A low pressure system associated with former Tropical Storm Beryl reorganized north of Bermuda on Saturday and the National Hurricane Center designated the system as Subtropical Storm Beryl. At 2:00 p.m. EDT on Saturday the center of Subtropical Storm Beryl was located at latitude 36.4°N and longitude 65.7°W which put it about 575 miles (930 km) south-southwest of Halifax, Nova Scotia. Beryl was moving toward the northeast at 12 m.p.h. (19 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 1010 mb.
The remnants of former Tropical Storm Beryl moved slowly across the northern Caribbean Sea and then over the southeastern Bahamas to a position northwest of Bermuda. A low pressure system formed at the surface. Bands of showers and thunderstorms developed and began to revolve around the the low pressure system. The low pressure system moved under the eastern side of an upper level trough. The trough contains colder air in the upper levels and it was also producing southwesterly winds which were blowing toward the top of the surface low pressure system. The southwesterly winds were generating moderate vertical wind shear and the strongest rainbands were occurring on the eastern side of the surface low. Some drier air was moving around the western and southern part of the upper level trough, which may have contributed to the weaker bands on the western side of the circulation. The presence of the upper level trough and the asymmetrical distribution of thunderstorms around the surface low prompted the National Hurricane Center to designate the system as a subtropical storm.
Subtropical Storm Beryl will move through an environment marginally favorable for intensification during the next 24 hours. Beryl will move over water where the Sea Surface Temperature is near 26°C. The upper level trough will continue to produce moderate vertical wind shear. The wind shear and the drier air will inhibit intensification. Subtropical Storm Beryl could intensify a little more during the next 24 hours. Beryl will move over colder water later on Sunday and it will start to weaken when that occurs.
The upper level trough was steering Subtropical Storm Beryl toward the northeast and a general motion in that direction is forecast to continue for several more days. On its anticipated track Subtropical Storm Beryl will pass south of Nova Scotia on Sunday. Beryl could be near Newfoundland by Tuesday.
Hurricane Chris weakened slowly on Wednesday as it passed well south of Nova Scotia. At 11:00 p.m. EDT on Wednesday the center of Hurricane Chris was located at latitude 39.6°N and longitude 63.0°W. Chris was moving toward the northeast at 29 m.p.h. (46 km/h). The maximum sustained wind speed was 85 m.p.h. (140 km/h) and there were wind gusts to 100 m.p.h. (160 km/h). The minimum surface pressure was 980 mb.
Hurricane Chris exhibited the structure of a hurricane on Thursday, but the clouds did not rise quite as high because it was over slightly cooler water. There was still an eye at the center of circulation. Several bands of showers and thunderstorms were revolving around the core of the circulation. The rainbands were weaker in the southwestern part of the hurricane because some drier air was entering that part of the circulation. Storms in the core of the circulation were generating upper level divergence.
Hurricane Chris is likely to weaken again on Thursday. It will start to move over much cooler water where there is less energy in the upper ocean. In addition an upper level trough over the eastern U.S. will produce southwesterly winds which will blow toward the upper part of the hurricane. Those winds will cause strong vertical wind shear. The shear will undercut the upper level divergence and tilt the circulation toward the northeast with height. Hurricane Chris will start to make a transition to an extratropical cyclone when the effects of the cooler water and stronger shear begin to alter the structure of the hurricane.
The upper level trough was steering Hurricane Chris rapidly toward the northeast and that motion is expected to continue for several more days. On its anticipated track Hurricane Chris will be near Labrador on Thursday night. The extratropical cyclone that results from the transition of Hurricane Chris will be near Iceland during the weekend.
Former Tropical Storm Chris strengthened to a hurricane southeast of Cape Hatteras on Tuesday. At 5:00 p.m. EDT on Tuesday the center of Hurricane Chris was located at latitude 33.7°N and longitude 72.4°W which put it about 205 miles (330 km) east-southeast of Cape Hatteras, North Carolina. Chris was moving toward the northeast at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h). The minimum surface pressure was 980 mb.
Hurricane Chris strengthened on Tuesday when it moved northeast of cooler water Chris had mixed to the surface while it was meandering off the coast of the Carolinas. An eye with a diameter of 30 miles (50 km) formed at the center of circulation. A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in the eastern side of that ring of storms. Bands of showers and thunderstorms were revolving around the core of Hurricane Chris. The strongest rainbands were in the eastern half of the circulation. Drier air near the western half of the circulation was contributing to the weaker bands in that part of the hurricane. Storms in the core of the circulation were generating upper level divergence which was pumping mass away to the north and east of the hurricane. Winds to hurricane force extended out about 20 miles (30 km) from the center of circulation. Winds to tropical storm force extended out about 95 miles (155 km) from the center.
Hurricane Chris will move through an environment favorable for intensification on Wednesday. Chris will move over water where the Sea Surface Temperature is near 28°C. An upper level trough over the northeastern U.S. will produce southwesterly winds that will blow toward the top of the hurricane. The winds speeds are similar at most levels and they will not generate a lot of vertical wind shear during the next 24 hours. Hurricane Chris will strengthen on Wednesday and it could intensify rapidly. Chris will move over cooler water when it gets north of the Gulf Stream and it will start to weaken when that occurs.
The trough over the northeastern U.S. will steer Hurricane Chris toward the northeast. On its anticipated track Chris will move away from the coast of North Carolina. Chris could be south of Nova Scotia in about 36 hours and it could be near Newfoundland in several days.
Elsewhere, the remnants of former Tropical Storm Beryl crossed Hispaniola and they were moving toward the southeastern Bahamas. At 2:00 p.m. EDT on Tuesday the center of Former Tropical Storm Chris was located at latitude 20.1°N and longitude 72.6°W which put it about 40 miles (65 km) northeast of Port de Paix, Haiti. It was moving toward the northwest at 17 m.p.h. (28 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 1013 mb. A reconnaissance aircraft is scheduled to investigate the system on Wednesday if there are signs that it could be reorganizing into a tropical cyclone.
Kate intensified into the fourth Atlantic hurricane of 2015 as it raced northeastward. At 10:00 a.m. EST on Wednesday the center of Hurricane Kate was located at latitude 36.8°N and longitude 60.5°W which put it about 395 miles (635 km) northeast of Bermuda and about 780 miles (1160 km) south-southwest of Cape Race, Newfoundland. Kate was moving toward the northeast at 45 m.p.h. (72 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 985 mb.
The organization of Hurricane Kate improved on Wednesday when a partial eyewall wrapped around the northern and western sides of the center of circulation. The structure of Kate is somewhat tilted toward the northeast by stronger southwesterly wind in the upper levels of the atmosphere. However, Kate currently has a warm core and it is still a tropical cyclone. Kate is moving over water where the Sea Surface Temperature (SST) is near 25°C. In a day or so the effects of strong vertical wind shear and cooler SSTs will cause Hurricane Kate to begin a transition to an extratropical cyclone.
Strong westerly winds are steering Kate rapidly toward the northeast and that general motion is expected to continue during the next few days. Kate could approach the United Kingdom as a strong extratropical cyclone during the weekend.
An instrument on a satellite indicated that there could be surface winds to tropical storm force in an area of thunderstorms east of the center of Tropical Depression Eight and the National Hurricane Center designated the system as Tropical Storm Henri. At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Henri was located latitude 31.3°N and longitude 60.7°W which put it about 250 miles (405 km) east-southeast of Bermuda. Henri was moving toward the north at 5 m.p.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 1008 mb.
Henri is not a very well organized tropical storm. An upper level low centered north of Bermuda is causing brisk southwesterly winds over the top of Henri. The vertical wind shear is blowing the tops off of thunderstorms that start to form near the center of circulation. As a result of the wind shear, the stronger thunderstorms are all located well to the east of the center of the tropical storm. Henri is over warm Sea Surface Temperatures (SSTs) which are above normal in that part of the western Atlantic Ocean. So, there is plenty of energy to support intensification. However, as long as the upper level low creates significant vertical wind shear, intensification will be minimal. It is possible that as Henri moves toward the north that the wind shear could decrease. In that case Henri could intensify during the next day or two before it moves over cooler SSTs.
An upper level trough over the eastern U.S. should steer Henri toward the north during the next several day. On its anticipated track, Henri could pass near Newfoundland during the weekend. Henri could be in the process of transitioning from a tropical storm to an extratropical cyclone at that time, but it could still bring strong winds and rain to parts of extreme eastern Canada.