Monthly Archives: October 2016

Hurricane Matthew Moves Across the Bahamas Toward Florida

Hurricane Matthew moved away from Cuba and across the Southeastern Bahamas on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Matthew was located at latitude 23.4°N and longitude 76.4°W which put it about 125 miles (205 km) south-southeast of Nassau, Bahamas and about 325 miles (525 km) southeast of West Palm Beach, Florida.  Matthew was moving toward the northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 135 m.p.h. (220 km/h).  The minimum surface pressure was 961 mb.  Hurricane Matthew was a Category 3 hurricane on the Saffir-Simpson Scale.

A Hurricane Warning is in effect for the portion of the coast from Golden Beach, Florida to Fernandina Beach including Lake Okeechobee.  A Hurricane Watch has been issued for the portion of the coast of Florida from Fernandina Beach to Edisto Beach, South Carolina.  A Tropical Storm Warning is in effect for the portion of the coast from Chokoloskee to Golden Beach, Florida and for the Florida Keys from Seven Mile Bridge eastward including Florida Bay.  A Tropical Storm Watch has been issued for the portion of the coast from Chokoloskee, Florida to Suwanee River.  Hurricane Warnings are also in effect for the Southeastern Bahamas including the Inaguas, Mayaguana, Acklins, Crooked Island, Long Cay, Ragged Island, and for the Central Bahamas including Long Island, Exuma, Rum Cay, San Salvador and Cat Island.  A Hurricane Warning is in effect for the northwestern Bahamas including the Abacos, Andros Island, Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence.

Hurricane Matthew weakened after it passed over southwestern Haiti and the eastern end of Cuba.  The structure of the eyewall deteriorated on Wednesday morning, when the core of Hurricane Matthew started to move north of Cuba.  After a few hours over the warm water around the Bahamas, a circular eyewall began to reform around the center of circulation.  The eyewall appeared to weaken for a time on Wednesday afternoon, but it then became much more well organized around a distinct eye appeared on Wednesday night.  The loss of organization around the eye resulted in a decrease in the maximum sustained wind speed to 115 m.p.h. and an increase in the  minimum surface pressure to 964 mb.

Hurricane Matthew appeared to be intensifying on Wednesday night.  A reconnaissance aircraft observed a minimum surface pressure that was several millibars lower and the structure of the core of the hurricane was displaying more organization.  Thunderstorms around the eye of Hurricane Matthew were beginning to generate stronger upper level divergence which was pumping mass out in all directions.  The divergence was allowing the surface pressure to decrease as measured by the recon plane.

Hurricane Matthew 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 light and there is little vertical wind shear.  As the minimum pressure decrease, the pressure gradient force will accelerate the air faster and the wind speeds will increase.  Hurricane Matthew could become a Category 4 hurricane on Thursday and there is a chance it could get near Category 5.

A ridge of high pressure is steering Matthew toward the northwest and that general motion is expected to continue on Thursday.  The center of strong hurricanes sometimes wobble a bit from side to side in response to bursts of thunderstorms in the eyewall, but the general motion is likely to be toward the northwest.  The center of Hurricane Matthew is passing just west of the Exumas in the Bahamas.  Matthew is likely to pass near Nassau on New Providence and near Andros Island on Thursday morning.

On its anticipated track Hurricane Matthew could be very near the southeast coast of Florida by Thursday evening.  Matthew could make landfall in the portion of the coast between Fort Lauderale and West Palm Beach or the center could stay just offshore.  The center of Hurricane Matthew is forecast to move along the east coast of Florida on Friday.  An upper level trough approaching from the west is expected to turn Hurricane Matthew toward the northeast on Friday night or Saturday.  However, the timing and location of that turn is still uncertain.  It could occur near the coast of Georgia and South Carolina or it could occur a little sooner and move the center of Matthew back over the Atlantic Ocean.

Hurricane Matthew poses a serious potential risk to the southeast coast of the U.S.  The Hurricane Intensity Index (HII) is 20.6.  The Hurricane Size Index (HSI) is 15.7 and the Hurricane Wind Intensity Size index (HWISI) is 36.3.  Those indices indicate that Matthew will be capable of causing regional wind damage.  Matthew could get bigger and stronger before it reaches Florida, which would increase the risk.  If Matthew tracks along the coast or just inland, will bring hurricane force winds to the populated areas on the east coast of Florida.  In addition, strong easterly winds north of the center of Hurricane Matthew will blow water toward the coast and create the potential for dangerous storm surges.  Matthew will move slowly enough that locally heavy rain could fall and fresh water flooding could also create problems.

Hurricane Matthew Crosses Southwest Haiti, Watches Issued for Florida

Hurricane Matthew crossed the western end of the Tiburon Peninsula of Haiti on Tuesday morning.  The eye emerged intact over the Golfe de la Gonave and the center of Hurricane Matthew is about half way between Haiti and the eastern end of Cuba.  At 2:00 pm. EDT on Tuesday the center of Hurricane Matthew was located at latitude 19.4°N and longitude 74.3°W which put it about 65 miles (105 km) east-southeast of Guantanamo, Cuba.  Matthew was moving toward the north at 10 m.p.h. (16 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 949 mb.

A Hurricane Watch has been issued for the portion of the coast of Florida from Deerfield Beach to the Volusia/Brevard County line.  A Tropical Storm Watch has been issued from Seven Mile Bridge in the Florida Keys to Deerfield Beach.  Hurricane Warnings are in effect for Haiti and 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, Ragged Island, and for the Central Bahamas including Long Island, Exuma, Rum Cay, San Salvador and Cat Island.  A Hurricane Warning is in effect for the northwestern Bahamas including the Abacos, Andros Island, Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence.  A Hurricane Watch has been issued for the Cuban province of Camaguey.  A Tropical Storm Warning is in effect for the Turks and Caicos and the south coast of the Dominican Republic from Barahona to Haiti.  Tropical Storm Watches have been issued for the northern coast of the Dominican Republic from Puerto la Plata to Haiti.

Even after passing over the mountains of the Massif de la Hotte on the southwestern peninsula of Haiti, the structure of Hurricane Matthew remained well organized.  Matthew has a circular eye with a diameter of 24 miles (39 km).  The eye is surrounded by a ring of strong thunderstorms.  The wind field around Hurricane Matthew actually expanded after it crossed southwestern Haiti.  Winds to hurricane force extend out about 60 miles (95 km) from the center of circulation.  Thunderstorms around the eye are generating upper level divergence which is pumping out mass in all directions.  Additional rainbands are rotating around the core of Matthew.

Hurricane Matthew is moving through a very favorable environment.  It is moving over water where the Sea Surface Temperature is 30°C.  The winds in the upper levels are weak and the is little vertical wind shear.  Hurricane Matthew could weaken slightly when the center passes over eastern Cuba, but it will likely restrengthen when it moves over the very warm water around the Bahamas.  Matthew is likely to remain a Category 4 hurricane on the Saffir-Simpson Scale. and it could become a Category 5 hurricane while it is moving over the Bahamas.  Hurricane Joaquin almost reached Category 5 while it was near the Bahamas in early October last year.

Matthew is moving around the western end of subtropical high pressure system, which is steering the hurricane toward the north.  That general motion is expected to continue for another 12 hours or so.  The high is expected to strengthen and extend west on Wednesday.  When that happens, Hurricane Matthew will be steered more toward the northwest.  On its anticipated track Hurricane Matthew will move across the eastern end of Cuba later on Tuesday and across the Bahamas on Wednesday.  Hurricane Matthew could be very near the east coast of Florida on Thursday.  Matthew could come very close to the coast of South Carolina on Friday and it could be near the coast of North Carolina on Saturday morning.  It is still not clear if the eye of Hurricane Matthew will reach landfall in any of those places.

The Hurricane Intensity Index (HII) for Matthew is 29.8.  The Hurricane Size Index (HSI) is 19.5 and the Hurricane Wind Intensity Size Index (HWISI) is 49.3.  Those indices mean that Hurricane Matthew is capable of causing regional significant wind damage.  Matthew will also generate a significant storm surge over eastern Cuba and the Bahamas.  Water level rises will occur along the southeast coast of the U.S. where easterly winds push the water toward the shore.  Hurricane Matthew is stronger, but a little smaller than Hurricane Jeanne was in 2004, when Jeanne made landfall on the coast of Florida.

Hurricane Matthew Moves Toward Haiti, Threat to U.S. Increases

Hurricane Matthew moved toward Haiti on Monday and the threat to the U.S. increased.  At 5:00 pm. EDT on Monday the center of Hurricane Matthew was located at latitude 16.3°N and longitude 74.7°W which put it about 140 miles (220 km) south of Tiburon, Haiti.  Matthew was moving toward the north at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 140 m.p.h. (220 km/h) and there were wind gusts to 165 m.p.h. (265 km/h).  The minimum surface pressure was 940 mb.

Hurricane Warnings are in effect for Haiti and 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, Ragged Island, and for the Central Bahamas including Long Island, Exuma, Rum Cay, San Salvador and Cat Island.  Hurricane Watches have been issued for the Cuban province of Camaguey and the northwestern Bahamas including the Abacos, Andros Island, Berry Islands, Bimini, Eleuthera, Grand Bahama Island and New Providence, and for the Turks and Caicos.  A Tropical Storm Warning is in effect for Jamaica and the south coast of the Dominican Republic from Barahona to Haiti.  Tropical Storm Watches have been issued for the northern coast of the Dominican Republic from Puerto la Plata to Haiti.

The structure of Hurricane Matthew is well organized.  It has a circular eye with a diameter of 18 miles (29 km).  The eye is surrounded by a ring of strong thunderstorms.  Winds to hurricane force extend out about 40 miles (65 km) from the center of circulation.  Thunderstorms around the eye are generating upper level divergence which is pumping out mass in all directions.  Additional rainbands are rotating around the core of Matthew.

The Hurricane Intensity Index (HII) for Matthew is 28.2.  The Hurricane Size Index (HSI) is 15.1 and the Hurricane Wind Intensity Size Index (HWISI) is 43,3.  These indices suggest that Hurricane Matthew is capable of causing regional significant wind damage to Haiti.  Hurricane Matthew is very similar in size and intensity to what Hurricane Dennis was when Dennis hit northwest Florida in 2005.  Hurricane Matthew is stronger and a little bigger than Hurricane Sandy was when Sandy was over the northwestern Caribbean Sea in 2012.

Hurricane Matthew 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 not much vertical wind shear.  Matthew is likely to maintain its intensity as it moves toward Haiti.  If a rainband wraps around the eye, then an eyewall replacement cycle could cause temporary fluctuations in intensity.  The future path of Matthew could have a big impact on the intensity of the hurricane.  If the center of Matthew moves over southwestern Haiti, then the Massif de la Hotte could seriously disrupt the lower levels of the circulation.  Mountains in Massif de la Hotte extend up to 7700 feet (2347 meters).  On the other hand, if the eye and eyewall move just west of Haiti, then the inner core is likely to remain intact.  The water around the Bahamas is very warm and if the core of Hurricane Matthew is reasonably intact when it gets there, Matthew will likely regain its intensity.

Hurricane Matthew is moving around the southwestern end of a subtropical high pressure system, which has allowed the hurricane to move just east of due north.  That general motion is expected to continue for another day or so.  In about 24 hours the subtropical high is expected to strengthen and extend westward.  If the high does strengthen, it will force Hurricane Matthew to move more toward the northwest.  Guidance from numerical models has supported this scenario today.  The northwest motion could take Hurricane Matthew over the Central and Northwestern Bahamas during the middle of the week.  A northwesterly track could bring Hurricane Matthew close to Florida on Thursday and near the Mid-Atlantic Coast on Friday.  Based on guidance from the forecast models, the threat to the U.S. increased significantly on Monday.

Hurricane Matthew has the potential to cause regional significant wind damage to Haiti.  Even if the center moves west of Haiti, Matthew will produce very heavy rain and the potential for devastating flash floods and mudslides exists.  There will also be significant storm surges along the coasts of Haiti, the Dominican Republic and eastern Cuba.

Super Typhoon Chaba Threatens Japan and South Korea

Super Typhoon Chaba moved north on Monday and it threatened to bring strong winds and heavy rain to Japan and South Korea.  At 5:00 p.m. EDT on Monday the center of Super Typhoon Chaba was located at latitude 27.5°N and longitude 126.5°E which put it about 100 miles (160 km) west-northwest of Okinawa.  Chaba was moving toward the north at 11 m.p.h. (18 km/h).  The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 925 mb.

Typhoon Chaba is a compact well organized storm.  It has a clear circular eye surrounded by a ring of strong thunderstorms.  Winds to typhoon force extend out about 35 miles (55 km) from the center of circulation.  Additional rainbands are rotating around the core of Typhoon Chaba.  Thunderstorms at the core of Chaba are generating upper level divergence which is pumping mass out in all directions.

The Hurricane Intensity Index (HII) for Typhoon Chaba is 33.3.  The Hurricane Size Index (HSI) is 11.6 and the Hurricane Wind Intensity Size Index (HWISI) is 44.9.  These indices indicate that Typhoon Chaba is stronger, but slightly smaller than Hurricane Matthew which is over the Caribbean Sea.

Although Typhoon Chaba is still in a very favorable environment, it has probably peaked in intensity.  Chaba was the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale earlier today.  Chaba is currently moving over water where the Sea Surface Temperature (SST) is near 29°C.  The upper level winds are weak and there is little vertical wind shear.  Typhoon Chaba is likely to weaken gradually during the next 24 hours.  In about a day or so, Chaba will move over cooler SSTs.  In addition, when Chaba moves farther north it will move closer to the upper level westerly winds in the middle latitudes.  A combination of cooler SSTs and more vertical wind shear will increase the rate at which Typhoon Chaba will weaken.

Chaba is moving around the western end of a subtropical ridge which is steering the typhoon toward the north.  That general motion is expected to continue for about another 24 hours.  In about a day or so the westerly winds of the middle latitudes are expected to turn Chaba quickly toward the northeast.  On its anticipated track the core of Typhoon Chaba will pass west of the northern Ryukyu Islands.  Chaba could be near Jeju, South Korea and western Kyushu in 24 hours.

Chaba is a very strong typhoon.  Although it will weaken, Typhoon Chaba will bring strong winds and heavy rain to parts of South Korea and Japan.

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.