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.