Several Interesting Areas, But No Major Threats
As would be expected as we close in on mid August, the tropics are quite active tonight. In the Atlantic there are two areas being watched right now. The first is Tropical Depression 7. According to the latest advisory from the National Hurricane Center, Tropical Depression 7 is located just over 500 miles east of Barbados, and is racing west at 23 mph. TD 7 currently has maximum sustained winds of 35mph, and a minimum central pressure of 1009mb.
Forecast for TD 7
Tropical Depression 7 has two main factors working against it. The first is a very fast forward motion. It is very difficult for small, weak systems like this to organize when they are moving at over 20mph like TD 7 is. Another problem is dry air, as Figure 1 shows.
Figure 1: Water vapor image of TD 7.
While TD 7 has done a fairly good job at not letting the dry air disrupt its circulation, the dry, stable air is still preventing it from firing up a significant amount of convection. Shear, meanwhile, is moderate, as the SHIPS model indicates TD 7 will be going through 10-15 kts of shear for the next 36 hours or so but 15-25 kts after that. The National Hurricane Center forecasts little strengthening of TD 7 as they indicate a peak of only 40mph before dissipation in 3 days. I think the marginally favorable present shear conditions, combined with DMAX tonight, will give TD 7 enough of a boost for it to be named Gordon tomorrow morning, possibly at the 5 AM advisory. After that, however, I, like the NHC, see the system dissipating due to unfavorable conditions. A recon mission is scheduled to investigate the system tomorrow morning, and it wouldn't be shocking if they found TD 7 an open wave. The track forecast is a little tricky as it depends on intensity. A stronger TD 7 would be more likely to get pulled further north and track through the northern Caribbean. However, a weak one, like myself and the NHC forecast, is more likely to go south. Therefore, I think a track similar to that of the NHC, seen in Figure 2, or perhaps one slightly farther north, is likely.
Figure 2: Official NHC forecast track of TD 7.
Invest 93L Struggling
The other area being watched in the Atlantic is Invest 93L. 93L is located in the far Eastern Atlantic, near the Cape Verde islands. After looking good last night and into this morning, I was really buying that 93L would develop by tonight. However, drier air and cooler waters have prevented this as the NHC now gives this system only a 30% development chance in the next 48 hours as of their 2PM Tropical Weather Outlook. I still believe this system will eventually develop, and I'm not entirely ready to give up on the idea of this becoming a formidable storm eventually. After it passes the Cape Verde islands, 93L should be no threat to land for several days, so there is plenty of time to watch this situation unfold. Should it develop, a recurve definitely looks like the most likely scenario, as I continue to believe that will be the theme for this month.
Ernesto Attempting His Comeback
After dissipating over Mexico earlier today, Tropical Storm Ernesto is now emerging into the waters of the East Pacific. Since he was declared dissipated he is now Invest 94E. As of their 2PM TWO, the NHC is giving 94E a 70% chance of development in the next 48 hours. I put these odds higher, closer to 90%, since 94E already looks like a tropical cyclone. 94E is providing heavy rains to Mexico, but after it pulls away from the coast it should not be a threat to any land areas.
Figure 3: Invest 94E
Also in the East Pacific, former Hurricane Gilma has weakened to a tropical storm. Moving over cooler waters, Gilma should continue to weaken and poses no threat to any land areas.
Figure 4: Tropical Storm Gilma
I've posted a couple of these links on the blog, but if you've missed them these are the four most recent daily discussions I've helped to prepare with the Blue Hill Observatory:
Thank you for reading, and have a great night!