Tag Archives: St. Eustatius

Hurricane Warnings Issued for Carolinas for Hurricane Florence

Hurricane Warnings were issued for the Carolinas on Tuesday for the potential impacts of Hurricane Florence.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Florence was located at latitude 28.4°N and longitude 68.7°W which put it about 670 miles (1075 km) east-southeast of Cape Fear, North Carolina.  Florence was moving toward the west-northwest at 17 m.p.h. (28 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. (270 km/h).  The minimum surface pressure was 946 mb.

A Hurricane Warning was in effect for the portion of the coast from South Santee River, South Carolina to Duck, North Carolina.  Hurricane Watches were in effect for the portions of the coast from Edisto Beach to South Santee River, South Carolina and from Duck, North Carolina to the North Carolina-Virginia border.  Tropical Storm Watches were in effect for the portions of the coast from Duck, North Carolina to Cape Charles Light, Virginia and for Chesapeake Bay south of New Point Comfort.

Hurricane Florence completed an eyewall replacement cycle and it continues to be a powerful hurricane.  There was a circular eye with a diameter of 30 miles (48 km) at the center of Florence.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  The eyewall replacement cycle resulted in a larger circulation.

Winds to hurricane force extended out about 60 miles (95 km) from the center of circulation of Hurricane Florence.  Winds to tropical storm force extended out about 175 miles (280 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Florence was 28.2.  The Hurricane Size Index (HSI) was 18.9 and the Hurricane Wind Intensity Size Index (HWISI) was 47.1.  Hurricane Florence is capable of causing extensive significant damage.

Hurricane Florence will move through an environment favorable for strong hurricanes during the next 24 to 36 hours.  Florence will move over water where the Sea Surface Temperature is near 29°C.  it will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Florence is likely to maintain its intensity and it could strengthen.  If another eyewall replacement cycle occurs, then there could be fluctuations in intensity.

Hurricane Florence will move around the western end of a subtropical high pressure system over the western Atlantic Ocean.  The high will steer Florence toward the west-northwest during the next 24 to 36 hours.  On its anticipated track Hurricane Florence could approach the coast of the Carolinas later on Thursday.  The steering winds are forecast to weaken when Florence nears the coast and there is great uncertainty about the track when that occurs.  Hurricane Florence will bring strong winds to coastal North Carolina and eastern South Carolina.  Wind pushing water toward the shore will cause a significant storm surge.  A slow forward speed will mean that Hurricane Florence will drop a lot of rain and there is a risk of significant flooding of rivers and streams.

Elsewhere over the Atlantic Ocean, Tropical Storm Isaac was speeding toward the Lesser Antilles and Hurricane Helene was weakening far south of the Azores.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Isaac was located at latitude 14.5°N and longitude 52.3°W which put it about 580 miles (935 km) east of Martinique.  Isaac was moving toward the west at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 999 mb.  Tropical Storm Warnings were in effect for Dominica, Martinique and Guadeloupe.  Tropical Storm Watches were in effect for Antigua, Montserrat, St. Kitts and Nevis, and Saba and St. Eustatius.

At 11:00 p.m. EDT on Tuesday the center of Hurricane Helene was located at latitude 18.0°N and longitude 35.4°W which put it about 1479 miles (2370 km) south-southwest of the Azores.  Helene was moving toward the northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 973 mb.

Tropical Storm Chris Develops South of Cape Hatteras, Beryl Nears Lesser Antilles

Tropical Storm Chris developed south of Cape Hatteras on Sunday morning, while Tropical Storm Beryl neared the Lesser Antilles.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Chris was located at latitude 32.9°N and longitude 75.0°W which put it about 160 miles (260 km) south of Cape Hatteras, North Carolina.  Chris was nearly stationary.  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1006 mb.

Thunderstorms developed closer to the center of circulation on Sunday morning and the National Hurricane Center designated former Tropical Depression Three as Tropical Storm Chris.  The circulation of Chris was organizing quickly.  A band of showers and thunderstorms was wrapping around the center of circulation.  Several other rainbands were revolving around the core of the tropical storm.  The bands northwest of the center were weaker because there was drier air in that part of Chris.  The storms near the center of circulation were beginning to generate upper level divergence.

Tropical Storm Chris will remain in an environment favorable for intensification for the next two or three days.  The water in the upper portion of the Atlantic Ocean east of the Carolinas is warmer than normal.  Tropical Storm Chris will be over water where the Sea Surface Temperature is near 28°C.  Chris will be southeast of an upper level trough over the northeastern quarter of the U.S. and it will be under a small upper level ridge.  The upper level winds will be weak and there will be little vertical wind shear.  Tropical Storm Chris will continue to intensify and it could strengthen to a hurricane in the next day or two.

Since Tropical Storm Chris is under the small upper level ridge, the steering winds are weak.  Chris may not move much during the next 24 to 48 hours.  Tropical Storm Chris is forecast to linger of the coast of the Carolinas for several days.  Eventually an upper level trough will approach from the west and start to push Chris toward the northeast.

Elsewhere, Tropical Storm Beryl was nearing the Lesser Antilles on Sunday morning.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Beryl was located at latitude 14.4°N and longitude 57.9°W which put it about 210 miles (335 km) east of Martinique.  Beryl was moving toward the west-northwest at 23 m.p.h. (37 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1007 mb.

Tropical Storm Warnings were in effect for Dominica and Guadeloupe.  Tropical Storm Watches were in effect for Saba, St. Eustatius, St. Maarten, St. Martin, Martinique, St. Lucia, and St. Barthelemy.

Thunderstorms continued to develop near the center of Tropical Storm Beryl on Sunday morning and the weakening trend halted at least temporarily.  Beryl remained a small tropical storm.  Winds to tropical storm force only extended out about 45 miles (75 km) from the center of circulation.  There were several bands of showers and thunderstorms in the eastern half of Tropical Storm Beryl.  The bands in the western half of the circulation consisted primarily of showers and low clouds.

Tropical Storm Beryl is forecast to into a region where the easterly winds in the lower levels are stronger.  That would increase the vertical wind shear and make it difficult for the circulation to stay vertically coherent.  Beryl will move over water where the Sea Surface Temperature is near 27°C.  So, there will be enough energy in the upper ocean to support a tropical storm if the wind shear is not too strong.  Tropical Storm Beryl is forecast to weaken when it moves over the eastern Caribbean Sea, but that will depend on how strong the vertical shear gets.

Tropical Storm Beryl is moving south of the subtropical high over the Atlantic Ocean which is steering Beryl toward the west-northwest.  A general motion toward the west-northwest is forecast to continue for several more days.  On its anticipated track Tropical Storm Beryl will bring gusty winds and locally heavy rain to St. Lucia, Martinique, Dominica and Guadeloupe during the next few hours,

Tropical Storm Beryl Weakens East of the Lesser Antilles

Tropical Storm Beryl weakened on Saturday as it move closer to the Lesser Antilles.  At 11:00 p.m. EDT on Saturday the center of circulation was located at latitude 13.1°N and longitude 54.3°W which put it about 495 miles (795 km) east-southeast of the Lesser Antilles.  Beryl was moving toward the west-northwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1005 mb.

Tropical Storm Warnings were in effect for Dominica and Guadeloupe.  Tropical Storm Watches were in effect for Saba, St. Eustatius, St. Maarten, Martinique, St. Martin, St. Barthelemy, Barbados and St. Lucia.

Tropical Storm Beryl moved into a region where the easterly winds in the lower level were stronger and the increased vertical wind shear started to blow the lower part of the circulation to the west of the upper part of Beryl.  It also seemed to move into an area of drier air, which caused most of the stronger thunderstorms to weaken.  There was still a well organized circulation in the lower levels, but it weakened on Saturday.  More thunderstorms developed near the center of circulation and on the eastern side of Tropical Storm Beryl in recent hours.  If those storms persist then Beryl could strengthen again, but if they dissipate quickly, then the tropical storm could weaken again on Sunday.

Tropical Storm Beryl will move through an environment that contains factors that are favorable for intensification and other factors that are unfavorable.  Beryl will move over water where the Sea Surface Temperature is near 27°C.  It will move through an area where the lower level winds are stronger and so there will be more vertical wind shear.  There will be areas of moister air within a larger area of drier air.  If the recently developed thunderstorms persist on Sunday, then the Beryl could strengthen again.  However, if the storms dissipate in a few hours, then Tropical Storm Beryl could weaken further.  The small size of the circulation means that rapid changes in intensity can occur.

Tropical Storm Beryl was moving south of the subtropical high over the Atlantic Ocean.  The high was steering Beryl toward the west-northwest and that general motion is forecast to continue for the next several days.  On its anticipated track Tropical Storm Beryl could reach the Lesser Antilles on Sunday night.  There is a lot of uncertainty about how strong Beryl may be when it reaches those islands.

Elsewhere over the Atlantic Ocean Tropical Depression Three spun south of Cape Hatteras.  At 11:00 p.m. EDT on Saturday the center of Tropical Depression Three was located at latitude 32.9°N and longitude 75.1°W which put it about 160 miles (260 km) south of Cape Hatteras, North Carolina.  It was nearly stationary.  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1014 mb.