Typhoon Mekkhala strengthened to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Monday as it moved over the Western North Pacific Ocean east of northern Luzon.  At 11:00 a.m. EDT on Monday the center of Typhoon Mekkhala was located at latitude 18.3°N and longitude 125.9°E which put the center about 305 miles (490 km) east of Aparri, Philippines.  Mekkhala was moving toward the west-northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 937 mb.

Typhoon Mekkhala strengthened to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Monday.  A circular eye with a diameter of 25 miles (40 km) was present at the center of Typhoon Mekkhala.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Mekkhala’s circulation.  Storms near the center of Mekkhala generated strong upper level divergence that pumped mass away from the typhoon.  The removal of large amounts of mass caused the surface pressure to decrease.

The distribution of winds speeds in Typhoon Mekkhala was fairly symmetrical.  Winds to typhoon force extended out 25 miles (40 km) from the center of Mekkhala’s circulation.  Winds to tropical storm force extended out 140 miles (225 km) from the center of Typhoon Mekkhala.

The Hurricane Intensity Index (HII) for Typhoon Mekkhala is 29.9. The Hurricane Size Index (HSI) is 10.0 and the Hurricane Wind Intensity Size Index (HWISI) is 39.9.  Typhoon Mekkhala is similar in intensity to Hurricane Charley when Charley hit Southwest Florida in 2004.  Mekkhala is a little larger than Charley was.

Typhoon Mekkhala will move through an environment favorable for intensification during the next 24 hours.  Mekkhala will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the middle of an upper level ridge that is southwest of Japan. The upper level winds are weak in the middle of the ridge and there will be little vertical wind shear.  Typhoon Mekhala could intensify during the next 24 hours unless the inner end of a rainband wraps around the existing eye and eyewall.  If concentric eyewalls form, then an eyewall replacement cycle would cause Mekkhala to weaken.  Typhoon Mekkhala could strengthen to the equivalent of a Category 5 hurricane, if there is no eyewall replacement cycle.

Typhoon Mekkhala will move around the southwestern part of a high pressure system over the Western North Pacific Ocean.  The high pressure system will steer Mekkhala toward the northwest during the next 24 hours.  On its anticipated track, Typhoon Mekkhala will move toward the southern Ryukyu Islands.  Mekkhala could approach the southern Ryukyu Islands in 60 hours.