Although still not a Tropical Depression, the 1009mb Low has a very obvious mid-level circulation and convection has maintained the cloud tops at -70C or colder. It's presently at about 10N 39W and tracking WNW at 15-20 kts. The SSTs are marginal at 26C, and this will not improve unless it makes it to west of 50W where the ocean is warmer at higher latitudes. However, it remains in a very favorable low-shear environment. This is quite early in the season for a Cape Verde storm to develop. In recent memory, there was Bertha '96 who formed on July 5 at 34W. Then going all the way back to 1976, Ana formed on June 19 at 45W. I didn't search beyond 35 years ago, but the point is, it would be very rare if this developed to a named storm! As an aside, the disturbance is embedded in a SAL, or Saharan Air Layer. This is still a very active area of research in the tropical meteorology community, but basically, it's a dry layer of air, traceable by fine dust and sand particles, that originates from the Sahara Desert and blows out over the tropical Atlantic with the easterlies. The dry layer of air is unhealthy for convection, and sometimes you'll notice a diminished intensity in convection despite amply warm SSTs... look for this dust as a possible culprit! Today, the SAL reaches to the Lesser Antilles. On a technical note for those who are curious, you can typically see the SAL much better in the morning's visible imagery... it appears to almost vanish by afternoon/evening. This is the effect of forward scattering. You can see an example of the SAL at http://www.nrlmry.navy.mil/archdat/atlantic/tropics/vis/20030610.1145.goes-12.vis.x.trop.x.jpg which is from today at 1145Z.
Please visit my tropical Atlantic headquarters.
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