Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Typhoon Francisco Brings Wind and Rain to Kyushu

Typhoon Francisco brought wind and rain to Kyushu on Monday.  At 5:00 p.m. EDT on Monday the center of Typhoon Francisco was located at latitude 32.2°N and longitude 131.4°E which put it about 20 miles (35 km) north of Miyazaki, Japan.  Francisco was moving toward the west-northwest at 13 m.p.h. (20 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 969 mb.

Typhoon Francisco strengthened on Monday as it neared the coast of Kyushu.  A small eye developed at the center of circulation.  A ring of strong 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 Typhoon Francisco.  The stronger bands were primarily in the eastern half of the circulation.

The core of Typhoon Francisco made landfall on Kyushu just to the north of Miyazaki.  Typhoon Francisco will bring very heavy rain and strong gusty winds to much of Kyushu.  Francisco is forecast to turn toward the northwest and the center of circulation will move across the middle of Kyushu.  Locally heavy rain falling on steep terrain will create the potential for serious flash flooding in some locations.  Rainbands in the eastern half of Typhoon Francisco will also drop locally heavy rain over parts of western Shikoku and western Honshu.

Typhoon Francisco will weaken when it moves across Honshu, but then it will move over the Korea Strait and make another landfall in South Korea.  Francisco will bring gusty winds and locally heavy rain to parts of southern South Korea on Tuesday.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Lekima continue to meander east of Luzon.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Lekima was located at latitude 18.7° and longitude 129.3°E which put it about 670 miles (1085 km) south-southeast of Taipei, Taiwan.  Lekima was moving toward the southwest at 6 m.p.h. (10 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 990 mb.

Tropical Storm Lekima Forms East of Luzon

Tropical Storm Lekima formed east of Luzon on Sunday.  More thunderstorms developed near the center of former Tropical Depression 10W and the Japan Meteorological Agency designated the system as Tropical Storm Lekima.  At 5:00 a.m. EDT on Sunday the center of Tropical Storm Lekima was located at latitude 16.8°N and longitude 131.3°E which put it about 725 miles (1170 km) south-southeast of Okinawa.  Lekima was moving toward the northwest at 6 m.p.h. (10 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.

The distribution of thunderstorms around Tropical Storm Lekima was asymmetrical.  Many of the stronger thunderstorms were occurring in bands west of the center of circulation.  There were fewer thunderstorms in the eastern half of the circulation.  Lekima was near the western end 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 the wind shear was contributing to the asymmetrical distribution of thunderstorms.

Tropical Storm Lekima will move through an environment favorable for intensification during the next few days.  Lekima will move over water where the Sea Surface Temperature is near 31°C.  It will move gradually into a region where the upper level winds are weaker and the vertical wind shear will diminish.  Tropical Storm Lekima will intensify and it could strengthen into a typhoon early next week.

Tropical Storm Lekima will move around the southwestern part of a subtropical ridge over the Western North Pacific Ocean.  The ridge will steer Lekima toward the northwest.  On its anticipated track Tropical Storm Lekima could approach the southern Ryukyu Islands and Taiwan in about four days.  Lekima could be a typhoon by that time.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Francisco was speeding toward southwestern Japan.  At 5:00 a.m. EDT on Sunday the center of Tropical Storm Francisco was located at latitude 28.9°N and longitude 140.8°E which put it about 710 miles (1150 km) east-southeast of Kagoshima, Japan.  Francisco was moving toward the northwest at 19 m.p.h. (32 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 992 mb.

Tropical Storm Wipha Drops Heavy Rain on Vietnam and China

Tropical Storm Wipha dropped heavy rain on parts of northeastern Vietnam and southern China on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Wipha was located at latitude 21.3°N and longitude 107.4°E which put it about 60 miles (95 km) northeast of Hai Phong, Vietnam.  Wipha was moving toward the west-southwest at 10 m.p.h. (16 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 990 mb.

The circulation around Tropical Storm Wipha exhibited much greater organization on Friday even though it was moving close to the coast of southern China.  There was a tighter inner core and more thunderstorms were occurring in the bands revolving around the core.  Storms near the core were generating upper level divergence which was pumping mass away from the tropical storm in all directions.  The appearance of Tropical Storm Wipha on satellite imagery was much more circular and symmetrical.  The strongest winds were occurring in the part of the circulation that was still over water.

Tropical Storm Wipha was being steering slowly toward the west-southwest by a subtropical ridge over China and the adjacent waters of the Western North Pacific Ocean.  The combination of greater organization and slow movement will allow Wipha to drop very heavy rainfall over coastal regions of southern China and northern Vietnam.  Prolonged heavy rain will very likely cause flash flooding in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Francisco was strengthening slowly east-southeast of Iwo To.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Francisco was located at latitude 23.2°N and longitude 149.4°E which put it about 545 miles (880 km) east-southeast of Iwo To.  Francisco was moving toward the northwest at 16 m.p.h. (26 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 995 mb.

Tropical Storm Francisco Forms Northeast of the Marianas

Tropical Storm Francisco formed northeast of the Marianas  on Thursday night.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Francisco was located at latitude 20.4°N and longitude 152.4°E which put it about 800 miles (1290 km) east-southeast of Iwo To.  Francisco was moving toward the northwest at 11 m.p.h. (17 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 998 mb.

A surface low pressure system developed southeast of an upper low north of the Marianas and the Japan Meteorological Agency designated the system as Tropical Storm Francisco.  The distribution of thunderstorms around Francisco was asymmetrical.  Stronger thunderstorms were occurring east of the center of circulation and in a band south of the center of Tropical Storm Francisco.  Bands in other parts of the circulation consisted primarily of showers and lower clouds.  The upper low was producing southwesterly winds which were causing moderate vertical wind shear.  The wind shear was the main factor responsible for asymmetrical distribution of thunderstorms.

Tropical Storm Francisco will move through an environment somewhat favorable for intensification during the next 24 hours.  Francisco will move over water where the Sea Surface Temperature is near 29°C.  The upper low north of the Marianas will continue to cause moderate vertical wind shear during the next day or so.  Tropical Storm Francisco could intensify slowly on Friday.  Francisco will move farther north of the upper low over the weekend.  When it gets farther away from the upper low, the wind shear will diminish and Tropical Storm Francisco could strengthen more quickly.

Tropical Storm Francisco will move southwest of a subtropical ridge over Western North Pacific Ocean.  The ridge will steer Francisco toward the northwest.  On its anticipated track Tropical Storm Francisco could be northeast of Iwo To in about 48 hours.  Francisco could approach southwestern Japan in about fours days.  It is forecast to be a typhoon by that time.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Wipha was moving slowly near the south coast of China.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Wipha was located at latitude 21.1°N and longitude 109.2°E which put it about 25 miles (40 km) south of Beihai, China.  Wipha was moving toward the southwest at 2 m.p.h. (3 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. (80 km/h).  The minimum surface pressure was 990 mb.

Tropical Storm Wipha Brings Wind and Rain to South China

Tropical Storm Wipha brought wind and rain to south China on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Wipha was located at latitude 20.5°N and longitude 110.6°E which put it about 50 miles (80 km) southeast of Leizhou, China.  Wipha was moving toward the west-northwest at 8 m.p.h. (13 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 990 mb.

The circulation around Tropical Storm Wipha contained a large rainband in the southern half of the tropical storm and another large rainband in the northern half of the circulation.  The rainband in the southern half of Wipha brought wind and rain to Hainan Island.  The rainband in the northern part of the tropical storm brought wind and rain to south China including Hong Kong.  Persistent heavy rain was creating the potential for flash floods in parts of southern China.

Tropical Storm Wipha was moving around the southwestern part of a subtropical ridge over the Western North Pacific Ocean.  The ridge will steer Wipha toward the west-northwest during the next 24 to 36 hours.  On its anticipated track Tropical Storm Wipha will move close to the coast of south China and northeastern Vietnam.  Wipha will continue to bring gusty winds and drop locally heavy rain over those regions on Thursday.

Tropical Storm Wipha Forms South of Macau

Tropical Storm Wipha formed south of Macau late on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Wipha was located at latitude 18.8°N and longitude 112.6°E which put it about 175 miles (285 km) south of Macau.  Wipha was moving toward the northwest at 6 m.p.h. (10 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.

The circulation around Tropical Storm Wipha was large, but Wipha did not have a well formed inner core.  Winds to tropical storm force extended out about 200 miles (320 km) from the center of circulation.  However, there were no strong thunderstorms near the center.  Stronger thunderstorms were occurring in bands well to the south and east of the center of circulation.  Bands northwest of the center consisted primarily of showers and lower clouds.

The large lower level circulation of Tropical Storm Wipha was just to the southeast of an upper low over the northwestern part of the South China Sea.  The upper low was circulating some drier air over the northwestern part of Wipha.  It was also causing some vertical wind shear.  The drier air and wind shear were inhibiting the formation of thunderstorms in the northwestern part of Tropical Storm Wipha.

Tropical Storm Wipha will move through an environment somewhat favorable for intensification during the next 24 hours.  Wipha will move over water where the Sea Surface Temperature is near 30°C.  The upper low will continue to inhibit the strengthening of Tropical Storm Wipha.  If thunderstorms begin to develop near the center of Wipha, then the tropical storm could strengthen.

Tropical Storm Wipha will move around the southwestern part of a subtropical ridge over the Western North Pacific Ocean.  The ridge will steer Wipha toward the northwest during the next 24 hours.  On its anticipated track the center of Tropical Storm Wipha will be near the northern part of Hainan Island and the south coast of China in 18 to 24 hours.  Wipha could move more toward the west when it reaches the Gulf of Tongking.  Although Tropical Storm Wipha will bring gusty winds to southern China and northern Vietnam, locally heavy rain and the potential for floods will be greater risks.

Tropical Storm Nari Drops Heavy Rain on Honshu

Tropical Storm Nari dropped locally heavy rain and producing gusty winds on Honshu on Friday night.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Nari was located at latitude 35.2°N and longitude 137.0°E which put it about 10 miles (15 km) east of Nagoya, Japan.  Nari was moving toward the north-northeast at 15 m.p.h. (24 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 1000 mb.

Tropical Storm Nari was dropping locally heavy rain over parts of central Honshu.  The heaviest rain was falling in bands located in the western half of the circulation.  Heavier rain was falling in the area between Nagoya, Osaka and Kyoto.  Bands of heavier rain were also falling north of Nagoya.  Most of the bands in the eastern half of Tropical Storm Nari consisted primarily lighter showers and lower clouds.  The heavier rain could produce flash flooding in some locations.

Tropical Storm Nari will move more toward the east-northeast on Saturday.  The center of Nari is forecast to pass north of Tokyo.  Tropical Storm Nari will continue to drop locally heavy rain over central and eastern Honshu when it moves over those locations.

Tropical Storm Nari Develops South of Japan

Tropical Storm Nari developed south of Japan on Thursday night.  The Japan Meteorological Agency designated a low pressure system south of Honshu as Tropical Storm Nari when the maximum sustained wind speed reached 40 m.p.h. (65 km/h).  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Nari was located at latitude 30.2°N and longitude 136.9°E which put it about 350 miles (565 km) south of Nagoya, Japan.  Nari was moving toward the north at 14 m.p.h. (22 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 1000 mb.

The circulation around Tropical Storm Nari exhibited more of a hybrid structure than the structure of a pure tropical cyclone.  Tropical Storm Nari developed when an upper level low pressure system stalled south of the Japan.  A surface circulation formed beneath the upper low and then more thunderstorms formed closer to the center of circulation.  The original upper level low was located southwest of the surface low on Thursday night.  The upper level low was producing southwesterly winds which were blowing across the surface low.  Those winds were creating vertical wind shear.  The circulation around Tropical Storm Nari showed evidence of the effect of that wind shear.  The stronger thunderstorms were in a band that curved around north and west of the center of circulation.  Bands south and east of the center consisted primarily of showers and lower clouds.  The wind field around Tropical Storm Nari was also asymmetric.  Winds to tropical storm force extended out about 115 miles (185 km) to the east of the center of circulation, but only extended out about 60 miles (95 km) to the west of the center.

Tropical Storm Nari will move through an environment only marginally favorable for intensification.  Nari will move over water where the Sea Surface Temperature is near 28°C.  The upper low will continue to cause vertical wind shear, which will inhibit intensification.  The upper low will also pull some drier air around the southern side of the circulation.  Nari could strengthen a little during the next 24 hours if more thunderstorms develop closer to the center of circulation.  Tropical Storm Nari will move under stronger westerly winds in about a day or so.  Those winds will cause more vertical wind shear and they should prevent further intensification.

Tropical Storm Nari will be steered by the interaction of the upper low and a subtropical ridge over the western North Pacific Ocean.  Those two features are likely to steer Nari toward the north during the next 24 hours.  On its anticipated track Tropical Storm Nari could approach the coast of Honshu near Nagoya in about 24 hours.  Nari will move more toward the east when it reaches the stronger westerly winds in a day or so.  Tropical Storm Nari could bring gusty winds and locally heavy rain to central Honshu on Saturday.

Tropical Storm Danas Speeds Toward South Korea

Tropical Storm Danas sped toward South Korea on Friday as it moved quickly north-northeast over the East China Sea.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Danas was located at latitude 32.3°N and longitude 125.1°E which put it about 190 miles (305 km) south-southwest of Mopko, South Korea.  Danas was moving toward the north-northeast at 19 m.p.h. (30 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 987 mb.

The distribution of thunderstorms around Tropical Storm Danas remained asymmetrical on Friday.  The strongest thunderstorms were occurring in bands well to the east of the center of circulation.  Bands closer to the center and on the western side of the circulation consisted primarily of showers and lower clouds.  An upper level trough over eastern China was producing southwesterly winds which were blowing toward the top of the circulation.  Those winds were causing moderate vertical wind shear and they were the reason for the asymmetrical distribution of thunderstorms.  The wind field also exhibited the effects of the wind shear.  Winds to tropical storm force extended out about 200 miles (320 km) from the center of Danas on the eastern side of the circulation, but only extended out about 120 miles (195 km) on the western side of the tropical storm.

Tropical Storm Danas will remain in an environment only marginally favorable for intensification until it makes landfall in South Korea.  Danas will move over water where the Sea Surface Temperature is near 30°C.  The upper level trough over eastern China will continue to cause moderate vertical wind shear.  Tropical Storm Danas could intensify a little during the next 12 hours, but it will weaken after the center moves over South Korea.

Tropical Storm Danas will move around the western end of a subtropical ridge over the western North Pacific Ocean.  The ridge and the upper level trough will interact to steer Danas rapidly toward the north-northeast.  On its anticipated track the center of Tropical Storm Danas will make landfall on the southwestern coast of South Korea in about 12 hours.  Danas will bring gusty winds and locally heavy rain to South Korea on Saturday.  The heaviest rain will fall over the southeastern half of South Korea.  Locally heavy rain in that region could cause flash floods.  The outer rainbands of Tropical Storm Danas could also drop locally heavy rain over western Kyushu.

Tropical Storm Danas Nears Southern Ryukyu Islands

Tropical Storm Danas moved near the southern Ryukyu Islands late on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Danas was located at latitude 23.9°N and longitude 124.1°E which put it about 30 miles (50 km) south of Ishigaki, Japan.  Danas was moving toward the north at 21 m.p.h. (34 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 990 mb.

The circulation around Tropical Storm Danas exhibited a little more organization on Wednesday.  More thunderstorms formed near the center of circulation and several bands of showers and thunderstorms formed in the eastern half of the circulation.  The bands north and west of the center consisted primarily of showers and lower clouds.  Storms near the center began to generate upper level divergence which pumped mass away to the northeast of the tropical storm.  Winds to tropical storm force extended out about 125 miles (200 km) from the center of circulation.

Tropical Storm Danas will move into an environment somewhat favorable for intensification.  Danas will move over water where the Sea Surface Temperature is near 30°C.  A small upper level low near Taiwan will produce southwesterly winds which blow toward the top of the circulation around Tropical Storm Danas.  Those winds were the reason why the stronger rainbands were in the eastern half of the circulation.  Those winds will cause moderate vertical wind shear, which will inhibit intensification.  However, the shear will have less of an effect since Danas will move in the same direction as the upper level winds.  Tropical Storm Danas is likely to intensify during the next 24 hours and there is a chance it could strengthen into a typhoon.

Tropical Storm Danas will move around the western end of a subtropical ridge over the western North Pacific Ocean.  The ridge will steer Danas toward the north-northeast.  On its anticipated track Tropical Storm Danas will move through the southern Ryukyu Islands during the next few hours.  Danas will bring gusty winds and locally heavy rain when it passes over those islands.  Tropical Storm Danas will move over the East China Sea toward southwestern Japan and South Korea during the next several days.