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Tropical Cyclone Three South-Southwest of Karachi, Pakistan

13.9N 54.8E

June 1st, 2010 Category: Tropical Storms

Tropical Storm Three (03A) - May 31st, 2010

Tropical Storm Three (03A) - May 31st, 2010

Enhanced image

Enhanced image

Track of TC 03A - March 31st, 2010 © Univ. of Wisconsin

Track of TC 03A

Tropical Cyclone Three (TC03A), located approximately 570 nm south-southwest of Karachi, Pakistan, has tracked north-northwestward at 4 knots over the past six hours.

Animated infrared satellite imagery indicates that TC03A has continued to consolidate with improved convective banding and central convection despite light to moderate, easterly vertical wind shear (VWS).

A NOAA-18 89 ghz image depicts multiple convective bands over the western semi-circle with the center positioned on the northeastern edge of a deep convective burst. There is fair confidence in the current position based on this image.

TC 03A is forecast to intensify at a 10-15 knot per day rate but will weaken rapidly after making landfall near TAU 96 and will dissipate by TAU 120. Maximum significant wave height is 17 feet.

The current intensity is assessed at 35 knots and is based on Dvorak estimates of 35 knots. Recent buoy observations near the center also support a strengthening system. A buoy 110 nm south-southeast indicated SLP near 1002.2 mb and SST of 30C, and a buoy 110 nm north indicated SLP near 1000.0 mb and SST near 31C.

The LLCC is located within a generally favorable environment under an upper-level anticyclone with good outflow aloft. As indicated on the total precipitable water product, the system has a deep moisture envelope. VWS has decreased slightly over the past 12 hours and is expected to decrease further within the next 12-24 hours.

TC 03A is tracking slowly along the western periphery of the low- to mid-level subtropical ridge (STR), which is centered over western, central India. The system is expected to track slowly northward but should accelerate by TAU 48 as the STR builds.

By TAU 72, TC 03A should turn northeastward and accelerate as the system crests the STR axis and moves under the influence of a deepening midlatitude shortwave trough. The majority of the model guidance supports this track with the exception of WBAR, which shows a slow westward track.

Both the GFS and GFDN display erroneous tracks through TAU 48 but come into better agreement in the extended TAUs. The GFS 500 mb heights and vorticity indicate two vorticity maxima rotating cyclonically within an elongated circulation. This error accounts for the erroneous north-northwestward track through TAU 48.

The GFDN indicates an unrealistic eastward track into the steering ridge through TAU 24. Since these errors appear to offset each other, this forecast is close to but faster than the consensus. The ECMWF solution supports the current forecast and is close to the model consensus.

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