Tag Archives: 04E

Hurricane Dora Weakens South of Baja California

Hurricane Dora weakened as it moved over cooler water south of Baja California on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Dora was located at latitude 19.6°N and longitude 111.4°W which put it about 245 miles (400 km) south-southwest of the southern tip of Baja California. Dora as moving toward the west-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 995 mb.

Tropical Storm Dora is moving over water where the Sea Surface Temperature (SST) is near 24°C.  The circulation of Tropical Storm Dora is still very well organized but it is unable to extract sufficient energy from the upper ocean to maintain its intensity.  As a result, the showers and thunderstorms are not rising as far into the atmosphere and the circulation is spinning down.  There is little vertical wind shear and so the circulation is still symmetrical, but it is not as vigorous.  The lack of wind shear will cause the weakening to occur more slowly than it would have if the upper level winds were stronger.

A subtropical ridge is steering Tropical Storm Dora toward the west-northwest and that general motion is expected to continue for anther day or two.  On its anticipated track, Tropical Storm Dora will move farther away from Baja California.  The forecast track would keep Dora over cooler SSTs and it should continue to weaken.

Dora Rapidly Intensifies Into First Eastern Pacific Hurricane of 2017

Tropical Storm Dora intensified rapidly into a hurricane during the overnight hours.  Dora is the first hurricane to develop over the Eastern North Pacific during 2017.  At 11:00 a.m. EDT on Monday the center of Hurricane Dora was located at latitude 17.3°N and longitude 106.3°W which put it about 220 miles (350 km) south of Cabo Corrientes, Mexico.  Dora was moving toward the west-northwest at 13 m.p.h. (20 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 985 mb.

The circulation of Hurricane Dora is very well organized.  A circular eye exists at the center of circulation.  A ring of strong thunderstorms surrounds the eye.  Additional bands of showers and thunderstorms are revolving around the core of the circulation.  Thunderstorms in Dora are generating well developed upper level divergence which is pumping large quantities of mass out in all directions.

Dora is a small hurricane.  Wind to hurricane force extend out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extend out about 80 miles (130 km) from the center.  The Hurricane Intensity Index (HII) is 12.7.  The Hurricane Size Index (HSI) is 7.3.  The Hurricane Wind Intensity Size Index (HWISI) is 20.0.

Hurricane Dora will move through an environment favorable for intensification for another 12 to 18 hours.  It is currently over water where the Sea Surface Temperature (SST) is near 28°C.  Dora will move over SSTs that will gradually be cooler, but they should be warm enough to support further intensification for another 12 to 18 hours.  Hurricane Dora is moving through an area where upper level winds are weak and there is almost no vertical wind shear.  Hurricane Dora is likely to strengthen further during the next few hours.  Dora will move over much cooler SSTs when it passes south of Baja California and it will begin to weaken on Tuesday.

A subtropical ridge to the north of Dora is steering the hurricane toward the west-northwest and that general motion is expected to continue for another 24 to 48 hours.  On its anticipated track the center of Hurricane Dora will pass south of Baja California.

TD 04E Strengthens Rapidly Into Tropical Storm Dora

Tropical Depression Four-E strengthened rapidly into Tropical Storm Dora on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Dora was located at latitude 16.4°N and longitude 104.3°W which put ti about 290 miles (470 km) south-southeast of Cabo Corrientes, Mexico.  Dora was moving toward the west-northwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 996 mb.

The circulation of Tropical Storm Dora organized quickly on Sunday.  A primary rainband wrapped tightly around the center of circulation.  An eyelike feature appeared to be forming on microwave and infrared satellite images.  Additional bands of showers and thunderstorms developed outside the core of Tropical Storm Dora.  Thunderstorms around the core generated upper level divergence which pumped out mass in all directions.

Tropical Storm Dora will be moving through an environment very favorable for intensification on Monday.  It will move over water where the Sea Surface Temperature (SST) is near 29°C.  An upper level ridge over Mexico is producing easterly winds that are blowing toward the top of the circulation, but there is little vertical wind shear.  A combination of warm water and little shear will allow Dora to intensify into a hurricane during the next 24 hours.  The rate of intensification could increase once the formation of the eye is complete.  Dora will move over cooler SSTs on Tuesday.  The cooler SSTs will initially halt the intensification.  When Dora is unable to extract sufficient energy from the upper ocean it will start to weaken.

A subtropical ridge northeast of Dora is steering the tropical storm toward the west-northwest and a general west-northwesterly motion is expected to continue for another day or two.  On its anticipated track the center of Tropical Storm Dora will remain southwest of Mexico.  Dora will pass south of Baja California on Tuesday.

Tropical Depression Four-E Forms South of Acapulco

Tropical Depression Four-E formed south of Acapulco, Mexico on Saturday.  At 11:00 p.m. EDT on Saturday the center of Tropical Depression Four-E was located at latitude 14.3°N and longitude 100.0°W which put it about 180 miles (290 km) south of Acapulco.  It was moving toward the west-northwest at 10 m.p.h. (16 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.

A distinct surface center of circulation developed within a larger area of thunderstorms south of Mexico on Saturday.  Showers and thunderstorms began to consolidate near the center.  Additional bands of showers and thunderstorms formed outside the core of the circulation.  The thunderstorms began to produce upper level divergence which pumped mass away from the core of the depression.

Tropical Depression Four-E will move through an environment favorable for intensification during the next several days.  It will move over water where the Sea Surface Temperature is near 30°C.  An upper low over the western Gulf of Mexico is enhancing the upper level divergence to the northeast of the tropical depression.  An upper level ridge over Mexico is producing easterly winds which are blowing toward the top of the circulation, but the vertical wind shear is minimal.  Tropical Depression Four-E could intensify in a tropical storm on Sunday.  It has a chance to become a hurricane early next week before it reaches cooler water south of Baja California.

A subtropical ridge over Mexico is steering Tropical Depression Four-E toward the west-northwest and that general motion is expected to continue for another two or three days.  On its anticipated track the center of Tropical Depression Four-E is expected to remain south of the coast of Mexico.  Rainbands in the northern portion of the circulation could produce locally heavy rain over parts of southern Mexico.  The greatest risk would be for flash floods in those areas.

Tropical Storm Darby Intensifies as Hurricane Celia Weakens

Tropical Storm Darby intensified on Tuesday as it moved in the trail of weakening Hurricane Celia.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Darby was located at latitude 15.4°N and longitude 110.4°W which put it about 520 miles (835 km) south of the southern tip of Baja California.  Darby was moving toward the west at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 1000 mb.

Farther west Hurricane Celia continued to weaken slowly on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Celia was located at latitude 18.0°N and longitude 110.4°W which put it about 1360 miles (2190 km) west of the southern tip of Baja California.  Celia was moving toward the northwest at 12 m.p.h. (19 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 986 mb.

More thunderstorms developed near the center of Tropical Storm Darby on Tuesday.  However, most of the stronger thunderstorms were southwest of the center of circulation.  An upper level ridge near the west coast of Mexico was producing northeasterly winds which are blowing over the top of the tropical storm.  The vertical wind shear caused the asymmetric distribution of convection.  Despite the vertical wind shear the circulation in the lower levels was well developed.

Tropical Storm Darby is over water where the Sea Surface Temperature is near 30°C and Darby is expected to intensify into a hurricane.

Hurricane Celia is moving over water where the Sea Surface Temperature is near 25°C.  Since the hurricane is extracting less energy from the ocean, the thunderstorms are not as tall and Celia is slowly weakening.  The hurricane is in an area where the vertical wind shear is minimal and so the weakening trend is likely to occur at a slower rate than normal.

A subtropical ridge north of the Celia and Darby is steering the two tropical storms toward the west and that general motion is expected to continue for the next few days.

Hurricane Celia Develops West of Mexico

The next in a series of tropical systems over the Eastern North Pacific Ocean developed into Hurricane Celia on Sunday.  At 11:00 p.m. EDT on Sunday the center of Hurricane Celia was located at latitude 15.0°N and longitude 123.5°W which put it about 1040 miles (1675 km) west-southwest of the southern tip of Baja California.  Celia was moving toward the west at 13 m.p.h. (20 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 988 mb.

The circulation of Hurricane Celia is well developed.  A primary spiral band loops around the center of circulation and a small eye is apparent intermittently on satellite imagery.  The strongest winds are occurring within 20 miles (30 km) of the center of circulation.  Although there are numerous thunderstorms in the core of Hurricane Celia, they are not as tall as one might expect.  It could be that slightly cooler water was mixed to the surface by Hurricane Blas and the cooler water is causing the thunderstorms to reach their Equilibrium Level at a lower height.  In spite of the shorter thunderstorms, the circulation is generating upper level divergence in all directions.

The environment is favorable for intensification.  Hurricane Celia is moving over water where the Sea Surface Temperature (SST) is near 28°C.  The winds in the upper levels are weak and there is not much vertical wind shear.  Celia could intensify while is remains over warmer SSTs.  The hurricane will start to move over cooler SSTs in about another 24 hours, which will contribute to a less favorable environment.

A subtropical high pressure system north of Celia is steering the hurricane toward the west and that general motion is expected to continue during the next few days.  On its anticipated track Hurricane Celia will continue to move farther away from Mexico.