Monthly Archives: October 2015

Tropical Cyclone Chapala Becomes Equivalent of Cat. 4 Hurricane

Tropical Cyclone Chapala intensified rapidly on Friday and it became the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Chapala was located at latitude 13.9°N and longitude 59.9°E which put it about 405 miles (655 km) east-southeast of Salalah, Oman.  Chapala was moving toward the west-southwest at 5 m.p.h. (8km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h).  The minimum surface pressure was 932 mb.

Tropical Cyclone Chapala is a very well organized tropical cyclone.  It has a well defined eye and a strong core of thunderstorms around the eye.  Those storms generated upper level divergence which pumped out mass and allowed the surface pressure to fall rapidly.

Chapala is an environment favorable for tropical cyclones.  It is over warm Sea Surface Temperatures and the upper level winds are light.  So, there is little vertical wind shear.  However, a secondary eyewall may be developing and eyewall replacement cycles could cause fluctuations in intensity for the next day or two.  When Chapala approaches the Arabian peninsula, it will start to pull in very dry air, and that will weaken the tropical cyclone even before it makes landfall.

A subtropical ridge is steering Chapala toward the west and that general steering motion is expected to continue for another 36 to 48 hours.  As Chapala reaches the western end of the ridge, it could turn more toward the northwest.  Tropical Cyclone Chapala could be approaching the coast of Yemen in 48 to 60 hours.

Tropical Cyclone Chapala Intensifies Rapidly

Tropical Cyclone Chapala intensified rapidly on Thursday and it is almost the equivalent of a major hurricane.  At 11:00 p.m. EDT on Thursday the center of Tropical Cyclone Chapala was located at latitude 14.2°N and longitude 61.5°E which put it about 535 miles (865 km) east-southeast of Salalah, Oman.  Chapala was moving toward the west at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (210 km/h). The minimum surface pressure was 956 mb.

Chapala has a very well organized, symmetrical circulation.  There is a well formed eye which is surrounded by a ring of strong thunderstorms.  Several spiral bands are rotating around the core of the cyclone.  The thunderstorms surrounding the eye are generating upper level divergence which is pumping out mass in all directions.

Tropical Cyclone Chapala is an environment that favors further intensification.  It is over water where the Sea Surface Temperature is around 28°C.  The upper level winds are light and there is not much vertical wind shear.  Chapala could intensify to the equivalent of a Category 4 hurricane on Friday.  After that time eyewall replacement cycles could cause fluctuations in intensity.

A ridge in north of Chapala is steering the tropical cyclone toward the west.  That same general steering motion is expected to continue for another two or three days.  On its anticipated track Tropical Cyclone Chapala could be approaching the area near the border between Oman and Yemen in 48 to 60 hours.  It could be an intense tropical cyclone at that time.

Tropical Cyclone 04A Organizes in the Arabian Sea

A center of circulation organized quickly within a broader area of thunderstorms over the Arabian Sea on Wednesday and the system was designated Tropical Cyclone 04A.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone 04A was located at latitude 13.7°N and longitude 64.0°E which put it about 705 miles east-southeast of Salalah, Oman.  The tropical cyclone was moving toward the west-northwest at 6 m.p.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 993 mb.

The organization of Tropical Cyclone 04A improved significantly on Wednesday.  A primary rainband wrapped almost entirely around the center of circulation and there were indications on various satellite images that an eye could be forming.  Additional rainbands were beginning to form in the circulation outside the core.  Thunderstorms near the center of circulation were generating upper level divergence, especially on the northeast side of the tropical cyclone.

The environment is favorable for further intensification.  Tropical Cyclone 04A is over water where the Sea Surface Temperature is near 28°C.  Although there are strong upper level westerly winds north of the cyclone, the upper level winds over it are relatively light.  As a result there is not a lot of vertical wind shear over Tropical Cyclone 04A.  The cyclone is likely to intensify during the next several days and it could intensify rapidly.  It could attain hurricane intensity in a day or two and it could eventually become the equivalent of a major hurricane.

A ridge north of Tropical Cyclone 04A is steering it slowly toward the west-northwest.  The ridge is expected to continue steering the cyclone toward the west during the next few days.  On its anticipated track Tropical Cyclone 04A could approach the coast of Oman and Yemen in four or five days.

Patricia Is Strongest East Pacific Hurricane on Record

Hurricane Patricia continued to intensify rapidly during the overnight hours and it is now the strongest hurricane on record for the Eastern North Pacific.  At 11:00 a.m. EDT on Friday the center of Hurricane Patricia was located at latitude 17.6°N and longitude 105.5°W which put it about 125 miles (200 km) southwest of Manzanillo, Mexico.  Patricia was moving toward the north at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 200 m.p.h. (320 km) and there were wind gusts to 245 m.p.h. (400 km/h).  The minimum surface pressure was 880 mb.

A Hurricane Warning is in effect for the portion of the coast between Sas Blas and Punta San Telmo, Mexico.  A Tropical Storm Warning and a Hurricane Watch is in effect for the portion of the coast from Punta San Telmo to Lazaro Cardenas, Mexico.

Hurricane Patricia has broken a number of records.  The maximum sustained wind speed increased from 85 m.p.h. to 200 m.p.h. between 5:00 a.m. EDT on Thursday and 5:00 a.m. EDT on Friday.  The rate of increase of 115 m.p.h. in 24 hours is the fastest rate of intensification observed in the Eastern Pacific. It exceeds the 100 m.p.h. in 24 hours that occurred in Hurricane Linda in 1997.  Interestingly, 1997 was also an El Nino year.  The minimum surface pressure of 880 mb is the lowest ever recorded in the National Hurricane Center’s Area of Responsibility which includes the Atlantic and Eastern North Pacific Oceans.  It is lower than the 882 recorded when Hurricane Wilma was over the Caribbean Sea in 2005.

Hurricane Patricia is an extremely dangerous hurricane.  It has a Hurricane Intensity Index (HII) of 50.0, a Hurricane Size Index (HSI) of 11.3 and a Hurricane Wind Intensity Size Index (HWISI) of 61.3.  Those indices mean that Patricia will be capable of causing catastrophic regional damage when it reaches the west coast of Mexico north of Manzanillo later on Friday.  Hurricane Patricia will be capable of causing catastrophic wind damage, generating a potentially destructive storm surge near the coast and producing heavy rain and flooding as it moves inland.

Category 5 Hurricane Patricia Threatens West Coast of Mexico

Hurricane Patricia continued to intensify very rapidly on Thursday night and it reached Category 5 on the Saffir-Simpson Scale.  At 11:00 p.m. EDT on Thursday the center of Hurricane Patricia was located at latitude 16.2°N and longitude 105.1°W which put it about 200 miles (320 km) south-southwest of Manzanillo, Mexico.  Patricia was moving toward the north-northwest at 10 m.p.h.  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h).  The minimum surface pressure was 924 mb.

The government of Mexico has issued a Hurricane Warning for the portion of the coast from San Blas to Punta San Telmo.  A Hurricane Watch and a Tropical Storm Warning is in effect for the portion of the coast from Punta San Telmo to Lazaro Cardenas.

Hurricane Patricia has a Hurricane Intensity Index (HII) of 35.0.  The Hurricane Size Index (HSI) is 12.4 and the Hurricane Wind Intensity Size Index (HWISI) is 47.4.  Those indices mean that Hurricane Patricia is capable of causing catastrophic regional damage.  Hurricane Patricia is currently about the same size that Hurricane Dennis was before Dennis hit the northern coast of the Gulf of Mexico in 2005.  However, Patricia is stronger than Dennis was at that time.

Hurricane Patricia remains in an environment with warm Sea Surface Temperatures and little vertical wind shear.  Only an eyewall replacement cycle could cause weakening in the short term.  When Hurricane Patricia moves farther north, it will start to encounter upper level winds blowing from the southwest, which will increase the wind shear.  The wind shear could start to weaken Patricia later on Friday.

Hurricane Patricia is moving around the western end of ridge and the hurricane has turned toward the north.  When Patricia encounters the southwesterly winds in the upper levels, it will turn toward the northeast.  On its anticipated track Hurricane Patricia could make landfall on the west coast of Mexico between San Blas and Boca de Apiza on Friday night.  Even though Hurricane Patricia could weaken somewhat before it makes landfall, it will still be a very dangerous hurricane.  Hurricane Patricia poses a major threat to cause significant regional wind damage and a storm surge at the coast.  Heavy rain could produce serious flooding, especially as Patricia moves inland over steeper terrain.

Hurricane Patricia Intensifies Rapidly to Category 4

Hurricane Patricia intensified rapidly on Thursday and it reached Category 4 on the Saffir-Simpson Scale.  The maximum sustained wind speed in Patricia increased from 60 m.p.h. to 130 m.p.h. in 24 hours, which qualified as very rapid intensification.  At 5:00 p.m. EDT on Thursday the center of Hurricane Patricia was located at latitude 15.4°N and longitude 104.6°W which put it about 250 miles (400 km) south of Manzanillo, Mexico.  Patricia was moving toward the west-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 953 mb.  The Hurricane Intensity Index (HII) for Patricia was 25.1, the Hurricane Size Index (HSI) was 10.4 and the Hurricane Wind Intensity Size Index was 35.5.  Those indices mean that Patricia is almost as strong and just a little larger than Hurricane Charley was when it hit southwest Florida in 2004.

The government of Mexico has issued a Hurricane Warning for the portion of the coast from San Blas to Punta San Telmo.  It has also issued a Hurricane Watch and a Tropical Storm Warning for the portion of the coast from Punta San Telmo to Lazaro Cardenas.

Patricia is a small hurricane, but it has a very well organized circulation.  A ring of strong thunderstorms surrounds a small, 12 mile (19km), eye (sometimes called a pinhole eye because of the way it looks on satellite images).  Multiple spiral bands are rotating around the core fo the circulation.  Thunderstorms in the core are generating strong upper level divergence in all directions.

Hurricane Patricia remains in a very favorable environment.  It is over water were the Sea Surface Temperature is near 30°C.  An upper level ridge over the top of Patricia is keeping the vertical wind shear to a minimum.  Patricia could intensify further, although if concentric eyewalls develop, then eyewall replacement cycles could produce fluctuations in wind speeds.

Hurricane Patricia is moving around the western end of a ridge that extends from the Gulf of Mexico over Mexico.  When Patricia reaches the end of ridge on Friday, it will turn toward the north.  As the hurricane moves farther north it will encounter westerly winds in the southern end of an upper level trough.  Those winds will turn Hurricane Patricia toward the northeast.

On its anticipated track Hurricane Patricia could approach the west coast of Mexico late on Friday.  It will pose a serious threat to the coast at that time.  Patricia will bring strong winds, heavy rain and a storm surge to the coast.  Very heavy rain could fall as Hurricane Patricia moves inland and serious flooding will be possible, especially in the more mountainous areas of Mexico.  The remnants of Hurricane Patricia could eventually move over parts of Texas and add moisture and rain to that region.

Typhoon Champi Bringing Wind and Rain to Iwo To

A portion of the northern eyewall of Typhoon Champi is over Iwo To and it is bringing wind and rain to the island.  A weather station on Iwo To is reporting east-northeasterly winds at 47 m.p.h. (75 km/h) with gusts to 73 m.p.h. (118 km/h).  At 11:00 p.m. EDT on Wednesday the center of Typhoon Champi was located at latitude 23.8°N and longitude 141.6°E which put it about 75 miles (120 km) south of Iwo To.  Champi was moving toward the northeast at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (230 km/h).  The minimum surface pressure was 945 mb.

The inner core of Typhoon Champi became much more well organized during the past 12 hours and it now has a clear circular eye that is approximately 30 miles (48 km) across.  The eye is surrounded by a ring of strong convection which contains the strongest winds.  The core is also generating upper level divergence which is pumping out mass.

Typhoon Champi will be in a favorable environment for another 12 hours.  It is moving over water where the Sea Surface Temperature is near 28.5°C.  The upper level winds are light and there is not much upper level divergence.  Champi could intensify further on Thursday, but it will move into a less favorable environment when it moves farther north.  Once Champi gets north of latitude 27°N, it will move over cooler SSTs.  Typhoon Champi will start to encounter strong upper level westerly winds at about the same time.  The combination of cooler water and more vertical wind shear will steadily weaken Champi.

Typhoon Champi is moving northward around the western end of a subtropical ridge.  When it reaches the upper level westerly winds, those winds will accelerated Champi toward the east-northeast until it transforms into an extratropical cyclone over cooler waters.  On its anticipated track the center of Champi will pass southeast of Iwo To, but it will bring strong winds and rain to that island for another 12 hours or so.

Tropical Storm Patricia Intensifies Quickly and Mexico Issues Warnings

Tropical Storm Patricia reorganized and intensified quickly on Wednesday and the government of Mexico issued warnings for portions of its west coast.  At 5:00 p.m. EDT on Wednesday the center of Tropical Storm Patricia was located at latitude 13.1°N and longitude 99.5°W, which put it about 265 miles (425 km) south of Acapulco, Mexico and about 515 miles (830 km) southeast of Manzanillo.  Patricia was moving toward the west at 16 m.p.h. (26 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 995 mb.

The government of Mexico has issued a Hurricane Warning for the portion of the coast from Cabo Corrientes to Punta San Telmo.  A Tropical Storm Warning and a Hurricane Watch has been issued for the portion of the coast from Punta San Telmo to Lazaro Cardenas.  A Tropical Storm Watch has been issued for the portion of the coast from Lazaro Cardenas to Tecpan de Galeana.

A NOAA aircraft investigated Tropical Storm Patricia on Wednesday and it found that the center of circulation had reorganized farther west of the remnants of the center that existed on Tuesday.  The new center was west of the northerly low level winds blowing out of the Gulf of Tehuantepec and it was in a more favorable environment.  Thunderstorms are developing near the center of circulation and multiple spiral bands are rotating around the center.

Patricia is moving over water where the Sea Surface Temperature is near 31°C and there is a lot of energy in the upper ocean.  The upper level winds are light and there is not much vertical wind shear.  The lack of wind shear is allowing the thunderstorms near the center to pump out mass and the surface pressure is decreasing.  Patricia will remain a favorable environment until it approaches the west coast of Mexico later this week.  Rapid intensification is likely and Patricia could intensify into a major hurricane before it reaches the coast.

A ridge over the Gulf of Mexico and Mexico is steering Patricia toward the west and that motion is expected to continue for another day or so.  After that time Patricia will reach the western end of the ridge and it will turn toward the north.  On its anticipated track Patricia could be nearing the west coast of Mexico on Friday.

 

Tropical Storm Patricia Forms South of Mexico

A center of circulation began to consolidate inside an area of thunderstorms south of the Gulf of Tehuantepec on Tuesday and the National Hurricane Center designated the system as Tropical Storm Patricia.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Patricia was located at latitude 13.1°N and longitude 95.3°W which put it about 220 miles (355 km) south-southeast of Puerto Escondido, Mexico.  Patricia was moving toward the west-southwest at 5 m.p.h. (8 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 of Tropical Storm Patricia was still organizing on Tuesday.  A cluster of thunderstorms formed northeast of the center of circulation earlier on Tuesday, but those storms weakened during recent hours.  A primary rainband extends around the western and southern side of the circulation.  However, there is not much convection northwest of the center of circulation.

Tropical Storm Patricia is over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level ridge surrounds Patricia and it should produce light winds near the tropical storm.  Warm SSTs and little vertical wind shear should allow for intensification.  However, closer to the surface northerly winds blowing across the Gulf of Tehuantepec could be transporting some drier air toward the western side of the circulation.  The drier air could explain the current lack of thunderstorms in that part of Patricia.  Over time the favorable large scale environment should allow for intensification and Patricia could eventually become a hurricane.

A ridge of high pressure north of Patricia is steering the tropical storm toward the west.  That steering motion is expected to continue for another day or so.  When Patricia reaches the western end of the ridge, it will turn toward the north.  Patricia could be approaching the western coast of Mexico on Friday and it could be a hurricane at that time.

Olaf Becomes a Cat. 4 Hurricane

Hurricane Olaf intensified rapidly on Monday and it reached Category 4 on the Saffir-Simpson Scale.  At 11:00 p.m. EDT on Monday the center of Hurricane Olaf was located at latitude 10.1°N and longitude 139.5°W which put it about 1235 miles (1985 km) east-southeast of Hilo, Hawaii.  Olaf was moving toward the west at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 140 m.p.h. (220 km/h) and there were wind gusts to 165 m.p.h. (270 km/h).  The minimum surface pressure was 949 mb.

Olaf is a small but well organized hurricane.  The core is very symmetrical.  Hurricane Olaf has a clear eye with a diameter of about 12 miles (19 km/h) and the eye is surrounded by a ring of strong thunderstorms.  Several spiral rainbands are rotating around the inner core of the hurricane.  Upper level outflow channels to the northeast and southwest of Olaf are carrying mass away from the center of circulation, which is allowing the surface pressure to decrease.

Hurricane Olaf is moving just south of a band of stronger upper level westerly winds.  It is in an area of modest vertical wind shear.  The ocean beneath Hurricane Olaf has Sea Surface Temperatures  near 29°C.  The compact structure of Olaf allowed the hurricane to efficiently convert energy it extracted from the ocean to kinetic energy associated with higher wind speeds.  Olaf could remain in a favorable environment for another day or two, which may allow for further intensification.  However, if eyewall replacement cycles begin to occur, they will cause fluctuations in the intensity of Hurricane Olaf.

A subtropical ridge north of Olaf is steering the hurricane toward the west and that general steering motion is expected to continue for another day or two.  The western end of the subtropical ridge is expected to weaken later this week and that should allow Olaf to turn toward the north.  On its anticipated track, Olaf would turn toward the north before it reaches the Hawaiian Islands.