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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highly unlikey, they are both their own circulations
RBG shows awesome firing of the storm activity surrounding TD 3
Based on? The HWRF, SHIPS, and all of their basis is on 27-28C waters and light shear...once it gradually organizes and gets an inner core those conditions make it ripe steady intensification, especially when an eye forms. We've seen this time and again.
And if the HWRF was always wrong they wouldn't use it.
LOL... r u sure, I sure wouldnt mind it hitting Chavez's mansion in Venezuela
Take a glance @ this water vapor image note the large patches of dry air across the tropical atlantic.
thats the forecast
Is it possible that these three systems will be interacting with each other, for better or worst..
I am guessing where one goes the others will follow.
and the add one more system to the fray, look behind the wave exiting Africa, another system in a few days
Is that even possible, that TD3 takes over Ana...
Link
I agree! Everyone keeps saying S Fla...Nope!!! Its the GOM's storm!
Yes it is. Wilma ate something if I remember.
I don't think the GOM has web servers.
If it did, the link would be in my blog with all of my other favorite tropical/severe links.
???
HWRF intensity predictions have never materialized!! Of course I cannot remember every storm but just last year it had IKE at 170mph in the Gulf, and one time over Miami too...IKE was barely a Cat 2!
Of course HWRF mey get it right once in a while but I for one DO NOT believe its intensity guidance!
Look at TD3 right now - not much deep convection anywhere espacially at its center!!
Theres an ull just northwest of tiny ana produing southwesterly shear and combined with some dry air iam just not sure ana will survive.Models have done a poor job forcasting upper conditions.
Same here...
Hmm can't believe I've waited this long to say this, but time to put ya on ignore. Too much flip flopping around.
is that thing over the keys getting any stronger?
Wilma ate what was left of TS Alpha.
Shear is effecting this system (10-20kts) from the base of an upper level low, not dry air. It has been like this ever since Ana formed. Dry air intrusion is not too evident.
Yup Alpha due to the Fujiwara Effect however Ana is expected to pick up forward speed so dunno if that'll happen
Quoting WeatherStudent:
Adrian, both of these features are gonna fizzle out and that's final. Very A typical of an El Nino Hurricane Season.
???
LOL...you kill me WS....
However...the heaviest and most prolific period of rainfall looks
to be Monday into Tuesday. The tropical wave will begin to pull to
the west of the region...allowing for the strongest lift and deep
moisture to sweep into the area. This moisture will be fed by deep
southerly flow off the Gulf of Mexico. With little convective
inhibition in place...have went with likely probability of precipitation across the
forecast area for Monday. Temperatures will remain below
normal...due to the rainfall and cloud cover expected to be in
place. The heaviest rains look to pull to the west and farther
inland Monday night into Tuesday. However...fairly strong and deep
Omega values on the eastern side of the inverted trough
axis...combined with ample moisture will allow for another round
of likely probability of precipitation for Tuesday afternoon. Given the likelihood of
heavy rainfall...some flooding issues may develop...and will have
to monitor for the need to issue a Flash Flood Watch for Monday.
In addition...some minor coastal flooding may develop due to an
expected higher than average tide and some swells emanating in
from the central Gulf of Mexico.
I think the tip of cuba or even Cozumel would be the Hurricane Capital
Yeah which we all knew was going to happen!!!! They always curve away!
exactly.. ???
People that are calling out TD3 don't know what they are talking about in my opinion. This thing has the potential to become a serious threat.
interesting.. there is a definate counter clock wise spin on the radar, possibly at the surface too.. very breezy over miami right now
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