Tag Archives: Yap

Typhoon Mangkhut Strengthens Into Equivalent of Cat. 5 Hurricane

Typhoon Mangkhut strengthened 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 Mangkhut was located at latitude 13.7°N and longitude 138.0°E which put it about 290 miles (470 km) north of Yap.  Mangkhut was moving toward the west at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 915 mb.

Typhoon Mangkhut is strong and well organized.  It has a symmetrical circulation with a circular eye at the center.  A ring of strong thunderstorms surround the eye and the strongest winds are occurring in the ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Typhoon Mangkhut.  Storms near the core were generating strong upper level divergence which was pumping large quantities of mass away from the typhoon in all directions.

Typhoon Mangkhut has a large circulation.  Winds to typhoon force extend out about 65 miles (105 km) from the center of circulation.  Winds to tropical storm force extend out about 210 miles (375 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Mangkhut is 35.0.  The Hurricane Size Index (HSI) is 22.1 and the Hurricane Wind Intensity Size Index (HWISI) is 57.1.  Typhoon Mangkhut is capable of causing extensive catastrophic damage.

Typhoon Mangkhut will be moving through an environment very favorable for powerful typhoons.  Mangkhut will be moving over water where the Sea Surface Temperature is near 30°C.  It will move through an area were the upper level winds are weak and there will be little vertical wind shear.  Typhoon Mangkhut could maintain its intensity for several more days unless eyewall replacement cycles cause fluctuations in the wind speed.

Typhoon Mangkhut is moving south a ridge of high pressure over the Western North Pacific Ocean.  The ridge will steer Mangkhut in a general west-northwesterly direction during the next few days.  On its anticipated track Typhoon Mangkhut could approach northern Luzon in about three days.  Mangkhut could be near Hong Kong in about five days.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Barijat was moving southeast of Hong Kong.  At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Barijat was located at latitude 20.5°N and longitude 116.5°E which put it about 215 miles (345 km) southeast of Hong Kong.  Barijat was moving toward the west-southwest 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 1000 mb.

Tropical Storm Jelawat Strengthens West of Guam

Tropical Storm Jelawat strengthened west of Guam late on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Jelawat was located at latitude 12.3°N and longitude 135.5°E which put it about 230 miles (375 km) northwest of Yap and about 600 miles (970 km) west of Guam.  Jelawat was moving toward the north 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 994 mb.

After being affected by strong vertical wind shear for about 36 hours, Tropical Storm Jelawat began to strengthen late on Tuesday.  Many more thunderstorms formed near the center of circulation.  The circulation became much more symmetrical.  Bands of showers and thunderstorms formed in all parts of the circulation.  The storms near the center of circulation started to generate upper level divergence which pumped mass away from the tropical storm.

Tropical Storm Jelawat will be moving through an environment favorable for intensification during the next several days.  Jelawat will move over water where the Sea Surface Temperature is near 28°C.  Tropical Storm Jelawat is moving around the western end of an upper level ridge.  The ridge is producing southerly winds which are blowing toward the tropical storm.  The winds are producing some vertical wind shear, but the shear is not as strong as it has been.  Tropical Storm Jelawat will intensify during the next day or two and it could strengthen into a typhoon.

The ridge is steering Tropical Storm Jelawat toward the north and the northerly motion is expected to continue for another 12 to 24 hours.  Jelawat will move more toward the northeast in a day or so after it rounds the western end of the ridge.  On its anticipated track Tropical Storm Jelawat will move away from Yap and it will remain west of Guam.

Tropical Storm Jelawat Forms Near Yap

Tropical Storm Jelawat formed near Yap on Sunday.  At 2:00 p.m. EDT on Sunday the center of Tropical Storm Jelawat was located at latitude 7.6°N and longitude 138.4°E which put it about 120 miles (195 km) south of Yap.  Jelawat was moving toward the northwest 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 998 mb.

A low level center of circulation formed near the eastern edge of a cluster of thunderstorms near Yap on Sunday and the Japan Meteorological Agency designated the system as Tropical Storm Jelawat.  Tropical Storm Jelawat does not have a well organized circulation.  There is a distinct low level center of circulation, but most of the stronger thunderstorms are occurring west of the center of circulation.  The bands in the eastern half of the circulation consist mainly of showers and low clouds.  An upper level ridge over the Central North Pacific Ocean is producing strong easterly winds which are blowing across the top of the circulation.  Those winds are generating strong vertical wind shear and the shear is the main reason for the asymmetrical distribution of storms.

Tropical Storm Jelawat will be moving through an environment that is somewhat favorable for intensification.  Jelawat will move over water where the Sea Surface Temperature is near 28°C.  However, the upper level ridge will continue to cause vertical wind shear.  If the shear is not too strong and the circulation remains vertically coherent, then Tropical Storm Jelawat could strengthen during the next several days.   Some models predict this scenario and forecast that Jelawat will intensify into a typhoon.  Alternatively, if the wind shear increases further, strong upper level winds could blow the upper half of the circulation away from the lower level circulation.  If that occurs, Tropical Storm Jelawat will weaken.

The ridge over the Central North Pacific is steering Tropical Storm Jelawat toward the northwest.  Jelawat will reach the western end of the ridge in 12 to 24 hours.  The tropical storm will turn more toward the north when it reaches the end of the ridge.  On its anticipated track the center of Tropical Storm Jelawat is forecast to pass between Yap and Palau.

Tropical Storm Saola Develops West of Guam

Tropical Storm Saola developed west of Guam on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Saola was located at latitude 14.8°N and longitude 134.8°E which put it about 375 miles (605 km) northwest of Yap.  Saola was moving toward the west-northwest at 24 m.p.h. (39 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 997 mb.

The core of the circulation of Tropical Storm Saola became more well organized on Tuesday.  The center of circulation strengthened and more thunderstorms developed close to the center  Bands of showers and thunderstorms formed outside the core of Tropical Storm Saola.  Many of the showers and storms formed southwest of the center.  There were fewer showers and storms northeast of the center.  The storms near the core of Saola began to produce upper level divergence which was pumping mass away from the tropical storm.

Tropical Storm Saola will move through an environment that will be somewhat favorable for intensification.  Saola will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of Tropical Storm Saola is producing easterly winds which are blowing toward the top of the circulation.  Those winds are causing moderate vertical wind shear which is inhibiting the intensification of Tropical Storm Saola.  The upper level winds are forecast to weaken which would cause the wind shear to decrease.  The decreased wind shear should allow Tropical Storm Saola to intensify during the next several days and it could eventually strengthen into a typhoon.

The upper level ridge has been steering Tropical Storm Saola toward the west-northwest.  An upper level trough east of Asia is forecast to weaken the ridge.  When the ridge weakens,Tropical Storm Saola will turn more the north.  On its anticipated track Tropical Storm Saola will remain east of the Philippines and Taiwan.  Tropical Storm Saola could approach Okinawa in about 72 hours.  Saola could be a typhoon when it approaches Okinawa.

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.

TD 03W Intensifies Into Tropical Storm Muifa

Tropical Depression 03W intensified into Tropical Storm Muifa on Tuesday as it moved slowly northwest of Yap.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Muifa was located at latitude 13.3°N and longitude 134.6°E which put it about 335 miles (540 km) northwest of Yap.  Muifa was moving toward the west-northwest at 4 m.p.h. (6 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 1000 mb.

The circulation of Tropical Cyclone Muifa is not well organized.  There is a well defined low level center.  However, almost all of the showers and thunderstorms are in a cluster east of the low level center.  There are almost no showers and thunderstorms in the western half of the circulation.  Few well defined rainbands are evident in the eastern half of the circulation.  The cluster of thunderstorms east of the center of circulation is generating some upper level divergence which appears to be pumping mass out to the northwest of the tropical storm.

Tropical Storm Muifa will be moving through an environment that will be marginally favorable for intensification.  Muifa will move over water where the Sea Surface Temperature will be near 29.5°C.  A subtropical ridge east of Muifa is producing easterly winds which are blowing toward the tropical storm.  Tropical Storm Muifa is currently south of the upper level westerly winds in the middle latitudes.  Muifa is currently in a region where the upper level winds are weaker and the vertical wind shear is moderate.  Areas of stronger vertical wind shear surround the tropical storm.  Tropical Storm Muifa could intensify a little more during the next 24 hours before it reaches an area where the shear is stronger.

Tropical Storm Muifa is moving around the western end of the subtropical ridge to its east and the steering winds are weak.  As a result Muifa is moving slowly toward the west-northwest.  A gradual turn toward the north is forecast as Tropical Storm Muifa moves around the end of the ridge.  Muifa will reach an area of westerly winds as it moves farther north and the tropical storm is forecast to recurve toward the northeast.

Tropical Depression 03W Forms Northwest of Yap

Tropical Depression 03W formed northwest of Yap on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Depression 03W was located at latitude 12.5°N and longitude 135.2°E which put it about 260 miles (420 km) northwest of Yap.  The depression was moving toward the west at 10 m.p.h. (16 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 1003 mb.

A cluster of thunderstorms developed southeast of the Marianas during the weekend.  The cluster moved slowly toward the west-northwest and the circulation gradually exhibited signs of greater organization.  Satellite imagery indicated that a center of circulation formed in the lower levels of the circulation and the system was designated as Tropical Depression 03W on Monday.

The circulation of Tropical Depression 03W is still organizing.  Although there is a distinct low level center, the distribution of showers and thunderstorms is asymmetrical.  Many of the showers and thunderstorms are forming east of the center of circulation.  There are few showers and thunderstorms in the western half of the circulation.  Thunderstorms just to the east of the center of the circulation are generating some upper level divergence that is pumping out mass to the west and north of the center of circulation.

Tropical Depression 03W will be moving through an environment that will be somewhat favorable for intensification.  It will move over water where the Sea Surface Temperature will be near 30°C.  A ridge of high pressure east of the depression is producing easterly flow that is blowing toward the depression.  The flow may be pushing the lower part of the circulation to the west of the middle and upper portions.  Vertical wind shear could be an inhibiting factor.  Some intensification is forecast during the next day or two and the depression could intensify into a tropical storm.

The ridge of the depression is steering it toward the west.  The depression is expected to turn toward the northwest when it reaches the western end of the depression in a day or so.

Tropical Storm Nock-ten Forms Near Yap

Tropical Storm Nock-ten formed near Yap on Wednesday.  At 10:00 p.m. EST on Wednesday the center of Tropical Storm Nock-ten was located at latitude 9.1°N and longitude 138.4°E which put it about 85 miles (140 km) southeast of Yap.  Nock-ten 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 993 mb.

A distinct center of circulation developed in an area of thunderstorms near Yap and the system was named Tropical Storm Nock-ten.  The circulation of Nock-ten is still organizing.  A small well defined center exists at the core of the circulation.  A band of thunderstorms is beginning to wrap around the center.  Several additional bands of thunderstorms formed in the northern part of the circulation.  Thunderstorms near the center are beginning to generate upper level divergence which is pumping mass out to the west of the center.

Tropical Storm Nock-ten will move through an environment that is moderately favorable for intensification.  Nock-ten will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of Nock-ten is producing southeasterly winds which are blowing across the top of the tropical storm.  Those winds are preventing upper level divergence to east of Nock-ten.  Those winds are also causing moderate vertical wind shear which is slowing the rate of intensification.  When Nock-ten moves a little farther west, the vertical wind shear is expected to diminish and faster intensification could occur.  Nock-ten could intensify into a typhoon during the next several days.

A subtropical ridge north of Nock-ten is steering the tropical storm toward the northwest.  That general motion is expected to continue for another day or two.  The ridge could strengthen during the weekend and it could turn Nock-ten more toward the west in a couple of days.  On its anticipate track Tropical Storm Nock-ten could approach the Philippines in three or four days.  Nock-ten could be a typhoon by the time it reaches the Philippines.

Tropical Storm Melor Forms West of Yap

A well defined center of circulation developed within an area of thunderstorms on Friday and the system was designated Tropical Storm Melor (28W).  At 4:00 p.m. EST on Friday the center of Tropical Storm Melor was located at latitude 10.4°N and longitude 134.9°E which put it about 210 miles (335 km) north-northeast of Koror, Palau.  Melor was moving toward the west-northwest at 17 m.p.h. (27 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 997 mb.

Tropical Storm Melor organized quickly on Friday.  A rainband wrapped about three quarters of the way around the center of circulation and an eyewall may be forming.  Outer rainbands are also rotating around the center of circulation.  Thunderstorms around the center of circulation are producing upper level divergence.

The environment around Tropical Storm Melor is favorable for further intensification.  It is over water where the Sea Surface Temperatures are warm.  An upper level ridge is producing light southerly winds over the top of Melor, but there is only modest vertical wind shear.  Once a fully developed eye forms at the center of Melor, the tropical storm could intensify rapidly.  Melor could become a typhoon on Saturday and it could become the equivalent of a major hurricane in 48 to 73 hours.

A subtropical ridge north of Melor is steering the tropical storm toward the west-northwest and that general motion is expected to continue during the next two or three days.  On its anticipated track, Melor could reach the Central Philippines within 72 hours.  It could be a strong typhoon at that time.

Typhoon In-Fa Passes North of Yap

The center of Typhoon In-Fa passed north of Yap on Saturday.  At 10:00 p.m. EST on Saturday the center of Typhoon In-Fa was located at latitude 13.7°N and longitude 136.0°E which put it about 285 miles (465 km) north-northwest of Yap.  In-Fa was moving toward the west-northwest at 19 m.p.h. (31 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 944 mb.

The structure of Typhoon In-Fa deteriorated slightly on Saturday, but it remains the equivalent of a major hurricane.  Fewer thunderstorms formed in the northwestern quadrant of the circulation and there are indications that a gap may have opened on the northwestern side of the eyewall.  It is possible that some drier air could have been pulled into that part of the circulation.  However, an eye may still exist at the center of circulation and there are multiple bands around the eastern and southern sides of the typhoon.

Typhoon In-Fa is moving over water where the Sea Surface Temperature is near 29°C.  The upper level winds over the top of the circulation are light and there is not much vertical wind shear over the core of the typhoon.  Typhoon In-Fa could maintain its intensity or weaken slowly on Sunday.  When it moves farther north, it will encounter stronger southwesterly winds which will increase the vertical wind shear.  When the wind shear increases, the rate of weakening will increase.

A subtropical ridge is steering Typhoon In-Fa toward the west-northwest and that general motion is expected to continue for another day or so.  In-Fa could reach the western end of the ridge and turn northward on Monday.  In 36 to 48 hours the southwesterly upper level winds will start to push the typhoon toward the northeast.  On its anticipated track Typhoon In-Fa could be near Iwo To in about four days.