Tag Archives: Guam

Tropical Storm Jelawat Weakens Rapidly Over the Northern Marianas

Tropical Storm Jelawat weakened rapidly over the Northern Marianas on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Jelawat was located at latitude 19.3°N and longitude 145.5°E which put it about 50 miles (80 km) north-northwest of Agrihan.  Jelawat was moving toward the east-northeast at 14 m.p.h. (22 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.

Former Typhoon Jelawat moved into an area where there were upper level westerly winds blowing at 50 m.p.h. (80 km/h).  Those strong upper level winds created enough vertical wind shear to blow the upper two thirds of the circulation east of the lower part of the circulation.  The remaining strong thunderstorms were weakening well to the east of the lower level circulation.  Tropical Storm Jelawat consisted primarily of narrow bands of showers and low clouds that were revolving around the center of circulation.  Jelawat may bring brief gusty winds and showers to the northernmost islands in the Marianas.

Typhoon Jelawat Rapidly Intensifies Into Equivalent of Major Hurricane

Typhoon Jelawat intensified rapidly on Friday into the equivalent of a major hurricane.  At 11:00 a.m. EDT on Friday the center of Typhoon Jelawat was located at latitude 17.1°N and longitude 139.5°E which put it about 440 miles (710 km) northwest of Guam.  Jelawat was moving toward the east-northeast at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h).  The minimum surface pressure was 926 mb.

Typhoon Jelawat intensified rapidly on Friday.  There was a small circular eye at the center of circulation.  A ring of very strong storms surrounded the eye and the strongest winds were occurring in that ring of storms.  Several spiral bands were revolving around the core of the circulation.  Storms near the core were generating well developed upper level divergence which was pumping large quantities of mass away to the east of the typhoon.  The removal of mass allowed the surface pressure to decrease rapidly and that produced a a rapid increase in wind speed.

Winds to typhoon force extend out about 45 miles (75 km) from the center of Typhoon Jelawat.  Winds to tropical storm force extend out about 175 miles (280 km) from the center of circulation.  The Hurricane Intensity Index (HII) for Typhoon Jelawat is 31.6.  The Hurricane Size Index (HSI) is 17.7 and the Hurricane Wind Intensity Size Index (HWISI) is 49.3.

Typhoon Jelawat is in an environment favorable for strong typhoons, but it may be near its peak in intensity.  Jelawat will move over water where the Sea Surface Temperature is near 28°C.  Typhoon Jelwat has moved around the western end of an upper level ridge which is producing easterly winds that are blowing toward the top of the circulation.  The winds are causing some vertical wind shear, but the shear has not inhibited intensification.  When Typhoon Jelawat moves farther to the northeast it will move under stronger easterly and the wind shear will increase.  More shear will cause Jelawat to weaken during the next few days.

A subtropical ridge to the east of Typhoon Jelawat is steering the typhoon toward the east-northeast.  A general motion toward the east-northeast is expected to continue for several more days.  On its anticipated track Typhoon Jelawat could approach the northernmost islands in the Marianas in about 48 hours.

Typhoon Jelawat Strengthens West-Northwest of Guam

Former Tropical Storm Jelawat strengthened into a typhoon as it moved west-northwest of Guam on Thursday.  At 11:00 p.m. EDT on Thursday the center of Typhoon Jelawat was located at latitude 15.9°N and longitude 137.7°E which put it about 520 miles (840 km) west-northwest of Guam.  Jelawat was moving toward the east-northeast at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 972 mb.

Typhoon Jelawat strengthened quickly on Thursday night.  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 Jelawat.  Storms in the core of the circulation were generating upper level divergence which was pumping mass away to the northeast of the typhoon.  Winds to typhoon force extended out about 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out about 145 miles (230 km) from the center.

Typhoon Jelawat will move through an area favorable for intensification on Friday.  Jelawat will move over water where the Sea Surface Temperature is near 28°C.  Typhoon Jelawat has moved around the western end of an upper level ridge which is producing southwesterly winds which are blowing toward the top of the circulation.  Those winds are producing some vertical wind shear, but the wind shear is not strong enough to prevent intensification.   Typhoon Jelwat is likely to intensify further on Friday.

The upper level ridge is steering Typhoon Jelawat toward the east-northeast and that general motion is expected to continue for several more days.  On its anticipated track Typhoon Jelawat is expected to pass northwest of Guam.  Jelawat could approach the northernmost islands in the Marianas in about two or three days.

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 Lan Brings Wind and Rain to Japan

Typhoon Lan brought wind and rain to parts of Japan on Sunday.  At 5:00 p.m. EDT on Sunday the center of Typhoon Lan was located at latitude 35.2°N and longitude 139.1°E which put it about 50 miles southwest of Tokyo, Japan.  Lan was moving toward the northeast at 37 m.p.h. (60 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (155 km/h).  The minimum surface pressure was 960 mb.

Typhoon Lan weakened significantly before it reached Japan.  Lan moved over cooler water south of Japan.  Strong upper level westerly winds caused strong vertical wind shear.  The circulation of Lan pulled drier air into the western half of the circulation.  The combination of cooler water, strong shear and drier air caused the significant weakening.  In addition the shear was strong enough to push the heavier rain to the northeast of the center of Typhoon Lan.

Lan was still a typhoon when it made landfall in Honshu despite the unfavorable environment.  A weather station at the Tokyo International Airport reported a wind speed of 56 m.p.h. (90 km/h).  Some areas in eastern Honshu experienced periods of heavy rain and gusty winds.  The drier air will limit the rainfall after the center of the typhoon passes a given location.

The strong westerly winds will steer Typhoon Lan rapidly toward the northeast.  Lan will move east of Honshu in a few hours.  The strong vertical wind shear and cooler, drier air will cause Typhoon Lan to transition to a strong extratropical cyclone east of Japan.

While Typhoon Lan races across eastern Japan, Tropical Depression 27W organized southeast of Guam.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression 27W was located at latitude 9.3°N and longitude 147.4°E which put it about 360 miles (580 km) southeast of Guam.  It was moving toward west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gust to 45 m.p.h.  The minimum surface pressure was 1004 mb.

Tropical Depression 27W will move through an environment that will be somewhat favorable for development during the next several days.  It will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge centered northeast of the Marianas is producing easterly winds which are blowing over the top of the depression.  Those winds are causing moderate vertical wind shear.  The shear is inhibiting the organization of the circulation and it is slowing the development of the depression.  The shear is forecast to decrease during the next several days and the depression could strengthen into a tropical storm if a distinct low level center forms.

Tropical Depression 27W is near the southwestern end of the ridge to its northeast.  The ridge is currently steering the depression toward the west.  It is forecast to move around the end of the ridge and turn more toward the north during the next few days.  On its anticipated track the depression could be near Guam in about 24 hours.  It could be a tropical storm at that time.

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 Meari Intensifies Into a Typhoon

A well organized core developed at the center of Tropical Storm Meari on Friday and it intensified into a typhoon.  At 5:00 p.m. EDT on Friday the center of Typhoon Meari was located at latitude 17.0°N and longitude 140.0°E which put it about 425 miles (685 km) west-northwest of Saipan.  Meari was moving toward the north-northeast at 10 m.p.h. (16 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. (145 km/h).  The minimum surface pressure was 979 mb.

A strong center of circulation finally developed within a broader area of low pressure that contained Tropical Storm Meari.  An inner rainband wrapped around the center and an eye appeared on microwave satellite imagery.  The formation of a tight inner core allowed Meari to strengthen into a typhoon.  There are some rainbands east of the center of Typhoon Meari, but most of the stronger thunderstorms are occurring in bands south and west of the center.  Thunderstorms in the core of Typhoon Meari are now generating upper level divergence which is pumping out mass.  Typhoon Meari is now a well organized tropical cyclone.

Typhoon Meari is moving through an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  An upper level ridge is over Meari which is resulting in light winds in the upper levels and little vertical wind shear.  In fact the upper level ridge is enhancing the divergence generated by the typhoon.  Typhoon Meari should continue to strengthen during the next 24 hours.  Since a well formed core now exists at the center, a period of rapid intensification is quite possible.

Typhoon Meari is moving around the western end of a subtropical ridge which is steering it toward the north-northeast.  That general motion is expected to continue for another day or so.  When Typhoon Meari gets farther north, westerly winds from the middle latitudes will push it toward the northeast more quickly.  On its anticipated track, Typhoon Meari could be near the northernmost Marianas in about 36 hours.  Meari could be a strong typhoon at that time.  Although no warnings are currently in effect, people on Alamagan, Pagan and Agrihan need to monitor the movement of Typhoon Meari.