Tag Archives: Tropical Storm Merbok

Typhoon Muifa Moves Toward Eastern China

Typhoon Muifa moved toward eastern China on Tuesday morning. At 11:00 a.m. EDT on Tuesday the center of Typhoon Muifa was located at latitude 27.2°N and longitude 123.7°E which put it about 280 miles (450 km) south-southeast of Shanghai, China. Muifa was moving toward the north-northwest at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h). The minimum surface pressure was 964 mb.

The circulation around Typhoon Mauifa exhibited good organization on Tuesday morning. A circular eye was present at the center of Muifa. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Muifa. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The wind field around Typhoon Muifa way very symmetrical. Winds to typhoon force extended out 40 miles (65 km) from the center of Muifa. Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Muifa was 17.8. The Hurricane Size Index (HSI) was 17.1 and the Hurricane Wind Intensity Size Index (HWISI) was 34.9. Typhoon Muifa was capable of causing regional serious damage.

Typhoon Muifa will move through an environment that will be unfavorable for intensification during the next 24 hours. Muifa will move over water where the Sea Surface Temperatures are near 27˚C. An upper level trough over China will produce southwesterly winds that will blow toward the top of Muifa’s circulation. Those winds will cause the vertical wind shear to increase during the next 24 hours. The increase in wind shear and cooler water will cause Typhoon Muifa to weaken gradually.

Typhoon Muifa will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Muifa toward the north-northwest during the next 24 hours. On its anticipated track Typhoon Muifa will make landfall on the east coast of China south of Shanghai in 18 hours. The center of Muifa could make landfall near Ningbo. Typhoon Muifa will bring strong winds and locally heavy rain to the region around Shanghai. Heavy rain could cause flash floods in some locations in eastern China.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Merbok strengthened north-northwest of Wake Island and Tropical Depression 16W also strengthened southwest of Iwo To. At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Merbok was located at latitude 26.2N and longitude 162.7°E which put it about 500 miles (805 km) north-northwest of Wake Island. Merbok was moving toward the north-northwest at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 984 mb.

At 11:00 a.m. EDT on Tuesday the center of Tropical Depression 16W was located at latitude 22.6N and longitude 139.6°E which put it about 190 miles (310 km) southwest of Iwo To. The tropical depression was moving toward the northeast at 6 m.p.h. (10 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.

Typhoon Muifa Brings Wind and Rain to Southern Ryukyu Islands

Typhoon Muifa brought wind and rain to the southern Ryukyu Islands on Monday. At 11:00 a.m. EDT on Monday the center of Typhoon Muifa was located at latitude 25.2°N and longitude 124.0°E which put it about 55 miles (90 km) north of Ishigaki, Japan. Muifa was moving toward the north-northwest at 5 m.p.h. (8 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 967 mb.

Typhoon Muifa continued to bring wind and rain to the southern Ryukyu Islands on Monday. The center of Typhoon Muifa was moving slowly away from Ishigakijima. The strongest winds were measured in Ishigakijima after the eye passed over. A weather station on Ishigakijima measured a sustained wind speed of 68 m.p.h. (109 km/h). The same weather station measured a surface pressure of 968.3 mb when the eye of Typhoon Muifa passed over it. The weather station measured 11.71 inches (297.5 mm) of rain during the passage of Muifa. Bands in the eastern side of Muifa’s circulation also dropped heavy rain over Miyakojima.

The circulation around Typhoon Muifa remained well organized on Monday. A circular eye was present at the center of Muifa’s circulation. The eye was surrounded by a broken ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Muifa. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

Winds to typhoon force extended out 45 miles (75 km) from the center of Typhoon Muifa. Winds to tropical storm force extended out 110 miles (175 km) from the center of Muifa. The Hurricane Intensity Index (HII) for Typhoon Muifa was 16.5. The Hurricane Size Index (HSI) was 15.4 and the Hurricane Wind Intensity Size Index (HWISI) was 31.9. Muifa was capable of causing regional serious damage.

Typhoon Muifa will move through an environment that will become unfavorable for intensification during the next 36 hours. Muifa will move over water where the Sea Surface Temperatures are near 30˚C. However, an upper level trough over China will produce southwesterly winds that will blow toward the top of Muifa’s circulation. Those winds will cause the vertical wind shear to increase during the next 36 hours. The increase in wind shear will cause Typhoon Muifa to start to weaken.

Typhoon Muifa will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Muifa slowly toward the north-northwest during the next 36 hours. The strong winds and locally heavy rain in the southern Ryukyu Islands will gradually diminish during the next 24 hours as Typhoon Muifa moves farther away. On its anticipated track Typhoon Muifa could approach the east coast of China south of Shanghai in 36 hours.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Merbok continued to strengthen northwest of Wake Island. At 11:00 a.m. EDT on Monday the center of Tropical Storm Merbok was located at latitude 22.9°N and longitude 162.8°E which put it about 350 miles (565 km) northwest of Wake Island. Merbok was moving toward the northeast at 10 m.p.h. (16 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.

Eye of Typhoon Muifa Passes over Ishigakijima

The eye of Typhoon Muifa passed directly over Ishigakijima on Sunday night. A weather station on Ishigakijima measured a surface pressure of 968.3 mb. At 11:00 p.m. EDT on Sunday the center of Typhoon Muifa was located at latitude 24.4°N and longitude 124.2°E which put it about 5 miles (10 km) east of Ishigaki, Japan. Muifa was moving toward the north-northwest at 5 m.p.h. (8 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 967 mb.

Typhoon Muifa developed two concentric eyewalls and began an eyewall replacement cycle as it slowly approached Ishigakijima on Sunday. The inner end of rainband wrapped around the existing eye and eyewall and a larger outer eyewall surrounded them. Low level convergence became concentrated in the outer eyewall and the thunderstorms in the inner eyewall weakened. The remnants of the inner eyewall were visible on satellite images as a ring of showers and lower clouds. The outer eyewall had a diameter of 60 miles (95 km). The strongest winds were occurring in the outer eyewall. Bands of showers and thunderstorms were revolving around the core of Typhoon Muifa. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The eyewall replacement cycle caused Typhoon Muifa to weaken as it approached Ishigakijima. Winds to typhoon force extended out 35 miles (55 km) from the center of Typhoon Muifa. Winds to tropical storm force extended out 120 miles (195 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Muifa was 16.5. The Hurricane Size Index (HSI) was 13.9 and the Hurricane Wind Intensity Size Index (HWISI) was 30.4. Typhoon Muifa was capable causing regional serious damage.

Typhoon Muifa will move through an environment favorable for intensification during the next 24 hours. Muifa will move over water where the Sea Surface Temperatures are near 30˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Muifa could intensify during the next 24 hours after the inner eyewall completely dissipates. Since Typhoon Muifa will move slowly, its winds could mix cooler water up to the surface of the ocean. Cooler water would limit potential intensification.

Typhoon Muifa will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Muifa slowly toward the north-northwest during the next 36 hours. Typhoon Muifa will continue to produce strong winds and locally heavy rain in the southern Ryukyu Islands during the next 24 hours. The strongest winds and heaviest rain are likely to affect Ishigakijima. Gusty winds and locally heavy rain could also affect Miyakojima. On its anticipated track Typhoon Muifa could approach the east coast of China near Shanghai in 60 hours.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Merbok was slowly strengthening west-northwest of Wake Island. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Merbok was located at latitude 21.6°N and longitude 161.6°E which put it about 365 miles (595 km) west-northwest of Wake Island. Merbok was moving toward the east-northeast 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 1000 mb.

Tropical Storm Merbok Makes Landfall Near Hong Kong

Tropical Storm Merbok made landfall near Hong Kong on Monday.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Merbok was located at latitude 23.5°N and longitude 114.9°E which put it about 55 miles (85 km) north-northeast of Hong Kong.  Merbok was moving toward the north at 11 m.p.h. (17 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 1005 mb.

Tropical Storm Merbok intensified before it made landfall and the maximum sustained wind speed was around 55 m.p.h. (85 km/h) at the time of landfall.  Merbok began to weaken after landfall and the strongest winds are now occurring in bands over the the open water.  Merbok is producing locally heavy rain in bands east of the center if circulation.  The heavy rains represent the greatest risk and flooding is possible over parts of eastern China.  Merbok is a fairly small tropical storm and the heavier rain will fall primarily to the east of the track of Merbok.  Merbok should gradually spin down as it moves farther inland.

Tropical Storm Merbok Moves Closer to China

Tropical Depression 04W intensified into Tropical Storm Merbok on Sunday as it moved closer to the coast of China.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Merbok was located at latitude 19.9°N and longitude 115.7°E which put it about 220 miles (360 km) south-southeast of Hong Kong.  Merbok was moving toward the north-northwest at 16 m.p.h. (26 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.

The structure of Tropical Storm Merbok is asymmetrical.  Most of the thunderstorms are occurring east and south of the center of circulation.  A primary rainband curves about halfway around the southeastern side of the center.  Additional bands of showers and thunderstorms exist outside the core in southeastern half of Merbok.  There are bands in the northwestern half of the circulation but they consists primarily of low clouds and showers.  The thunderstorms in the primary rainband are producing upper level divergence which is pumping out mass to the south of Tropical Storm Merbok.

Tropical Storm Merbok is moving through an environment that is marginally favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 29°C.  Merbok is moving under the eastern end of an upper level ridge which is producing northerly winds which are blowing toward the top of the tropical storm.  Those northerly winds are creating moderate vertical wind shear, but they are also enhancing the upper level divergence to the south of Merbok.  Tropical Storm Merbok appears to be pulling some drier air from China into the northwestern part of the circulation.  The combination of moderate vertical wind shear and drier air could be the reason for the asymmetrical distribution of thunderstorms.

Tropical Storm Merbok has a chance to intensify a little more before it makes landfall.  The effects of the moderate vertical wind shear and drier air should limit any intensification and Merbok is likely to remain a tropical storm until it makes landfall.

Merbok is moving around the western end of a subtropical ridge which is steering the tropical storm toward the north-northwest.  That general motion is expected to continue for another day or so.  On its anticipated track the center of Tropical Storm Merbok will reach the coast of China between Hong Kong and Shantou in 12 to 18 hours.  Tropical Storm Merbok will bring gust winds and locally heavy rain.  When Merbok moves inland over eastern China, it will reach the westerly winds in the middle latitudes and those winds will turn the tropical storm toward the east.