Typhoon Malakas Turns Toward Japan

Typhoon Malakas made the expected northeast turn toward Japan on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Malakas was located at latitude 27.1°N and longitude 123.8°E which put it about 265 miles (425 km) west of Okinawa.  Malakas was moving toward the northeast at 11 m.p.h. (145 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 967 mb.

The structure of Typhoon Malakas is slowly changing as it moves toward the north and encounters a little more wind shear.  Malakas still has an eye, but the thunderstorms around the eyewall are not strong as they were 24 hours ago and a few small breaks may be developing in the eyewall.  There are still a number of rainbands spiraling around the typhoon.  The core of Typhoon Malakas is still generating upper level divergence.  Overall, Malakas is still a well organized, if weaker, typhoon.

Typhoon Malakas has moved around the western end of a subtropical ridge and it has turned toward the northeast.  An upper level trough west of Japan will steer Malakas toward the northeast at a faster speed on Sunday.  On its anticipated track Typhoon Malakas will approach southwestern Kyushu in about 36 hours,  It will bring strong wind and heavy rain to southwestern Japan in about two days.

Strong Typhoon Malakas Turns North Toward Southernmost Ryukyu Islands

Strong Typhoon Malakas made the expected turn toward the north on Friday and it began to move parallel to the east coast of Taiwan toward the southwesternmost Ryukyu Islands.  At 5:00 p.m. EDT on Friday the center of Typhoon Malakas was located at latitude 23.4°N and longitude 123.0°E which put it about 100 miles (160 km) southwest of Ishigaki, Japan.  Malakas was moving toward the north at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 130 m.p.h. (215 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 937 mb.

Malakas is a strong well organized typhoon.  It has a well formed eye at the center of circulation surrounded by a ring of strong thunderstorms.  Additional bands of thunderstorms are rotating around the core of Malakas and there are more thunderstorms in the southern half of the circulation.  Winds to typhoon force extend out about 35 miles (55 km) in all directions from the center of circulation.  The upper level divergence is strongest to the south of Typhoon Malakas.

Typhoon Malakas is in a very favorable environment.  It is moving over water where the Sea Surface Temperature (SST) is near 29°C.  The upper level winds are not too strong and there is little vertical wind shear.  Typhoon Malakas could intensify a little more during the next 24 hours.  When Typhoon Malakas moves farther north, it will move over cooler SSTs.  In addition there is an upper level trough over eastern China which will cause southwesterly winds and increasing vertical wind shear when Malakas gets farther north.

Typhoon Malakas is moving around the western end of a subtropical ridge and it is likely to continue to move north for another 24 hours or so.  In about a day, the upper level trough over eastern China will start to turn Malakas toward the northeast.  On its anticipated track Typhoon Malakas could approach southwestern Kyushu in about three days.

The center of Typhoon Malakas is passing east of Taiwan.  Some of the rainbands in the western part of the circulation will move over Taiwan, but the core of the typhoon where the strongest wind is occurring will stay east of there.  The center of Malakas will pass west of Ishigaki and Okinawa, but it could move over some of the smaller islands at the very southwestern end of the Ryukyu Islands.  Malakas could cause significant damage on those islands.

Tropical Storm Karl Develops over the Eastern Atlantic

More thunderstorms developed near the center of Tropical Depression 12 and the National Hurricane Center named it Tropical Storm Karl on Thursday night.  Karl is the third tropical storm to form over the Atlantic Ocean this week.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Karl was located at latitude 17.9°N and longitude 32.5°W which put it about 1930 miles (3150 km) east of the Leeward Islands.  Karl was moving toward the west at 14 m.p.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.

The circulation of Tropical Storm Karl is asymmetrical.  Karl does have a large circular low level wind fields.  However the thunderstorms are northeast of the center of circulation, although some thunderstorms have developed closer to the northeast side of the center in recent hours.  Southwesterly winds in the upper levels are generating moderate vertical wind shear, which has contributed to the asymmetrical distribution of thunderstorms.  In addition, the upper level winds are inhibiting upper level divergence to the west of Tropical Storm Karl.

Tropical Storm Karl is moving through an environment that is not very favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 27°C.  There is moderate vertical wind shear, which will make it hard for thunderstorms to persist near the center of the tropical storm.  Karl could move into an area where the upper level winds are not as strong in a day or two.  The environment could be more favorable for intensification at that time.

A subtropical ridge north of Karl is steering the tropical storm toward the west.  The ridge is expected to get stronger and it should steer Tropical Storm Karl toward the west or west-southwest during the next few days.

Typhoon Malakas Moves Toward Taiwan and the Ryukyu Islands

Typhoon Malakas moved toward Taiwan and the southernmost Ryukyu Islands on Thursday.  At 8:00 p.m. EDT on Thursday the center of Typhoon Malakas was located at latitude 20.1°N and longitude 124.7°W which put it about 285 miles (460 km) south of Ishigaki, Japan.  Malakas was moving toward the northwest at 15 m.p.h. (24 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 956 mb.

The structure of Typhoon Malakas is well organized.  A small eye has been evident intermittently on satellite imagery.  More of the thunderstorms are forming south of the center of circulation, although there are spiral bands of thunderstorms in all quadrants of the circulation.  The thunderstorms in the core of Typhoon Malakas are generating upper level divergence which is pumping out mass in all directions.  The circulation of Typhoon Malakas has been in a rough equilibrium during the past 24 hours and the intensity has remained relatively steady.

Typhoon Malakas is moving through an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  Although there is an upper level trough over China and an upper level low to the northeast of Malakas, the upper level winds around the typhoon are relatively light.  There is not much vertical wind shear.  Typhoon Malakas could strengthen further during the next 24 hours.

Typhoon Malakas is moving around the western end of a subtropical ridge.  Malakas turned more toward the northwest on Thursday.  It is expected to move more toward the north on Friday as is reaches the western end of the ridge.  When Malakas moves farther north, the upper level trough over China will steer the typhoon quickly toward the northeast toward the southern end of Kyushu.  On its anticipated track Typhoon Malakas will be near northeastern Taiwan and the southernmost Ryukyu Islands in about 24 hours.

Typhoon Malakas is smaller than Typhoon Meranti was, but Typhoon Malakas is capable of causing significant wind damage.  It will also bring heavy rain.  Since areas on Taiwan received heavy rain when Typhoon Meranti moved past them, it will take less additional rain to create the potential for flash flooding.

Tropical Storm Julia Edges Farther from the Southeast U.S.

Tropical Storm Julia moved slowly eastward on Thursday which took it farther from the Southeastern coast of the U.S.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Julia was located at latitude 32.1°N and longitude 77.1°W which put it about 150 miles (245 km) south-southeast of Wilmington, North Carolina.  Julia was moving toward the east at 8 m.p.h. (13 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 1007 mb.

The circulation of Tropical Storm Julia is not well organized.  All of the stronger thunderstorms are well to the east of the center of circulation.  The broad low level circulation is elongated from the west-southwest of the east-northeast.  There are no thunderstorms close to the center of circulation.

Tropical Storm Julia is in an environment that is unfavorable for intensification.  It is moving over water where the Sea Surface Temperature is near 29°C.  So, there is sufficient energy in the upper ocean to support intensification.  However, upper level westerly winds are causing strong vertical wind shear.  The upper level winds have at least temporarily blown the upper part of the circulation east of the lower third of the circulation.  As long as the upper level winds are as strong as they are now, Tropical Storm Julia will slowly weaken.  If the upper level winds slow down, then more thunderstorms could develop near the center and Julia could get a little stronger.  With the current strong vertical wind shear Tropical Storm Julia should slowly weaken during the next few hours.

The vertical structure of Tropical Storm Julia maintained enough integrity that the westerly winds pushed the thunderstorms toward the east and they dragged the low level center with them.  However, it now appears that the vertical parts of the circulation have separated.  The low level circulation is being steered slowly back toward the southwest by a surface high pressure system to the north of Julia.  Tropical Storm Julia could move erratically during the next several days.  As long as no thunderstorms form near the center, it will drift slowly toward the southwest.  Any time thunderstorms form near the center of circulation, the taller storm will be pushed toward the east.

Strong Typhoon Meranti Nears Landfall in China

Strong Typhoon Meranti is near a landfall on the east coast of China close to Xiamen.  At 11:00 a.m. EDT on Wednesday the center of Typhoon Meranti was located at latitude 23.9°N and longitude 118.4°E which put it about 40 miles (65 km) south-southeast of Xiamen, China.  Meranti was moving toward the northwest at 14 m.p.h. (22 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 931 mb.

Meranti has weakened during the past 24 hours, but it remains a strong typhoon.  The Hurricane Intensity Index (HII) for Typhoon Meranti is 29.9.  The Hurricane Size Index (HSI) is 24.5 and the Hurricane Wind Intensity Size Index is 54.4.  These indices suggest that Typhoon Meranti is capable of causing widespread significant damage when it makes landfall.  As a comparison, the HII for Hurricane Ivan just before it made landfall on the Gulf Coast in 2004 was 22.1, the HSI was 34.1 and the HWISI was 56.2.  Thus, Typhoon Meranti is stronger than Hurricane Ivan was, but Meranti is also smaller than Ivan was in 2004.  The HWISI for Typhoon Meranti is close to what it was for Hurricane Ivan.

The center and inner eyewall of Typhoon Meranti moved just south of the southern end of Taiwan.  Since the eyewall stayed over water, it remained intact.  However, the outer concentric eyewall and much of the northern half of the circulation did move across Taiwan.  Flow over the mountains on Taiwan did weaken the northern half of the circulation, while the center and southern half of the circulation remained intact.  Since the core of the circulation stayed over the water, Typhoon Meranti stayed stronger than it would have if the inner eye had moved over Taiwan.

Most of the stronger thunderstorms and heavier rain are near the center of circulation and south of the center.  There are rainbands in other parts of Typhoon Meranti and some of those rainbands are already bringing heavy rain to parts of eastern China.

Typhoon Meranti is moving around the western end of a subtropical ridge which is steering it toward the northwest.  Meranti is expected to turn more toward the north as it move inland over China.  On its anticipated track Typhoon Meranti is expected to move northwest over Fujian province and then turn north toward Nanchang.

Typhoon Meranti is capable of causing significant wind damage over eastern China.  In addtion strong winds will create a significant storm surge along the coast near Xiamen.  Heavy rain will spread inland over Fujian province and the rain could create the potential for flooding over parts of eastern China.

Tropical Storm Julia Forms over Northeast Florida

Although tropical storms normally form over an ocean, Tropical Storm Julia formed over northeast Florida on Tuesday.  The National Hurricane Center (NHC) had tracked a tropical disturbance from Africa across the Atlantic Ocean to Florida.  NHC had designated the system as Invest 93L for tracking purposes.  Although the disturbance moved over the Florida peninsula on Monday, a distinct center of circulation developed at the surface on Tuesday while the disturbance moved north over the northeastern part of Florida.  An area of stronger thunderstorms formed over the Atlantic Ocean east of the center of circulation on Tuesday afternoon and persisted into Tuesday evening.  Because the system had a distinct surface center, persistent thunderstorms and winds to tropical storm force, the National Hurricane Center named it Tropical Storm Julia at 11:00 p.m. EDT on Tuesday and initiated advisories on the Julia.

At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Julia was located at latitude 30.3°N and longitude 81.6°W which put it about 5 miles (10 km) west of Jacksonville, Florida.  Julia was moving toward the north-northwest at 9 m.p.h. (15 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 1009 mb.

A Tropical Storm Warning has been issued for the portion of the coast from Ponte Vedra Beach, Florida to Altamaha Sound, Georgia.

The circulation of Tropical Storm Julia is very asymmetrical.  Most of the thunderstorms and rain are north and east of the of circulation.  There are few storms or rain west and south of the center.  One primary rainband extends part of the way around the southeastern portion of the circulation.  The thunderstorms to the east of the center are generating upper level divergence which is pumping out mass to the northeast of the circulation.

Since the center of Tropical Storm Julia is over land, intensification would normally be unlikely.  However, about half of the circulation is over water where the Sea Surface Temperature is near 28.5°C.  In addition, the atmospheric environment is favorable for strengthening.  The upper level winds are not too strong and the vertical wind shear is moderate.  It is possible that the wind speeds could increase in the thunderstorms in the part of the circulation that is over the Atlantic Ocean on Wednesday.

The steering currents around Tropical Storm Julia are quite complicated.  There is an upper low over the Gulf of Mexico, a ridge over the western Atlantic Ocean and an upper level trough moving toward the Great Lakes and East Coast of the U.S.  The upper low and ridge over the western Atlantic combined to steer Julia mainly toward the north-northwest on Tuesday.  At times the asymmetric circulation and the upper level divergence to the east of the circulation caused the center to move east as well.  It is likely that this motion will continue on Wednesday.  The center of Julia could move very close to the coast of Georgia.  If the center remains inland, then Tropical Storm Julia will start to weaken slowly.  If the center moves over the water, then it could intensify and persist longer.

The primary risk posed by Tropical Storm Julia will be locally heavy rain and the potential for flash flooding.  Winds and waves along the coast will cause rip currents and some beach erosion.  Water rises of several feet (one meter) will be possible.

Extremely Powerful Typhoon Meranti Nearing Southern Taiwan

The center of extremely powerful Typhoon Meranti moved closer to the southern end of Taiwan during the past few hours.  At 5:00 p.m. EDT on Tuesday the center of Typhoon Meranti was located at latitude 21.1°N and longitude 121.3°E which put it about 65 miles (105 km) south-southeast of Hengchun, Taiwan.  Meranti was moving toward the west-northwest at 11 m.p.h. (18 km/h).  The maximum sustained wind speed was 190 m.p.h. (305 km/h) and there were wind gusts to 230 m.p.h. (370 km/h).  The minimum surface pressure was 887 mb.

Typhoon Meranti is large and powerful.  The Hurricane Intensity Index (HII) is 46.1.  The Hurricane Size Index (HSI) is 27.9 and the Hurricane Wind Intensity Size Index (HWISI) is 74.0.  As a source of comparison, when Hurriane Katrina was at its peak intensity as a Category 5 hurricane over the Gulf of Mexico in 2005, its HII was 38.6, its HSI was 33.7, and its HWISI was 72.3.  Typhoon Meranti is stronger than Hurricane Katrina was, but Meranti is a little smaller than Katrina was in 2005.  The indices suggest that Typhoon Meranti is capable of causing widespread catastrophic damage.

The circulation of Typhoon Meranti is symmetrical and very well organized.  It possess a tight core consisting of a small inner eye surrounded by a ring of very tall thunderstorms.  A second, larger outer eyewall completely surrounds the inner eye.  The strongest winds are occurring in the inner eyewall near the center of circulation.  Winds to typhoon force are also occurring in the outer eyewall and extend out at least 80 miles (130 km) from the center of circulation.  Additional bands of strong thunderstorms are rotating around the outer eyewall.  Typhoon Meranti is generating strong upper level divergence which is pumping out large quantities of mass and is allowing the surface pressure to be so low.

Typhoon Meranti is probably at its peak intensity.  It is still moving over water where the Sea Surface Temperature is near 31°C.  However, the northwestern edge of the outer eyewall appears to be moving over the southern end of Taiwan.  As more of the circulation moves over Taiwan, there will be some disruption of the airflow.  The center of Typhoon Meranti could move very close to the southern tip of Taiwan.  If the center of Meranti moves over southern Taiwan, then the typhoon will weaken more quickly.  It currently appears that the center of Typhoon Meranti could move just south of the southern tip of Taiwan, and on that track the typhoon would not weaken as quickly.  When Typhoon Meranti moves west of Taiwan, it will move over slightly cooler SSTs before it reaches China.  Meranti will weaken more before it reaches China, but it will still be a significant typhoon when it makes landfall there.

The center of Typhoon Meranti is wobbling a little as the inner eye rotates around inside the outer eyewall.  If one averages the wobbles, then then core of Meranti is moving on a general west-northwesterly track.  On its anticipated track, the center of Typhoon Meranti will pass very near the southern end of Taiwan during the next few hours.  It could turn slightly toward the northwest as it moves west of Taiwan.  Typhoon Meranti could make a landfall on the coast of China between Xiamen and Shantou in about 24 hours.

Typhoon Meranti is an extremely dangerous storm.  It is capable of causing widespread catastrophic wind damage.  In addition, its intensity and size will produce very heavy rainfall, especially on the eastern slopes of the mountains on Taiwan.  Flash flooding is likely.  Typhoon Meranti will also produce heavy rain over eastern China and additional flooding is likely in that region.  Typhoon Meranti will also cause a significant storm surge in low lying coastal areas.

Typhoon Meranti Becomes Equivalent of Cat. 5 Hurricane and Threatens Taiwan

Typhoon Meranti rapidly intensified into the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale as it moved on a course that threatens Taiwan.  At 11:00 a.m. EDT on Monday the center of Typhoon Meranti was located at latitude 19.2°N and longitude 127.6°E which put it about 495 miles (800 km) southeast of Taiwan.  Meranti was moving toward the west-northwest at 14 m.p.h. (23 km/h).  The maximum sustained wind speed was 180 m.p.h. (290 km/h) and there were wind gusts to 220 m.p.h. (355 km/h).  The minimum surface pressure.

Meranti is a large dangerous typhoon.  The Hurricane Intensity Index (HII) is 42.2.  The Hurricane Size Index (HSI) is 25.5 and the Hurricane Wind Intensity Size Index (HWISI) is 67.7.  Those indices suggest that Typhoon Meranti is capable of causing widespread catastrophic damage.

The structure of Typhoon Meranti is very well organized.  A well formed circular eye is surrounded by a ring of very tall thunderstorms.  Additional strong spiral bands of thunderstorms are rotating around the core of the circulation.  Typhoon Meranti is generating strong upper level divergence which is pumping out mass in all directions.

Typhoon Meranti is moving through an environment that will allow it to maintain much of its intensity until it reaches Taiwan.  It is moving over water where the Sea Surface Temperature is near 31°C.  The upper level winds are weak and there is not much vertical wind shear.  If a rainband wraps around the existing eye, then an eyewall replacement cycle could temporarily weaken Typhoon Meranti.

A subtropical ridge is steering Typhoon Meranti toward the west-northwest and that general motion is expected to continue for several more days.  On its anticipated track Typhoon Meranti will be very near the southern tip of Taiwan in about 36 hours.  After it moves past Taiwan it is forecast to move into eastern China.

Meranti is an extremely dangerous typhoon.  It is capable of causing widespread catastrophic wind damage.  In addition it will produce very heavy rain and flooding is a serious concern.

Tropical Storm Ian Forms in the Middle of the Atlantic

Tropical Storm Ian formed on Monday in the middle of the Atlantic Ocean.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Ian was located at latitude 21.8°N and longitude 50.4°W which put it about 1140 miles (1840 km) southeast of Bermuda.  Ian was moving toward the northwest at 13 m.p.h. (21 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. (95 km/h).  The minimum surface pressure was 1007 mb.

The circulation of Tropical Storm Ian is not well organized.  A large upper low west of Ian is generating strong southwesterly winds which are blowing across the top of the tropical storm.  There is a large cyclonic circulation in the lower levels, but there are no thunderstorms near the center of circulation.  The thunderstorms are forming northeast of the center in a rainband that is well removed from the core of the storm.

Tropical Storm Ian will through a hostile environment during the next several days.  Although Ian will move over water where the Sea Surface Temperature is near 29°C, the upper level trough will continue to cause strong vertical wind shear.  Ian is not likely to strengthen in the short term.  Eventually, later this week Ian will move farther from the upper level trough and it could strengthen somewhat at that time, if the low level circulation persists.

Tropical Storm Ian is moving around the western end of a subtropical ridge which is steering it toward the northwest and that general motion is expected to continue for another day or two.  When Ian moves farther north, it will turn toward the northeast and the tropical storm will begin to move faster.