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July 2012

Atlantic Still Quiet, though Tropical Wave May Bring Wetness to Bahamas and SE U.S.

   Posted by Levi at 7:44am on July 11, 2012

I apologize for the lack of posts since Debby’s dissipation. Summer has been busy so far for me.

The Atlantic remains quiet through the first 10 days of July, as was expected. It will continue to be this way through at least the end of the month the way things currently look. El Nino years favor a quick-firing start to the season in June, but a quick ramp-down to start the heart of summer. Our next real shot at tropical development will likely not come until August when the MJO comes back to the Atlantic and drags some upward motion out of the eastern Pacific, where they have a whole train of storms going, and moves it into the Atlantic as the African wave train strengthens.

Speaking of waves, the only somewhat interesting feature to watch right now is a very large, dry tropical wave along 45W that has no thunderstorms associated with it, but can be seen with a vigorous signature in the mid-level flow.

This wave will be moving WNW into the the region between the Bahamas, Bermuda, and the SE U.S. during the next 4-7 days, being steered towards this region by a strong Bermuda High to the north. While none of the computer models currently do anything with this wave, moisture will be becoming more abundant in the SW Atlantic as the wave moves in, and upper-level temperatures are and will continue to be colder than normal due to significant upper-level troughing over the Bahamas, which overlaying 28-29C waters can cause some instability. As a result, some convection can be expected off the SE U.S. coast that may bring some wetness to the Bahamas and the coastal SE U.S. over the weekend. Given the large size of the wave, tropical or subtropical development chances seem low for now, especially with no excitement from the computer models, but expect the atmosphere to become rather soupy in the region with at least some thunderstorm activity, perhaps a little more than currently forecasted by some of the models.

CMC 96-hour forecast:

If you couldn’t tell, I’m showing off some of the new graphics I have been developing in my spare time. The first image was a GDAS analysis of 650mb meridional wind/heights, and the 2nd was the well-known Canadian model forecast. These and more products can be found on the Analysis Tools page. I will be adding more as time goes on.

Overall, the Atlantic in general will likely remain void of significant tropical activity until August. Remember, a fast start doesn’t always mean an above-normal hurricane season. We should end up with a near normal storm count by the end of it.

We shall see what happens!