west pacific Tropical Storm Leepi

[Somerset Squall]

Tropical Depression 04W has formed about 300 miles east of Manila, Philippines. Sustained winds are currently 25kts. The depression is fairly large and broad but the convection is becoming better organised about the centre with time, and banding features are beginning to take shape. The steering pattern is rather much the same as with TS Yagi last week - a ridge to the east is set to drive 04W northwards for the first 48hrs, followed by a turn towards the east as the 04W reaches the northern extent of the ridge. For about the next 48hrs, shear should remain low, and outflow good. Therefore, 04W should become a tropical storm. JTWC anticipates a peak of 45kts though my hunch would be that 04W may become a little stronger than this but not significantly so. Beyond 48hrs, shear begins to rise and sea temps cool along track, initiating extatropical transition south of Japan.

 

[Somerset Squall]

Tropical Depression 04W has become Tropical Storm Leepi, with sustained winds of 35kts. The storm remains a large and sprawling system with multiple convective bands but unimpressive centralised convection. Leepi should strengthen modestly over the next day or two in a favourable environment, but the storm's structure argues against significant strengthening.

[Somerset Squall]

The large, sprawling nature of Leepi has meant that it has failed to intensify, and remains a 35kt tropical storm. However, just recently convection has deepened near the centre, something that has not occured so far in Leepi's life. As Leepi nears the mid-lattitude westerly wind belt, outflow should improve and the storm should strengthen at least modestly before it runs further north into shear.

[Somerset Squall]

Strong northerly shear has affected Leepi overnight, and the storm remains at 35kt intensity. Convection has been sheared south of a poorly defined LLCC. Leepi has continued to move north, west of Okinawa, and will soon recurve eastwards south of Japan. Extratropical transition will begin very soon as sea temperatures continue to decline and shear remains high. Strengthening of this weak storm is no longer expected.

[Coast]

 

Tropical Storm Leepi Morning Update and a new Tropical Depression

 

Tropical Storm Leepi continues to affect the Miyako Islands of Japan. The storm has also left the Philippine Area of Responsibility earlier this morning. TS Leepi was last located approximately 120km north northwest of Miyako-jima or about 300km west southwest of Okinawa. Maximum sustained winds are at 65kph with gusts of up to 85kph. TS Leepi is moving northward at 25kph.

 

VIS Image from NRLMRY

 

 

Latest visible satellite image shows that Leepi is starting to feel the effects of the increase in wind shear. Convective activity is now more confined on the southern semi-circle with the low-level center becoming slightly exposed. We are also seeing multiple vortices forming and rotating around Leepi’s true center.

 

Radar Image from JMA

 

 

Leepi moved near the Miyako Islands earlier this morning bringing gusty winds and moderate rains. Many stations in the islands have reported seeing winds of up to 100kph along with rainfall amounts of 50 to even 80mm. Most of the bands are now moving away from Miyako although residual rains may still impact the region. Meanwhile, Okinawa should start seeing isolated rain showers beginning this afternoon. For the latest rainfall reports and radar images out of Japan, click HERE (JMA Website).

 

Tropical Storm Leepi will move just west of Okinawa later this afternoon. The system is forecast to start accelerating and turning more to the northeast as it rounds the sub-tropical ridge. Leepi is also forecast to move very near the Kyushu Island by Friday morning. By then, the system should begin transitioning into an extra-tropical cyclone as it interacts with the baroclinic zone.

 

Meanwhile, a new Tropical Depression has been classified by the Japan Meteorological Agency. This new system is located in the South China Sea, just west of the Philippine Islands. This system (also classified as Invest 94W by the NRLMRY) is exhibiting strong convective activity and an improving curved banding near the center. JMA expects it to become a Tropical Storm within 24 hours while the Joint Typhoon Warning Center (JTWC) has upgraded the system’s chance to MEDIUM.

 

 

http://www.westernpacificweather.com/2013/06/20/tropical-storm-leepi-morning-update-and-a-new-tropical-depression/

 

 

 

[Somerset Squall]

Leepi degenerated into a remnant low last night south of South Korea. The remnant low is now extratropical moving eastwards south of Japan.