Tag Archives: U.S. Virgin Islands

Tropical Storm Fred Passes South of Puerto Rico

Tropical Storm Fred was passing south of Puerto Rico on Tuesday night. At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Fred was located at latitude 17.6°N and longitude 66.8°W which put it about 45 miles (75 km) south-southwest of Ponce, Puerto Rico. Fred was moving toward the west at 17 m.p.h. (28 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 1009 mb.

Tropical Storm Warnings were in effect for Puerto Rico including Culebra and Vieques and the U.S. Virgin Islands. A Tropical Storm Warning was also in effect for the portion of the coast from Punta Palenque to Cabo Frances Viejo, Dominican Republic. A Tropical Storm Watch was in effect for the portion of the coast from Cabo Frances Viejo to the northern border with Haiti. A Tropical Storm Watch was in effect for the portion of the coast from Gonaives, Haiti to the northern border with the Dominican Republic. Tropical Storm Watches were also in effect for the Southeastern Bahamas and the Turks and Caicos.

A reconnaissance plane was able to identify a low level center of circulation in a low pressure system previously designated at Potential Tropical Cyclone Six on Tuesday evening and the National Hurricane Center upgraded the system to Tropical Storm Fred. The circulation around Tropical Storm Fred was still organizing. The low level center was about 45 miles (75 km) to the north of the center of circulation in the middle levels. The circulation in the middle levels was moving closer to the low level center. The strongest thunderstorms were occurring on the southern side of the low level center and near the center in the middle levels. Winds to tropical storm force extended out 45 miles (75 km) from the center in the northeastern quadrant of Fred. Winds in the other parts of the circulation were blowing at less than tropical storm force.

Tropical Storm Fred will move through an environment favorable for intensification during the next 12 hours. Fred will move over water where the Sea Surface Temperatures are near 28°C. It will be under a small upper level ridge. The upper level winds in the ridge are weak and there will be little vertical wind shear. Tropical Storm Fred is likely to strengthen during the next 12 hours. The center of Fred will be near the eastern part of the Dominican Republic in about 12 hours. Tropical Storm Fred is likely to weaken on Wednesday while the center is near Hispaniola.

Tropical Storm Fred will move of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Fred toward the west-northwest during the next several days. On its anticipated track Tropical Storm Fred will approach the eastern Dominican Republic in 12 hours. Fred could be over the northern coast of Hispaniola on Wednesday night. Bands in the northern side of Tropical Storm Fred will produce gusty winds and locally heavy rain over Puerto Rico on Tuesday night. Fred could drop heavy rain on parts of the Dominican Republic and Haiti on Wednesday. Heavy rain could cause flash floods in some locations.

Potential Tropical Cyclone Six Prompts Watches for Puerto Rico, U.S. Virgin Islands, Dominican Republic

Potential Tropical Cyclone Six prompted the issuance of Tropical Storm Watches for Puerto Rico, the U.S. Virgin Islands, the Dominican Republic and some of the Lesser Antilles on Monday afternoon. At 5:00 p.m. EDT on Monday the center of Potential Tropical Cyclone Six was located at latitude 14.2°N and longitude 59.2°W which put it about 165 miles (270 km) east-southeast of Dominica. The potential tropical cyclone was moving toward the west-northwest at 15 m.p.h. (24 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. (75 km/h). The minimum surface pressure was 1010 mb.

Tropical Storm Watches were issued for the U.S. Virgin Islands and Puerto Rico including Culebra and Vieques. A Tropical Storm Watch was issued for the coast of the Dominican Republic from Punta Palenque to the northern border with Haiti. Tropical Storm Watches were also issued for Dominica, Guadeloupe and Martinique.

The National Hurricane Center designated a low pressure system east of the Lesser Antilles (formerly designated at Invest 94L) as Potential Tropical Storm Six on Monday afternoon in order to issue the Tropical Storm Watches. The circulation around Potential Tropical Cyclone Six exhibited more organization on Monday. More thunderstorms formed in bands revolving around the center of the low pressure system. Storms near the center of circulation began to generate upper level divergence that pumped mass away from the low pressure system. The removal of mass should allow the surface pressure to decrease.

Potential Tropical Cyclone Six will move through an environment favorable for intensification during the next 24 hours. It will move over water where the Sea Surface Temperatures are near 28°C. The low pressure system will move under a small upper level ridge near the Lesser Antilles. The upper level winds are weak in the ridge and there will be little vertical wind shear. Potential Tropical Cyclone Six could develop into a tropical storm by the time it reaches the Lesser Antilles.

Potential Tropical Cyclone Six will move south of a subtropical high pressure system over the Atlantic Ocean. The high will steer the low pressure system toward the west-northwest during the next several days. On its anticipated track Potential Tropical Cyclone Six will move over the central Lesser Antilles on Monday night. It will bring gusty winds and locally heavy rain. Heavy rain could cause flash floods in some locations. Potential Tropical Cyclone Six could approach Puerto Rico later on Tuesday.

Tropical Storm Karen Drops Heavy Rain on Puerto Rico and the Virgin Islands

Tropical Storm Karen dropped heavy rain on parts of Puerto Rico and the Virgin Islands on Tuesday.  At 2:00 p.m. EDT on Tuesday the center of Tropical Storm Karen was located at latitude 17.5°N and longitude 66.0°W which put it about 65 miles (105 km) south of San Juan Puerto Rico.  Karen was moving toward the north at 8 m.p.h. (13 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 Puerto Rico including Vieques and Culebra, the U.S. Virgin Islands and the British Virgin Islands.

The circulation around Tropical Storm Karen exhibited more organization on Tuesday afternoon.  A new low level center of circulation formed a little farther to the west near a cluster of stronger thunderstorms.  The minimum surface pressure decreased by several millibars.  More thunderstorms formed near the center of circulation and in bands revolving around the center.  Storms near the newly reformed center of circulation were generating more upper level divergence which was pumping mass away from the tropical storm.  The removal of mass was what allowed the surface pressure to decrease.  Winds to tropical storm force extended out about 80 miles (130 km) from the center of circulation.

Tropical Storm Karen will move through an environment favorable for intensification during the next 24 to 48 hours.  Karen will move over water where the Sea Surface Temperature is near 29°C.  Karen has moved under the middle of an upper level ridge over the eastern Caribbean Sea where the upper level winds are weaker.  There will be less vertical wind shear during the next day or two.  The environment around Tropical Storm Karen will support intensification.  However, the center of Karen will pass over Puerto Rico during the next 24 hours.  The mountains in Puerto Rico will disrupt the circulation in the lower levels and Tropical Storm Karen will weaken when it passes over those mountains.  Karen will likely strengthen again when it moves north of Puerto Rico.

Tropical Storm Karen will move around the western end of a subtropical high pressure system over the Atlantic Ocean.  The high will steer Karen toward the north during the next day or two.  On its anticipated track Tropical Storm Karen will move across Puerto Rico during the next 24 hours.  Karen will drop heavy rain on parts of Puerto Rico, the U.S. Virgin Islands and the British Virgin Islands.  Prolonged heavy rain will create a high risk for flash floods in those areas.

Elsewhere over the Atlantic Ocean, Tropical Storm Jerry was moving slowly toward Bermuda and Tropical Storm Lorenzo was strengthening west of the Cabo Verde Islands.  At 2:00 p.m. EDT the center of Tropical Storm Jerry was located at latitude 30.9°N and longitude 69.1°W which put it about 270 miles (435 km) west-southwest of Bermuda.  Jerry was moving toward the north-northeast at 7 m.p.h. (11 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 992 mb.  A Tropical Storm Warning was in effect for Bermuda.

At 11:00 a.m. EDT on Tuesday the center of Tropical Storm Lorenzo was located at latitude 12.4°N and longitude 29.3°W which put it about 270 miles (435 km) west-southwest of the Cabo Verde Islands.  Lorenzo was moving toward the west-northwest 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 997 mb

Tropical Storm Dorian Strengthens, Hurricane Warnings for Virgin Islands

Tropical Storm Dorian strengthened on Wednesday morning and it was on the verge of becoming a hurricane.  Hurricane Warnings were issued for Vieques, Culebra, the U.S. Virgin Islands and the British Virgin Islands. At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Dorian was located at latitude 17.5°N and longitude 64.5°W which put it about 25 miles (40 km) south of St. Croix.  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 999 mb.

Hurricane Warnings were in effect for Vieques, Culebra, the U.S. Virgin Islands, and the British Virgin Islands.  A Tropical Storm Warning and a Hurricane Watch was in effect for Puerto Rico.  A Tropical Storm Watch was in effect for the portion of the coast of the Dominican Republic from Isla Saona to Samana.

The circulation around Tropical Storm Dorian exhibited much greater organization on Wednesday morning.  A ring of strong thunderstorms wrapped almost completely around the center of circulation.  The strongest winds were occurring in the northeastern part of that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Dorian.  Storms near near the core were generating upper level divergence which was pumping mass away to the north and northeast of the tropical storm.  The circulation also increased in size on Wednesday morning.  Winds to tropical storm force extended out about 70 miles (110 km) from the center of circulation.

Tropical Storm Dorian will move through an environment favorable for intensification during the next few days.  Dorian will move over water where the Sea Surface Temperature is near 29°C.  It will move northeast of an upper level low during the next 24 hours.  The low will produce some southerly winds which will blow toward the top of the circulation, but the winds will not be strong enough to prevent intensification.  The wind shear will decrease on Friday and Dorian could strengthen into a major hurricane near the Bahamas.

The upper level low will help to steer Tropical Storm Dorian toward the northwest during the next 24 to 36 hours.  A ridge of high pressure will build north of Dorian on Friday.  The ridge will block Dorian from moving north and it will steer Dorian toward the west-northwest.  On its anticipated track Tropical Storm Dorian will pass over the Virgin Islands near the eastern end of Puerto Rico today.  Dorian will be near the northern Bahamas on Saturday and it could approach the east coast of Florida by Sunday night.  Dorian could be a major hurricane when it approaches the east coast of the U.S.

Elsewhere over the Atlantic Ocean, former Tropical Storm Erin weakened to a tropical depression.  At 11:00 a.m. EDT on Wednesday the center of Tropical Depression Erin was located at latitude 33.6°N and longitude 72.8°W which put it about 190 miles (305 km) southeast of Cape Hatteras, North Carolina.  Erin was moving toward the northwest at 13 m.p.h. (20 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. (75 km/h).  The minimum surface pressure was 1006 mb.

Tropical Storm Dorian Moves Toward Puerto Rico

Tropical Storm Dorian moved toward Puerto Rico on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Dorian was located at latitude 16.0°N and longitude 63.0°W which put it about 275 miles (440 km) east-southeast of Ponce, Puerto Rico.  Dorian was moving toward the northwest at 13 m.p.h. (20 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 1006 mb.

A Hurricane Watch was issued for Puerto Rico.  Tropical Storm Warnings were in effect for Puerto Rico, Culebra, Vieques, the U.S. Virgin Islands and the British Virgin Islands.  A Tropical Storm Watch was issued for the coast of the Dominican Republic from Isla Saona to Puerto Plata.

The original low level center of Tropical Storm Dorian passed south of Barbados and St. Lucia on Tuesday morning.  Dorian dropped heavy rain and there were reports of flash floods on Martinique.  The original center weakened on Tuesday afternoon and a new low level center formed about 60 miles farther to the north.  The formation of a new center of circulation caused the forecast future track of Tropical Storm Dorian to be shifted northward as well.

Even with the formation of a new center of circulation, the overall circulation around Tropical Storm Dorian did not change much on Tuesday.  The circulation around Dorian remained small.  Winds to tropical storm force only extended out about 45 miles (75 km) from the center of circulation.  A broken ring of thunderstorms surrounded the new low level center.  Bands of showers and thunderstorms were revolving the center of Tropical Storm Dorian.  Storms near the center were producing upper level divergence which was pumping mass away to the north of the tropical storm.

Tropical Storm Dorian will move through an environment somewhat favorable for intensification on Wednesday.  Dorian will move over water where the Sea Surface Temperature is near 29°C.  An upper level low northwest of Puerto Rico will produce southerly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, which will inhibit intensification.  A large mass of drier air is north of Tropical Storm Dorian and the drier air could also inhibit intensification if it gets pulled into the circulation around Dorian.  The small size of the circulation around Tropical Storm Dorian means that it could weaken or strengthen quickly if the environmental conditions change significantly.  Dorian is likely to weaken when it crosses Puerto Rico on Wednesday night.

The upper low northwest of Puerto Rico will help to steer Tropical Storm Dorian toward the northwest on Wednesday.  On its anticipated track Tropical Storm Dorian could reach Puerto Rico by Wednesday evening.  Dorian will bring gusty winds and it will drop locally heavy rain on Puerto Rico.  Locally heavy rain could cause flash floods in some locations.  A high pressure system will build north of Tropical Storm Dorian on Thursday and Friday.  The high will turn Dorian back toward the west-northwest.  Dorian could approach the east coast of Florida on Sunday.

Elsewhere over the Atlantic Ocean, Tropical Depression Six strengthened into Tropical Storm Erin southeast of Cape Hatteras on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Erin was located at latitude 31.9°N and longitude 72.1°W which put it about 300 miles (485 km) southeast of Cape Hatteras, North Carolina.  Erin was moving toward the west at 2 m.p.h. (3 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. (65 km/h).  The minimum surface pressure was 1005 mb.  Tropical Storm Erin is forecast to move northeast toward Nova Scotia.

Category 5 Hurricane Maria Bearing Down on Puerto Rico

Category 5 Hurricane Maria was bearing down on Puerto Rico on Tuesday night.  The eye was very near St. Croix.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Maria was located at latitude 17.3°N and longitude 64.7°W which put it about 30 miles (45 km) south-southeast of St. Croix and about 120 miles (190 km) southeast of San Juan, Puerto Rico.  Maria was moving toward the west-northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 175 m.p.h. (280 km/h) and there were wind gusts to 215 m.p.h. (345 m/h).  The minimum surface pressure was 909 mb.

Hurricane Warnings were in effect for Puerto Rico, Culebra, Vieques, the U.S. Virgin Islands, the British Virgin Islands, and for the portion of the coast from Cabo Engano to Puerto Plata, Dominican Republic.  Hurricane Watches were in effect for the Turks and Caicos, the Southeastern Bahamas, Saba, St. Maarten, St. Martin, St. Eustatius, St. Barthelemy, and the portion of the coast from Isla Saona to Cabo Engano, Dominican Republic.  Tropical Storm Warnings were in effect for Saba, St. Eustatius, St. Maarten, the portion of the coast from Puerto Plata,, Dominican Republic to the northern border with Haiti and for the portion of the coast from Cabo Engano to Punta Palenque, Dominican Republic,

Hurricane Maria is a very well organized powerful hurricane.  It has a small inner eye and a second outer eyewall extends most of the way around the inner eyewall.  The strongest winds are occurring in the inner eyewall.  Additional spiral bands are revolving around the core of the circulation.  The concentric eyewalls have caused the circulation of Hurricane Maria to increase in size.  Winds to hurricane force now extend out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extend out about 160 miles (260 km) from the center.

The Hurricane Intensity Index (HII) for Hurricane Maria is 40.4.  The Hurricane Size Index (HSI) is 19.2 and the Hurricane Wind Intensity Size Index (HWISI) is 59.6.  Those indices indicate that Hurricane Maria is capable of causing regional catastrophic damage.

Hurricane Maria will continue to move through an environment favorable for powerful hurricanes until it reaches Puerto Rico.  Maria will move over water where the Sea Surface Temperature is near 29°C.  The upper level winds are weak and there is little vertical wind shear.  If the outer eyewall completely encircles the inner eyewall, then an eyewall replacement cycle could cause some weakening.  Hurricane Maria will weaken more if the center moves directly over Puerto Rico.  The amount of weakening will depend on the stage of the eyewall replacement cycle at the time of landfall.

Hurricane Maria is being steered toward the west-northwest by the subtropical high pressure system over the Atlantic Ocean.  The western end of the high is forecast to weaken during the next several days.  The weakening of the high will allow Hurricane Maria to move more toward the north.  The core of Hurricane Maria will pass near or over St. Croix during the next few hours.  On its anticipated track Hurricane Maria will reach Puerto Rico on Wednesday morning.

Hurricane Maria is a very dangerous hurricane.  It is capable of causing catastrophic damage.  Maria will also drop very heavy rain over Puerto Rico and there is the potential for significant flash flooding.  Maria could also cause a storm surge of up to 12 feet (4 meters) along the coast.

Elsewhere, Hurricane Jose weakened to a tropical storm east of the U.S.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Jose was located at latitude 37.9°N and longitude 70.8°W which put it about 230 miles (375 km) south of Nantucket.  Jose was moving toward the northeast at 9 m.p.h. (15 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 973 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Woods Hole to Sagamore Beach, Massachusetts including Block Island, Martha’s Vineyard, Nantucket and Cape Cod.  A Tropical Storm Watch was in effect for the portion of Long Island from Fire Island Inlet to Port Jefferson.

Hurricane Maria Strengthens to Cat. 5 Near Leeward Islands

Hurricane Maria quickly strengthened to a Category 5 hurricane on the Saffir-Simpson Scale on Monday.  At 8:00 p.m. EDT on Monday the center of Hurricane Maria was located at latitude 15.3°N and longitude 61.1°W which put it about 15 miles (25 km) east-southeast of Dominica.  Maria was moving toward the west-northwest at 9 m.p.h. (15 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 925 mb.

Hurricane Warnings were in effect for Puerto Rico, Culebra, Vieques, Dominica, Guadeloupe, St. Kitts, Nevis, Martinique, Montserrat, the U.S. Virgin Islands and the British Virgin Islands.  Hurricane Watches were in effect for Saba, St. Eustatius, St. Maarten, Anguilla, St. Martin, St. Barthelemy and the portion of the coast from Isla Saona to Puerto Plata, Dominican Republic.  Tropical Storm Warnings were in effect for Anguilla, St. Lucia, Antigua, Barbuda, Saba, St. Eustatius and St. Maarten.  Tropical Storm Watches were in effect for St. Vincent, the Grenadines and the portion of the coast from Puerto Plata to the Haiti/Dominican Republic border.

Hurricane Maria has a tight compact circulation.  There is a small eye with a diameter of 10 miles (16 km) at the center of circulation.  The eye is surround by a ring of strong thunderstorms and the strongest winds are occurring in that ring of storms.  Additional bands of showers and thunderstorms are revolving around the core of Maria.  The overall circulation of Hurricane Maria is small.  Winds to hurricane force only extend out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force only extend out about 125 miles (200 km) from the center.

The Hurricane Intensity Index (HII) for Hurricane Maria is 35.0.  The Hurricane Size Index (HSI) is 9.1 and the Hurricane Wind Intensity Size Index (HWISI) is 44.1.

Hurricane Maria will continue to move through an environment very favorable for strong hurricanes.  Maria will move over water where the Sea Surface Temperature is near 29°C.  The upper level winds are weak and there is little vertical wind shear.  Hurricane Maria could strengthen further.  Since the eye of Hurricane Maria is so small, it would be easy for a rainband to wrap around the eye.  If that happens, then an eyewall replacement cycle could begin and the cycle could result in a temporary weakening of the hurricane.

Hurricane Maria is being steered to the west-northwest by the subtropical high pressure system over the Atlantic Ocean.  That high is forecast to weaken and Maria is likely to move more toward the northwest during the next several days.  On its anticipate track the center of Hurricane Maria will pass very close to Dominica and Guadeloupe on Monday night.  Maria could pass near Montserrat, St. Kitts and Nevis on Tuesday.  It could be near the U.S. Virgin Islands on Tuesday night and Hurricane Maria will approach Puerto Rico on Wednesday.

Hurricane Maria is a small but very dangerous hurricane.  The winds in the core of Hurricane Maria are capable of causing extensive damage.  In addition, heavy rain falling over steep terrain will likely produce flash floods.  Hurricane Maria will affect some of the same islands that were severely damaged by Hurricane Irma.  Maria will significantly hamper efforts in some places to recover from the effects of Hurricane Irma.

Elsewhere over the Atlantic Ocean, Hurricane Jose has begun the transition to an extratropical cyclone as it moves northward off the east coast of the U.S.  At 5:00 p.m. EDT on Monday the center of Hurricane Jose was located at latitude 34.8°N and longitude 71.1°W which put it about 445 miles (720 km) south of Nantucket, Massachusetts.  Jose was moving toward the north at 10 m.p.h. (16 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 977 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Watch Hill, Rhode Island to Hull, Massachusetts including Block Island, Martha’s Vineyard and Nantucket.  Tropical Storm Watches were in effect for the portion of the coast of Long Island from Fire Island Inlet to Port Jefferson and from New Haven, Connecticut to Watch Hill, Rhode Island.

The structure of Hurricane Jose began to change on Monday from the more circular shape of a purely tropical hurricane to an asymmetrical shape seen more commonly in extratropical cyclones.  Drier air wrapped around the western and southern sides of the circulation.  Most of the strong thunderstorms and heavy rain were occurring in the northern half of Jose.  Winds to hurricane force extended out about 60 miles (95 km) north of the center, but there were few if any winds to hurricane force south of the center.  The circulation of Hurricane Jose is much larger than the circulation of Hurricane Maria.  Winds to tropical storm force extend out about 320 miles (515 km) from the center of Jose.

The Hurricane Intensity Index for Hurricane Jose was 10.4.  The Hurricane Size Index for Jose was 15.6 and the Hurricane Wind Intensity Size Index was 26.0.

Hurricane Jose will move into an environment that is unfavorable for hurricanes on Tuesday.  Jose will stay over warm Sea Surface Temperatures until it moves north of the Gulf Stream.  Once Jose moves north of latitude 38°N, it will start to move over cooler water.  An upper level trough over the eastern U.S. is producing southerly winds which are causing moderate vertical wind shear over Jose.  Cooler water and moderate shear would normally cause a hurricane to weaken.  However, as Hurricane Jose makes the transition to an extratropical cyclone, it will start to be powered by the temperature difference between warm and cold air.  The transition to an extratropical cyclone can sometimes produce a stronger storm when it occurs.

Hurricane Jose is moving around the western end of the subtropical high.  Another surface high pressure system is forecast to move north of Jose when the hurricane approaches the northeastern U.S.  The second high will block the northward motion and it will force Hurricane Jose to move toward the east.  Some models are forecasting that Jose could make a clockwise loop southeast of Cape Cod.  Hurricane Jose could bring gusty winds and high waves to sections of the coast in the northeastern U.S. during the next few days.

Maria Becomes a Hurricane, Jose Prompts Watches for Northeast U.S.

A reconnaissance plane found that Tropical Storm Maria had intensified into a hurricane as it moved toward the Leeward Islands on Sunday afternoon.  At the same time Hurricane Jose moved farther north and Tropical Storm Watches were issued for the coast of the northeastern U.S.  At 5:00 p.m. EDT on Sunday the center of Hurricane Maria was located at latitude 13.8°N and longitude 57.5°W which put it about 275 miles (445 km) east-southeast of Dominica.  Maria was moving toward the west-northwest 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. (150 km/h).  The minimum surface pressure was 982 mb.

Hurricane Warnings were in effect for Guadeloupe, Dominica, St. Kitts, Nevis and Montserrat.  Hurricane Watches were in effect for the U.S. Virgin Islands, the British Islands, Saba, St. Eustatius, St. Maarten, St. Martin, St. Barthelemy, and Anguilla.  Tropical Storm Warnings were in effect for Martinique, St. Lucia, Antigua, Barbuda, Saba, and St. Eustatius.  Tropical Storm Watches were in effect for Barbados, St. Vincent and the Grenadines.

A reconnaissance plane found sustained winds to hurricane force when it investigated Hurricane Maria on Sunday afternoon.  The plane reported a circular eye with a diameter of 32 miles (52 km) at the center of circulation.  The eye was surrounded by an almost complete ring of thunderstorms.  The ring was broken south of the center.  The strongest winds wind occurring in that ring of thunderstorms.  Additional bands of showers and thunderstorms were developing in the eastern half of the circulation.  There were fewer showers and thunderstorms in the western half of Maria.  Hurricane Maria was generating upper level divergence which was pumping away mass and allowing the surface pressure to decrease.

Hurricane Maria will move through an environment that will be favorable for intensification.  Maria will move over water where the Sea Surface Temperature is near 29°C.  An upper level low over Caribbean Sea is causing southern winds which are blowing near the eastern side of Hurricane Maria.  Those winds do not appear to be causing significant vertical wind shear.  Hurricane Maria is likely to continue to intensify as it moves toward the Leeward Islands.  Maria could intensify rapidly once a fully closed eye develops.

Hurricane Maria is being steered toward the west-northwest by the subtropical high pressure system over the Atlantic Ocean and that general motion is expected to continue for several more days.  On its anticipated track Hurricane Maria could reach the Leeward Islands by later on Monday.  Maria could be near Puerto Rico by Wednesday.  Hurricane Maria will affect some of the same islands damaged by Hurricane Irma a few days ago.  Strong winds and heavy rain will significantly impact recovery efforts in those areas.

A reconnaissance plane also found that Hurricane Jose was stronger on Sunday afternoon.  At 5:00 p.m. EDT on Sunday the center of Hurricane Jose was located at latitude 31.5°N and longitude 71.8°W which put it about 335 miles (535 km) southeast of Cape Hatteras, North Carolina.  Jose was moving toward the north at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 90 m.p.h. (150 km/h) and there were wind gusts to 105 m.p.h. (170 km/h).  The minimum surface pressure was 967 mb.

Tropical Storm Watches have been issued for the portions of the coast from Fenwick Island, Delaware to Sandy Hook, New Jersey and from East Rockaway Inlet, New York to Plymouth, Massachusetts including Long Island Sound, Block Island, Martha’s Vineyard and Nantucket.

Hurricane Jose strengthened on Sunday as it moved over water where the Sea Surface Temperature was near 29°C.  An eye appeared at times on visible satellite imagery.  The circulation of Hurricane Jose increased in size which often happens when hurricanes move north out of the tropics.  Winds to hurricane force extended out about 60 miles (95 km) from the center of circulation.  Winds to tropical storm force extended out about 290 miles (470 km) from the center.

Hurricane Jose will move through an environment which will be marginal for further intensification.  Jose will move over water which is warm enough to support intensification.  However, an upper level trough over the eastern U.S. is producing southerly winds which are blowing toward the top of the circulation.  Those winds are producing strong vertical wind shear and they could weaken Jose during the next several days.  Jose will be moving over warm water until it gets north of the Gulf Stream.  If the upper level winds slow, then Jose could get stronger.

Hurricane Jose is being steered northward by the subtropical high over the Atlantic Ocean and the trough over the eastern U.S.  On its anticipated track the center of Jose is forecast to move toward the northeastern U.S. and turn toward the east before it reaches the coast.  If Jose follows the forecast track, then the core of the hurricane would remain offshore.  However, the circulation of Jose is large enough that even if the center stays offshore, there could still be tropical storm force winds along the coast.

Hurricane Irma Strengthens to Cat. 4, Watch in effect for Puerto Rico

Hurricane Irma strengthened to Category 4 on the Saffir-Simpson Scale on Monday and a Hurricane Watch was issued for Puerto Rico and the U.S. Virgin Islands.  At 5:00 p.m. EDT on Monday the center of Hurricane Irma was located at latitude 16.7°N and longitude 54.4°W which put it about 490 miles (790 km) east of the Leeward Islands.  Irma was moving toward the west at 13 m.p.h. (20 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 944 mb.

Hurricane Warnings are in effect for Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius, St. Maarten, St. Martin, and St. Barthelemy.  Hurricane Watches are in effect for Guadeloupe, the British Virgin Islands, the U.S. Virgin Islands, Puerto Rico, Vieques and Culebra.  A Tropical Storm Warning is in effect for Guadeloupe.  A Tropical Storm Watch is in effect for Dominica.

The circulation of Hurricane Irma has been going through a series of eyewall replacement cycles.  A plane flying through Irma reported concentric eyewalls earlier today.  The two eyewalls appear to have merged.  A small circular eye is at the center of circulation.  A ring of strong thunderstorms surrounds the eye and the strongest winds are occurring in that ring of storms.  Additional bands of showers and thunderstorms are revolving around the core of Hurricane Irma.  Storms around the center are generating strong upper level divergence which is pumping away mass in all directions from the hurricane.

Hurricane Irma has been increasing in size.  Winds to hurricane force extend out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extend out about 140 miles (225 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Irma is 25.1.  The Hurricane Size Index (HSI) is 13.6.  The Hurricane Wind Intensity Size index (HWISI) is 38.7.

Hurricane Irma will move through an environment very favorable for tropical cyclones.  Irma will move over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Hurricane Irma could strengthen further and it has a chance to reach Category 5 on the Saffir-Simpson Scale.  Hurricane Irma is likely to go through additional eyewall replacement cycles, which will cause fluctuations in its intensity, but Irma should remain a strong hurricane as it nears the northern Leeward Islands.

The subtropical high pressure system over the Atlantic Ocean has been steering Hurricane Irma toward the west and that general motion is expected to continue for another 12 to 24 hours.  After that time Irma is expected to turn more toward the west-northwest.  On its anticipated track Hurricane Irma will approach the northern Leeward Islands late on Tuesday.  Hurricane Irma could approach Puerto Rico on Wednesday.

Hurricane Irma Moves Toward Leeward Islands, Watches Issued

Hurricane Irma moved toward the northern Leeward Islands on Sunday and Hurricane Watches were issued for a number of those islands.  At 11:00 p.m. EDT on Sunday the center of Hurricane Irma was located at latitude 17.2°N and longitude 51.0°W which put it about 710 miles (1145 km) east of the Leeward Islands.  Irma was moving toward the west-southwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 140 m.p.h. (225 km/h).  The minimum surface pressure was 961 mb.

Hurricane Watches were in effect for Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius, St. Maarten, St, Martin, and St. Barthelemy.

The circulation of Hurricane Irma is very well organized.  There is a nearly circular eye with a diameter of 30 miles (48 km) at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in the northeastern part of the ring.  Bands of showers and thunderstorms are revolving around the core of Hurricane Irma.  Thunderstorms around the core are generating strong upper level divergence which is pumping mass away in all directions from the hurricane.  Winds to hurricane force extend out about 35 miles (55 km) from the center.  Winds to tropical storm force extend out about 140 miles (225 km) from the center.

The Hurricane Intensity Index (HII) for Hurricane Irma is 20.6.  The Hurricane Size Index (HSI) is 11.7 and the Hurricane Wind Intensity Size Index (HWISI) is 32.3.

Hurricane Irma will move through an environment favorable for intensification.  Irma will move over water where the Sea Surface Temperature is near 29°C and there is warmer water farther west.  The upper level winds are weak and there is little vertical wind shear.  Hurricane Irma could intensify into a Category 4 hurricane on the Saffir-Simpson Scale.  There is a possibility that Irma could strengthen to Category 5 when it passes near the northern Leeward Islands and moves toward the Bahamas.  Hurricane Irma has already completed several eyewall replacement cycles and there could be more.  Each eyewall replacement cycle could result in fluctuations in the intensity of Hurricane Irma.

A strong subtropical high pressure system over the Atlantic Ocean is steering Hurricane Irma toward the west-southwest.  The high is forecast to weaken just a bit during the next several days and Hurricane Irma is expected to move more toward the west-northwest.  On its anticipated track Hurricane Irma will approach the northward Leeward Islands on Tuesday night.  It will be a strong, dangerous hurricane at that time.