Tag Archives: 06E

Tropical Storm Fabio Develops West of Mexico

Tropical Storm Fabio developed west of Mexico on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Fabio was located at latitude 12.0°N and longitude 107.4°W which put it about 770 miles (1240 km) south-southeast of the southern tip of Baja California.  Fabio was moving toward the west-northwest at 13 m.p.h. (20 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.

The circulation of Tropical Storm Fabio was still organizing.  There was a broad low level center of circulation, but it did not have a well developed inner core.  Multiple bands of showers and thunderstorms were revolving around the broad low level center.  The storms in the rainbands were generating some upper level divergence which was starting to pump mass away from the tropical storm.

Tropical Storm Fabio will move through an environment that is very favorable for intensification.  Fabio will move over water where the Sea Surface Temperature is near 28.5°C.  An upper level ridge northeast of Tropical Storm Fabio will produce easterly winds which will blow toward the top of the circulation.  However, the wind speed will be similar at all levels and there will not be much vertical wind shear.  Tropical Storm Fabio will continue to intensify in the favorable environment.  Once a primary rainband wraps around the center of circulation, an inner core will develop.  Tropical Storm Fabio could intensify rapidly when an eye starts to form.  Fabio could strengthen into a major hurricane in two or three days.

Tropical Storm Fabio was moving south of a subtropical ridge which was steering the tropical storm toward the west-northwest.  A general west-northwesterly motion is expected to continue during the next few days.  On its anticipated track the center of Tropical Storm Fabio will pass well to the south of Baja California.

Elsewhere over the Eastern North Pacific Ocean Tropical Depression Emilia continued to weaken over cooler water.  At 11:00 a.m. EDT on Sunday the center of Tropical Depression Emilia was located at latitude 19.3°N and longitude 123.0°W which put it about 880 miles (1415 km) west-southwest of the southern tip of Baja California.  Emilia was moving toward the west-northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1006 mb.

Tropical Storm Emilia Develops South of Baja California

Tropical Storm Emilia developed south of Baja California on Thursday morning.  At 11:00 a.m. EDT on Thursday the center of Tropical Storm Emilia was located at latitude 14.4°N and longitude 112.4°W which put it about 610 miles (980 km) south-southwest of the southern tip of Baja California.  Emilia was moving toward the west-northwest at 14 m.p.h. (22 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 distribution of thunderstorms around Tropical Storm Emilia was asymmetrical.  Most of the showers and thunderstorms were occurring in bands west and north of the center of circulation.  The center was located near the eastern edge of a cluster of thunderstorms.  Bands east of the center consisted of showers and low clouds.  The cluster of storms west of the center of circulation was generating upper level divergence which was pumping mass away to the west and north of the tropical storm.

Tropical Storm Emilia will move through an environment somewhat favorable for intensification during the next day or two.  Emilia will move over water where the Sea Surface Temperature is near 28°C.  An upper level ridge centered near the southern tip of Baja California was producing northeasterly winds which were blowing toward the top of the circulation.  Those winds were causing moderate vertical wind shear and they were probably the reason why most of the thunderstorms were located west and north of the center of circulation.  The vertical shear is likely to limit intensification during the next 24 hours.  The shear is forecast to decrease on Friday and Tropical Storm Emilia could strengthen faster if that occurs.

The portion of the ridge in the middle troposphere was steering Tropical Storm Emilia toward the west-northwest and that general motion is expected to continue for several more days.  On its anticipated track Emilia will move farther away from 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.

Hurricane Fernanda Intensifies Rapidly to Category 4

Hurricane Fernanda intensified rapidly to Category 4 on the Saffir-Simpson Scale on Friday.  At 5:00 p.m. EDT on Friday the center of Hurricane Fernanda was located at latitude 10.7°N and longitude 119.7°W which put it about 1060 miles (1710 km) southwest of the southern tip of Baja California.  Fernanda was moving toward the west 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 155 m.p.h. (250 km/h).  The minimum surface pressure was 960 mb.

A clear circular eye formed at the center of Hurricane Fernanda.  The eye is surrounded by a ring of very strong thunderstorms and the strongest winds are occurring in the eyewall.  Additional bands of showers and thunderstorms formed outside the core of Fernanda.  There are more bands in the eastern half of the hurricane, but the overall circulation is fairly symmetrical.  The thunderstorms in the core of Fernanda are generating strong upper level divergence which is pumping mass away from the hurricane.

Fernanda is a small hurricane.  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 70 miles (110 km) from the center.  The Hurricane Intensity Index (HII) is 25.1.  The Hurricane Size Index (HSI) is 9.0 and the Hurricane Wind Intensity Size Index (HWISI) is 34.1.  The indices indicate that Hurricane Fernanda is somewhat similar in size and strength to Hurricane Charley in 2004 when Charley was approaching the southwest coast of Florida.

Hurricane Fernanda will remain in an environment very favorable for intensification for another 24 to 48 hours.  It will move over water where the Sea Surface Temperature (SST) is near 28.5°C.  The upper level winds are weak and there is little vertical wind shear.  Hurricane Fernanda has a chance to intensify into a Category 5 hurricane on the Saffir-Simpson Scale before it moves into a less favorable environment.  When a hurricane becomes as intense as Hurricane Fernanda is, an outer rainband can wrap around the eye and an eyewall replacement cycle can occur.  If an eyewall replacement cycle occurs in Hurricane Fernanda, then fluctuations in intensity may also happen.  Eventually Fernanda will move over cooler SSTs and the hurricane will start to weaken.

Hurricane Fernanda is moving south of a subtropical ridge and the ridge is steering the hurricane a little south of due west.  A general westward motion is forecast to continue during the next few days.  On its anticipated track Hurricane Fernanda will continue to move farther away from Mexico.  Fernanda could approach Hawaii by the end of next week.

Fernanda Rapidly Intensifies Into a Hurricane

Former Tropical Storm Fernanda rapidly intensified into a hurricane on Thursday.  At 5:00 p.m. EDT on Thursday the center of Hurricane Fernanda was located at latitude 11.2°N and longitude 116.0°W which put it about 900 miles (1450 km) south-southwest of the southern tip of Baja California.  Fernanda was moving toward the west at 12 m.p.h. (19 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 990 mb.

A primary rainband wrapped around the center of circulation and an eye appeared intermittently on visible satellite images on Thursday afternoon.  The improved organization of the inner core of Fernanda allowed it to intensify rapidly into a hurricane.  The distribution of thunderstorms become more symmetrical and circulation exhibited a more circular appearance.  Thunderstorms in the inner core began to generate strong upper level divergence which pumped out mass in all directions.  The divergence of mass allowed the surface pressure to decrease and the wind speeds to increase rapidly.

Hurricane Fernanda will move through an environment that will be favorable for further intensification during the next two days.  Fernanda will move over water where the Sea Surface Temperature (SST) is near 29°C.  An upper level ridge northeast of Fernanda is producing easterly winds which are blowing toward the top of the hurricane.  However, the speed of the upper level winds decreased on Thursday and there is less vertical wind shear.  A combination of a well organized inner core, warm SSTs and reduced vertical wind shear resulted in rapid intensification of Fernanda into a hurricane.  Rapid intensification could continue for another 24 to 36 hours and Fernanda is forecast to become a major hurricane on Friday.

A subtropical ridge to the north of Fernanda is steering the hurricane toward the west and a general westerly motion is expected to continue for several more days.  On its anticipated track Hurricane Fernanda will move farther away from Mexico.

TD 6E Strengthens Into Tropical Storm Fernanda

Tropical Depression Six-E strengthened into Tropical Storm Fernanda on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Fernanda was located at latitude 11.9°N and longitude 113.1°W which put it about 790 miles (1270 km) south-southwest of the southern tip of Baja California.  Fernanda was moving toward the west at 9 m.p.h. (15 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 1004 mb.

Thunderstorms on the western side of the center of Tropical Storm Fernanda increased on Wednesday night.  Several bands of showers of thunderstorms formed in the western half of the circulation, but the distribution of convection remained asymmetrical.  There were few showers and thunderstorms in the eastern half of the circulation.  The thunderstorms in the western half of the were generating upper level divergence which was pumping out mass to the west of Tropical Storm Fernanda.

Tropical Storm Fernanda is currently in an environment that is moderately favorable for intensification.  It is moving over water where the Sea Surface Temperature (SST) is near 29.5°C.  An upper level ridge north of Fernanda is producing easterly winds which are blowing toward the top of the tropical storm.  Those winds are causing moderate vertical wind shear and the shear may be the cause of the asymmetrical distribution of thunderstorms.  Fernanda is likely to move into an area where the upper level winds are weaker and the shear will decrease.  Warm SSTs and less wind shear should allow Tropical Storm Fernanda to intensify into a hurricane later this week.  Once an eye forms, a period of rapid intensification will be possible and Fernanda could eventually become a major hurricane.

A subtropical ridge north of Fernanda is steering the tropical storm westward and a general westerly motion is expected to continue for the next few days.  On its anticipated track Tropical Storm Fernanda will move away from Mexico and it could move into the Central Pacific in a few days.

Tropical Storm Estelle Forms As Hurricane Darby Nears Peak Intensity

Tropical Storm Estelle developed late Friday over the Eastern North Pacific as Hurricane Darby neared its peak intensity farther west.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Estelle was located at latitude 15.2°N and longitude 108.3°W which put it about 370 miles (600 km) southwest of Manzanillo, Mexico.  Estelle was moving toward the west-northwest at 12 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 1005 mb.  Estelle is the fifth tropical storm to form over the Eastern North Pacific during the month of July.

Meanwhile, about 950 miles west of Estelle, Hurricane Darby neared its peak intensity.  At 11:00 p.m. EDT on Friday the center of Hurricane Darby was located at latitude 17.3°N and longitude 122.1°W which put it about 880 miles (1415 km) west-southwest of the southern tip of Baja California.  Darby was moving toward the west-northwest at 9 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 972 mb.

The large circulation around Tropical Storm Estelle is still organizing.  A primary rainband is wrapping around the western side of the center.  Several spiral bands of thunderstorms are forming farther away from the core of the tropical storm.  Storms near the center are beginning to produce upper level divergence, but it is not currently well developed.

The environment around Estelle is favorable for gradual intensification.  Estelle is moving over water where the Sea Surface Temperature is near 29°C.  An upper level ridge north of Estelle is generating easterly winds which are blowing over the top of the tropical storm.  There is enough vertical wind shear to slow the rate of intensification, but the shear is probably not strong enough to keep Estelle from intensifying.  Storms like Estelle with large initial circulations can intensify slowly as a tighter core develops within the larger circulation.

Hurricane Darby is a well formed mature hurricane.  It has a well developed eye surrounded by a narrow ring of strong thunderstorms.  Several spiral bands are rotating around the core of Darby.  The thunderstorms near the center of circulation are generating upper level divergence which is pumping out mass in all directions.

Hurricane Darby is probably close to its peak intensity.  It is moving over water where the Sea Surface Temperature is near 27°C and Darby will be moving over cooler water during the next few days.  There is not much vertical wind shear, and Darby may have a chance to intensify during the next 12 to 24 hours.  However, Darby will reach cooler water in about a day and then the hurricane will being to weaken.

A subtropical ridge located north of Hurricane Darby and Tropical Storm Estelle is expected to steer both cyclones toward the west during the next few days.