Monthly Archives: September 2016

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.

Tropical Storm Paine Intensifying Quickly Southwest of Baja California

The Eastern North Pacific Ocean continues to spin out tropical cyclones.  Tropical Storm Paine intensified quickly on Sunday as it moved southwest of Baja California.  In 24 hours Paine intensified from a tropical depression to near hurricane strength.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Paine was located at latitude 19.5°N and longitude 113.8°W which put it about 345 miles (555 km/h) southwest of the southern tip of Baja California.  Paine was moving toward the northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 992 mb.

Tropical Storm Paine moved through a very favorable environment on Sunday.  The Sea Surface Temperature (SST) was near 28°C.  The upper level winds were light and there was little vertical wind shear.  The favorable environmental conditions allowed a tight inner core to develop rapidly at the center of Tropical Storm Paine.  Infrared and microwave satellite imagery suggest that an eye could be forming at the center of Paine.  A nearly complete ring of strong thunderstorms surrounds the developing eye.  A primary rainband exists in the eastern part of the circulation.  Thunderstorms at the core of Tropical Storm Paine are generating upper level divergence which is pumping out mass in all directions.

Tropical Storm Paine will be in a favorable environment for another 12 to 18 hours.  It is likely to intensify into a hurricane on Monday.  After that time Paine will start to move over cooler SSTs and it should start to weaken.  The air over the cooler SSTs is also drier and more stable and Paine could weaken quickly on Tuesday.

Tropical Storm Paine is moving around the western end of a ridge over Mexico which is steering it toward the northwest.  When Paine reaches the western end of the ridge axis, it will move more toward the north.  On its anticipated track Tropical Storm Paine will pass to the west of the southern end of Baja California during the next several days.

Powerful Typhoon Malakas Nearing Kyushu

Powerful Typhoon Malakas moved steadily closer to Kyushu on Sunday.  At 11:00 p.m. EDT on Sunday the center of Typhoon Malakas was centered at latitude 29.7°N and longitude 127.9°E which put it about 210 miles (340 km) southwest of Kagoshima, Japan.  Malakas was moving toward the east-northeast at 13 m.p.h. (21 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 948 mb.

The circulation of Typhoon Malakas remains well organized and it is taking on the typical structure of a strong tropical cyclone that is starting to recurve.  The size of the eye increased during the past 24 hours.  The eye is surrounded by a ring of strong thunderstorms which is thinner south of the eye.  There are several strong rainbands, but they are primarily in the northern half of the circulation.  The circulation is beginning to pull drier air around the southern side of Malakas which is why the rainbands in that part of the typhoon are weaker.  Thunderstorms in the core of Typhoon Malakas are generating upper level divergence that is pumping out mass toward the northeast.

Typhoon Malakas is moving through an environment that should allow it to maintain its intensity during the next few hours.  It is moving over water where the Sea Surface Temperature is near 29°C.  An upper level trough to the west of Japan is generating southwesterly winds which are blowing across the top of the circulation.  However, the vertical wind shear is moderate enough to allow Typhoon Malakas to maintain its intensity in the short term.  When Malakas moves farther to the northeast, it will move into a region where where upper level winds are stronger and the vertical wind shear will increase.  More vertical wind shear and the interaction of the circulation with Kyushu, Shikoku and Honshu will cause Malakas to weaken.

The upper level trough will continue to steer Typhoon Malakas toward the northeast.  On its anticipated track the center of Malakas will be near southwest Kyushu in about 12 hours.  It will be near Shikoku in 20 hours and is could be near Honshu in 30 hours.

Typhoon Malakas will bring strong winds and heavy rain to southwestern Kyushu.  It is likely to still be a typhoon when it passes near the coast of Shikoku.  Malakas could be a tropical storm when it passes south of Kyoto and when it moves near Tokyo in a couple of days.  Malakas could bring wind and heavy rain to the coastal portions of Honshu later this week.

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.