Tag Archives: Iwo To

Tropical Storm Meari Reorganizes West of Guam

The circulation designated as Tropical Storm Meari reorganized west of Guam on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Meari was located at latitude 15.0°N and longitude 139.0°E which put it about 415 miles (670 km) west of Guam.  Meari was moving toward the north-northeast at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 990 mb.

Tropical Storm Meari initially formed as a smaller counterclockwise circulation within a much broader cyclonic circulation that stretched from the Northern Mariana Islands toward the Philippines.  The initial surface center weakened on Thursday and a new center of circulation organized northeast of the original center.  A primary rainband began to wrap around the southern and east side of the low level center.  Numerous other bands of showers and thunderstorms were forming within the broader cyclonic circulation.  More bands of showers and thunderstorms were developing southwest of the new center and fewer bands were northeast of the center.  The new center of circulation is still consolidating and Tropical Storm Meari still does not have a well developed core.

Although Meari is still not well organized, the tropical storm is moving through an environment that is favorable for intensification.  Tropical Storm Meari is moving over water where the Sea Surface Temperature is near 30°C.  An upper level ridge is located over Tropical Storm Meari and the upper level winds are weak.  So, there is little vertical wind shear.  Warm water and little shear should allow Tropical Storm Meari to continue to intensify.  The lack of a well formed inner core and the large broad cyclonic circulation will slow the rate of strengthening.

The reformation of the center of circulation farther toward the northeast caused the forecast track guidance from numerical models to shift to a more northeasterly track.  If the current center of Tropical Storm Meari persists, it is located near the western end of a subtropical ridge.  Meari is expected to move toward the northeast around the western end of the ridge.  When Meari moves farther north, westerly winds in the middle latitudes will accelerate the tropical storm toward the northeast.

Tropical Storm Mindulle Forms Northwest of Guam

A smaller center of circulation consolidated within a much larger cyclonic gyre that extends from the Marianas north to Japan and west to China and the system has been designated Tropical Storm Mindulle.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Mindulle was located at latitude 19.5°N and longitude 141.0°E which put it about 410 miles (655 km) south of Iwo To.  Mindule was moving toward the north-northwest at 11 m.p.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 992 mb.

The circulation around Tropical Storm Mindulle is still organizing.  A primary rainband is wrapping about three quarters of the way around the broad center of circulation.  There are few thunderstorms close to the core of tropical storm.  Scattered thunderstorms are forming in broken bands outside the primary rainband.  The thunderstorms in the primary rainband are generating some upper level divergence which is mainly pumping mass to the southwest of the center of circulation.

Tropical Storm Mindulle is in an environment that is favorable for slow intensification.  It is moving over water where the Sea Surface Temperature is near 31°C.  The upper level pattern near Mindulle is quite complex with a number of different features.  A narrow upper level ridge is just north of Mindulle and it is producing northeasterly winds that are blowing across the top of the tropical storm.  The northeasterly winds are contributing to the fact that most of the thunderstorms are west of the center of circulation and they are causing moderate vertical wind shear.  The vertical wind shear is inhibiting intensification.  Tropical Storm Mindulle is expected to extract enough energy from the ocean to intensify.  However, intensification will be slow while the core of the circulation organizes.

Tropical Storm Mindule is moving around the eastern portion of the large cyclonic gyre mentioned above.  That gyre is steering Mindulle toward the north-northwest and a general motion toward the north is expected to continue.  On its anticipated track Tropical Storm Mindulle could pass near Iwo To in about 24 hours.  Mindulle could be near Tokyo, Japan in about three days.

Tropical Storm Chanthu Forms South of Japan

A center of circulation consolidated near a cluster of thunderstorms south of Japan on Saturday and the system was designated as Tropical Storm Chanthu.  At 11:00 p.m. EDT on Saturday the center of Tropical Storm Chanthu was located at latitude 21.2°N and longitude 143.1°E which put it about 295 miles (475 km) south-southeast of Iwo To.  Chanthu was moving toward the northeast at 14 m.p.h. (23 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.

Although a distinct center of circulation exists in the lower levels of Tropical Storm Chanthu, the storm is not well organized.  Southwesterly winds in the upper levels are causing vertical wind shear which is tilting the upper portion of the circulation toward the northeast.  Most of the thunderstorms associated with Tropical Storm Chanthu are occurring in the northeastern quadrant of the circulation.  Several broken rainbands extend into the southern portion of the circulation, but there are few thunderstorms in the western half of Chanthu.

Tropical Storm Chanthu is moving through an environment that is marginally favorable for intensification.  Chanthu is moving over water where the Sea Surface Temperature is near 30°C.  However, an upper level trough west of Chanthu is causing the southwesterly winds which are blowing across the top of the tropical storm.  Moderate vertical wind shear will inhibit intensification in the short term.  As Tropical Storm Chanthu moves farther north, it could move into a region where the upper level winds are not as strong.  If the vertical wind shear decreases, then Chanthu could intensify.

Winds from the upper level trough are steering Tropical Storm Chanthu toward the northeast.  As the tropical storm moves farther north, a subtropical ridge located east of Chanthu will steer it more toward the north.  On its anticipated track, the center of Tropical Storm Chanthu is expected to pass east of Iwo To in about 24 hours.  Tropical Storm Chanthu could be approaching the coast of Japan near Tokyo in about three or four days.

Tropical Storm Omais Forms over the Northern Marianas

A very broad area of low pressure developed enough of the characteristics of a tropical cyclone to be classified as Tropical Storm Omais on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Omais was located at latitude 19.5°N and longitude 146.2°E which put it about 380 miles (615 km) north-northeast of Guam.  Omais was moving toward the north at 3 m.p.h. (5 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 996 mb.

The circulation of Tropical Storm Omais is not well organized.  Several clusters of thunderstorms exist about 100 miles (160 km) east and south of the center of the very broad low pressure system.  No thunderstorms are occurring in the western half of the low or near the center of the circulation.  An inner core does not exist at this time and the strongest winds are occurring in the clusters of thunderstorms well removed from the center.

Tropical Storm Omais is in an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level environment is also somewhat favorable for intensification.  An upper level low is northwest of Omais and an upper level ridge is east of the tropical storm.  Those two features are generating southwesterly winds which are blowing over the top of Tropical Storm Omais.  The vertical wind shear is inhibiting the organization and intensification of Omais.

The environment should allow Tropical Storm Omais to intensify, but the large circulation will reduce the rate of intensification.  As the wind field contracts and the strongest winds move closer to the center of circulation, the structure of Tropical Storm Omais will move closely resemble a typical tropical cyclone.  When an inner core forms at the center of circulation, the rate of intensification may increase.

Tropical Storm Omais is near the western end of a subtropical ridge.  The steering currents are weak, but Omais is likely to move slowly toward the north in the short term.  A faster motion is expected over the weekend.  On its anticipated track Tropical Storm Omais will move near the northernmost Marianas and pass east of Iwo To.

In-Fa Weakens to a Tropical Storm on Its Way to Iwo To

In-Fa weakened below typhoon intensity on Tuesday as it moved toward Iwo To.  At 10:00 p.m. EST on Tuesday the center of Tropical Storm In-Fa was located at latitude 20.1°N and longitude 135.3°E which put it about 540 miles (870 km) southwest of Iwo To.  In-Fa was moving toward the northeast at 10 m.p.h. (16 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 994 mb.

A large upper level trough that extends south of Japan is producing strong southwesterly winds over the top of Tropical Storm In-Fa.  Those winds are causing strong vertical wind shear which is tilting the upper portion of the circulation of the tropical storm toward the northeast.  The stronger thunderstorms are all located northeast of the center of In-Fa.  It also appears drier air is wrapping around the southwestern part of the circulation.  The strong vertical wind shear will continue to weaken Tropical Storm In-Fa.  As it moves into a cooler environment In-Fa will gradually make a transition to an extratropical cyclone during the next 48 hours.

The upper level trough will continue to steer Tropical Storm In-Fa toward the northeast while it makes the transition to an extratropical cyclone.  On its anticipated track In-Fa could bring tropical storm force winds to Iwo To in 24 to 36 hours.

Typhoon In-Fa Turns Toward Iwo To

Typhoon In-fa turned northeast and started to move toward Iwo To late on Monday.  At 10:00 p.m. EST on Monday the center of Typhoon In-Fa was located at latitude 19.0°N and longitude 132.6°E which put it about 695 miles (1120 km) southwest of Iwo To.  In-Fa was moving toward the northeast at 13 m.p.h. (21 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 956 mb.

Although In-Fa may be beginning to respond to increased vertical wind shear, it remains a well organized typhoon.  There are signs that a cloud filled eye still exists at the core of In-Fa.  The eye is surround by a ring of strong thunderstorms.  The outer portion of In-Fa’s circulation is becoming more asymmetrical, which is probably the result of increased wind shear.  Most of the thunderstorms outside the core are north and east of the center of circulation.  There are few thunderstorms in the southwestern part of In-Fa.

Typhoon In-Fa is currently over water where the Sea Surface Temperature (SST) is near 28°C.  In-Fa will move over increasingly cooler SSTs as it moves northeast.  The strength of the upper level southwesterly winds will increase as In-Fa moves northeast.  The combination of cooler SSTs and more vertical wind shear will cause Typhoon In-Fa to weaken during the next several days.  It could weaken to a tropical storm by Wednesday.

An upper level trough is steering Typhoon In-Fa toward the northeast and that general motion is expected to continue during the next 48 hours.  In-Fa could start to move faster as the upper level winds increase.  In-Fa could be near Iwo To in about 48 hours.

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.

In-Fa Intensifies Back Into a Typhoon and a Tropical Storm Warning Is Issued for Guam

In-Fa intensified rapidly back into a typhoon on Thursday and a Tropical Storm Warning was issued for Guam.  At 10:00 p.m. EDT on Thursday the center of Typhoon In-Fa was located at latitude 10.1°N and longitude 148.1°E which put it about 365 miles (590 km) southeast of Guam.  In-Fa was moving toward the west-northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 954 mb.

After weakening slightly on Wednesday, In-Fa intensified rapidly back into a typhoon on Thursday.  Typhoon In-Fa has a compact tightly wound structure with a small inner core and a tiny pinhole eye.  The strongest winds are contained in the ring of thunderstorms around the pinhole eye.  Many of the strongest thunderstorms outside the eyewall are located southwest of the eye, but there are spiral bands in all quadrants of the storm.  The storms around the core of Typhoon In-Fa are generating upper level divergence in all directions.

Typhoon In-Fa is an environment favorable for intensification.  It is over water where the Sea Surface Temperature is near 29°C.  The upper level winds around In-Fa are light and there is not much vertical wind shear.  In-Fa is likely to intensify more during the next day or two.

A subtropical ridge north of In-Fa is steering the typhoon to the west-northwest and that general motion is expected to continue for another 48 hours.  On its anticipated track the center of In-Fa is likely to pass about 100 miles (160 km) to 150 miles (240 km) south of Guam in about 18 to 24 hours.  The center of Typhoon In-Fa is likely to pass about 200 miles (320 km) northeast of Yap in about 48 hours.

Typhoon Champi Bringing Wind and Rain to Iwo To

A portion of the northern eyewall of Typhoon Champi is over Iwo To and it is bringing wind and rain to the island.  A weather station on Iwo To is reporting east-northeasterly winds at 47 m.p.h. (75 km/h) with gusts to 73 m.p.h. (118 km/h).  At 11:00 p.m. EDT on Wednesday the center of Typhoon Champi was located at latitude 23.8°N and longitude 141.6°E which put it about 75 miles (120 km) south of Iwo To.  Champi was moving toward the northeast at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h).  The minimum surface pressure was 945 mb.

The inner core of Typhoon Champi became much more well organized during the past 12 hours and it now has a clear circular eye that is approximately 30 miles (48 km) across.  The eye is surrounded by a ring of strong convection which contains the strongest winds.  The core is also generating upper level divergence which is pumping out mass.

Typhoon Champi will be in a favorable environment for another 12 hours.  It is moving over water where the Sea Surface Temperature is near 28.5°C.  The upper level winds are light and there is not much upper level divergence.  Champi could intensify further on Thursday, but it will move into a less favorable environment when it moves farther north.  Once Champi gets north of latitude 27°N, it will move over cooler SSTs.  Typhoon Champi will start to encounter strong upper level westerly winds at about the same time.  The combination of cooler water and more vertical wind shear will steadily weaken Champi.

Typhoon Champi is moving northward around the western end of a subtropical ridge.  When it reaches the upper level westerly winds, those winds will accelerated Champi toward the east-northeast until it transforms into an extratropical cyclone over cooler waters.  On its anticipated track the center of Champi will pass southeast of Iwo To, but it will bring strong winds and rain to that island for another 12 hours or so.

Strong Typhoon Champi Intensifies South of Iwo To

Typhoon Champi intensified rapidly on Sunday and it reached the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.  At 5:00 p.m. EDT on Sunday the center of Typhoon Champi was located at latitude 20.3°N and longitude 140.3°E which put it about 325 miles (525 km) south-southwest of Iwo To.  Champi was moving toward the north-northeast at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 924 mb.

The circulation of Typhoon Champi is very well organized.  It has a well defined eye and there could be a rainband wrapping around the center to create concentric eyewalls.  Multiple spiral bands are revolving around the center of circulation.  Winds to typhoon force extend out 40 miles (65 km) from the center.  Well developed upper level divergence is pumping out mass in all directions.

Typhoon Champi is moving over water where the Sea Surface Temperature is near 29°C.  The winds in the upper levels are relatively light and there is not much vertical wind shear.  Champi will remain in a favorable environment for another 24 to 48 hours.  Eyewall replacement cycles could cause fluctuations in intensity during that period.  When it moves north of latitude 25°N, Champi will encounter the upper level westerly winds in the middle latitudes which will cause significant vertical wind shear.  Champi will weaken as the wind shear increases.

Champi is moving slowly northward as it curves around the western end of a subtropical ridge.  It will continue to move northward for another day or two.  When it begins to be affected by the upper level westerly winds, Champi will accelerate toward the northeast.  On its anticipated track Typhoon Champi will approach Iwo To in 48 to 60 hours.  Champi will be a large, strong typhoon at that time.