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
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 | 100 | 101 | 102 | 103 | 104 | 105 | 106 | 107 | 108 | 109 | 110 | 111 | 112 | 113 | 114 — Blog Index
interesting.. there is a definate counter clock wise spin on the radar, possibly at the surface too.. very breezy over miami right now
I agree. If Ana hits S. FL, it should still move into the Gulf to reorganize.
The forecast was for it to move WSW for a while.. then curve WNW, dont think this sudden WSW movement is strange at all
Do you have proof of this comment or you been taking the wrong medicine again list the other morning?
Does the term MONSTER mean anything ... It looks very powerful already!
uhh.. huh? Your joking right?
Seems like some people think El Nino is an absolute guarantee that they are safe and that everything will either poof or curve out to see. Which as you can ask 23 this too, its totally untrue.
Those system seem to feed each other. as of now not so much, but there is clearly a visible counter mirror circulation going on. And in such process i belive the stronger one gains more. Which might influence storm speed and the rise of the chance to absorb even more.
Also the pattern suggest that these circulating patterns improve each other, hence increase the conditions for incoming systems.
For our scenario rightnow it would require substantial slowing or temporary stalling of 1 system.
It will be intresting to see this in the coming days when a storm interacts with land or higher SST.
Link
hopefully Bill won't be as bad
It becomes a "sudden death match" to move more north?
Quoting WeatherStudent:
Adrian, both of these features are gonna fizzle out and that's final. Very A typical of an El Nino Hurricane Season.
Do you have proof of this comment or you been taking the wrong medicine again list the other morning?
is there a Dr. in the house??
According to what I read on Hurricane City a few years ago Grand Cayman is hit the most by tropical systems in the Atlantic basin. They did go into the Pacific.
don't take your eye off the ball or it could smack you in the face
Conditions at SANF1 as of
(11:00 am EDT)
1500 GMT on 08/15/2009:
Continuous Winds TIME
(EDT) WDIR WSPD
11:00 am SW ( 227 deg ) 23 kts
10:50 am SSW ( 195 deg ) 26 kts
10:40 am S ( 178 deg ) 25 kts
10:30 am SSE ( 164 deg ) 25 kts
10:20 am SSE ( 155 deg ) 21 kts
10:10 am SE ( 145 deg ) 18 kts
Station SANF1 - Sand Key, FL
evrything is possible, but in this case is not likely due to thes systems a very apart each other and ana is increasing it speed..
been reading back on some posts..
folks.. no one is "a target or not a target" at this point. be real... for the next 5 days those models will change every 3 hours.
it will sway way to the north and south so many times over the next few days you all will make yourself nuts.
These systems will strengthen and weaken and die and come back etc. This is an El Nino year so lots of shear out there to blow the tops off these systems.
It is fun, but don't be making Declarations about it hitting or not hitting your area.
Best place to be 3-4 days out is in the center of the cone, because then it is for sure it will not hit your area. LOL just kidding.. that is a joke not a statement! :o)
Come on, Dude. There is a big difference in educated speculation and plain old misinformation. The later can be very dangerous.
Send the doctor over to WeatherStudent's place, check if his brain and hands are connected and functioning properly, sorry mate,,, your Ignored Name #11
Well, I guess we can mail out the warnings then.
Good perspective. Was gonna post something like that but yours is better.
Thats a pretty good one KOG.
?? you can clearly see its ingested some dry air as there are is no CU.Dry air is also disrupting its inflow to its southwest .
That my friend is a soon to be Humberto like cousin
knock yourself out, nice try tho ...
:)
Viewing: 5501 - 5551
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 | 100 | 101 | 102 | 103 | 104 | 105 | 106 | 107 | 108 | 109 | 110 | 111 | 112 | 113 | 114 — Blog Index