Two African waves that may develop
Hello everyone, it's Jeff Masters back with you again after a long stretch of vacation. Now that the peak part of hurricane season is upon us, I'll be with you every day for the next few months, in what promises to be an unusually active Atlantic hurricane season. We've got several threats to talk about today, most notably a strong African wave near 12.5°N 30.5°W, about 400 miles west-southwest of the Cape Verde Islands. This system, dubbed Invest 92L by NHC, is moving west to west-northwest at 10 - 15 mph, and has the potential to develop into a tropical depression or tropical storm before arriving near the northern Lesser Antilles Islands early next week. Recent visible satellite loops show that 92L is beginning to develop a surface circulation, and heavy thunderstorms are slowly building along the western edge of the center. However, a separate area of heavy thunderstorms lies 400 miles to the east, just south of the Cape Verde Islands, and this blob is interfering with consolidation of the center near the blob of heavy thunderstorms at 30.5°W. Water vapor satellite loops show that a large area of dry air from Africa lies just to the west of 92L, but the atmosphere in the immediate vicinity of 92L is moist, so dry air is currently not a problem for the storm. The SHIPS model is diagnosing low shear, 5 - 10 knots, over 92L, but the University of Wisconsin CIMSS analysis shows that moderate shear of 10 - 20 knots is affecting 92L. Sea surface temperatures are 26.5° - 27°C, which is very close to the 26.5°C threshold usually needed to support a tropical storm.
Figure 1. Noon satellite photo of Invest 92L.
Forecast for 92L
Low to moderate wind shear of 5 - 15 knots is predicted along 92L's path over the coming three days, which should allow the storm to steadily organize, assuming it can shut out any incursions of dry air that might intrude. The latest 00Z and 06Z model runs of the four best models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET) show little or no development of 92L, and NHC gave 92L just a 20% chance of developing into a tropical depression by Friday morning in their 8am outlook. Given the recent improvement in the satellite appearance of 92L, I would put these odds at 30%. A steady west to west-northwest motion for 92L is predicted by all of the models, which would put the storm in the vicinity of the northern Lesser Antilles Islands by Sunday. On Saturday and Sunday, 92L is expected to enter a region where an upper-level low pressure system will bring high wind shear of 20 knots to the storm, which should slow development. This upper-level low is also expected to turn 92L more to the northwest, so the storm may pass north of the Lesser Antilles. It is too early to know if 92L will recurve out to sea and potentially threaten Bermuda, or continue to the northwest towards the U.S. East Coast.
Figure 2. NASA MODIS image taken at 10:40am EDT 8/10/11 of the tropical wave emerging from the coast of Africa. The GFS model is predicting this system will develop into a tropical storm early next week. Image credit: NASA.
Tropical wave emerging from the coast of Africa
A strong tropical wave currently emerging from the coast of Africa near 8°N has a modest amount of spin and heavy thunderstorm activity associated with it, and has the potential to develop early next week once it moves past the Cape Verde Islands. The GFS model has been developing this system into a tropical storm in several of its recent runs. A westerly track towards the Lesser Antilles is expected by the GFS model.
Jeff Masters
Reader Comments
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Apparently that resets comments.
Uh oh taz JFV is back.
Sure is, at the end of the image 92L starts to twist up the image too, lol.
thats what am seeing it i think its at 10N and 30W but the nhc dos not see it yet
yup he been poofed
I think we see the same thing, :)
Kind of reminds me of the whole Earl-Fiona scenario that happened last year when Earl was forecast to curve out to sea and Fiona was the 'real threat' to the states. Never materialized.
Bingo.
We have no real idea what the conditions or patterns will be even 3 days out, much less two weeks out. Right now its all speculation, we don't know what to expect. That trough, as mentioned, is going to be quick to move out. Timing is key. No one can say with 100% certainty 92L & 93L will be a US storm or a fish, or if they even will develop.
i seriously thought i was seeing things...cant even fathom that happening...
Well said...
My ignore list has tripled since the beginning of the season, most of them consist of Jasons, but a few JFVs and a couple other trolls.
LOL!
They could probably be more than all the storms we've had so far COMBINED.
This far out I wouldn't put much Fay-th in it, but stranger things have happened...
I don't think that's the real one. The real one came by my blog and left a "nice" comment.
Thew center is basically between the convection to the N &SE.
Family blog, 09, family blog.
i never do...but that was just wicked regardless of whether is was 14 days out or 3 days out...
yup
No, of course, that little loop-de-loop there was mighty fine.
Like this?
Ah ha! Most excellent news indeed!
Why would they say that JFV?
We are talking about 2 weeks away from the U.S. lol, just way too far out.
It is fun to speculate, my early speculation is that Florida will avoid another strike, and the storm may go out to sea again.
Convection does appear to be building closer to 92L's center. This is going to be a great race to see who gets designated and named.
Really? Anyone that forecasts anything definitive over 5 days out should be fired IMO. That is just plain reckless.
I thought you said this was a family blog Gro?
the nhc needs too move the center 92L too the S all so 93L looks good
That's a pretty good one. I've always liked Gordon's track.
I am very glad for the heavy rain, but unfortunately rainfall amounts aren't as heavy in the east side of Florida where the drought is improving, but they need much more rain than I do. Due to the tropical nature of the convection, these estimates are actually low compared to some of the totals.
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