Friday, October 12, 2012

Tropical Storm Patty (2012)

Storm Active: October 11-13

On October 11, a low pressure center formed at the tail end of a frontal boundary extending from the northeast Atlantic down to near Hispaniola. Disturbed weather increased near the low during the following day, as the low became disassociated with the trough to its northeast.

Over the next several days, another frontal boundary began to approach the low, causing a sharp increase in wind shear. However, the low did not get caught in the flow ahead of the front, but instead remained nearly stationary just to the northeast of the Bahamas through October 10. Despite being expected to merge with the front, the system maintained its identity, and in fact became more organized, as thunderstorm activity concentrated near the center.

By the afternoon of October 11, the low had achieved enough deep convection to be considered a tropical cyclone and so was classified Tropical Depression Sixteen. That evening, the convection increased and covered the exposed circulation, and the cyclone was therefore updated to Tropical Storm Patty. Late that night, Patty unexpectedly strengthened further, and reached its peak intensity of 45 mph winds and a pressure of 1005 mb.

On October 12, a combination of strong southwesterly upper-level winds and a northeasterly low-level flow started to pull the circulation apart. Patty weakened to a tropical depression that evening as the center once again became completely exposed. By the morning of October 13, the circulation was no longer closed, and Patty was declared a remnant low. The remnants combined with a trough of the U.S. east coast shortly afterward.

Patty as a disorganized tropical storm struggling to survive just north of the Bahamas.

Track of the short-lived Patty. Most of the positions indicate occurred when the cyclone was non-tropical (triangles), with only the tiny clump of circles accounting for Patty's time as a tropical cyclone, in which it moved little.

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