Tropical Cyclone Bune (19P) Shows Persistent Deep Convection – March 27th, 2011
Animated multispectral satellite imagery shows persistent deep convection during the past 12 hours. Position confidence is high based on a 27 nm ragged eye appearing at 26/0532z in infrared satellite imagery. A 26/0629z SSMIS 37 ghz microwave image verifies this position as well.
Initial intensity is based on PGTW and PHFO Dvorak estimates of 65 knots. Water vapor imagery indicates radial outflow, and upper level analysis places the system just east of a weak upper level ridge which is ahead of a
much stronger trough.
TC 19P is in a weak steering environment and moving slowly southwestward along the western periphery of a subtropical ridge (STR). The strong mid-latitude trough approaching from the west will begin to erode the STR and result in the system tracking more southward during the next 12-24 hours.
After TAU 36, TC Bune is expected to track southeastward and then begin extratropical transition by TAU 48. As the system continues to turn southeastward ahead of the trough, increased vertical wind shear and decreased sea surface temperatures will cause the system to weaken slightly prior to completing extratropical transition near TAU 72.