Disturbance 90L close to tropical depression strength; TD 2 may rise again
A strong tropical wave (90L), with a large circulation and a moderate amount of heavy thunderstorm activity, is a few hundred miles southwest of the Cape Verdes Islands, off the coast of Africa. This morning's QuikSCAT pass shows that 90L has a large circulation, but this circulation is not yet well-formed, as it is elongated along an east-west axis. Satellite imagery from the European METEOSAT satellite show that the heavy thunderstorms associated with 90L are gradually becoming better organized, with some spiral banding evident on the south side of the storm. Satellite intensity estimates from NOAA already put 90L at tropical depression strength with 30 mph winds, but the storm does not yet have a well enough formed circulation to be classified as a depression. Water vapor imagery shows that since 90L is forming several hundred miles south of the dry air of the Saharan Air Layer (SAL), the storm should not be affected by dry air and dust as much as Tropical Depression Two was. However, there is some dry air from the SAL being sucked into the circulation of 90L, and this is retarding its development.
Wind shear is moderate, about 10 - 15 knots, but is forecast to fall to the low range, 5 - 10 knots, later today. Shear is then forecast to remain low for the next five days. Sea Surface Temperatures are about 28°C, and will remain in the 27 - 28°C range the next five days. The combination of low wind shear and sufficiently warm SSTs should allow 90L to develop into a tropical depression by Saturday, and potentially reach hurricane strength by Wednesday. Most of our reliable models strengthen 90L into a hurricane by Wednesday, when the storm is expected to be near the northern Lesser Antilles Islands. One important outlier is the ECMWF model, which has 90L passing to the north of the islands, and eventually recurving out to sea east of Bermuda. The ECMWF was by far the most reliable model for forecasting hurricane tracks last year. However, all of our models are pretty unreliable going out 5 days in advance for systems that have yet to reach tropical depression strength. Once 90L becomes a tropical depression and develops a well-formed circulation, the models will have a better handle on forecasting where it will go.
Figure 1. The remnants of Tropical Depression Two (left side of image) and tropical wave 90L (right side of image).
Tropical Depression Two may come back
Tropical Depression Two died yesterday, but may rise again. Satellite loops of the remnants of the storm show that heavy thunderstorms are again attempting a comeback near the axis of what is now a tropical wave. However, dry air continues to interfere with the development of the thunderstorm activity, and moderately high wind shear of 15 - 20 knots is also inhibiting the process. Wind shear over the remnants of TD 2 is expected to remain in the moderate range, 10 - 20 knots, over the next four days. Sea Surface Temperatures (SSTs) are 27°C, but will warm to 28°C two days from now. There is plenty of dry, stable air from the Saharan Air Layer (SAL) to the north and west that will continue to cause the storm problems. The relatively cool SSTs and dry air mean that any re-development of the storm will be slow to occur. NHC has given the system a medium (30 - 50% chance) of becoming a tropical depression again by Sunday morning. Only one reliable model, the NOGAPS, is predicting regeneration of TD 2. The NOAA Hurricane Hunters are flying research missions into the remnants of TD 2 today and Saturday.
I'll have an update Saturday morning, or earlier, if significant developments occur.
Jeff Masters
Reader Comments
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90L is TD3....
Yes Models are in good agreement but to me TD3 is barely a TD; I have seen much beter looking TDs before - this one has still has a broad circualtion moving WSW, center of which I make to be at 11.2N - 34.5W at the moment!
Just my opinion, ofcousre, but intesinty 3-5 days out is overdone - greatly may I add...!! We shall see...
He's got A LOT to update, lol.
A couple of margarita's and a shot of Jager
No convergence.
Ana fast or trough slow, then Ana south of MIA.
Ana slow or trough fast, then Ana misses FL entirely.
Trough weakens...(likely) prob FL somewhere and a recurve...(with very little chance of emerging into GoM.)
Where is Jeff's new post.. its almost noon.
boarding up......lol..j/k
Satellite estimates indicate its almost a TS already. Its not overdone, if anything it could be underdone if the conditions are as favorable as the HWRF shows it.
That depends if you are talking Country or State. If you are comparing to the W. Pacific then you have to use the USA as a whole. I am sure someone on here knows the most likely country to be hit.
That would be a safe assumption... and you live a little to close to Zoo...
GOM system looks invest worthy.
Ike i agree...GOM is way too hot....
it was moving WSW a moment ago, seems to be moving just south of due west now, if not due west.. the forecast was for it to move WSW for 6 hours then move W to WNW
GOM is in trouble
ummmmm... no
Ana looks terrible.
what
Within the possible measurement error of vortex fixes...even if we had HHunters in there.
Uh no I'll just take frontal storms lest we incur 2001 all over again...
Has more convection then Ah-nah.
If Ana goes toward the south of the cone it will be bad for both Hispaniola and Ana.
Almost no chance for South America to affect TD3. The weakness in the ridge will eventually pull it WNW.
HWRF intersity guidance has never materialized - always over cooking it - you know that!
TD3 will be barely a Hurricane before the Islands - my prediction! :)
None of the models currently suggest this.
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