TD 2 struggling; new African wave bears watching
Tropical Depression Two is struggling. The depression still has a good chance of becoming the Atlantic hurricane season's first named storm this week, but the dry, Saharan air that surrounds the storm, combined with moderately high levels of wind shear, are interfering with the storm's organization. Satellite loops of the storm show that heavy thunderstorm activity is limited to the west side of the depression. This is due to strong winds out of the southeast that are creating a moderate 15 - 20 knots of wind shear. The intensity and coverage of these thunderstorms is meager, thanks to the large amount of dry air to TD 2's north that is getting wrapped into the circulation. This morning's QuikSCAT pass showed a well-formed surface circulation, with top winds of about 30 - 35 mph.
Wind shear over TD 2 is expected to remain in the moderate range, 10 - 20 knots, over the next five days. Sea Surface Temperatures (SSTs) are a marginal 26 - 27°C, and will not change much over the next three days. There is plenty of dry, stable air from the Saharan Air Layer (SAL) to to TD 2's north that will continue to cause the storm problems. The relatively cool SSTs and dry air mean that TD 2 will not be able to intensify quickly. However, it does appear likely that TD 2 has enough going for it that it will eventually be able to become Tropical Storm Ana sometime in the next three days. Most of the computer models show some weak development, but none of them predict TD 2 will become a hurricane. It is unusual for storms forming this far north to make it all the way across the Atlantic to hit the Lesser Antilles Islands. For now, TD 2 doesn't concern me as much as the new tropical wave to its southeast, just off the coast of Africa.
Figure 1. Tropical Depression Two (left center of image) and a new tropical wave (right side of image), newly emerged from the coast of Africa.
Elsewhere in the Atlantic
A strong tropical wave with some rotation and plenty of heavy thunderstorm activity left the coast of Africa yesterday, and is located a few hundred miles south of the Cape Verdes Islands. The GFS and ECMWF models continue to predict the development of this wave late this week. Both of these models indicate that the wave would track further south than Tropical Depression Two, and could impact the Lesser Antilles Islands in about seven days. This storm bears close attention over the coming days.
Two other tropical waves, one that just passed through the Lesser Antilles Islands, and one about 300 miles east of the islands, are mentioned in NHC's Graphical Tropical Weather Outlook. Both of these waves have very limited heavy thunderstorm activity that is not increasing, and are not a threat to develop over the next two days. None of the computer models develop either of these waves.
Felicia moves through Hawaiian Islands as a tropical depression
Tropical Storm Felicia weakened to a tropical depression before passing through the Hawaiian Islands yesterday. The storm brought scattered heavy rains of 1 - 2 inches to the islands, and no damage was reported. Felicia is only the 10th tropical cyclone of tropical depression strength or higher to hit the islands since 1950. Four other tropical cyclones have passed within 75 miles of the islands during that time period.
Be careful clicking on external links in blog comments
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I'll have an update Thursday morning.
Jeff Masters
Reader Comments
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That's just an area of vorticity, which most shower and thunderstorm complexes have since air has a tendency to spin around an area of low pressure. The GFS doesn't and hasn't as of yet shown an organized tropical system developing in the Gulf. What it is showing is an open wave approaching the northern gulf.
No surprise...no clear evidence of an organized low level circ yet but it should start to organize, slowly.
I'm not trying to be a downcaster and say the proto-bill isn't something to watch, because it is. It's August, it's a CV-wave, etc. Just saying that the long-range GFS predicition is no more accurate than any random predicition one could make.
Link
Why do I keep thinking of Charley when I see this GFSX...
And to pat, im using the quotation marks to refer to the waves as thats what the modeling shows them as. When not refering to a model I'll try to use a different designation =]
That's a killer too, it's TD2's only moisture tap with dry stable air to the N and W.
Yes.
and along line of clouds to the north like a tail is beeing feed but is
is that good or bad for the system ike
So "pre" disturbs continuity but Robocop pics don't...hmmmm :-)
Clouds to the south...according to the NHC...no.
Yup, that's the one...sometimes the GFDL and HWRF can show other systems.
De-terming strength is impossible this far out. So far its a guessing game. But we're pretty sure that wave's going to develop.
This is the type of situation the models handle the best. A large area of energy and a relatively straight forward steering pattern. Add agreement between 2 of the best models and confidence increases. Steering may become a bit more complex beyond 60W but for the most part I can't disagree with the model track depiction so far.
TD 2 Multiplatform Satellite Surface Wind Analysis,wind field
There are many other problems with continuity in this blog other than "pre-this" or "pre-that". If the admin has a problem with this language then they will voice it. Users of the blog need to refrain from attempting to police it as if they have any kind of jurisdiction or athority to do so. Carry on...
Nicely coincides with the same initial location as the CMC. Really sweet. Hello TX/LA
Most are still pretty agressive down the road (ECMWF, GFS) but some (12z GFS) are taking a bit longer to develop it.
Yes I've seen it before and was prettyconfident that was the case. Not sure if it has been discussed on the blog yet that the GFDL "develops" the wave
Another wave rolling off the coast too...
If this the case can we please get rid of the link prompt...
A-U-T-H-O-R-I-T-Y,..authority
Pllllllllllllllllllllllttttttttttttttttt...LOL
Ike, is that image showing a likelihood to usher a system into Texas? Making sure I am translating correctly.
The models might be relatively accurate up to 60W...but that's a long way from the GOM/US Coast. And even up to 60W the margin of error on the predicition is easily +/- 500 miles to the north or south, which would make a huge difference in how it behaves beyond 60W.
Whats probably going to happens is TD 2 will attain its Ana status later today and probably stay rather minimal and ultimately weaken in a few days.
I disagree, like in hockey, the users can somewhat police themselves. Patraps point is well taken, it's confusing to read entries with the 'pre's'.
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