Tag Archives: 12E

Tropical Storm Jova Develops South of Baja California

A center of circulation developed within the remnants of former Hurricane Franklin on Friday and the National Hurricane Center designated the low pressure system as Tropical Storm Jova.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Jova was located at latitude 19.3°N and longitude 109.8°W which put it 250 miles (400 km) south of the southern tip of Baja California.  Jova 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 1003 mb.

The surface center of former Hurricane Franklin was disrupted as it passed over the mountains in Mexico.  However, the middle and upper portions of the circulation crossed the mountains relatively intact.  When the upper parts of the former hurricane emerged over the Eastern North Pacific Ocean, it took nearly a day for the vertical transfer of kinetic energy to spin up a new surface circulation.  Eventually a new surface circulation developed and the National Hurricane Center (NHC) classified the system as Tropical Storm Jova.  Established protocol is that when NHC ceases issuing an advisories on a tropical cyclone, the system is given a new name if it redevelops in a different basin.

The circulation of Tropical Storm Jova is broad, but winds to tropical storm force are occurring primarily in the northeastern quadrant of the circulation.  Most of the thunderstorms are occurring in a band that wraps around the western and southern sides of the center of circulation.  There are fewer thunderstorms in the eastern and northern sides of Tropical Storm Jova,  There is a broad counterclockwise circulation and a distinct center, but the horizontal structure is not well organized.

Tropical Storm Jova will be moving through an environment favorable for intensification during the next 24 hours.  Jova will move over water where the Sea Surface Temperature is near 30°C.  An upper lever ridge over northern Mexico is producing easterly winds which are blowing toward the top of the tropical storm.  Those winds are generating vertical wind shear.  The shear is moderate and it will inhibit intensification.  Tropical Storm is likely to intensify during the next 24 hours, but the broad circulation and vertical wind shear will limit the intensification.  In a day or two Tropical Storm Jova will move over cooler Sea Surface Temperatures and it will start to weaken.

A ridge in the middle levels is steering Tropical Storm Jova toward the west-northwest.  The ridge is expected to steer Tropical Storm Jova toward the west during the next several days.  On its anticipated track Tropical Storm Jova will move farther west of Mexico.

Tropical Storm Kay Forms South of Baja California

A distinct center of circulation consolidated within a cluster of thunderstorms south of Baja California and the National Hurricane Center designated the system as Tropical Storm Kay.  At 5:00 a.m. EDT on Friday the center of Tropical Storm Kay was located at latitude 18.4°N and longitude 110.9°W which put it about 315 miles (510 km) south-southwest of the southern tip of Baja California.  Kay 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.

The circulation of Tropical Storm Kay is only moderately well organized.  Most of the stronger thunderstorms are occurring in a band that wraps around the western side of the circulation.  There are also scattered thunderstorms in broken bands around the tropical storm, but much of the convection is occurring in the western half of Kay.  The thunderstorms in the primary rainband are generating some upper level divergence which is moving air to the west of the Tropical Storm Kay.

Tropical Storm Kay is moving through an environment that is marginally favorable for intensification in the short term.  Kay is moving over water where the Sea Surface Temperature (SST) is near 29°C.  An upper level ridge to the north of Kay is generating northeasterly winds which are blowing across the top of the tropical storm.  The moderate vertical wind shear is inhibiting intensification and it is also contributing to the asymmetrical distribution of thunderstorms.  The effect of the warm SSTs could allow for some additional intensification during the next 24 hours.  Tropical Storm Kay will be moving over cooler SSTs during the weekend and the effect of the effect of the cooler water with less energy will weaken the storm.

Tropical Storm Kay is moving around the western end of a subtropical ridge and that is steering the storm toward the northwest.  That general motion is expected to continue for another 24 to 48 hours.  When Tropical Storm Kay moves over cooler SSTs, the thunderstorms will weaken and the circulation will become shallower.  The shallower circulation will be steered by the winds closer to the surface, which are expected to turn Tropical Storm Kay more toward the west in a couple of days.  On its anticipated track Tropical Storm Kay will pass west of Baja California.

Trio of Cat. 4 Hurricanes Churn Across the Pacific

A trio of powerful Category 4 hurricanes on the Saffir-Simpson Scale churned across the Central and Eastern North Pacific on Saturday night.  At 11:00 p.m. EDT on Saturday the center of Hurricane Ignacio was located at latitude 17.0°N and longitude 147.6°W which put it about 525 miles (845 km) east-southeast of Hilo, Hawaii.  Ignacio was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there wind gusts to 170 m.p.h. (275 km/h).  The minimum surface pressure was 951 mb.

At 11:00 p.m. EDT on Saturday the center of Hurricane Jimena was located at latitude 13.3°N and longitude 127.5°W which put it about 1330 miles (2140 km) west-southwest of the southern tip of Baja California.  Jimena was moving toward the west-northwest at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there were wind gusts to 170 m.p.h. (275 km/h).  The minimum surface pressure was 945 mb.

At 11:00 p.m. EDT on Saturday the center of Hurricane Kilo was located at latitude 18.4°N and longitude 176.2°W which put it about 680 miles (1095 km) south of Midway Island.  Kilo was moving toward the west-northwest at 9 m.p.h.  The maximum sustained wind speed was 135 m.p.h. (215 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 948 mb.

Ignacio is the only one of the three powerful hurricane to pose an imminent threat to land.  On its anticipated track Ignacio could be northeast of the Big Island of Hawaii in about 48 hours.  Tropical Storm Watches have been issued for Hawaii County and Maui County including the islands of Maui, Molokai, Lanai and Kahoolawe.  An upper level trough passing north of Hawaii will cause westerly winds and increasing vertical wind shear over Ignacio as it moves closer to Hawaii.  Ignacio should weaken but it could still be a hurricane when it makes its closest approach to Hawaii.  Given the size of the circulation around Ignacio, Tropical Storm Watches were issued for some of the islands.

Jimena may be the most well organized of the three hurricanes.  It has concentric eyewalls and a very symmetrical structure.  Eyewall replacement cycles will cause fluctuations in the intensity of Jimena.  However, it is in a very favorable environment and it could reach Category 5 intensity at some point.  Fortunately, Jimena is about 1500 miles (2420 km) east of Ignacio and it is a long way from any land area.

After days when strong vertical wind shear kept Kilo a weak disorganized tropical depression, it intensified very rapidly during the past 48 hours.  Kilo is over warm Sea Surface Temperatures  and it could intensify a little more.  Kilo is not currently a threat to any land.