Tag Archives: California

Oho Becomes a Hurricane Southeast of Hawaii

The circulation around Tropical Storm Oho became much more organized on Tuesday and it intensified into a hurricane.  At 5:00 p.m. EDT on Tuesday the center of Hurricane Oho was located at latitude 16.6°N and longitude 150.2°W which put it about 385 miles (620 km) east-southeast of Hilo, Hawaii.  Oho was moving toward the northeast at 18 m.p.h. (30 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 975 mb.

A primary rainband wrapped tightly around the center of circulation and created a banded eye feature.  In addition other rainbands developed around the core of the circulation and Oho looks much more like a tropical cyclone today.  Thunderstorms near the center of circulation are generating upper level divergence, especially northeast of the center.  The upper level divergence caused the surface pressure to decrease and the wind speeds to increase.

Hurricane Oho is moving over water where the Sea Surface Temperature (SST) is near 28°C.  The upper level winds are currently fairly light and there is not much vertical wind shear.  The conditions are favorable for intensification and Oho could get stronger during the next 24 hours.  After that time Oho will move over cooler SSTs and the vertical wind shear will increase.  Oho should start to weaken and begin a transition to an an extratropical cyclone.

A large upper level trough north of Hawaii will steer Hurricane Oho toward the northeast during the next few days.  On its anticipated track Oho will pass about 400 miles east of Hawaii.  The extratropical stage of Hurricane Oho could approach the Pacific Northwest in three or four days.

Tropical Storm Oho Passing Southeast of Hawaii

Tropical Storm Oho moved slowly southeast of Hawaii on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Oho was located at latitude 15.0°N and longitude 153.6°W which put it about 340 miles (545 km) south-southeast of Hilo, Hawaii.  Oho was moving toward the northeast at 6 m.p.h. (10 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 984 mb.

Tropical Storm Oho is only partially organized.  A partial eyewall wrapped around the western and southern sides of the center of circulation.  However, most of the stronger thunderstorms are located southwest of the center.  A weak upper level ridge south of Hawaii appears to be generating some northeasterly winds over the top of Oho, which is causing some vertical wind shear.  The wind shear is inhibiting the organization of the circulation of the tropical storm.

Tropical Storm Oho is over water where the Sea Surface Temperature (SST) is near 28.5°C.  The wind shear could decrease on Tuesday and that could allow Oho to increase to hurricane intensity.  Oho will move northward over cooler SSTs later this week.  A combination of cooler water and more vertical wind shear will cause Oho to weaken and make a transition to an extratropical cyclone.

A large upper level trough northwest of Hawaii is expected to move eastward and begin to steer Oho toward the northeast.  On its expected track, Oho will pass southeast of Hawaii.  The extratropical cyclone that is currently Tropical Storm Oho could be approaching the west coast of the U.S. by the weekend.

Tropical Depression 16E Could Bring Heavy Rain to Southwest U.S.

A center of circulation organized within a cluster of thunderstorms west of Baja California on Sunday and the system was designated Tropical Depression Sixteen-E.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression Sixteen-E (TD16E) was located at latitude 25.0°N and longitude 113.7°W which put it about 90 miles (145 km) west of Cabo San Lazaro, Mexico.  TD16E was moving toward the north-northwest at 14 m.p.h. (22 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. (70 km/h).  The minimum surface pressure was 1003 mb.

Tropical Depression 16E has only a few hours before it will move over the central part of Baja California.  Although it is over water where the Sea Surface Temperature is near 27°C little, if any, intensification is expected.  When TD16E crosses Baja California, the terrain and increased vertical wind shear are likely to blow the upper portion of the circulation northward faster than the lower portion of the circulation.  The high clouds could reach parts of the southwestern U.S. within 24 hours.  Moving over mountains will disrupt the lower part of the circulation, but the rotation in the middle levels could persist for several days as it moves northward.

An upper level ridge centered over Texas and an upper level low west of Baja California are combining to steer TD16E northward and that general motion should continue for the next several days.  On its anticipated track TD16E could reach the coast of Baja California near Punta Abreojos in about 12 hours.  It could then move across Baja and the Gulf of California and make a second landfall on the coast west of Hermosillo on Monday morning.  TD16E or its remnants could be approaching southern Arizona later on Monday.  Convection and a flow of moisture associated with TD16E could produce locally heavy rainfall when it is forced to rise of mountains.  It could cause flooding in parts of Baja California, northwestern Mexico and the southwestern U.S.

Dolores Becomes a Major Hurricane

Hurricane Dolores intensified rapidly on Tuesday night and it has reached Major Hurricane status.  At 11:00 a.m. EDT on Wednesday the center of Hurricane Dolores was located at latitude 18.4°N and longitude 110.2°W which put it about 310 miles (500 km) south of Cabo San Lucas, Mexico.  The maximum sustained wind speed was 130 m.p.h. (215 km/h) which made Dolores a Category 3 hurricane on the Saffir-Simpson Scale.  There were wind gusts to 160 m.p.h. (260 km/h) and the minimum surface pressure was 946 mb.

Dolores is currently over water where the Sea Surface Temperature (SST) is around 29°C.  It is generating well developed upper level outflow which is pumping out mass and there is not much vertical wind shear.  Dolores could strengthen some more during the next 24 hours, although eyewall replacement cycles could produce fluctuations in intensity.  When Dolores moves north of latitude 20°N, it will move over cooler SSTs and it should start to weaken.  Given its size and intensity, it could take several days for the circulation around Dolores to spin down.

A ridge in the middle levels is steering Dolores toward the west-northwest.  That general steering pattern is expected to continue during the next few days and Dolores poses no current threat to land.

Hurricane Blanca Heading for West Coast of Baja California

Hurricane Blanca turned toward the north-northwest on Saturday and it appears headed toward the west coast of Baja California.  At 11:00 p.m. EDT on Saturday the center of Hurricane Blanca was located at latitude 19.2°N and longitude 110.4°W which put it about 255 miles (415 km) south of Cabo San Lucas, Mexico.  Blanca was moving toward the north-northwest at 10 m.p.h. (17 km/h).  The maximum sustained wind speed was 120 m.p.h. (185 km/h) and there were gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 952 mb.  The Hurricane Intensity Index (HII) was 22.1, the Hurricane Size Index (HSI) was 20.2 and the Hurricane Wind Intensity Size Index (HWISI) was 42.3.  The government of Mexico has issued a Hurricane Watch for the portion of the coast from Cabo San Lucas to Santa Fe.  A Tropical Storm Warning has been issued for the portion of the coast from Loreto to Puerto San Andresito including Cabo San Lucas.  Tropical Storm Watches have been issued for the portions of the coast from Puerto San Andresito to Punta Abreojos and from Loreto to Mulege.

Hurricane Blanca intensified early on Saturday as it was moving over water where the Sea Surface Temperature (SST) was near 28°C.  It is currently over water where the SST is closer to 27°C and it will move over cooler water when it gets north of latitude 20°N.  As a result it will be unable to extract enough energy from the upper ocean to maintain its current intensity.  An upper level ridge over Mexico also seems to be generating some easterly winds near Blanca and those winds are responsible for vertical wind shear on the eastern half of the circulation.  The combination of shear and cooler SSTs should steadily weaken the hurricane on Sunday.  However, it has a well organized circulation and it will spin down relatively slowly.  The rate of weakening will increase once it moves over SSTs that are cooler than 26°C.  Blanca could still have hurricane force winds when it nears the southern tip of Baja California.

A mid-level ridge over Texas and northern Mexico and a trough over the southwestern U.S. are combining to steer Blanca toward the north-northwest.  That track should continue as long as the vertical structure of the hurricane remains intact.  As Blanca weakens over cooler water, the vertical integrity of the circulation will not be as strong.  Some storms that move just west of Baja California, as Blanca is forecast to do, have the upper portion of their circulation decouple from the lower level circulation.  In those cases the middle and upper level portions of the circulation continue to move northward across Baja California and into the southwestern U.S., while the low level circulation stalls and spins down west of Baja California.  On its anticipated track Blanca could bring some strong winds to portions of southern Baja California, but the greater risks are high waves and locally heavy rainfall that could produce flooding.