Tag Archives: Hurricane Matthew

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.