Around August 29, an upper-level low pressure area began to produce thunderstorm activity over the northeastern Gulf of Mexico. It moved over land shortly afterward, which temporarily stifled development. On the 30th, the system emerged over the Atlantic just east of Georgia and developed a surface circulation. It was moving around the northwestern edge of a ridge, and followed the boundary northeast. By the afternoon of August 31, enough convection had appeared near the center for the low to be upgraded to Tropical Depression Fifteen.
The depression was located over warm water, but it was quickly moving into an area with higher shear out of the west. As a result, the center swirl remained exposed on satellite imagery. Winds increased a little in the thunderstorms east of the center on September 1, which bumped up the system to tropical storm strength. It was named Tropical Storm Omar (the name Nana was given to a western Caribbean storm earlier that same afternoon). The earliest "O" storm record fell; it was previously held jointly by 2005's Ophelia, which was named on September 7, and 2011's Nate, which was named also on that date. The 15th "named" storm was the "N" storm and not the "O" in 2011 because of the unnamed tropical storm that formed August 31 of that year.
Omar put up a decent fight against unfavorable upper-level winds, which became more northerly overnight and into September 2. It maintained tropical depression status through that afternoon as it passed well north of Bermuda. However, shear was really piling on. It exceeded 40 knots by early that evening and Omar weakened to a depression. The struggling cyclone still produced enough convection intermittently to maintain its status through September 3. Omar also interacted with a nontropical low to its northeast that day and took a dip toward the east-southeast. Remarkably, it was still hanging on a day later.
A front began to approach the system from the northwest and it turned toward the north on September 5. This brought it over cooler water, finally bringing Omar's journey to a close late that afternoon when it was downgraded to a remnant low.
Omar was a weak tropical cyclone beset by strong shear, but it managed to hang on a few days longer than expected.
Omar did not affect any land areas.
No comments:
Post a Comment