Tag Archives: Pohnpei

Tropical Storm Sanvu Develops Northwest of Pohnpei

Tropical Storm Sanvu developed over the Western North Pacific Ocean northwest of Pohnpei on Wednesday night. At 5:00 a.m. EDT on Thursday the center of Tropical Storm Sanvu was located at latitude 9.3°N and longitude 156.8°E which put it about 165 miles (265 km) north-northwest of Pohnpei. Sanvu was moving toward the 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 1000 mb.

Former Tropical Depression 01W strengthened on Wednesday night and the Japan Meteorological Agency designated the system as Tropical Storm Sanvu. The inner end of a rainband wrapped around the center of Sanvu’s circulation. Other bands of showers and thunderstorms were revolving around the center of circulation. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 60 miles (95 km) from the center of circulation.

Tropical Storm Sanvu will move through an environment favorable for intensification during the next 24 hours. Sanvu will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the axis of an upper level ridge over the equatorial Western North Pacific Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Tropical Storm Sanvu could intensify during the next 24 hours. Sanvu will move under the northern side of the upper level ridge on Friday and the vertical wind shear will increase. Tropical Storm Sanvu is likely to weaken when the wind shear increases.

Tropical Storm Sanvu will move around the southern side of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Sanvu toward the northwest during the next 24 hours. On its anticipated track, Tropical Storm Sanvu will move farther away from Pohnpei. Sanvu will be northeast of Chuuk and Fananu on Thursday evening.

Tropical Depression 01W Forms South of Pohnpei

Tropical Depression 01W formed over the Western North Pacific Ocean south of Pohnpei on Wednesday morning. At 11:00 a.m. EDT on Wednesday the center of Tropical Depression 01W was located at latitude 5.2°N and longitude 158.2°E which put it about 145 miles (235 km) south of Pohnpei. Tropical Depression 01W was moving toward the west-northwest 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 1004 mb.

A low pressure system over the Western North Pacific Ocean south of Pohnpei strengthened on Wednesday morning and both the Japan Meteorological Agency and the U.S. Joint Typhoon Warning Center classified the system as a tropical depression. The circulation around Tropical Depression 01W exhibited more organization on Wednesday morning. Bands of showers and thunderstorms were revolving around the center of Tropical Depression 01W. Storms near the center generated upper level divergence that pumped mass away from the tropical depression.

Tropical Depression 01W will move through an environment favorable for intensification during the next 24 hours. The tropical depression will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the axis of an upper level ridge over the equatorial Western North Pacific Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Tropical Depression 01W is likely to intensify to a tropical storm during the next 24 hours.

Tropical Depression 01W will move around the southern side of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer the tropical depression toward the northwest during the next 24 hours. On its anticipated track, Tropical Depression 01W will pass west of Pohnpei. The tropical depression could be northeast of Chuuk and east of Fananu on Thursday.

Tropical Storm In-Fa Intensifying, Typhoon Watch for Fananu

Tropical Storm In-Fa intensified quickly on Tuesday and it caused watches and warnings to be issued for the area around Chuuk.  At 10:00 p.m. EST on Tuesday the center of Tropical Storm In-Fa was located at latitude 6.0°N and longitude 156.3°E which put it about 385 miles (620 km) east-southeast of Fananu and about 985 miles (1590 km) east-southeast of Guam.  In-Fa was moving toward the west-northwest 18 m.p.h. (29 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 983 mb.  A Typhoon Watch has been issued for Fananu.

The circulation of Tropical Storm In-Fa organized rapidly on Tuesday.  A tight core formed in the center of circulation and an eyelike feature appeared on satellite images.  A small ring of thunderstorms formed around the eye and a large primary rainband wrapped around the circulation.  The circulation became more symmetrical and upper level outflow began to create divergence in most directions.

Tropical Storm In-Fa remains in an environment favorable for intensification.  It is over water where the Sea Surface Temperature is near 30°C.   The upper level winds are light and the vertical wind shear is modest.  In-Fa is likely to continue to intensify and now that an inner core has developed, it could intensify rapidly.  In-Fa could become a typhoon on Wednesday and it could become the equivalent of a major hurricane later this week.

A subtropical ridge north of In-Fa is steering the tropical storm toward the west-northwest and that general motion is expected to continue for the rest of the week.  On its anticipated track In-Fa will approach Fananu in about 24 hours and it could be a typhoon at that time.  In-Fa could be approaching Guam in about three days as a typhoon.

Tropical Depression 27W Forms Southeast of Pohnpei

A center of circulation formed in an area of thunderstorms southeast of Pohnpei and the system was designated Tropical Depression 27W (TD 27W).  At 10:00 p.m. EST on Monday the center of Tropical Depression 27W was located at latitude 4.7°N and longitude 162.3°E which put it about 360 miles (585 km) east-southeast of Pohnpei.  TD 27W was moving to the west at 17 m.p.h. (27 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1001 mb.

The circulation of TD 27W is still organizing.  A clearly defined low level center of circulation formed near the northern edge of an area of thunderstorms.  However, most of the stronger thunderstorms are southwest of the center.  Those storms are generating upper level divergence that is expanding south and west of the center.

Tropical Depression 27W is in an environment that favors further intensification.  It is over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of TD 27W is producing light easterly winds over the top of the depression.  The vertical wind shear is modest, and it should only slow the rate of intensification.  Intensification could be slow initially as a stronger inner core forms around the center of circulation.  Once the core of the circulation consolidates, then intensification could occur more quickly.  TD 27W could become a tropical storm within 24 to 36 hours and it could be a typhoon in three or four days.

A subtropical ridge north of TD 27W is steering the depression toward the west.  A gradual turn toward the west-northwest is expected and that general motion is expected to continue for much of the week.  On its anticipated track TD 27W could be near Pohnpei in about 24 hours and it could bring tropical storm force winds and heavy rain.  The tropical cyclone could be approaching Guam by the end of the week and it could be a typhoon by that time.

Tropical Depression 07W Forms South of Pohnpei

The active period over the tropical Western North Pacific Ocean continues with the development of another tropical cyclone south of Pohnpei.  At 8:00 p.m. EDT on Wednesday the center of Tropical Depression 07W was located at latitude 4.4°N and longitude 156.8°E which put it about 160 miles south-southeast of Pohnpei.  The tropical depression was stationary.  The maximum sustained wind speed was 35 m.p.h. and there were gusts to 50 m.p.h.  The minimum surface pressure was 1004 mb.

A low level circulation center formed within a broad area of thunderstorms and the system was classified as Tropical Depression 07W.  The strongest thunderstorms are mainly located in the northwestern part of the circulation.  An upper level ridge located east of the depression is generating southeasterly winds over the top of it which is producing modest vertical wind shear.  The wind shear is the probably reason why most of the thunderstorms are northwest of the center of circulation.  The wind shear will also limit the rate of intensification during the next day or two.  Eventually the depression is expected to move farther west into an area with less wind shear and it could intensify more quickly.

Tropical Depression 07W is located near the western end of a subtropical ridge and the steering currents are relatively weak.  It may not move much for the next 12 to 24 hours.  Later this week the ridge is expected to strengthen and steer the depression toward the west-northwest.  On its projected track the depression could approach Pohnpei in two or three days.