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Tropical Storm Norma Drifts Near Baja California, Otis Rapidly Intensifies to Cat. 2 Hurricane

Tropical Storm Norma drifted near Baja California on Sunday, while Hurricane Otis rapidly strengthened into a Category 2 hurricane on the Saffir-Simpson Scale.  At 8:00 p.m. EDT on Sunday the center of Tropical Storm Norma was located at latitude 21.3°N and longitude 111.2°W which put it about 140 miles (220 km) south-southwest of Cabo San Lucas, Mexico.  Norma was moving toward the northwest at 6 m.p.h. (9 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 1001 mb.

A Tropical Storm Watch was in effect for the portion of the coast from Los Barriles to Todos Santos, Mexico.

Tropical Storm Norma retains some of the structural features that it had when it was a hurricane.  The remnants of a large circular eye form the center of circulation.  A broken ring of strong thunderstorms surrounds the remnants of the eye and the strongest winds are occurring in that ring.  Bands of showers and weaker thunderstorms are revolving around the core of Tropical Storm Norma.  Some of the outer rainbands of Norma are already dropping heavy rain over parts of the southern end of Baja California.

Tropical Storm Norma will move through an environment that will be only marginally favorable for intensification during the next day or so.  Norma will move over water where the Sea Surface Temperature is near 28°C.  An upper level trough west of North America is producing southwesterly winds which are blowing toward the top of the circulation.  Those winds are causing moderate vertical wind shear.  The circulation of Norma may also be drawing some cooler more stable air into the western part of the tropical storm.  Tropical Storm Norma could intensify somewhat during the next 24 hours, but it will eventually move over cooler water and weaken.

A ridge in the middle troposphere located east of Norma is steering the tropical storm toward the northwest and that general motion is expected to continue for another day or so.  When Norma weakens, it will be steered by the winds in the lower levels of the atmosphere.  Those winds will push Tropical Storm Norma more toward the west during the middle of the weak.  On its anticipated track the center of Tropical Storm Norma is forecast to remain west of Baja California.

Hurricane Otis intensified very rapidly on Sunday from a weak tropical storm to a Category 2 hurricane on the Saffir-Simpson Scale.  At 5:00 p.m. EDT on Sunday the center of Hurricane Otis was located at latitude 17.0°N and longitude 127.3°W which put it about 1200 miles (1930 km) west-southwest of the southern tip of Baja California.  Otis was moving toward the north at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 973 mb.

Hurricane Otis has a very small circulation, which allowed to strengthen very rapidly when the environment became more favorable.  A small eye formed at the center of Hurricane Otis and a tight ring of very strong thunderstorms surrounded the eye.  Those storms began generating upper level divergence which pumped mass away from the center of circulation.  The pressure decreased quickly and the wind speed increased very rapidly.  Hurricane Otis still has a small circulation.  Winds to tropical storm force only extend out about 70 miles (110 km) from the center.

Hurricane Otis may be near its peak intensity.  Otis is still moving over water where the Sea Surface Temperature is near 27°C, but it will soon move over cooler water.  Hurricane Otis will move nearer to the upper level trough west of North America and the hurricane will encounter stronger vertical wind shear.  Because Otis is a small hurricane, it could weaken almost as fast as it intensified.

A small midlevel ridge east of Otis is steering the hurricane toward the north.  Much like Tropical Storm Norma, Otis will be steered by winds lower in the atmosphere when it weakens.  Those winds are forecast to steer Otis more toward the west-southwest later this week.

Tropical Depression 16E Forms, Flood Risk for Mexico

Tropical Depression Sixteen-E formed south of Mexico on Wednesday morning.  At 11:00 a.m. EDT on Wednesday the center of Tropical Depression Sixteen-E was located at latitude 16.2°N and longitude 101.7°W which put it about 105 miles (165 km) south of Zihuatanejo, Mexico.  It was moving toward the north-northeast at 5 m.p.h. (8 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.

A Tropical Storm Watch was issued for the portion of the coast from Zihuatanejo to Punta Maldonado, Mexico.

A distinct center of circulation formed in a cluster of thunderstorms south of Mexico and that National Hurricane Center designated the system as Tropical Depression Sixteen-E on Wednesday morning.  The circulation of the depression was still organizing.  Several bands of showers and thunderstorms were developing south and east of the center of circulation.  There were fewer showers and thunderstorms in the northwestern quadrant of the circulation and the depression may have been pulling in drier air from Mexico.

The depression has 12 to 18 hours to strengthen before it makes landfall on the coast of Mexico.  It will move over water where the Sea Surface Temperature is near 30°C.  An upper level trough extends from the eastern U.S. to Mexico.  The trough is producing westerly winds which are blowing toward the top of the circulation.  Those winds are generating moderate wind vertical shear, which will inhibit intensification.  Tropical Depression Sixteen-E could strengthen into a tropical storm before it reaches the coast of Mexico.

The upper level trough is forecast to steer Tropical Depression Sixteen-E toward the east.  On its anticipated track the depression could make landfall east of Zihuatanejo in less than 24 hours.  The depression will bring gusty winds, but heavy rain poses a greater threat.  Heavy rain falling in steeper terrain could cause flash floods.

Elsewhere over the Eastern North Pacific Ocean, Tropical Depression Fifteen-E was moving farther away from Mexico.  Tropical Depression Fifteen-E formed when momentum from the upper half of the circulation of former Hurricane Katia spun up a new surface circulation over the Eastern North Pacific.  At 11:00 a.m. EDT on Wednesday the center of Tropical Depression Fifteen-E was located at latitude 14.9°N and longitude 120.6°W which put it about 890 miles (1435 km) southwest of the southern tip of Baja California.  It was moving toward the west at 9 m.p.h. (15 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 1004 mb.

Kenneth Rapidly Intensifies Into a Hurricane

One time Tropical Storm Kenneth rapidly intensified into a hurricane on Sunday.  At 5:00 p.m. EDT on Sunday the center of Hurricane Kenneth was located at latitude 16.2°N and longitude 128.4°W which put it about 1290 miles (2075 km) west-southwest of the southern tip of Baja California.  Kenneth was moving toward the west at 14 m.p.h. (22 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 980 mb.

The structure of Hurricane Kenneth improved significantly during the past few hours.  A small circular eye emerged at the center of circulation.  A ring of strong thunderstorms surrounded the eye and the strongest winds are occurring in this ring of thunderstorms.  Additional bands of showers and thunderstorms intensified south and east of the center.  Thunderstorms near the core of Kenneth were generating strong upper level divergence which was pumping mass away from the hurricane.

Hurricane Kenneth will continue to move through an environment favorable for intensification on Monday.  Kenneth will move over water where the Sea Surface Temperature (SST) is near 28.5°C.  Hurricane Kenneth is moving through a region where the winds in the upper levels are weak and there is not much vertical wind shear.  Hurricane Kenneth could continue to intensify for another 12 to 24 hours.  The speed of the upper level winds could increase in a day or so, and more vertical wind shear would inhibit intensification.  Eventually Hurricane Kenneth will move over cooler SSTs and start to weaken.

Kenneth if moving south of a subtropical ridge which is steering the hurricane toward the west.  The ridge is forecast to continue to steer Kenneth westward for another 12 to 24 hours.  Hurricane Kenneth will turn toward the north when it reaches the western end of the ridge.  On its anticipated track Hurricane Kenneth would pose no direct threat to land.

Tropical Storm Kenneth Develops Southwest of Baja California

Tropical Storm Kenneth developed southwest of Baja California on Friday.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Kenneth was located at latitude 15.0°N and longitude 119.1°W which put it about 810 miles (1305 km) southwest of the southern tip of Baja California.  Kenneth was moving toward the west at 15 m.p.h. (24 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.

A distinct center of circulation developed in a tropical wave southwest of Baja California on Friday.  Thunderstorms began to form near the center and the National Hurricane Center designated the system as Tropical Storm Kenneth, which was the 11th named tropical storm to form over the Eastern North Pacific during 2017.

A cluster of thunderstorms formed near the core of Tropical Storm Kenneth on Friday.  Even after thunderstorms formed near the core, the circulation of Tropical Storm Kenneth was asymmetrical.  Bands of showers and thunderstorms developed in the western half of the circulation.  The bands in the eastern half of the circulation consisted primarily of showers and low clouds.  Thunderstorms near the core of Kenneth were generating upper level divergence which was pumping mass away to the west of the tropical storm.

Tropical Storm Kenneth will move through an environment that will be favorable for intensification during the next several days.  Kenneth will move over water where the Sea Surface Temperature is near 28.5°C.  An upper level ridge to the north of Tropical Storm Kenneth is producing easterly winds which are blowing toward the top of the circulation.  Those winds are producing moderate vertical wind shear which is probably the cause of the asymmetrical circulation of the tropical storm.  Even though there is moderate vertical wind shear, Tropical Storm Kenneth is likely to intensify and it could become a hurricane in a couple of days.

Tropical Storm Kenneth is begin steered toward the west by a subtropical ridge to the north of the tropical storm.  The subtropical ridge will continue to steer Tropical Storm Kenneth toward the west-northwest for another day or two.  When Tropical Storm Kenneth reaches the western end of the subtropical ridge, it will turn more toward the north.

Tropical Storms Hilary and Irwin Interact As They Weaken

Tropical Storms Hilary and Irwin started to interact on Thursday as both storms began to weaken.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Hilary was located at latitude 18.3°N and longitude 117.3°W which put it about 575 miles (925 km) west-southwest of the southern tip of Baja California.  Hilary was moving toward the west-northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were gust to 85 m.p.h. (140 m.p.h.).  The minimum surface pressure was 992 mb.

At 11:00 p.m. EDT on Thursday the center of Tropical Storm Irwin was located at latitude 14.9°N and longitude 124.6°W which put it about 1105 miles (1780 km) west-southwest of the southern tip of Baja California.  Irwin was moving toward the west at 2 m.p.h. (3 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 1000 mb.

Hilary weakened below hurricane intensity on Thursday.  It appeared that the circulation drew in drier more stable air around the northwestern side of the circulation.  The drier air reduced the formation of showers and thunderstorms and the core of the circulation weakened.  At the same time upper level divergence from Tropical Storm Hilary increased the vertical wind shear over Tropical Storm Irwin.  Irwin was over water where the Sea Surface Temperature is near 28.5°C and it was able to extract enough energy from the ocean to maintain most of its intensity.

Tropical Storms Hilary and Irwin will move over water where the Sea Surface Temperature is near 28°C on Friday.  However, the combination of drier, more stable air and vertical wind shear is likely to keep both of the storms from strengthening.  Hilary and Irwin will move over cooler water during the weekend and both tropical storms are likely to weaken when that occurs.

Tropical Storm Hilary is being steering toward the west-northwest by a subtropical high pressure system to the north of the tropical storm.  Hilary is forecast to continue moving toward the west-northwest.  Tropical Storm Hilary is larger than Irwin.  Winds to tropical storm force extend out about 110 miles (180 km) in Tropical Storm Hilary.  Winds to tropical storm force extend out about 70 miles (110 km) in Tropical Storm Irwin.

The centers of the two tropical storms are only about 540 miles (870 km) apart.  When Tropical Storm Hilary passes north of Irwin, Tropical Storm Irwin is forecast to start to revolve around the larger Tropical Storm Hilary.  Irwin is expected to turn toward the north after Tropical Storm Hilary passes by.  Some models are forecasting the that the centers of the two tropical storms will approach each other and the larger Tropical Storm Hilary will eventually absorb Tropical Storm Irwin.

Hurricanes Hilary and Irwin Churn Over Eastern Pacific

Hurricanes Hilary and Irwin continued to churn over the Eastern North Pacific Ocean on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Hilary was located at latitude 16.0°N and longitude 109.8°W which put it about 475 miles (765 km) south of the southern tip of Baja California.  Hilary was moving toward the west-northwest at 12 m.p.h.  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 973 mb.

At 11:00 p.m. EDT on Tuesday the center of Hurricane Irwin was located at latitude 16.1°N and longitude 120.9°W which put it about 855 miles (1375 km) west-southwest of the southern tip of Baja California.  Irwin was moving toward the west at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surface pressure was 980 mb.

Hilary is the larger and stronger of the two hurricanes.  Hurricane Hilary has a small circular eye surrounded by a ring of strong thunderstorms.  A rainband spirals around the western and southern sides of the core of the circulation.  Thunderstorms in the core are generating strong upper level divergence which is pumping out mass in all directions.  Winds to tropical storm force extend out about 90 miles (145 km) from the center.

Hurricane Irwin has a smaller circulation.  Irwin has a small eye.  Most of the thunderstorms are occurring in the northwestern quadrant of the circulation.  Winds to tropical storm force extend out only about 70 miles (110 km) from the center of circulation.

Hurricane Hilary is moving through a more favorable environment.  Hilary is moving over water where the Sea Surface Temperature is near 29°C.  The upper level winds are weak and there is little vertical wind shear near Hilary.  Hurricane Irwin is moving over water where the Sea Surface Temperature is near 28°C.  An upper level low northwest of Irwin appears to be producing westerly winds which are undercutting the upper level divergence generated by thunderstorms near the core of the hurricane.  Some drier air also seems to wrapping around the eastern side of the circulation.

Hurricane Hilary is moving faster than Hurricane Irwin and Hilary is getting closer to Irwin.  The two hurricanes are expected to interact later this week.  Since Hilary is bigger and stronger than Irwin, Hilary is forecast to become the dominant circulation.  Hurricane Hilary is expected to continue to move in west-northwesterly direction.  When Hilary gets closer to Hurricane Irwin, Irwin is forecast to begin to revolve around Hilary in an interaction called the Fujiwhara effect.  On their anticipated tracks Hurricanes Hilary and Irwin are expected to remain south of the southern tip of Baja California.

Tropical Storm Irwin Forms, Greg Gets Larger, Hilary Strengthens

Tropical Depression Ten-E intensified into Tropical Storm Irwin, the circulation of Tropical Storm Greg increased in size and Tropical Storm Hilary strengthened on Sunday.  At 5:00 p.m. EDT on Sunday the center of Tropical Storm Irwin was located at latitude 14.9°N and longitude 116.6°W which put it about 705 miles (1135 km) southwest of the southern tip of Baja California.  Irwin was moving toward the west 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 1003 mb.

At 5:00 p.m. EDT on Sunday the center of Tropical Storm Greg was located at latitude 14.4°N and longitude 130.1°W which put it about 1445 miles (2325 km) west-southwest of the southern tip of Baja California.  Greg was moving toward the west at 14 m.p.h. (22 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 1001 mb.

At 5:00 p.m. EDT on Sunday the center of Tropical Storm Hilary was located at latitude 14.9°N and longitude 102.9°W which put it about 410 miles (660 km) south-southeast of Manzanillo, Mexico.  Hilary was moving toward the west-northwest at 9 m.p.h. (15 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 was 999 mb.

A primary rainband wrapped around the western and southern sides of the center of circulation of Tropical Depression Ten-E and the National Hurricane Center upgraded the system to Tropical Storm Irwin.  Several other bands of showers and thunderstorms were developing over the southern half of the circulation.  There were fewer showers and thunderstorms in the northern half of the circulation.  Thunderstorms near the center of circulation were generating some upper level divergence.

Tropical Storm Irwin will move through an environment that will be somewhat favorable for intensification.  Irwin will move over water where the Sea Surface Temperature (SST) is near 28°C.  An upper level ridge northwest of Irwin are generating northeastern winds which are blowing toward the top of the circulation.  Those winds are generating moderate vertical wind shear and the shear may be the cause of the asymmetric distribution of showers and thunderstorms.  Tropical Storm Irwin could intensify during the next 24 to 48 hours.

The circulation of Tropical Storm Greg grew in size on Sunday.  However, Tropical Storm Greg will move into a less favorable environment during the next several days.  Tropical Storm Greg is over water where the SST is near 28°C, but it will move over cooler water in a day or two.  Greg could intensify in the short term, but it will weaken by midweek.

Tropical Storm Hilary is moving through a very favorable environment.  Hilary is moving over water where the SST is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Tropical Storm Hilary could be beginning a period of rapid intensification.  Hilary is forecast to become a hurricane on Monday and it could be a major hurricane later this week.

A subtropical ridge is steering all three tropical storms in a general west-northwesterly direction.  Tropical Storms Greg, Hilary and Irwin are likely to continue to move a little to the north of due west during the next three days.  On its anticipated track Tropical Storm Hilary is expected to remain west of the west coast of Mexico.

Tropical Storms Fernanda and Greg Continue West Across the Pacific

Tropical Storms Fernanda and Greg continued to move west across the Pacific Ocean on Thursday.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Fernanda was located at latitude 18.4°N and longitude 141.4°W which put it about 900 miles (1445 km) east of Hilo, Hawaii.  Fernanda was moving toward the west at 12 m.p.h. (19 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 1000 mb.

At 11:00 p.m. EDT on Thursday the center of Tropical Storm Greg was located at latitude 14.3°N and longitude 117.4°W which put it about 770 miles (1240 km) southwest of the southern tip of Baja California.  Greg was moving toward the west at 10 m.p.h. (16 km/h).  The maximum 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 1003 mb.

Tropical Storm Fernanda is moving through an environment that is unfavorable for intensification.  Fernanda is moving over water where the Sea Surface Temperature (SST) is near 26°C.  An upper level trough northeast of Hawaii is producing southwesterly winds which are causing strong vertical wind shear over Fernanda.  Tropical Storm Fernanda has a strong low level circulation but the vertical wind shear will blow the tops off any new thunderstorms that form.  The shear is likely to cause Fernanda to continue to weaken and the low level circulation is likely to gradually spin down.

Tropical Storm Greg did not intensify much on Thursday but recent satellite images seem to indicate that Greg may be getting more organized.  A primary band of showers and thunderstorms has wrapped about two thirds of the way around the eastern and northern sides of the center of circulation.  Upper level outflow from Tropical Storm Fernanda, which is farther west and an upper level low northwest of Greg were generating strong southerly winds which were blowing toward the top of the tropical storm.  Those winds were causing strong vertical wind shear over Tropical Storm Greg.  The upper low appears to be moving farther away from Greg.  Tropical Storm Greg is moving over water where the SST is near 28°C.  If the vertical shear diminishes and the circulation organizes, then there is sufficient energy in the upper ocean to allow Greg to intensify into a hurricane.

A subtropical ridge north of Greg is steering the tropical storm toward the west.  A general westerly motion is expected to continue during the next several days.  Tropical Storm Greg could take a path similar to the track of Tropical Storm Fernanda.

Active East Pacific With Fernanda, Greg and TD 8E

The tropical Eastern North Pacific Ocean continued to be very active on Tuesday with Hurricane Fernanda, Tropical Storm Greg and Tropical Depression Eight-E.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Fernanda was located at latitude 16.5°N and longitude 134.4°W which put it about 1375 miles east of Hilo, Hawaii.  Fernanda was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 976 mb.

At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Greg was located at latitude 14.6°N and longitude 110.1°W which put it about 490 miles (785 km) southwest of Manzanillo, Mexico.  Greg was moving toward the west at 10 m.p.h. (16 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 1003 mb.

At 11:00 p.m. EDT on Tuesday the center of Tropical Depression Eight-E was located at latitude 14.8°N and longitude 119.9°W which put it about 860 miles (1385 km) southwest of the southern tip of Baja California.  It was moving toward the west at 5 m.p.h. (8 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 1007 mb.

Although Hurricane Fernanda is the strongest of the three tropical cyclones over the Eastern North Pacific Ocean, it is slowly weakening as it moves over cooler Sea Surface Temperatures  (SSTs).  Hurricane Fernanda is over water where the SSTs are near 26.5°C and it will move over cooler water as it moves west toward Hawaii.

Tropical Storm Greg strengthened on Tuesday as it moved over water where the SSTs are near 29°C.  A primary rainband wrapped around the western side of the center of circulation.  Additional showers and thunderstorms formed closer to the center.  Greg is also expected to move west as it moves south of a subtropical ridge.

The future of Tropical Depression Eight-E is less certain.  Upper level divergence from Hurricane Fernanda is creating strong vertical wind shear over the stop of the depression.  The strong wind shear is causing the circulation of the depression to be poorly organized.  There are few showers and thunderstorms in the northern portion of the circulation because of the strong shear.  The stronger upper level winds could shear the top of the circulation away from the lower level circulation of the depression.  It is also possible that Tropical Storm Greg could catch up to the depression and absorb the remnants of the depression into its circulation.

Hurricane Fernanda Slowly Weakens As It Moves West

Hurricane Fernanda weakened slowly as it moved farther west over the Eastern North Pacific Ocean on Sunday.  At 11:00 p.m. EDT on Sunday the center of Hurricane Fernanda was located at latitude 13.0°N and longitude 129.2°W which put it about 1440 miles (2315 km) west-southwest of the southern tip of Baja California.  Fernanda was moving toward the west-northwest at 12 m.p.h. (19 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. (220 km/h).  The minimum surface pressure was 960 mb.

Hurricane Fernanda completed at least one eyewall replacement cycle in which an outer eyewall formed around the original eyewall.  Eventually, the inner eyewall dissipated and a larger eye formed inside the outer eyewall.  The eyewall replacement cycle weakened Hurricane Fernanda when the stronger, inner eyewall dissipated.  Although Hurricane Fernanda is weaker, it is still a powerful hurricane.  There is a circular eye at the center of circulation.  A ring of strong thunderstorms still 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 the circulation.  Thunderstorms in the core of Hurricane Fernanda are generating strong upper level divergence which are pumping out mass in all directions.

Hurricane Fernanda is moving over water where the Sea Surface Temperature (SST) is near 29°C.  The upper level winds are weak and there is little vertical wind shear.  Fernanda will gradually move over cooler SSTs.  When Fernanda moves over the cooler SSTs, it will extract less energy from the ocean and the hurricane will continue to weaken.  The weakening could occur very gradually because the wind shear is limited.

Hurricane Fernanda is moving south of a subtropical high pressure system which is steering the hurricane toward the west-northwest.  The subtropical high is expected to steer Fernanda toward the west-northwest during the next several days.