Tropical Storm Chaba Forms East of Guam

A center of circulation developed within an area of thunderstorms east of Guam on Tuesday and the Japan Meteorological Agency designated the system as Tropical Storm Chaba.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Chaba was located at latitude 14.2°N and longitude 147.7°E which put it about 225 miles (360 km) east of Guam.  Chaba was moving toward the west at 17 m.p.h. (27 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.

The circulation of Tropical Storm Chaba is still organizing.  The distribution of thunderstorms is asymmetrical.  There are more thunderstorms east of the center of circulation.  Additional thunderstorms are forming west of the center of circulation and some rainbands are developing.  The thunderstorms near the center of Tropical Storm Chaba are generating upper level divergence which is pumping mass out in all directions.

Tropical Storm Chaba is moving through an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are light and there is not significant vertical wind shear.  Tropical Storm Chaba is likely to continue to intensify as the circulation gets better organized.  Chaba could become a typhoon later this week.

A subtropical ridge to the north of Chaba is steering the tropical storm toward the west and that general motion is expected to continue for another 24 to 36 hours.  When Tropical Storm Chaba moves farther west, it will get closer to the western end of the subtropical ridge and Chaba is likely to turn more toward the west-northwest.  On its anticipated track Tropical Storm Chaba will move through the Marianas between Guam and Saipan and Tinian on Wednesday.  Chaba could be approaching Okinawa in about five days.

Powerful Typhoon Megi Nearing Landfall on Taiwan

Powerful Typhoon Megi is within a few hours of making landfall on the east coast of Taiwan.  At 11:00 p.m. EDT on Monday the center of Typhoon Megi was located at latitude 23.3°N and longitude 122.6°E which put it about 175 miles (280 km) southeast of Taipei, Taiwan.  Megi was moving toward the northwest at 15 m.p.h. (24 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 947 mb.

Megi is a large powerful typhoon and it is the equivalent of a major hurricane.  It has a big circular eye with a diameter of about 60 miles (95 km).  Winds to typhoon force extend out about 50 miles (80 km) from the center and winds to tropical storm force extend out over 200 miles (320 km) from the center.

The Hurricane Intensity Index (HII) for Typhoon Megi is 20.6.  The Hurricane Size Index (HSI) is 21.1 and the Hurricane Wind Intensity Size Index (HWISI) is 41.7.  Those indices suggest that Typhoon Megi is capable of causing widespread major wind damage.  The HII for Typhoon Megi is the same as the HII for Hurricane Rita when it made landfall in Louisiana in 2005.  The HSI for Megi is slightly smaller than the HSI for Rita.  Thus, Typhoon Megi is as intense as Hurricane Rita was when it made landfall, but Megi is slightly smaller than Rita was in 2005.

A subtropical ridge is steering Typhoon Megi toward the northwest.  Typhoon Megi will make landfall on the east coast of Taiwan near Hualien in a few hours.  Megi will cross Taiwan and it will make a second landfall on the east coast of China near Quanzhou and Xiamen in about 24 hours.  Typhoon Megi will bring strong winds and very heavy rain to the northern two thirds of Taiwan.  The heavy rain will create a serious risk for flash flooding.  Megi will weaken as it crosses Taiwan,   Typhoon Megi will also bring gusty winds and heavy rain when it reaches the east coast of China.  Typhoon Meranti caused serious damage in parts of Fujian province and Typhoon Megi will bring heavy rain to some of those same areas.  The northern side of Typhoon Megi may also bring gusty winds to the southernmost Ryukyu Islands.

Typhoon Megi Strengthens As It Moves Closer to Taiwan

Typhoon Megi strengthened quickly on Saturday as it moved steadily closer to Taiwan.  At 11:00 p.m. EDT on Saturday the center of Typhoon Megi was located at latitude 19.4°N and longitude 131.0°E which put it about 685 miles (1105 km) east-southeast of Taipei, Taiwan.  Megi was moving toward the west northwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (205 km/h).  The minimum surface pressure was 963 mb.

Megi is a large well organized typhoon.  Winds to typhoon force extend out about 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extend out more than 200 miles (320 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Megi is 17.8.  The Hurricane Size Index (HSI) is 18.7 and the Hurricane Wind Intensity Size Index (HWISI) is 36.5.

The circulation of Typhoon Megi is very symmetrical.  Numerous bands of thunderstorms are rotating around the center.  A circular eye appears to be forming at the center of circulation.  Thunderstorms near the center and in the rainbands are generating upper level divergence which is pumping out large quantities of mass in all directions.

Typhoon Megi is moving through a very favorable environment.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Typhoon Megi is likely to continue to intensify and it could become the equivalent of a major hurricane on Sunday.

Typhoon Megi is moving southwest of a subtropical ridge which is steering it toward the west-northwest and that general motion is expected to continue for several more days.  On its anticipated track Typhoon Megi will approach Taiwan in about 48 hours.

Typhoon Megi is large and dangerous typhoon.  It is likely to bring strong winds and heavy rain to Taiwan.

Tropical Storm Karl Approaching Bermuda

Tropical Storm Karl continued to move steadily toward Bermuda on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Karl was located at latitude 29.9°N and longitude 65.1°W which put it about 165 miles (270 km) south of Bermuda.  Karl was moving toward the north at 13 m.p.h. (20 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 988 mb.

A Hurricane Watch has been issued for Bermuda.  A Tropical Storm Warning is also in effect for Bemruda.

Tropical Storm Karl strengthened on Friday, but its structure remained asymmetrical.  Almost all of the thunderstorms are in a primary rainband that wraps around the northern and western sides of the center of circulation.  There are few if any thunderstorms south and east of the center.  It appears as it vertical wind shear is tilting the circulation toward the northwest.  The upper level center appears to be located 20 to 30 miles (30 to 50 km) northwest of the low level center.  The thunderstorms in the primary rainband are producing upper level divergence which is pumping out mass to the east of Tropical Storm Karl.  The upper level divergence pumped out enough mass on Friday to allow the surface pressure to decrease by about 10 mb.  However, the vertical wind shear and lack of thunderstorms to the east of the center limited the increase in wind speed at the surface.

Tropical Storm Karl is moving over water where the Sea Surface Temperature is near 29°C.  So, there is enough energy in the upper ocean to support a stronger storm.  However, an upper level trough to the west of Karl is creating significant vertical wind shear, which is likely to limit intensification in the short term.  When Tropical Storm Karl, turns east and moves farther from the upper level trough, the shear could decrease and Karl could strengthen.  In addition Karl will begin a transition to an extratropical cyclone and that transition often produces and increase in the wind speed.  So, Tropical Storm Karl does have a chance to become a hurricane during the weekend.

Tropical Storm Karl is moving around the western end of a subtropical ridge which is steering it toward the north.  It is likely to keep moving in that direction for another six to twelve hours.  When Tropical Storm Karl nears Bermuda it will encounter stronger westerly winds which will turn it eastward.  Karl is likely to move quickly toward the east-northeast on Saturday and Sunday.  On its anticipated track Tropical Storm Karl will pass near Bermuda on Saturday morning.  It will bring a period of gusty winds and heavy rain.

Tropical Storm Megi Forms West of the Marianas

Tropical Storm Megi formed west of the Marianas on Friday.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Megi was located at latitude 16.4°N and longitude 137.1°E which put it about 1160 miles (1870 km) east-southeast of Taipei, Taiwan.  Megi was moving toward the west at 15 m.p.h. (24 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/).  The minimum surface pressure was 996 mb.

The circulation of Tropical Storm Megi is still organizing.  A distinct center of circulation is still consolidating.  There are more thunderstorms south and east of the center of circulation, but bands of thunderstorms are beginning to develop in other quadrants of the storm.  The thunderstorms closer to the center are generating upper level divergence which is pumping out mass.  Outflow channels could be developing to the northwest and southeast of Tropical Storm Megi.

Tropical Storm Megi is moving into an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are not very strong and there is little vertical wind shear.  Tropical Storm Megi is likely to continue to intensify while the circulation becomes better organized.  Once a well formed core develops at the center of Megi, it could intensify more rapidly.  Tropical Storm Megi is likely to become a typhoon during the weekend.

Tropical Storm Megi is moving along the southwestern side of a subtropical ridge, which is steering it toward the west.  A westerly or west-northwesterly motion is expected to continue for the next few days.  On its anticipated track Tropical Storm Megi could approach Taiwan in about three days.  Megi is likely to be a typhoon at that time.

Karl Becomes a Tropical Storm Again and Warning Issued for Bermuda

Reconnaissance aircraft investigating Tropical Depression Karl on Thursday afternoon found that it had intensified into a tropical storm again and a Tropical Storm Warning was issued for Bermuda.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Karl was located at latitude 25.5°N and longitude 63.2°W which put it about 480 miles (770 km) south-southeast of Bermuda.  Karl 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 1005 mb.

The structure of Tropical Storm Karl became more organized on Thursday, but the circulation is not well organized.  Most of the thunderstorms are occurring in a primary rainband that spirals around the eastern and northern portions of the circulation.  There are other fragmented rainbands farther to the east of the center of circulation.  There are few thunderstorms or bands south and west of the center and there may be drier air in that part of Tropical Storm Karl.  Thunderstorms in the primary rainband were beginning to generate some upper level divergence.

Tropical Storm Karl is moving into an environment that is more favorable for intensification.  Karl is moving farther away from an upper level low that is west of the the tropical storm.  As the distance between Tropical Storm Karl and the upper low increases, the vertical wind shear will decrease.  Karl is moving over water where the Sea Surface Temperature is near 30°C.  Tropical Storm Karl is likely to intensify slowly until the primary rainband wraps around the center of circulation.  If a tight inner core develops at the center of Karl, then it could intensify more quickly after that happens.

Tropical Storm Karl is moving around the western end of a subtropical high pressure system.  The high is steering Karl in a generally northwesterly direction.  Karl is likely to move more toward the north as it goes around the western end of the high.  When Karl gets northwest of the axis of the high pressure system, the westerly winds in the middle latitudes will start to turn it more toward the northeast.  On its anticipated track, Tropical Storm Karl could be near Bermuda in about 36 hours.  Tropical Storm Karl could bring wind and rain to Bermuda during the weekend.

 

Tropical Storm Lisa Develops West of the Cape Verde Islands

Tropical Depression Thirteen intensified into Tropical Storm Lisa west of the Cape Verde Islands on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Lisa was located at latitude 16.4°N and longitude 31.0°W which put it about 465 miles (750 km) west of the Cape Verde Islands.  Lisa was moving toward the northwest at 12 m.p.h. (19 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 1004 mb.

The degree of organization of the circulation of Tropical Storm Lisa depends on the level of the atmosphere.  The low level circulation is not well organized.  There is a broad center of circulation, but it does not have a tight core of thunderstorms.  Most of the thunderstorms are east of the center of circulation.  There are also several fragmented rainbands in the eastern half of the circulation.  There are only lower clouds and a few showers in the western half of the circulation.  However, the circulation is more well organized in the upper levels.  The thunderstorms in the eastern half of the circulation are generating upper level divergence which is pumping out mass toward the northeast and toward the northwest.  It appears that the circulation could be tilted toward the northeast with height.

The environment around Tropical Storm Lisa is marginal for intensification.  Lisa is moving over water where the Sea Surface Temperature (SST) is near 28°C.  However, an upper level trough north of Lisa is producing southwesterly winds which are blowing across the tropical storm.  The winds are causing moderate vertical wind shear, which probably contributed to the asymmetrical distribution of thunderstorms.  Tropical Storm Lisa could intensify somewhat on Wednesday, if the upper level winds diminish.  When Lisa moves farther north later this week, it will move over cooler SSTs and into a region where the upper level winds are stronger.  Less energy in the upper ocean and more vertical wind shear will cause Tropical Storm Lisa to weaken later this week.

Tropical Storm Lisa is moving northwest toward a section of the subtropical ridge which is weaker.  Lisa is expected to continue to move in that general direction for the next several days.  Tropical Storm Lisa will move farther into the middle of the Atlantic Ocean and it will not threaten any land areas this week.

Tropical Storm Karl Intensifies a Little

After several days when Tropical Storm Karl was poorly organized and barely maintained tropical storm intensity, Karl intensified a little late on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Karl was located at latitude 19.7°N and longitude 50.5°W which put it about 760 miles (1225 km) east-northeast of the Leeward Islands.  Karl was moving toward the west-northwest at 14 m.p.h. (22 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 1005 mb.

Although the structure of Tropical Storm Karl improved a little during the past few hours, it is still not a well organized storm.  A cluster of thunderstorms (sometimes called a Central Dense Overcast or CDO) formed near the core of Tropical Storm Karl.  Additional thunderstorms developed in fragmented rainbands, which are primarily in the eastern half of the circulation.  The cluster of thunderstorms near the core of the circulation is beginning to generate upper level divergence.

Tropical Storm Karl is moving into a more favorable environment.  It is moving over water where the Sea Surface Temperature (SST) is near 28°C.  An upper level low to the west of Karl has been causing strong vertical wind shear over the top of the tropical storm.  However, the upper low is moving farther west of Karl and the vertical wind shear is lessening.  Warm SSTs and less vertical wind shear allowed Tropical Storm Karl to begin to get a little better organized.  Karl is likely to intensify slowly while the circulation organizes and a more well define structure develops.  Tropical Storm Karl will move over warmer SSTs during the next few days and it is forecast to become a hurricane later this week.

Tropical Storm Karl is moving around the southwestern portion of a subtropical ridge which is steering it toward the west-northwest.  Karl is likely to turn more toward the northwest during the next several days.  On its anticipated track Tropical Storm Karl is likely to move northeast of the Leeward Islands and head in the general direction of Bermuda.

Typhoon Malakas Bringing Gusty Winds and Rain to Shikoku and Honshu

Typhoon Malakas is bringing wind and rain to coastal areas of Shikoku and Honshu.  At 11:00 p.m. EDT on Monday the center of Typhoon Malakas was located near latitude 33.4°N and longitude 134.7°W which put it about 90 miles (145 km) southwest of Osaka, Japan.  Malakas was moving toward the northeast at 25 m.p.h. (40 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.

The structure of Typhoon Malakas is starting the transition from a tropical cyclone to an extratropical cyclone.  It retains an eye, but the thunderstorms in the southern part of the eyewall are thinning.  Most of the other thunderstorms are in rainbands north of the center of circulation.  Cooler, drier air is wrapping around the southern side of the circulation.  The strongest winds are occurring over the water near the center of circulation.  Heavy rain is falling over eastern Shikoku and southwestern Honshu near Osaka and Nagoya.

Although Typhoon Malakas is moving over water where the Sea Surface Temperature is near 28°C, it will continue to weaken as it makes the transition to an extratropical cyclone.  An upper level trough west of Japan is producing southwesterly winds which are blowing across the top of the circulation.  Also, almost half of the circulation is moving over land and the center will move over coastal sections of Honshu.  Increasing vertical wind shear and the added friction caused by the land will weaken Malakas to a tropical storm on Tuesday.

The upper level trough is steering Typhoon Malakas quickly toward the northeast and that general motion is expected to continue.  On its anticipated track Typhoon Malakas will pass south of Osaka and Nagoya.  The center of then Tropical Storm Malakas will move near Tokyo in about 18 hours.  Malakas will continue to bring gusty winds to coastal parts of Honshu.

Hurricane Paine Prompts Warnings for Part of Baja California

Tropical Storm Paine intensified into a hurricane on Monday and the government of Mexico issued a Tropical Storm Warning for a portion of the west coast of Baja California.  At 8:00 p.m. EDT on Monday the center of Hurricane Paine was located at latitude 23.4°N and longitude 116.5°W which put it about 315 miles (510 km) south-southwest of Punta Eugenia, Mexico.  Paine was moving toward the northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 105 m.p.h. (170 km/h).  The minimum surface pressure was 979 mb.

There is a Tropical Storm Warning in effect for the portion of the coast from Punta Eugenia to Cabo San Quintin.

The circulation of Hurricane Paine is showing signs of weakening.  It had a well formed eye surrounded by a ring of strong thunderstorms a few hours ago.  The eye is no longer apparent on infrared satellite imagery.  There are still thunderstorms near the center of circulation.  The circulation appears to be pulling cooler, drier and more stable air around the southwestern quadrant of Hurricane Paine.  More thunderstorms are occurring in rainbands in the northwestern quadrant of the circulation.  There are few thunderstorms in the rainbands in the eastern half of Hurricane Paine.

Hurricane Paine will be moving into an environment that will be very unfavorable for a tropical cyclone.  The center is currently moving over water where the Sea Surface Temperature (SST) is near 24°C.  It will move over water where the SST will be less than 22°C on Tuesday.  Less energy in the upper ocean and cooler, more stable air will cause the circulation to weaken and it could weaken quickly.  An upper level low southwest of California will generate some vertical wind shear which could separate the upper part of Hurricane Paine from the lower level circulation as Paine weakens.

Hurricane Paine is moving around the western end of a subtropical ridge over Mexico which is steering Paine toward the north.  On its anticipated track the center of Paine will pass west of Punta Eugenia on Tuesday.  The center or the upper part of the circulation could be near Cabo San Quintin on Wednesday morning.  It is expected to weaken to a tropical depression or a remnant low before it reaches Cabo San Quintin.  However, Paine could bring tropical storm force winds to a portion of the coast, which is why the Tropical Storm Warning was issued.