Tag Archives: Guam

Typhoon Soudelor Intensifies Rapidly and Moves Over Saipan

Typhoon Soudelor intensified rapidly during the 12 hours before it moved directly over Saipan.  At 11:00 a.m. EDT on Sunday the center of Typhoon Soudelor was located at latitude 15.3°N and longitude 145.3°E which put it about 25 miles (40 km) west-northwest of Saipan.  It was moving toward the west-northwest at 11 m.p.h. (18 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. (205 km/h).  The minimum surface pressure was 956 mb.  The airport on Saipan measured sustained wind to 54 m.p.h. (87 km/h) and wind gusts to 91 m.p.h. (147 km/h).  However, there were several observations when no wind speed was reported.  The minimum surface pressure reported was 958 mb.

Typhoon Soudelor organized quickly after the primary band wrapped completely around the center of circulation.  A tiny (4 mile wide) pinhole eye developed at the center of circulation and there are multiple bands of thunderstorms rotating around the center.   Soudelor is over warm Sea Surface Temperatures and there is little vertical wind shear.  Further intensification is likely and Soudelor could reach Super Typhoon status.

A subtropical ridge is steering Soudelor toward the west-northwest and that general motion is expected to continue for the next few days.  On its anticipated track Soudelor could approach the southernmost islands of Japan or Taiwan in four or five days.

Soudelor Almost a Typhoon as It Nears the Marianas

Tropical Storm Soudelor intensified on Saturday and it has almost reached typhoon status.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Soudelor was located at latitude 14.8°N and longitude 147.7°E which put it about 170 miles (275 km) east-southeast of Saipan.  Soudelor was moving toward the west-northwest at 18 m.p.h. (29 km/h).  The maximum sustained wind speed was 70 m.p.h. (115 km/h) and there were gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 978 mb.  A Typhoon Warning has been issued for Saipan and Tinian.  A Tropical Storm Warning has been issued for Rota.  A Typhoon Watch has been issued for Agrihan, Pagan and Alamagan.

The structure of Tropical Storm Soudelor improved on Saturday.  A long spiral band wrapped almost entirely around the center of circulation and numerous other spiral bands were apparent on satellite imagery.  There are more thunderstorms on the western side of the circulation.  Soudelor is moving over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of the tropical storm is causing light easterly winds over the circulation.  However, the vertical wind shear is modest and upper level divergence is increasing.  Soudelor is in a favorable environment.  Further intensification is likely and rapid intensification is possible.  Soudelor will very likely be a typhoon when it moves through Marianas.

A subtropical ridge is steering Soudelor toward the west-northwest and that pattern is expected to continue during the next few days.  On its anticipated track Soudelor will be near Saipan and Tinian in about 12 hours.  It could bring strong winds to those locations and other nearby islands.

Tropical Storm Chan-hom Bringing Wind and Rain to Guam

Tropical Storm Chan-hom is passing through the Marianas and bringing gusty winds and rain to Guam and Rota.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Chan-hom was located at latitude 14.3°N and longitude 144.8°E which put it about 10 miles (15 km) west of Rota.  Chan-hom was moving toward the west-northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 991 mb.

Despite being over warm water Chan-hom did not intensify on Saturday.  The circulation could be pulling in some drier air which is limiting the development of thunderstorms.  More thunderstorms developed near the inner core of Chan-hom late on Saturday.  There is not much vertical wind shear over the tropical storm.  If a well organized inner core forms, then intensification will be possible.  Chan-hom could become a typhoon after it moves west of the Mariana Islands.

The subtropical ridge steering Chan-hom is expected to continue to steer it toward the northwest during the next few days.  On its anticipated track Chan-hom could approach the southern islands of Japan in about four days.

Tropical Storm Chan-hom Moving Toward Marianas

Tropical Storm Chan-hom has resumed a northwesterly motion and it is moving toward the Mariana Islands.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Chan-hom was located at latitude 12.7°N and longitude 148.2°E which put it about 250 miles (400 km) east-southeast of Guam.  Chan-hom was moving toward the northwest at 11 m.p.h. (18 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 989 mb.  A Typhoon Watch is in effect for Guam, Rota, Tinian and Saipan.

The upper level low that produced the vertical wind shear which blew the top off Chan-hom on Thursday moved northeast and the upper level winds decreased on Friday.  A reduction in vertical wind shear allowed new thunderstorms to develop around the center of circulation and the circulation became better organized.  The thunderstorms near the center are beginning to generate upper level divergence and more spiral bands appear to be forming.  Chan-hom is over water where the Sea Surface Temperature is near 29°C.  The environment is favorable for intensification and rapid intensification is possible, if the wind shear remains modest.  Chan-hom could attain typhoon intensity before it reaches the Mariana Islands.

A subtropical ridge is steering Chan-hom toward the northwest and that ridge is expected to continue to steer it in the same general direction during the next few days.  On its anticipated track, Chan-hom could approach the Mariana Islands in about 24 hours.  The center could pass north of Guam, but it may pass near to Rota, Tinian or Saipan.  Chan-hom will bring wind and heavy rain to any islands it crosses.

Wind Shear Affecting Tropical Storm Chan-hom

Although Tropical Storm Chan-hom briefly reached typhoon intensity on Thursday, strong upper vertical wind shear quickly weakened it back to a tropical storm.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Chan-hom was located at latitude 10.3°N and longitude 148.0°E which put it about 325 miles (525 km) southeast of Guam.  Chan-hom was moving toward the west at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 981 mb.  A Typhoon Watch has been issued for Guam, Rota, Tinian and Saipan.

The combination of a upper level ridge and an upper level low produced strong northeasterly winds that blew the middle and upper portions of the circulation of Chan-hom west of the low level circulation.  The middle and upper parts of the circulation are about 100 miles (160 km) southwest of the surface center.  There are no thunderstorms currently near the surface center.  The upper level winds and the vertical wind shear they are producing are likely to continue to weaken Chan-hom on Friday.  The upper low is expected to move eastward during the next several days, which would result in a decrease in the wind shear.  If the surface circulation is still intact, it will be over warm Sea Surface Temperatures and reintensification would be possible.

Chan-hom is likely to be steered toward the west on Friday by the winds in the lower levels.  If new thunderstorms develop near the center and the height of the circulation increases, then a subtropical ridge in the middle levels could cause the tropical storm to turn toward the northwest.  If that turn occurs on Friday, it could put Chan-hom on a track toward Guam, Saipan or Tiniana.  If the turn occurs later in the weekend, then Chan-hom could pass to the south of those islands before it turns toward the northwest.

Tropical Storm Chan-hom Forms East of Guam

A center of circulation developed in an area of thunderstorms on the opposite side of the Equator from Tropical Cyclone Raquel and it was designated as Tropical Storm Chan-hom on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Chan-hom was located at latitude 11.0°N and longitude 156.5°E which put it about 250 miles (400 km) north-northeast of Oroluk atoll and about 800 miles (1290 km) east of Guam.  Chan-hom was moving toward the west at 22 m.p.h. (35 km/h).  The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 993 mb.

Tropical Storm Chan-hom formed over water where the Sea Surface Temperatures (SSTs) are around 29°C to 30°C and there is plenty of energy in the upper ocean to support intensification.  An upper level ridge located north of the tropical storm is generating easterly winds over the top of the circulation.  The easterly winds are generating moderate amounts of vertical wind shear and many of the stronger thunderstorms are occurring in the western half of the circulation.  Those thunderstorms are producing strong rising motion and upper level divergence is well developed on the western side of Chan-hom.  However the upper level easterly winds are interfering with upper level divergence on the eastern side of the tropical storm.  As a result, a modest rate of intensification is expected in the short term.  If the upper level winds were to lessen, then a more rapid rate of intensification would be possible.

The upper level ridge is expected to steer Chan-hom toward the west during the next several days.  On its anticipated track Chan-hom could approach Guam in about three days.  It could be a typhoon by that time.  However, there is some divergence in the track guidance from numerical models at the end of this week and that is producing uncertainty about the future track of Chan during that time period.

Typhoon Dolphin Hits Guam and Rota

The core of Typhoon Dolphin moved over Guam and Rota on Friday.  Andersen Air Force Base reported northwesterly winds at 75 m.p.h. with gusts to 106 m.p.h. in one of its hourly observations.  The base also reported a Peak Wind of 86 knots (100 m.p.h.) in another observation.  The international airport on Guam reported a Peak Wind of 70 knots (80 m.p.h.).  At 5:00 p.m. EDT on Friday the center of Typhoon Dolphin was located at latitude 15.1°N and longitude 143.0°E which put it about 120 miles northwest of Guam.  Dolphin was moving toward the northwest at 15 m.p.h.  The maximum sustained wind speed was 125 m.p.h. and there were gusts to 155 m.p.h.  The minimum surface pressure was 941 mb.

Typhoon Dolphin is intensifying rapidly.  It is over water there the Sea Surface Temperature is near 29°C and the upper level winds are light.  It has a well formed eye and thunderstorms around the center are pumping out mass.  Upper level divergence is occurring and their are outflow channels to the northeast and southwest.  Dolphin could continue to intensify rapidly for another 24 hours.

Dolphin is near the western end of a subtropical ridge and it should gradually turn toward the north and then the northeast.  Its anticipated track will take it farther away from Guam, but it could approach Iwo To in about 72 hours as a significant typhoon.

Typhoon Dolphin Nearing Guam

Typhoon Dolphin is bringing wind and rain to Guam and Rota.  At 11:00 p.m. EDT on Thursday the center of Typhoon Dolphin was located at latitude 13.7°N and longitude 146.6°E which put it about 100 miles east of Guam.  Dolphin was moving toward the west-northwest at 16 m.p.h.  The maximum sustained wind speed was 110 m.p.h. and there were gusts to 130 m.p.h.  The minimum surface pressure was 952 mb.  A Typhoon Warning is in effect for Guam, Rota, Saipan and Tinian.  The Hurricane Intensity Index is 19.2, the Hurricane Size Index is 12.8 and the Hurricane Wind Intensity Size Index is 32.0.  The indices suggest that Dolphin is capable of producing regional serious damage.

The circulation of Dolphin became more symmetrical on Thursday and radar images from Guam show a circular eye and eyewall.  The thunderstorms near the center are generating upper level outflow.  Dolphin is moving over warm Sea Surface Temperatures and it is in an area where the upper level winds are relatively light.  The combination of better organization, warm water, little vertical wind shear suggest that further intensification is likely.

A subtropical ridge is steering Dolphin toward the west-northwest and that steering pattern is likely to continue for another day or so.  As Dolphin moves near the western end of the subtropical ridge, it is likely to turn more toward the north.  Eventually, when the typhoon moves farther north, westerly winds will turn it toward the northeast.

The core of Typhoon Dolphin will pass near Guam and Rota during the next few hours.  The northern portion of Guam and Rota will experience the strongest winds and heaviest rainfall, although much of Guam will experience the effects of Dolphin.  The core of the typhoon will likely pass south of Saipan and Tinian, but those islands will still get hit by rainbands rotating around the northern half of the circulation.

 

Typhoon Dolphin Still Moving Toward Guam

Typhoon Dolphin continued to moved toward the west-northwest in the direction of Guam on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Dolphin was located at latitude 11.6°N and longitude 151.6°E which put it about 510 miles east-southeast of Guam.  Dolphin was moving toward the west-northwest at 15 m.p.h.  The maximum sustained wind speed was 105 m.p.h. and there were gusts to 125 m.p.h.  The minimum surface pressure was 956 mb.  A Typhoon Warning has been issued for Guam and Rota.  A Typhoon Watch and a Tropical Storm Warning has been issued for Saipan and Tinian.

Although the overall circulation of Dolphin remains well organized, many of the thunderstorms are located in a long spiral band that is trying to wrap around the center.  Some drier air may be wrapping around the western and southern sides of the circulation outside this band.  Dolphin is moving over warm Sea Surface Temperatures.  It is moving near the axis of an upper level ridge and the core of the typhoon is in an area with little vertical wind shear.  Except for the possible dry air, the conditions are favorable for further intensification.

Dolphin is being steered to the west-northwest by a subtropical ridge north of the typhoon.  The ridge is likely to continue to steer Dolphin in this direction for another day or two.  On the anticipated track Dolphin would approach Guam in 24 to 30 hours.  It could be a significant typhoon at that time.  After it passes Guam, Dolphin is expected to turn more toward the northwest as it moves around the western end of the subtropical ridge.

 

Dolphin Becomes a Typhoon and Heads Toward Guam

Tropical Storm Dolphin moved into a more favorable environment and intensified into a typhoon on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Typhoon Dolphin was located at latitude 10.2°N and longitude 155.8°W which put it about 350 miles east-northeast of Chuuk and about 810 miles east-southeast of Guam.  Dolphin was moving toward the west at 8 m.p.h.  The maximum sustained wind speed was 75 m.p.h. and there were gusts to 90 m.p.h.  The minimum surface pressure was 974 mb.

Dolphin moved closer to the axis of an upper level ridge and the vertical wind shear which was inhibiting its intensification diminished.  Since Dolphin is over water where the Sea Surface Temperature is near 29°C, the decreased shear allow it to intensify into a typhoon.  Dolphin has a small well organized core circulation with a tiny eye at its center.  Spiral bands of thunderstorms radiate out from the center.  The upper level outflow produced by those thunderstorms has increased and the removal of mass is allowing the surface pressure to decrease.  Dolphin is expected to remain in a region of modest vertical wind shear and further intensification is likely.  A period of rapid intensification is possible.

A subtropical ridge is steering Dolphin toward the west.  The ridge is expected to steer it toward the west-northwest during the next two or three days.  On its anticipated track Dolphin would approach Guam in 48 to 60 hours and it could be a significant typhoon at that time.