Tag Archives: EP09

Tropical Storm Howard Forms South of Baja California

Tropical Storm Howard formed over the Eastern North Pacific Ocean south of Baja California on Sunday afternoon. At 5:00 p.m. EDT on Sunday the center of Tropical Storm Howard was located at latitude 17.6°N and longitude 110.7°W which put it about 370 miles (595 km) south of the southern tip of Baja California. Howard was moving toward the northwest 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 1004 mb.

The circulation around former Tropical Depression Nine-E strengthened on Sunday afternoon and the National Hurricane Center designated the system as Tropical Storm Howard. The distribution of thunderstorms in Tropical Storm Howard was asymmetrical. The strongest thunderstorms were occurring in bands in the northern side of Howard’s circulation. Bands in the southern half of the circulation consisted primarily of showers and lower clouds. A small upper level low located southwest of Howard was causing southerly winds that were blowing toward the top of the tropical storm. Those winds were causing vertical wind shear. The vertical wind shear was allowing drier air to flow into the southern half of Tropical Storm Howard. The vertical wind shear and the drier air were causing the asymmetrical distribution of thunderstorms. Storms near the center of Howard’s circulation generated upper level divergence that pumped mass away to the north and east of the tropical storm. Winds to tropical storm force extended out 60 miles in the northern side of Tropical Storm Howard. The winds in the southern half of the circulation were blowing at less than tropical storm force.

Tropical Storm Howard will move through an environment favorable for intensification during the next 24 hours. Howard will move over water where the Sea Surface Temperatures are near 27˚C. The small upper level low southwest of Howard’s circulation is forecast to weaken. If the upper level low weakens, then the wind shear will decrease. If the wind shear decreases, then less drier air will flow into the southern part of the circulation. Tropical Storm Howard is forecast to strengthen during the next 24 hours.

Tropical Storm Howard will move around the southwestern part of a high pressure system over northern Mexico. The high pressure system will steer Howard toward the northwest during the next 24 hours. On its anticipated track Tropical Storm Howard is forecast to move parallel to the coast of southern Baja California. The center of Howard will remain 300 miles (480 km) west of southern Baja California during the next 24 hours.

Tropical Storm Jimena Develops East-southeast of Hawaii

Tropical Storm Jimena developed east-southeast of Hawaii on Thursday morning. At 5:00 a.m. EDT on Thursday the center of Tropical Storm Jimena was located at latitude 15.5°N and longitude 136.6°W which put it about 1265 miles (2040 km) east-southeast of Hilo, Hawaii. Jimena was moving toward the northwest at 7 m.p.h. (11 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.

More thunderstorms developed near the center of former Tropical Depression Nine-E on Thursday morning and the National Hurricane Center upgraded the system to Tropical Storm Jimena. The circulation around Jimena was asymmetrical. Many of the stronger thunderstorms were developing in the eastern half of Tropical Storm Jimena. Bands in the western half of Jimena consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 40 miles (65 km) in the northeastern quadrant of the circulation. The winds in the other parts of Jimena were blowing at less that tropical storm force.

Tropical Storm Jimena will move through an environment only marginally favorable for intensification during the next 24 hours. Jimena will move over water where the Sea Surface Temperatures are near 26°C. It will move through an area where the upper level winds are weak and there will be little vertical wind shear. Tropical Storm Jimena will move over cooler water on Friday. Jimena could strengthen a little during the next 24 hours, but it is likely to weaken when it moves over cooler water.

Tropical Storm Jimena will move around the southern side of a subtropical high pressure system over the Eastern North Pacific Ocean. The high will steer Jimena toward the west-northwest during the next several days. On its anticipated track Tropical Storm Jimena could be east-northeast of Hawaii in a few days.

Elsewhere over the Eastern North Pacific Ocean, Tropical Storm Hilda was weakening to the northeast of Tropical Storm Jimena. At 5:00 a.m. EDT on Thursday the center of Tropical Storm Hilda was located at latitude 20.1°N and longitude 129.2°W which put it about 1255 miles (2020 km) west of the southern tip of Baja California. Hilda was moving toward the west-northwest at 9 m.p.h. (15 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.

Hilda Intensifies to a Hurricane

Former Tropical Storm Hilda intensified to a hurricane over the Eastern North Pacific Ocean on Saturday night. At 11:00 p.m. EDT on Saturday the center of Hurricane Hilda was located at latitude 14.3°N and longitude 118.7°W which put it about 825 miles (1330 km) southwest of the southern tip of Baja California. Hilda was moving toward the west-northwest 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 985 mb.

Former Tropical Storm Hilda intensified rapidly to a hurricane on Saturday. The inner end of a rainband wrapped around the center of Hurricane Hilda and an eye appeared to be forming. Bands of showers and thunderstorms were revolving around the core of Hilda. Storms near the core generated upper level divergence that pumped mass away from the hurricane. Winds to hurricane force extended out 25 miles (40 km) from the center of Hilda. Winds to tropical storm force extended out 90 miles (145 km) from the center of circulation.

Hurricane Hilda will move through an environment favorable for intensification during the next 24 hours. Hilda will move over water where the Sea Surface Temperatures are near 28°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Hurricane Hilda is likely to continue to intensify on Sunday.

Hurricane Hilda will move south of a high pressure system over the Eastern North Pacific Ocean. The high will steer Hilda toward the west-northwest during the next several days. On its anticipated track Tropical Storm Hilda will continue to move farther away from Baja California.

Elsewhere, Tropical Depression Nine-E stalled west of Hurricane Hilda on Friday. At 11:00 p.m. EDT on Saturday the center of Tropical Depression Nine-E was located at latitude 11.5°N and longitude 127.5°W which put it about 1400 miles (2255 km) west-southwest of the southern tip of Baja California. The depression was stationary. 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 1007 mb.

Tropical Storm Hilda Develops South of Baja California

Tropical Storm Hilda developed south of Baja California on Friday. At 11:00 p.m. EDT on Friday the center of Tropical Storm Hilda was located at latitude 13.2°N and longitude 114.6°W which put it about 735 miles (1185 km) south-southwest of the southern tip of Baja California. Hilda was moving toward the west-northwest at 15 m.p.h. (24 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.

The circulation around a low pressure system south of Baja California exhibited more organization on Friday and the National Hurricane Center designated the system as Tropical Storm Hilda. The circulation around Tropical Storm Hilda was asymmetrical. A band of thunderstorms was wrapping around the western side of the center of Hilda. Other bands of showers and thunderstorms were revolving around the center of circulation. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 100 miles (160 km) to the east of the center of Tropical Storm Hilda. Winds in the western side of Hilda were blowing at less than tropical storm force.

Tropical Storm Hilda will move through an environment favorable for intensification during the next 36 hours. Hilda will move over water where the Sea Surface Temperatures are near 28°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Tropical Storm Hilda will intensify on Saturday and it could intensify to a hurricane during the next 36 hours.

Tropical Storm Hilda will move south of a high pressure system over the Eastern North Pacific Ocean. The high will steer Hilda toward the west-northwest during the next several days. On its anticipated track Tropical Storm Hilda will move farther away from Baja California.

Elsewhere, Tropical Depression Nine-E developed west of Tropical Storm Hilda on Friday. At 11:00 p.m. EDT on Friday the center of Tropical Depression Nine-E was located at latitude 12.5°N and longitude 126.2°W which put it about 1290 miles (2075 km) southwest of the southern tip of Baja California. The depression was moving toward the west at 6 m.p.h. (10 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 1007 mb.

Elida Strengthens to a Hurricane South of Baja California

Former Tropical Storm Elida strengthened to a hurricane south of Baja California on Monday afternoon.  At 5:00 p.m. EDT on Monday the center of Hurricane Elida was located at latitude 19.6°N and longitude 110.9°W which put it about 235 miles (380 km) south-southwest of the southern tip of Baja California.  Elida was moving toward the west-northwest at 14 m.p.h. (22 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 990 mb.

The circulation around Hurricane Elida exhibited better organization on Monday afternoon.  The inner end of a rainband was wrapping around the center of circulation.  Bands of showers and thunderstorms were revolving around the core of Elida.  The strongest thunderstorms were in bands in the southern and eastern parts of the hurricane.  Bands in the northwestern part of the circulation consisted primarily of showers and lower clouds.  Storms near the core of Elida were generating upper level divergence which was pumping mass away from the hurricane.  Winds to hurricane force extended out 20 miles (30 km) on the eastern side of the circulation.  Winds to tropical storm force extended out 70 miles (110 km) from the center.

Hurricane Elida will move through an environment favorable for intensification during the next 24 hours.  Elida will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Elida will strengthen on Tuesday.  Elida will move over cooler water during the middle of the week, which will cause it to weaken.

Hurricane Elida will move around the southern part of an ridge of high pressure that extended from northern Mexico over the Eastern North Pacific Ocean.  The ridge will steer Elida toward the west-northwest during the next several days.  On its anticipated track Hurricane Elida will gradually move farther away from Baja California.

Tropical Storm Elida Forms Southwest of Mexico

Tropical Storm Elida formed southwest of Mexico on Sunday morning.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Elida was located at latitude 16.4°N and longitude 105.4°W which put it about 195 miles (310 km) south-southwest of Manzanillo,, Mexico.  Elida was moving toward the west-northwest at 17 m.p.h. (28 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 1005 mb.

The circulation around former Tropical Depression Nine-E exhibited much more organization on Sunday morning and the National Hurricane Center designated the system as Tropical Storm Elida.  Microwave satellite imagery suggested than an eye could be forming at the center of Elida.  A band of thunderstorms wrapped around the eastern side of the center of circulation and the band could represent the beginning of an eyewall.  Other bands of showers and thunderstorms were revolving around the core of Elida.  Storms near the core were generating upper level divergence which was pumping mass away from the tropical storm.  Winds to tropical storm force extended out about 50 miles (80 km) from the center of circulation.

Tropical Storm Elida will move through an environment favorable for intensification during the next several days.  Elida will move over water where the Sea Surface Temperature is near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical storm Elida will continue to intensify and it could strengthen into a hurricane within 24 hours.  Elida could rapidly intensify if an eye and eyewall form and it could strengthen into a major hurricane within 48 to 72 hours.

Tropical Storm Elida will move south of a ridge that extends from northern Mexico over the Eastern North Pacific Ocean.  The ridge will steer Elida toward the west-northwest during the next few days.  On its anticipated track Tropical Storm Elida will pass south of Baja California.

Tropical Storm Henriette Forms Southwest of Baja California

Tropical Storm Henriette formed southwest of Baja California on Monday.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Henriette was located at latitude 19.7°N and longitude 112.2°W which put it about 265 miles (430 km) southwest of the southern tip of Baja California.  Henriette was moving toward the west-northwest 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 1005 mb.

The distribution of thunderstorms around Tropical Storm Henriette was highly asymmetrical.  Most of the thunderstorms were occurring southwest of the center of circulation.  Bands in other parts of the circulation consisted primarily of showers and lower clouds.  Tropical Storm Henriette was south of a narrow upper level ridge.  The ridge was producing northeasterly winds which were blowing across the top of Henriette.  Those winds were causing strong vertical wind shear and they were the cause of the asymmetrical distribution of thunderstorms.

Tropical Storm Henriette will be moving through a region that will be mostly unfavorable for intensification.  Henriette will move over water where the Sea Surface Temperature is near 28.5°C.  So, there will be sufficient energy in the upper ocean to support intensification.  However, the upper level ridge will continue to cause strong vertical wind shear which will prevent intensification.  Tropical Storm Henriette is likely to weaken in a day or two when it moves over colder water.

Tropical Storm Henriette will move south of a subtropical ridge over the Eastern North Pacific Ocean.  The ridge will steer Henriette toward the west-northwest during the next several days.  On its anticipated track Tropical Storm Henriette will move farther away from Baja California.

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.