Tag Archives: Invest 99P

Two Tropical Lows Form over South Pacific

Two tropical lows formed over the South Pacific Ocean on Saturday morning. The first Tropical Low formed over the Coral Sea east of the Cape York Peninsula. At 7:00 a.m. EST on Saturday the center of that Tropical Low was located at latitude 13.0°S and longitude 147.8°E which put it about 240 miles (350 km) northeast of Cooktown, Australia. The Tropical Low was nearly stationary. The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h). The minimum surface pressure was 1004 mb.

A well defined low level center of circulation formed in a small low pressure system over the Coral Sea on Saturday morning and the Australian Bureau of Meteorology designated the system as a Tropical Low. A Watch was issued for the portion of the east coast of the Cape York Peninsula from Cape Grenville to Cape Tribulation. The distribution of thunderstorms around the Tropical Low was asymmetrical. The distribution of thunderstorms around the Tropical Low was asymmetrical. The strongest thunderstorms were occurring in bands in the northwestern quadrant of the circulation. Bands in other parts of the circulation consisted primarily of showers and lower clouds. Storms near the center began to generate upper level divergence that pumped mass away from the Tropical Low.

The Tropical Low will move through an environment somewhat favorable for intensification during the next 24 hours. The Tropical Low will move over water where the Sea Surface Temperatures are near 30˚C. It will move under the northwestern part of an upper level ridge centered east of Australia. The ridge will produce easterly winds that will blow toward the top of the Tropical Low’s circulation. Those winds will cause some vertical wind shear and the shear will inhibit intensification. The Tropical Low could intensify gradually during the next 24 hours.

The Tropical Low will move north of a high pressure system centered east of Australia. The high pressure system will steer the Tropical Low toward the west during the next 24 hours. On its anticipate track the Tropical Low could approach the eastern Cape York Peninsula between Lockhart River and Cooktown in 36 hours. It could be a named tropical cyclone when it approaches the coast.

The second Tropical Low developed over the South Pacific Ocean west of Fiji. At 10:00 a.m. EST on Saturday the center of the second Tropical Low was located at latitude 18.6°S and longitude 173.3°E which put it about 320 miles (515 km) west-southwest of Nadi, Fiji. That Tropical Low was moving toward the southeast at 4 m.p.h. (6 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 1000 mb.

A distinct low level center of circulation developed in a large low pressure system over the South Pacific Ocean west of Fiji and the Fiji Meteorological Service designated the system as a tropical low. The circulation around the second Tropical Low was much larger than the one over the Coral Sea, but the distribution of thunderstorms was also asymmetrical. The strongest thunderstorms were occurring in bands north and east of the center of circulation. Bands south and west of the center consisted primarily of showers and lower clouds. Storms near the center generated upper level divergence that pumped mass away from Tropical Low.

The second Tropical Low will move through an environment favorable for intensification during the next 24 hours. The Tropical Low will move over water where the Sea Surface Temperatures are near 30˚C. It will move through an area where the upper level winds are weak and there will be little vertical wind shear. The Tropical Low is likely to intensify into a named tropical cyclone during the next 24 hours.

The second Tropical Low will be in an area where the steering currents are weak during the next 24 hours. It is likely to meander slowly over the South Pacific Ocean between Fiji and Vanuatu during the next day or so.

Tropical Low Strengthens Over Gulf of Carpentaria

A Tropical Low designated as Invest 99P by some agencies strengthened over the Gulf of Carpentaria on Saturday.  At 4:00 p.m. EST on Saturday the center of the Tropical Low was located at latitude 14.3°S and longitude 138.2°E which put it about 110 miles (180 km) east of Groote Eylandt, Australia.  The Tropical Low was moving toward the south at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h).  The minimum surface pressure was 1000 mb.

The Australian Bureau of Meteorology issued a Warning for the portion of the coast from Numbulwar to Kowanyama including Mornington Island.

More bands of thunderstorms began to develop around a Tropical Low on Saturday.  The bands were revolving around the center of circulation.  The Tropical Low will move through an environment favorable for intensification during the next 24 hours.  It will move over water where the Sea Surface Temperature is near 30°C.  The Tropical Low is under an upper level ridge and the upper level winds are weak.  There will be little vertical wind shear and the Tropical Low is forecast to strengthen into a tropical cyclone.

The Tropical Low will move around the western end of a high pressure system.  The high will steer the Low toward the south.  On its anticipated track the Tropical Low will approach the coast of Australia near the border between Queensland and the Northern Territory.  It will bring gusty winds and locally heavy rain.  Heavy rain could cause flash floods in some locations.