Tag Archives: Tropical Storm Karina

Tropical Storm Karina Forms Southwest of Baja California

Tropical Storm Karina formed southwest of Baja California on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Karina was located at latitude 17.6°N and longitude 114.7°W which put it about 480 miles (775 km) southwest of the southern tip of Baja California.  Karina was moving toward the west-northwest at 10 m.p.h. (16 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 1001 mb.

More thunderstorms formed near the center of a low pressure system southwest of Baja California on Sunday and the National Hurricane Center designated the system as Tropical Storm Karina.  The distribution of thunderstorms around Tropical Storm Karina was asymmetrical.  Many of the stronger thunderstorms were occurring in bands in the southwestern part of Karina’s circulation.  Bands in other parts of the tropical storm consisted primarily of showers and lower clouds.  Storms near the center of circulation began to generate upper level divergence which pumped mass away to the west of the tropical storm.  Winds to tropical storm force extended out 90 miles in the southwestern quadrant of Tropical Storm Karina.  Winds in other parts of the circulation were blowing at less than tropical storm force.

Tropical Storm Karina will move through an environment somewhat favorable for intensification during the next 24 hours.  Karina will move over water where the Sea Surface Temperature is near 28°C.  It will move south of an upper level ridge that extends from the southwestern U.S. over the Eastern North Pacific Ocean.  The ridge will produce northeasterly winds which will blow toward the top of Tropical Storm Karina.  Those winds will cause moderate vertical wind shear.  The shear will inhibit intensification, but it will not be strong enough to prevent Karina from intensifying.

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

Tropical Storms Karina and Lowell and the Fujiwhara Effect

I am sometimes asked what happens when two tropical cyclones get close to each other.  The answer depends on the relative size and intensity of the two systems and how close they come to each other.  The Fujiwhara Effect is the name given to the tracks taken by the two vorticies.  If the two tropical cyclones are of nearly equal size and intensity, then they tend to move cyclonically around a center of rotation that is roughly half way between them.  If one cyclone is much bigger and stronger, then the center of rotation is shifted toward the bigger and stronger cyclone.

Tropical Storm Lowell has a large circulation and a maximum sustained wind speed of around 50 m.p.h.  Tropical Storm Karina is located about 700 miles to the west-southwest of Lowell.  Karina has a much smaller circulation and it also has a maximum sustained wind speed of 50 m.p.h.  Some of the models are forecasting that the two tropical storms will rotate around a point closer to Lowell than to Karina (i.e. the Fujiwara Effect).  This would result in Lowell moving general west-northwest and pass to the north of Karina.  The larger circulation of Lowell could also pull Karina back toward the east-northeast as Karina passes south of Lowell.  It is also possible that the circulation of Lowell could be so big that it captures Karina and Karina eventually gets absorbed by Lowell.