24 September 2007

Atlantic getting active...

Since my last message, Ingrid, TD10, and Jerry formed.  Ingrid began on Sep 12 from an African easterly wave, and struggled against vertical shear and dry air for 5 days until degenerating to a low-level swirl then open wave near the Leeward Islands.  TD10 was only around for a few hours on Friday and formed and dissipated near the western Florida panhandle.
Jerry formed this past weekend in the far north central Atlantic, first as a subtropical depression, then transitioned to a weak tropical storm, and is presently undergoing a transition to extratropical.  None of the three systems were terribly noteworthy.

Now, there are several interesting items to discuss across the basin, each about 30 degrees apart.

First, there's a 1011mb Low in the southern Gulf of Mexico associated with a larger-scale trough.  It's quite active, but strongly sheared.  However, the shear is expected to lessen over the next day or two and perhaps allow this system to organize and drift westward toward Mexico.  http://www.ssd.noaa.gov/goes/flt/t4/vis-l.jpg

A potent easterly wave that left Africa on Sep 16 has been convectively active the whole trip across the Atlantic, and today is no exception.  It's crossing the Windward Islands now, and heading WNW toward Hispaniola.  Conditions are favorable for continued strengthening.  As it passed by Barbados earlier today, they recorded a pressure of 1009mb and winds of 18kts.  You can monitor the passage of the wave from the Martinique/Guadeloupe radar at http://www.meteo.fr/temps/domtom/antilles/pack-public/animation/animMOSAIC2.html.  The latest visible satellite image is at

The most well-organized system is an easterly wave out by 9N 35W (exited African coast back on Sep 21).  This is in an environment conducive to tropical cyclogenesis: SSTs of 28C and increasing along the future track, moderate vertical wind shear, and an embedded 1007mb Low.  It is tracking WNW at 12kts.  It should be able to gradually intensify; the only inhibiting factor is increasing shear as a trough nudges its way toward the system in the next few days.  Depending on how close the two get, this could be a hurricane or suffer the same fate as Ingrid.

Please visit my tropical Atlantic headquarters.

No comments:

Post a Comment