Hurricane Matthew Moving Slowly North Toward the Greater Antilles

Powerful Hurricane Matthew was moving slowly north over the Northwestern Caribbean Sea on Sunday night.  At 11:00 p.m. EDT on Sunday the center of Hurricane Matthew was located at latitude 14.7°N and longitude 75.0°W which put it about 255 miles south-southeast of Kingston, Jamaica.  Matthew was moving toward the north at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 170 m.p.h. (275 km/h).  The minimum surface pressure was 943 mb.

Hurricane Warnings are in effect for Haiti, Jamaica, the Cuban provinces of Guantanamo, Santiago de Cuba, Holguin, Granma and Las Tunas.  Hurricane Warnings are also in effect for the Southeastern Bahamas including the Inaguas, Mayaguana, Acklins, Crooked Island, Long Cay and Ragged Island.  A Hurricane Watch has been issued for the Cuban province of Camaguey, the Central Bahamas and the Turks and Caicos.  A Tropical Storm Warning is in effect for the south coast of the Dominican Republic from Barahona to the border with Haiti.  A Tropical Storm Watch has been issued for the north coast of the Dominican Republic from Puerto la Plata to the border with Haiti.

Matthew is a very well organized symmetrical hurricane.  There is a circular eye with a diameter of about 14 miles (22 km).  The eye is surrounded by a ring of strong thunderstorms.  Numerous bands of thunderstorms are rotating around the core of the circulation.  The thunderstorms are generating well developed upper level divergence which is pumping out mass.

The Hurricane Intensity Index (HII) is 29.9.  The Hurricane Size index (HSI) is 10.4 and the Hurricane Wind Intensity Size Index (HWISI) is 40.3.  The indices indicate that Hurricane Matthew is as strong as Hurricane Dennis was in 2005, but Matthew is a little smaller than Dennis was.

Hurricane Matthew will be moving through a very favorable environment.  Matthew will be 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.  There could be some fluctuations in intensity, especially if eyewall replacement cycles occur.  Matthew is likely to remain a powerful hurricane.

Hurricane Matthew has reached the western end of a subtropical high pressure system.  Matthew is likely to continue to move north around the western end of the subtropical high.  On its anticipated track Hurricane Matthew could be near Jamaica and western Haiti on Monday night.  Matthew could reach eastern Cuba on Tuesday and it could be over the Bahamas on Wednesday.

Hurricane Matthew is capable of causing region significant wind damage.  It will bring locally heavy rain to parts of Haiti, Jamaica and Cuba.  Matthew will also create dangerous storm surges along the coast.

Powerful Typhoon Chaba Passing South of Okinawa

Powerful Typhoon Chaba is passing south of Okinawa.  At 11:00 p.m. EDT on Sunday the center of Typhoon Chaba was located at latitude 24.5°N and longitude 127.3°E which put it about 180 miles (290 km) south of Okinawa.  Chaba was moving toward the northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 170 m.p.h. (280 km/h).  The minimum surface pressure was 935 mb.

The circulation of Typhoon Chaba is very well organized.  Chaba has a distinct circular eye surrounded by a ring of strong thunderstorms.  Other rainbands are rotating around the core of the circulation.  The thunderstorms in the core are generating upper level divergence which is pumping out mass to the north of Typhoon Chaba.

Typhoon Chaba is moving through a very favorable environment.  Chaba is moving over water where the Sea Surface Temperature (SST) is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Typhoon Chaba could intensify a little more during the next 12 to 24 hours.  When Chaba moves farther north, an upper level trough over eastern China will cause more vertical wind shear.  Increased wind shear and cooler SSTs will weaken the typhoon.

Typhoon Chaba is moving around the western end of a subtropical ridge which is steering it toward the northwest.  Chaba will gradually start to move more toward the north.  In about 36 hours the upper level trough over eastern China will begin to steer Typhoon Chaba toward the northeast.  On its anticipated track Typhoon Chaba will move through the Ryukyu Islands southwest of Okinawa during the next 24 hours.  Chaba would be southwest of Kyushu in about 36 hours.

Chaba is a powerful typhoon and it will bring gusty winds and heavy rain to the Ryukyu Islands including Okinawa.

Powerful Hurricane Matthew Turns Northwest

After completing a tight slow cyclonic loop near the northern coast of Colombia, Hurricane Matthew started moving toward the northwest on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Hurricane Matthew was located at latitude 13.8°N and longitude 73.6°W which put it about 360 miles (580 km) southeast of Kingston, Jamaica.  Matthew was moving toward the north-northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 940 mb.

A Hurricane Warning has been issued for Jamaica.  A Hurricane Warning is in effect for the coast of Haiti from the southern border with the Dominican Republic to Le Mole St. Nicholas.  A Hurricane Watch is in effect from Le Mole St. Nicholas to the northern border with the Dominican Republic.  A Hurricane Watch is also in effect for Cuba from Camaguey province to Guantanamo province.

Matthew is a compact hurricane.  It has a circular eye with a diameter of less than 10 miles (16 km).  The eye is surrounded by a tight ring of strong thunderstorms and the strongest winds are occurring in that ring.  Additional rainbands are rotating around the core of the circulation.  Thunderstorms in the core are generating upper level divergence which is pumping out mass to the east of Hurricane Matthew.

The Hurricane Intensity Index (HII) is 31.6.  The Hurricane Size Index (HSI) is 10.3 and the Hurricane Wind Intensity Size index (HWISI) is 41.9.  The indices indicate that Hurricane Matthew is as intense and a little smaller than Hurricane Dennis was when Dennis was over the northwestern Caribbean Sea in 2005.

Hurricane Matthew will continue to move through a favorable environment on Sunday.  It will move over water where the Sea Surface Temperature is near 30°.  An upper level trough west of Matthew will generate southwesterly winds which will blow near the northwestern part of the hurricane.  Although there will be some vertical wind shear, it may not have a significant impact on Hurricane Matthew.  If one of the rainbands wraps around the existing eye, then an eyewall replacement cycle could cause a temporary weakening of Hurricane Matthew.

Hurricane Matthew is moving around the western end of a subtropical high pressure system.  The combination of the subtropical high and the upper level trough to the west of Matthew should steer the hurricane toward the north-northwest on Sunday.  On its anticipate track Hurricane Matthew could reach Jamaica and southern Haiti on Monday afternoon.  Matthew could reach eastern Cuba on Monday night and it could be over the southeastern Bahamas on Tuesday.

Hurricane Matthew is a dangerous hurricane.  The indices suggest that it is capable of causing significant regional wind damage.  It could also bring flooding rains to parts of Haiti.  Hurricane Matthew could also produce dangerous storm surges on the south coasts of Haiti, Jamaica and Cuba.

Typhoon Chaba Rapidly Intensifies Into the Equivalent of a Major Hurricane

Typhoon Chaba intensified rapidly into the equivalent of a major hurricane on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Chaba was located at latitude 20.1°N and longitude 131.0°E which put it about 530 miles (855 km) south-southeast of Okinawa.  Chaba was moving toward the 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 957 mb.

The organization of the circulation of Typhoon Chaba improved significantly on Saturday.  It has a small circular eye which is surrounded by a ring of very strong thunderstorms.  Another primary band of thunderstorms wrapped around the western side of the typhoon.  Thunderstorms in the core of Typhoon Chaba produced strong upper level divergence which pumped out enough mass to allow the pressure at the surface to decrease very rapidly during the past 24 hours.

Typhoon Chaba will continue to move in an environment that is very favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is not much vertical wind shear.  Typhoon Chaba should continue to intensify for another 24 hours and it could reach major typhoon status.

Typhoon Chaba is moving around the western end of a subtropical ridge which is steering the typhoon toward the northwest.  Chaba should start to move more toward the north when it reaches the western end of the ridge.  On its anticipated track Typhoon Chaba could reach Okinawa in about 36 hours.  It will be a powerful typhoon when it moves through the Ryukyu Islands.

Hurricane Matthew Becomes the First Category 5 Atlantic Hurricane Since 2007

Hurricane Matthew continued its rapid intensification on Friday night and it became the first Atlantic hurricane to reach Category 5 on the Saffir-Simpson Scale since Hurricane Felix did so in 2007.  At 11:00 p.m. EDT on Friday the center of Hurricane Matthew was located at latitude 13.3°N and longitude 72.3°W which put it about 440 miles (710 km) southeast of Kingston, Jamaica.  Matthew was moving toward the west at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 941 mb.

The Hurricane Intensity Index (HII) for Matthew was 35.0.  The Hurricane Size Index (HSI) was 13.7 and the Hurricane Wind Intensity Size Index (HWISI) was 48.7.  These indices indicate that Hurricane Matthew is not as intense and slightly smaller than Hurricane Wilma was, when Wilma was a Category 5 hurricane over the northwestern Caribbean Sea in 2005.

A Hurricane Watch is in effect for Jamaica.  A Tropical Storm Watch is in effect for the portion of the coast from the Haiti/Dominican Republic border to Port-Au-Prince, Haiti.  A Tropical Storm Warning is in effect for the portion of the coast from the Colombia/Venezuela border to Riohacha, Colombia.

Hurricane Matthew remains in a very favorable environment of minimal vertical wind shear and warm Sea Surface Temperatures.  The intensity may fluctuate as a result of eyewall replacement cycles.

A strong subtropical high is steering Hurricane Matthew toward the west.  Matthew is slowing as it approaches the western end of the subtropical high.  It will turn toward the north when it reaches the western end of that high pressure system.  However, the location, time and sharpness of the turn to the north are still uncertain.  That uncertainty means that the longer term track of Hurricane Matthew is also uncertain.  We should get more clarity about the future direction of Hurricane Matthew during the next several days.

Matthew Rapidly Intensifies Into Category 4 Hurricane

Hurricane Matthew intensified very rapidly into a Category 4 hurricane on the Saffir-Simpson Scale as it moved across the southern Caribbean Sea on Friday.  At 5:00 p.m. EDT on Friday the center of Hurricane Matthew was located at latitude 13.5°N and longitude 71.6°W which put it about 75 miles (120 km) north of Punta Gallinas, Colombia.  Matthew was moving toward the west-southwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 140 m.p.h. (220 km/h). and there were wind gusts t0 165 m.p.h. (265 km/h).  The minimum surface pressure was 949 mb.

The Hurricane Size Index (HII) was 28.3.  The Hurricane Intensity Index (HII) was 13.2 and the Hurricane Wind Intensity Size Index (HWISI) was 41.5.  The indices mean that Hurricane Matthew is very similar in size and intensity to what Hurricane Ike was when Ike was northeast of the Leeward Islands in 2008.  The indices also mean that Hurricane Matthew is capable of producing regional significant wind damage.

Hurricane Matthew is very well organized and it efficiently extracted energy from the warm water of the Caribbean Sea to intensify rapidly on Friday.  It has a circular eye with a diameter of about 15 miles (24 km).  The eye is surrounded by a ring of very tall thunderstorms.  The thunderstorms are pumping out large quantities of mass which allowed the surface pressure to decrease by 44 mb during the past 24 hours.  There additional bands of thunderstorms, mainly in the eastern half of the circulation.

Hurricane Matthew will remain in a very favorable environment while it is over the Caribbean Sea.  It could intensify further.  When hurricanes become as strong as Matthew strong, they sometimes undergo eyewall replacement cycles.  During an eyewall replacement cycle, a hurricane first weakens and then strengthens again when the innermost eyewall dissipates.  If eyewall replacement cycles occur in Hurricane Matthew, then the intensity will fluctuate.

A strong subtropical high pressure system north of Matthew is steering the hurricane toward the west-southwest.  That general motion is expected to continue for another 24 hours.  When Matthew reaches the western end of the subtropical high, it will start to move toward the north.  Guidance from numerical models is still divergent about the details of the turn toward the north.  If the turn is sharper, it could mean that Hurricane Matthew moves toward Haiti.  If the turn is more gradual, it could mean that Matthew heads for Jamaica and eastern Cuba.  The uncertainty is the reason why watches have been posted for both Jamaica and Haiti.

Matthew is a very powerful hurricane.  It is capable of causing regional significant wind damage.  In addition Matthew will produce very heavy rain and the potential for dangerous flash flooding.  There is also the possibility of a significant storm surge along the coast.

Matthew Becomes a Hurricane Over the Eastern Caribbean Sea

Tropical Storm Matthew strengthened into a hurricane on Thursday as it moved over the eastern Caribbean Sea.  At 8:00 p.m. EDT on Thursday the center of Hurricane Matthew was located at latitude 14.2°N and longitude 68.1°W which put it about 150 miles (240 km) north-northeast of Curacao.  Matthew was moving toward the west at 15 m.p.h. (24 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 987 mb.

Tropical Storm Watches are in effect for Curacao, Bonaire and Aruba.  The government of Columbia has also issued a Tropical Storm Watch for the portion of the coast from the Columbia/Venezuela border to Riohacha.

The structure of Hurricane Matthew became much better organized on Thursday.  A primary rainband wrapped around the center of circulation.  An eye appears to be forming.  A ring of strong thunderstorms surrounds the eye on all sides except to the south.  Additional bands of thunderstorms developed in the northern and eastern parts of the circulation.  The storms near the eye generated upper level divergence which pumped out mass to the north and east of Hurricane Matthew.  The upper level divergence pumped out enough mass to allow the minimum pressure to decrease by 17 mb during the past 24 hours.

Hurricane Matthew will be moving into an environment that will be favorable for intensification.  It will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough over the western Caribbean Sea and an upper level ridge just east of Matthew are producing southwesterly winds which are blowing across the top of the hurricane.  The vertical wind shear made Hurricane Matthew’s structure asymmetrical earlier today, but the shear has been less in recent hours.  The effect of the wind shear will be to slow the rate of intensification, but it will not prevent intensification.  Hurricane Matthew will pass just north of the cost of South America and drier air could also slow the rate of intensification.

A strong subtropical high pressure system to the north of Matthew is steering the hurricane toward the west and that general motion is expected to continue for about another 48 hours.  When Hurricane Matthew reaches the western end of the ridge, it will turn toward the north.  Guidance from the numerical models continues to be quite divergent about when, where and how sharp the turn will be.  If Hurricane Matthew turns sooner and sharper, it could move over Haiti early next week.  On the other hand, if Matthew turns later and more gradually, it could affect Jamaica and eastern Cuba.  It is too early to know which scenario will eventually occur.

Hurricane Matthew could become a major hurricane over the Caribbean Sea and interests in the Greater Antilles should monitor its progress.

Tropical Storm Chaba Organizes and Moves Toward Okinawa

Tropical Storm Chaba strengthened on Thursday as it started to move toward Okinawa.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Chaba was located at latitude 13.8°N and longitude 138.6°E which put it about 1145 miles (1850 km) southeast of Okinawa.  Chaba was moving toward the west at 14 m.p.h. (22 km/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 996 mb.

The circulation of Tropical Storm Chaba showed signs of better organization on Thursday.  A primary rainband wrapped around the western and south sides of the circulation.  Additional bands of thunderstorms were forming on the southern and eastern side of Tropical Storm Chaba.  Thunderstorms near the core of Chaba were generating upper level divergence which was pumping mass out to the west, south and east of the tropical storm.

Tropical Storm Chaba is moving into an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level ridge to the north of Chaba is generating easterly winds which are blowing across the northern portion of the tropical storm.  However, those winds are not causing significant vertical wind shear.  The combination of warm SSTs and little vertical wind shear should allow Tropical Storm Chaba to intensify steadily during the next several days.  It could become a typhoon within 24 to 48 hours.  There is a chance that Chaba could become the equivalent of a major hurricane in three or four days.

A subtropical ridge to the north of Chaba is steering the tropical storm toward the west and that general motion is expected to continue in the short term.  When Chaba gets a little closer to the western end of the ridge, it will start to move toward the northwest and when Chaba reaches the western end of the ridge it will turn toward the north.  On it anticipated track Tropical Storm Chaba could be approaching Okinawa and the Ryukyu islands in about three days.  It could be a powerful typhoon at that time.

Tropical Storm Matthew Develops Near the Windward Islands

The National Hurricane Center determined that a surface circulation center formed within Invest 97L on Wednesday morning and it designated the system as Tropical Storm Matthew.  At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Matthew as located at latitude 13.4°N and longitude 60.7°W which put it about 35 miles (55 km) southeast of St. Lucia.  Matthew was moving toward the west at 21 m.p.h. (33 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 1008 mb.

Tropical Storm Warnings have been issued for Guadeloupe, Martinique, Barbados, Dominica, St. Lucia, and St. Vincent and the Grenadines.

The circulation of Tropical Storm Matthew is still organizing and it appears as if the surface center is located southwest of the mid-level center.  There are many more thunderstorms north and east of the center and there are fewer thunderstorms south and west of the center.  The strongest winds are occurring in the bands of thunderstorms northeast of the center of circulation.  The winds are much weaker in the western half of Tropical Storm Matthew.  The stronger thunderstorms northeast of the center of circulation are generating upper level divergence which is pumping mass out to the north and east of Matthew.

Tropical Storm Matthew will be moving into an environment that is favorable for intensification The Sea Surface Temperatures in the eastern and central Caribbean Sea are near 30°C.  The upper level winds are weak and there is not much vertical wind shear.  Even with those favorable conditions, several factors could slow the rate at which Tropical Storm Matthew intensifies.  First, it is moving west at 21 m.p.h. (33 km/h).  Sometimes tropical cyclones generate low level vertical wind shear when they move that quickly.  Second, the asymmetrical distribution of thunderstorms around the circulation of Matthew could prevent the tropical storm form efficiently using the energy it extracts from the ocean.  In addition, if Tropical Storm Matthew moves too close to the northern coast of South America, it could pull in some drier air, which would also slow the rate of intensification.  Even with those potential inhibiting factors, Tropical Storm Matthew is likely to become a hurricane by the end of the week and it could become a major hurricane while it is over the Caribbean Sea.

A subtropical high pressure system to the north of Matthew is steering the tropical storm toward the west and that general motion is expected to continue for several more days.  Tropical Storm Matthew is likely to slow down over the weekend as it gets closer to the western end of the subtropical high.  Matthew will likely turn toward the north during the weekend.  There is a great deal of variability in how quickly and sharply the models predict the turn will be.  Some models forecast a quick sharp turn toward the north that could eventually carry Matthew near Bermuda.  Other models forecast a later slower turn that occurs over the western Caribbean Sea and could take take Matthew closer to the U.S.  It is too early to know which scenario will be the right one.

Tropical Storm Matthew will bring gusty winds and locally heavy rain to the Windward Islands and southern Leeward Islands.  Interests in other parts of the Caribbean Sea, the Bahamas, U.S. and Bermuda should monitor the progress of Tropical Storm Matthew.

Invest 97L Poses Risk for Caribbean Sea

A tropical disturbance designated as Invest 97L poses a potential risk for locations around the Caribbean Sea.  At 8:00 p.m. EDT on Tuesday the center of Invest 97L was located at latitude 13.1°N and longitude 55.3°W which put it about 285 miles (460 km) east of Barbados.  Invest 97L was moving toward the west at 19 m.p.h. (31 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. (70 km/h).  The minimum surface pressure was 1008 mb.

A U.S. Air Force Reserve Hurricane Hunter aircraft flew a reconnaissance mission into Invest 97L on Tuesday afternoon.  The plane found the there were winds to near tropical storm force, but it could not identify a closed circulation.  The winds on the western side were weaker and the plane was unable to find a surface center.  There does seem to be cyclonic rotation above the surface at least on infrared satellite imagery.

The circulation in Invest 97L is still organizing.  Many of the stronger thunderstorms are forming north and east of the apparent center on satellite imagery.  Rainbands are also forming north and east of the center.  Recent satellite images suggest that some thunderstorms could be developing closer to the center of cyclonic rotation.  The current thunderstorms are generating upper level divergence which is pumping out mass to the north and east of the system.

Invest 97L is moving through an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 29°C.  The upper level winds over the majority of the circulation are relatively weak.  An upper level trough over the Caribbean Sea is generating vertical wind shear over the northern fringe of the circulation.  Invest 97L could become a tropical storm at any time.

A subtropical high pressure system to the north of Invest 97L is steering it toward the west and that general motion is expected to continue for another day or two.  On its anticipated track Invest 97L will move through the Windward Islands near Barbados, St. Lucia, Martinique, and Dominica on Wednesday.  It could bring gusty winds and locally heavy rain to those locations.