Tag Archives: 18E

Tropical Storm Nora Moves Into the Central Pacific

Tropical Storm Nora moved west of longitude 140°W on Sunday which meant that it officially crossed from the Eastern North Pacific into the Central North Pacific Ocean.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Nora was located at latitude 13.5°N and longitude 143.8°W which put it about 860 miles (1385 km) east-southeast of Hilo, Hawaii.  Nora was moving toward the west-northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 m.p.h.).  The minimum surface pressure was 993 mb.

Nora is a small tropical storm.  Wind to tropical storm force only extend out about 70 miles (110 km) from the center of circulation.  Most of the stronger thunderstorms are located northwest of the center of circulation and there is not much deep convection in the other parts of Nora.  Although Nora is over water where the Sea Surface Temperature is near 29°C, southerly winds in the upper levels appear to be causing vertical wind shear.  The wind shear is likely to increase as an upper level trough north of Hawaii gets closer to Nora.

Tropical Storm Nora is nearing the western end of a subtropical ridge which has been steering it toward the west.  If the vertical structure of Nora remains intact, the tropical storm should turn toward the north during the next day or two.  After that time the upper level trough north of Hawaii could sweep Nora toward the northeast.  An alternate and possibly more likely scenario, given the small size of Tropical Storm Nora, is that the vertical wind shear blows the upper portion of the circulation north of the surface circulation.  If that happens, then the surface circulation will be steered westward until it dissipates by the winds in the lower atmosphere.

Tropical Storm Nora Form Far East of Hawaii

Another Tropical Cyclone has formed over the Eastern North Pacific Ocean well east of Hawaii and the National Hurricane Center has upgraded Tropical Depression 18-E to Tropical Storm Nora.  At 11:00 p.m. EDT on Friday the center of Tropical Storm Nora was located at latitude 11.3°N and longitude 135.1°W which put it about 1470 miles (2365 km) east-southeast of South Point Hawaii.  Nora was moving toward the west at 16 m.p.h. (26 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 1006 mb.

The circulation inside Tropical Storm Nora is still in the process of organizing.  There is one primary rainband that wraps around the western and southern side of the tropical storm.  More thunderstorms are forming near the center, but a clearly defined core of convection has not yet developed.  The storms close to the center of circulation are producing more upper level divergence which is pumping out mass.

Tropical Storm Nora is in an environment that favors intensification,   The Sea Surface Temperature is warmer than 29°C,  The upper level winds are light and there is not much upper level divergence.  Nora is expected to intensify gradually into a hurricane.  Once a tight, well organized inner core develops, it could intensify more quickly.

A subtropical ridge north of Nora is steering the tropical storm westward.  That general steering pattern is expected to continue for another day or two.  When Nora reaches the western end of the subtropical ridge, it is expected to turn toward the north.