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The difference a day makes...

2:00pm EDT UPDATE:: TD One-E has been upgraded to Tropical Storm Aletta. At this point the tropical storm is of minimal strength and little else has changed since the previous discussion.

At this time yesterday, the area of convection in the Eastern Pacific was ragged at best. By yesterday afternoon a quick look at the satellite revealed a definite circulation at the surface by looking at the curved cumulus clouds. By today, it is definitely a full fledged tropical depression, and so the 2006 Pacific hurricane season begins!

The real reason why this disturbance was upgraded to a tropical depression is due to a large burst of convection. Taking a look at the infrared imagery clearly shows strong convection just off the Mexican coast.

Infrared satellite

While the comma shape of the infrared imagery is suggestive of a closed circulation, it is really the visible image that seals the deal. Taking a look at the visisble satellite shot shows healthy curved upper-level outflow to the north and slightly weaker outflow to the south. Looking at the low-level cumulus to the west of the center clearly show curvature in the clouds indicating a surface circulation.

Visible satellite

Steering currents in the area are weak so TD1-E is unlikely to make very much progress in this area. The models are showing nothing too exciting in the track and, in fact, contain quite a bit of slow wander with this system. Given rrecent trends, intensification into a tropical storm is likely to occur later today. Due to the depression's close proximity to the coast, a Tropical Storm Watch has been posted for the south-cental Pacific coast of Mexico from Punta Maldonado westward to Zihuatanejo.

Track and advisories

Posted by Bryan Woods | Permalink