for a few more hours until the core of the typhoon moves northwest of that region.  The heavy rain has the potential to cause floods and mudslides.  Although Typhoon Haima is likely to be weakening when it reaches the coast of China, it will still be capable of producing strong winds, heavy rain, floods and a storm surge along the coast.

Typhoon Haima Equal to Cat. 5 Hurricane, Threatens Luzon

Typhoon Haima intensified into the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Tuesday.  At 11:00 a.m. EDT on Tuesday the center of Typhoon Haima was located at latitude 15.9°N and longitude 128.4°E which put it about 400 miles (640 km) east of northern Luzon.  Haima was moving toward the west-northwest at 18 m.p.h. (29 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 919 mb.

Typhoon Haima completed an eyewall replacement cycle and it intensified as the outer eyewall contracted.  Haima is a very well organized, symmetrical typhoon.  Haima has a clear circular eye surrounded by a ring of very strong thunderstorms.  Thunderstorms in the core of Typhoon Haima are generating strong upper level divergence which is pumping away large quantities of mass in all directions.  Winds to typhoon force extend out about 65 miles (105 km) from the center.

Typhoon Haima is moving through a very favorable environment.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is very little vertical wind shear.  Typhoon Haima is moving on a track that is a little to the north of the track taken by Typhoon Sarika.  This means that the core of Haima is moving north of cooler water mixed to the surface by Typhoon Sarika.  Typhoon Haima could intensify more during the next 12 to 24 hours.  However, if another eyewall replacement cycle occurs, then there could be fluctuations in intensity.

A subtropical ridge is steering Typhoon Haima toward the west-northwest and that general motion is expected to continue for several more days.  On its anticipated track the core of Typhoon Haima will approach northern Luzon in about 24 hours.  After Haima moves across Luzon it will reach the western end of the ridge and turn more toward the northwest.  Typhoon Haima could be near the coast of China in 72 hours.

Haima is an extremely dangerous typhoon.  The Hurricane Intensity Index (HII) for Haima is 35.0.  The Hurricane Size Index (HSI) is 21.2 and the Hurricane Wind Intensity Size Index (HWISI) is 56.2.  The indices indicate that Typhoon Haima is capable of causing widespread catastrophic wind damage.  In addition Typhoon Haima will produce very heavy rain over northern Luzon including over some locations hit by Typhoon Sarika a few days ago.  The heavy rain will create the potential for flash floods and mudslides.  Haima will also generate a significant storm surge in locations where the wind pushes the water toward the coast.

Typhoon Sarika Making Landfall on Hainan Island

The center of Typhoon Sarika is making landfall on Hainan Island near Qionghai and Wanning.  At 11:00 p.m. EDT on Monday the center of Typhoon Sarika was located at latitude 19.1°N and longitude 110.4°E which put it near Qionghai, China.  Sarika was moving toward the west-northwest at 11 m.p.h. (18 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 976 mb.

The structure of Typhoon Sarika changed after it moved across the Philippines.  It developed a larger eye and more of the thunderstorms occurred in a primary rainband that wrapped around the western and southern parts of the circulation.  Sarika maintained that structure as it made landfall on Hainan Island, although were some indications in satellite imagery that they eye was contracting just prior to landfall.

Typhoon Sarika will weaken while the center passes over Hainan Island.  Sarika could be a tropical storm by the time the center emerges over the Gulf of Tongking.  The Sea Surface Temperature in the Gulf of Tongking is near 31°C.  So, evaporation could provide another source of energy and moisture while the center is over water.

Typhoon Sarika is being steered toward the west-northwest by a subtropical ridge and that general motion is expected to continue for another day or so.  On its anticipated track Typhoon Sarika will spend the next few hours moving across Hainan Island.  Sarika could make another landfall over northern Vietnam and southern China in about 24 to 30 hours.

The Hurricane Intensity Index (HII) was 11.5 for Typhoon Sarika.  The Hurricane Size Index (HSI) was 13.2 and the Hurricane Wind Intensity Size Index (HWISI) was 24.7.  These indices indicate that Typhoon Sarika is capable of causing regional, minor wind damage.  Sarika will also bring locally heavy which could cause floods over Hainan Island and parts of northern Vietnam and southern China.

Typhoons Sarika and Haima Churning Over Western North Pacific

Typhoons Sarika and Haima churned across the western North Pacific Ocean on Sunday.  At 11:00 p.m. EDT on Sunday the center of Typhoon Sarika was located at latitude 17.3°N and longitude 113.7°E which put it about 240 miles (390 km) east-southeast of Hainan Island.  Sarika was moving toward the west at 17 m.p.h. (27 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 970 mb.

At 11:00 p.m. EDT on Sunday the center of Typhoon Haima was located at latitude 13.2°N and longitude 135.9°E which put it about 935 miles (1505 km) east-southeast of Luzon.  Haima was moving toward the west-northwest at 17 m.p.h. (27 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h).  The minimum surface pressure was 956 mb.

The circulation of Typhoon Sarika was disrupted somewhat when it crossed northern Luzon.  Thunderstorms around the eye weakened and breaks developed in the eyewall.  More and stronger thunderstorms developed around the center of circulation today and an eye has become more apparent on satellite imagery.  Numerous rainbands are rotating around the rest of the circulation.  Upper level divergence is increasing, which will increase the removal of mass from the core of Typhoon Sarika.

Typhoon Sarika is moving through an environment that is favorable for intensification.  Sarika is moving over water where the Sea Surface Temperature is above 30°C.  The upper level winds are weak and there is little vertical wind shear.  Typhoon Sarika is likely to intensify during the next 24 hours and it could intensify quickly if the eye finishes reforming.

A subtropical ridge is steering Typhoon Sarika toward the west .  Sarika is nearing the western end of the ridge and the typhoon is expected to turn more toward the northwest.  On its anticipated track Typhoon Sarika could be near Hainan Island in about 24 hours.  After it crosses Hainan Island, Marika could approach the coast of northern Vietnam in about two days.  Typhoon Sarika will bring strong winds and very heavy rain to Hainan.  It will weaken when it moves across Hainan, but Sarika could also bring gusty winds and heavy rain to northern Vietnam and parts of southeastern China.

Typhoon Haima is developing into a very strong and dangerous typhoon.  Haima has a small eye at the center of circulation.  The eye is surrounded by a ring of very strong thunderstorms.  Rainbands are rotating around the core of the circulation.  Thunderstorms in the core of Typhoon Haima are generating upper level divergence which is pumping out mass in all directions.

Typhoon Haima is moving through an environment that is favorable for continued intensification.  It is moving over water where the Sea Surface Temperature is 30°C.  The upper level winds are weak and there is little vertical wind shear.  Typhoon Haima is likely to continue to intensify and it could reach super typhoon status.

A subtropical ridge is steering Typhoon Haima toward the west-northwest and that general motion is expected to continue for several more days.  On its anticipated track Typhoon Haima could be near the northern end of Luzon in about three days.  It could be a very powerful typhoon at that time.

Powerful Typhoon Sarika Makes Landfall in Luzon

Powerful Typhoon Sarika made landfall in Luzon near Baler on Saturday.  At 11:00 a.m. EDT on Saturday the center of Typhoon Sarika was located at latitude 15.3°N and longitude 122.3°E which put it near Baler, Philippines and about 130 miles (210 km) east-northeast of Manila.  Sarika was moving toward the west-northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h).  The minimum surface pressure was 941 mb.

Sarika is a powerful, well organized typhoon.  It has a circular eye surrounded by a ring of strong thunderstorms.  Additional rainbands are rotating around the core of Sarika.  The core of Typhoon Sarika is generating well developed upper level divergence which is pumping out mass in all directions.  Typhoon Sarika was intensifying rapidly until it made landfall.

The Hurricane Intensity Index (HII) for Typhoon Sarika is 20.6.  The Hurricane Size Index (HSI) is 17.0 and the Hurricane Wind Intensity Size Index (HWISI) is 37.6.  These indices indicate that Typhoon Sarika is capable of causing regional major wind damage.  Typhoon Sarika will also generate a storm surge along the coast of Luzon north of the eye where the wind will push water toward the coast.  Sarika will also produce heavy rain over northern Luzon which will create a risk of flash flooding and mudslides.

A subtropical ridge is steering Typhoon Marika toward the west-northwest and that general motion is expected to continue for several more days.  On its anticipated track across Luzon the center of Typhoon Sarika will pass near San Jose City,  Baguio and Dagupan.  The center of Sarika could emerge over the South China Sea near the Lingayen Gulf.  The core of Typhoon Sarika will move across the Sierra Madre Mountains and the Cordillera Central.  Where winds blow up the slopes of the mountains, rising motion will be stronger and the rainfall will be heavier.  The mountains will also disrupt the airflow in the lower part of Sarika’s circulation and the typhoon will weaken.

It could take the center of Typhoon Sarika about 12 hours to move across Luzon.  The environment of the Sea China Sea will  be favorable for intensification.  The Sea Surface Temperature is warm and there will be little vertical wind shear.  If the core of the circulation remains reasonably intact, then Typhoon Sarika could intensify again while it moves across the South China Sea.  Sarika could eventually move near Hainan Island and into northern Vietnam in a few days.