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Powerful Major Hurricane Nicole Nearing Bermuda

Hurricane Nicole intensified into a powerful major hurricane late on Thursday as it moved closer to Bermuda.  At 11:00 p.m. EDT on Thursday the center of Hurricane Nicole was located at latitude 30.1°N and longitude 66.4°W which put it about 180 miles (290 km) south-southwest of Bermuda.  Nicole was moving toward the north-northeast at 12 m.p.h. (19 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 950 mb.  Nicole is a Category 4 hurricane on the Saffir-Simpson Scale.  A Hurricane Warning is in effect for Bermuda.

Hurricane Nicole intensified very rapidly during the past 12 hours.  The maximum sustained wind speed increased from 100 m.p.h. (160 km/h) to 130 m.p.h. (215 km/h) during that time period.  The minimum surface pressure decreased from 970 mb to 950 mb at the same time.  Hurricane Nicole now has a large circular eye with a diameter of 35 m.p.h. (55 km).  Hurricane Nicole also increased in size as it intensified.  Winds to hurricane force now extend out 65 miles (105 km) from the center of circulation.  Wind to tropical storm force extend out 160 miles (260 km) from the center.

Nicole is a large powerful hurricane. The Hurricane Intensity Index (HII) is 25.1.  The Hurricane Size Index (HSI) is 20.6 and the Hurricane Wind Intensity Size Index (HWISI) is 45.7.  The indices indicate that Hurricane Nicole is capable of causing widespread significant wind damage.

Southwesterly winds on the eastern side of a upper level trough will steer Hurricane Nicole toward the northeast.  When Nicole moves further north, westerly winds will steer it more toward the northeast.  On its anticipated track the core of Hurricane Nicole will reach Bermuda on Thursday morning.  Nicole has the potential to be a very destructive hurricane.

Nicole Strengthens Into a Hurricane, Warning for Bermuda

Tropical Storm Nicole intensified into a hurricane on Tuesday afternoon and a Hurricane Warning was issued for Bermuda.  At 5:00 p.m. EDT on Tuesday the center of Hurricane Nicole was located at latitude 27.4°N and longitude 66.4°W which put it about 350 miles (565 km) south-southwest of Bermuda.  Nicole was moving toward the northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (155 km/h).  The minimum surface pressure was 980 mb.

The organization of the circulation of Hurricane Nicole improved rapidly on Tuesday afternoon.  The primary rainband wrapped around the center of circulation and an eye developed.  The eye currently has a diameter of about 30 miles (48 km).  A ring of strong thunderstorms surrounds the eye.  Those thunderstorms are producing well developed upper level divergence which is pumping out mass in all directions.  Additional rainbands are developing in the rest of the circulation.  Nicole is a relatively small hurricane.  Hurricane force winds only extend out about 35 miles (55 km) from the center and tropical storm force winds on extend out about 120 miles (195 km) from the center.

The environment around Hurricane Nicole became much more favorable on Tuesday afternoon.  The winds in the upper level weakened and the vertical wind shear diminished.  The weaker upper level winds also allowed the upper level divergence to pump out more mass and the pressure decreased 10 mb in six hours on Tuesday afternoon.  Less vertical wind shear allowed Hurricane Nicole to extract energy more efficiently from the ocean.  Hurricane Nicole is moving over water where the Sea Surface Temperature is near 28.5°C.  Nicole is likely to intensify for another 36 to 48 hours.  So, Hurricane Nicole will continue to intensify and it could intensify rapidly.  Nicole could be a major hurricane by the time it nears Bermuda.

Nicole is moving around the western end of a subtropical high pressure system which is steering the hurricane toward the northwest.  When Hurricane Nicole reaches the western end of the high, it will turn more toward the north.  As Hurricane Nicole moves farther north, the westerly winds in the middle latitudes will turn it toward the northeast.  On its anticipated track, Hurricane Nicole could approach Bermuda on Thursday morning.  It could be a major hurricane at that time.

Tropical Storm Nicole Prompts Hurricane Watch for Bermuda

While water rescues continued in parts of North Carolina and recovery efforts accelerated after the passage of Hurricane Matthew, Tropical Storm Nicole prompted the issuance of a Hurricane Watch for Bermuda.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Nicole was located at latitude 26.3°N and longitude 65.4°W which put it about 415 miles (670 km) south of Bermuda.  Nicole was moving toward the north at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 992 mb.

After becoming a hurricane last Thursday Nicole weakened back to a tropical storm during the weekend.  A combination of intermittent vertical wind shear and drier air caused the structure of Tropical Storm Nicole to deteriorate.  The eye disappeared and the thunderstorms in the rainbands weakened.  There appears to be a remnant of the eyewall, but it only consists of lower clouds and showers.  Several rainbands exist around the circulation, although they are not as strong as they were a few days ago.  Thunderstorms southeast of the center of circulation seem to have increased on Monday afternoon.  The new thunderstorms are generating some upper level divergence but it is not currently well developed.

Tropical Storm Nicole is an environment that is marginal for intensification.  An upper level trough north of Nicole is generating some vertical wind shear.  In addition cooler, drier air has moved close to the western part of the circulation of Tropical Storm Nicole.  On the other hand, Tropical Storm Nicole is moving over water where the Sea Surface Temperature is near 29°C.  So, there is plenty of energy in the upper ocean.  The vertical wind shear and drier air could prevent Tropical Storm Nicole from intensifying much on Tuesday.  The upper level trough will move off to the east and the vertical wind shear could decrease during the middle of the week.  If the shear diminishes and not much drier air gets pulled into the circulation, then Tropical Storm Nicole has a chance to intensify into a hurricane.

A high pressure system blocked the northward movement of Tropical Storm Nicole and the high even pushed Nicole toward the south at times during the weekend.  The high appears to be moving farther to the east, which is allowing Tropical Storm Nicole to move slowly toward the north.  As the high pressure system shifts to the east, it will start to steer Tropical Storm Nicole more toward the northwest.  When Nicole reaches the western end of the high, it will turn toward the northeast.  The westerly winds in the middle latitudes will accelerate Nicole toward the northeast later this week.  On its anticipated track the center of Tropical Storm Nicole could pass near Bermuda on Thursday.