Tag Archives: Bermuda

Low Pressure Develops East of the Bahamas

An area of low pressure developed east of the Bahamas and the system was designated as Invest 90L on Sunday afternoon.  At 5:00 p.m. EDT on Sunday the center of Invest 90L was located at latitude 24.0°N and longitude 71.0°W which put it about 260 miles (420 km) east of the Bahamas.  Invest 90L was moving toward the northwest at 11 m.p.h. (17 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.

The circulation of Invest 90L consists of a large asymmetrical low pressure system.  Most of the showers and thunderstorms are occurring northeast of the center of circulation.  Those showers and thunderstorms are being generated by convergence of winds from a large high pressure system over the north Atlantic Ocean into the area of low pressure.  A swirl of low clouds has emerged on the southwestern side of the low, but it is unclear if this is the actual center of circulation or is just a transient mesoscale feature.  A strong pressure gradient between the high pressure system and the low is producing an area of winds to tropical storm force northeast of the center of the low.  The winds are weaker in other parts of the circulation.

Invest 90L is in an environment that is mostly unfavorable for tropical cyclones.  It is moving over water where the Sea Surface Temperature is near 25°C.  So, there is less energy in the upper ocean to support tropical development.  An upper level trough over the southeastern U.S. is producing strong southwesterly winds which are blowing across the top of Invest 90L.  Those winds are producing strong vertical wind shear.  Marginal Sea Surface Temperatures and strong vertical wind shear make the classical development of a tropical cyclone unlikely.  However, the temperature in the upper troposphere is also cold and there may be enough instability in the atmosphere to produce thunderstorms.  If the wind shear decrease, then more thunderstorms could develop closer to the center of circulation and a subtropical cyclone could form.

The high over the north Atlantic is blocking northward movement of Invest 90L and the high is steering it toward the northwest.  A general northwesterly motion is expected to continue for another day or so.  Eventually the high will move off to the east and Invest 90L will start to move toward the northeast.  On its anticipated track Invest 90L will stay east of the U.S. and the Bahamas.  Invest 90L could pass close to Bermuda and it has the potential to bring gusty winds.

Hurricane Nicole Bringing Strong Winds and Heavy Rain to Bermuda

Hurricane Nicole is bringing strong winds and heavy rain to Bermuda on Thursday morning.  At 11:00 a.m. EDT on Thursday the center of Hurricane Nicole was located at latitude 32.3°N and longitude 64.6°W which put it about 10 miles (15 km) east of Bermuda.  Nicole was moving toward the northeast at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 140 m.p.h. (225 km/h).  The minimum surface pressure was 961 mb.  A Hurricane Warning remains in effect for Bermuda.

Nicole is a large powerful hurricane.  Winds to hurricane force extend out about 65 miles (105 km) from the center of circulation.  Winds to tropical storm force extend out about 180 miles (290 km) from the center.  The diameter of the eye is approximately 35 miles (55 km).

A weather station on Pearl Island reported sustained winds to 87 m.p.h. (141 km/h) with wind gusts to 119 m.p.h. (191 km/h).  An elevated weather station at Commissioner’s Point reported sustained winds to 92 m.p.h. (148 km/h) and wind gusts to 122 m.p.h. (196 km/h).

Hurricane Nicole is moving toward the northeast at 16 m.p.h. (26 km/h).  So, it will take approximately two hours for the eye of Hurricane Nicole to move across Bermuda.  After the eye passes, hurricane force winds in the southern half of Nicole will affect Bermuda.  The winds should gradually diminish later today when Hurricane Nicole moves northeast of Bermuda.

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.

Tropical Storm Karl Approaching Bermuda

Tropical Storm Karl continued to move steadily toward Bermuda on Friday.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Karl was located at latitude 29.9°N and longitude 65.1°W which put it about 165 miles (270 km) south of Bermuda.  Karl was moving toward the north at 13 m.p.h. (20 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 988 mb.

A Hurricane Watch has been issued for Bermuda.  A Tropical Storm Warning is also in effect for Bemruda.

Tropical Storm Karl strengthened on Friday, but its structure remained asymmetrical.  Almost all of the thunderstorms are in a primary rainband that wraps around the northern and western sides of the center of circulation.  There are few if any thunderstorms south and east of the center.  It appears as it vertical wind shear is tilting the circulation toward the northwest.  The upper level center appears to be located 20 to 30 miles (30 to 50 km) northwest of the low level center.  The thunderstorms in the primary rainband are producing upper level divergence which is pumping out mass to the east of Tropical Storm Karl.  The upper level divergence pumped out enough mass on Friday to allow the surface pressure to decrease by about 10 mb.  However, the vertical wind shear and lack of thunderstorms to the east of the center limited the increase in wind speed at the surface.

Tropical Storm Karl is moving over water where the Sea Surface Temperature is near 29°C.  So, there is enough energy in the upper ocean to support a stronger storm.  However, an upper level trough to the west of Karl is creating significant vertical wind shear, which is likely to limit intensification in the short term.  When Tropical Storm Karl, turns east and moves farther from the upper level trough, the shear could decrease and Karl could strengthen.  In addition Karl will begin a transition to an extratropical cyclone and that transition often produces and increase in the wind speed.  So, Tropical Storm Karl does have a chance to become a hurricane during the weekend.

Tropical Storm Karl is moving around the western end of a subtropical ridge which is steering it toward the north.  It is likely to keep moving in that direction for another six to twelve hours.  When Tropical Storm Karl nears Bermuda it will encounter stronger westerly winds which will turn it eastward.  Karl is likely to move quickly toward the east-northeast on Saturday and Sunday.  On its anticipated track Tropical Storm Karl will pass near Bermuda on Saturday morning.  It will bring a period of gusty winds and heavy rain.

Karl Becomes a Tropical Storm Again and Warning Issued for Bermuda

Reconnaissance aircraft investigating Tropical Depression Karl on Thursday afternoon found that it had intensified into a tropical storm again and a Tropical Storm Warning was issued for Bermuda.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Karl was located at latitude 25.5°N and longitude 63.2°W which put it about 480 miles (770 km) south-southeast of Bermuda.  Karl was moving toward the northwest at 16 m.p.h. (26 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 1005 mb.

The structure of Tropical Storm Karl became more organized on Thursday, but the circulation is not well organized.  Most of the thunderstorms are occurring in a primary rainband that spirals around the eastern and northern portions of the circulation.  There are other fragmented rainbands farther to the east of the center of circulation.  There are few thunderstorms or bands south and west of the center and there may be drier air in that part of Tropical Storm Karl.  Thunderstorms in the primary rainband were beginning to generate some upper level divergence.

Tropical Storm Karl is moving into an environment that is more favorable for intensification.  Karl is moving farther away from an upper level low that is west of the the tropical storm.  As the distance between Tropical Storm Karl and the upper low increases, the vertical wind shear will decrease.  Karl is moving over water where the Sea Surface Temperature is near 30°C.  Tropical Storm Karl is likely to intensify slowly until the primary rainband wraps around the center of circulation.  If a tight inner core develops at the center of Karl, then it could intensify more quickly after that happens.

Tropical Storm Karl is moving around the western end of a subtropical high pressure system.  The high is steering Karl in a generally northwesterly direction.  Karl is likely to move more toward the north as it goes around the western end of the high.  When Karl gets northwest of the axis of the high pressure system, the westerly winds in the middle latitudes will start to turn it more toward the northeast.  On its anticipated track, Tropical Storm Karl could be near Bermuda in about 36 hours.  Tropical Storm Karl could bring wind and rain to Bermuda during the weekend.

 

Tropical Storm Lisa Develops West of the Cape Verde Islands

Tropical Depression Thirteen intensified into Tropical Storm Lisa west of the Cape Verde Islands on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Lisa was located at latitude 16.4°N and longitude 31.0°W which put it about 465 miles (750 km) west of the Cape Verde Islands.  Lisa was moving toward the northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1004 mb.

The degree of organization of the circulation of Tropical Storm Lisa depends on the level of the atmosphere.  The low level circulation is not well organized.  There is a broad center of circulation, but it does not have a tight core of thunderstorms.  Most of the thunderstorms are east of the center of circulation.  There are also several fragmented rainbands in the eastern half of the circulation.  There are only lower clouds and a few showers in the western half of the circulation.  However, the circulation is more well organized in the upper levels.  The thunderstorms in the eastern half of the circulation are generating upper level divergence which is pumping out mass toward the northeast and toward the northwest.  It appears that the circulation could be tilted toward the northeast with height.

The environment around Tropical Storm Lisa is marginal for intensification.  Lisa is moving over water where the Sea Surface Temperature (SST) is near 28°C.  However, an upper level trough north of Lisa is producing southwesterly winds which are blowing across the tropical storm.  The winds are causing moderate vertical wind shear, which probably contributed to the asymmetrical distribution of thunderstorms.  Tropical Storm Lisa could intensify somewhat on Wednesday, if the upper level winds diminish.  When Lisa moves farther north later this week, it will move over cooler SSTs and into a region where the upper level winds are stronger.  Less energy in the upper ocean and more vertical wind shear will cause Tropical Storm Lisa to weaken later this week.

Tropical Storm Lisa is moving northwest toward a section of the subtropical ridge which is weaker.  Lisa is expected to continue to move in that general direction for the next several days.  Tropical Storm Lisa will move farther into the middle of the Atlantic Ocean and it will not threaten any land areas this week.

Tropical Storm Karl Intensifies a Little

After several days when Tropical Storm Karl was poorly organized and barely maintained tropical storm intensity, Karl intensified a little late on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Karl was located at latitude 19.7°N and longitude 50.5°W which put it about 760 miles (1225 km) east-northeast of the Leeward Islands.  Karl was moving toward the west-northwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1005 mb.

Although the structure of Tropical Storm Karl improved a little during the past few hours, it is still not a well organized storm.  A cluster of thunderstorms (sometimes called a Central Dense Overcast or CDO) formed near the core of Tropical Storm Karl.  Additional thunderstorms developed in fragmented rainbands, which are primarily in the eastern half of the circulation.  The cluster of thunderstorms near the core of the circulation is beginning to generate upper level divergence.

Tropical Storm Karl is moving into a more favorable environment.  It is moving over water where the Sea Surface Temperature (SST) is near 28°C.  An upper level low to the west of Karl has been causing strong vertical wind shear over the top of the tropical storm.  However, the upper low is moving farther west of Karl and the vertical wind shear is lessening.  Warm SSTs and less vertical wind shear allowed Tropical Storm Karl to begin to get a little better organized.  Karl is likely to intensify slowly while the circulation organizes and a more well define structure develops.  Tropical Storm Karl will move over warmer SSTs during the next few days and it is forecast to become a hurricane later this week.

Tropical Storm Karl is moving around the southwestern portion of a subtropical ridge which is steering it toward the west-northwest.  Karl is likely to turn more toward the northwest during the next several days.  On its anticipated track Tropical Storm Karl is likely to move northeast of the Leeward Islands and head in the general direction of Bermuda.

Tropical Storm Karl Develops over the Eastern Atlantic

More thunderstorms developed near the center of Tropical Depression 12 and the National Hurricane Center named it Tropical Storm Karl on Thursday night.  Karl is the third tropical storm to form over the Atlantic Ocean this week.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Karl was located at latitude 17.9°N and longitude 32.5°W which put it about 1930 miles (3150 km) east of the Leeward Islands.  Karl was moving toward the west at 14 m.p.h.  The maximum sustained wind speed was 45 m.p.h. (70 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 1005 mb.

The circulation of Tropical Storm Karl is asymmetrical.  Karl does have a large circular low level wind fields.  However the thunderstorms are northeast of the center of circulation, although some thunderstorms have developed closer to the northeast side of the center in recent hours.  Southwesterly winds in the upper levels are generating moderate vertical wind shear, which has contributed to the asymmetrical distribution of thunderstorms.  In addition, the upper level winds are inhibiting upper level divergence to the west of Tropical Storm Karl.

Tropical Storm Karl is moving through an environment that is not very favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 27°C.  There is moderate vertical wind shear, which will make it hard for thunderstorms to persist near the center of the tropical storm.  Karl could move into an area where the upper level winds are not as strong in a day or two.  The environment could be more favorable for intensification at that time.

A subtropical ridge north of Karl is steering the tropical storm toward the west.  The ridge is expected to get stronger and it should steer Tropical Storm Karl toward the west or west-southwest during the next few days.