Active tropics today

By: Dr. Jeff Masters , 12:15 AM GMT on September 24, 2007

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A disturbance ("94L") in the Gulf of Mexico has not gotten better organized today and has just about run out of time. Long range radar out of New Orleans shows the advance rain showers from 94L are already at the coast, and there are no signs of spiral banding, rotation, or organization in either the radar imagery or satellite loops of 94L. Wind shear has increased to 10-20 knots over the Gulf of Mexico, and it now appears unlikely 94L will be able to develop into a tropical depression.

Lesser Antilles disturbance 97L
Of greater concern is a tropical wave (97L) about 300 miles east of Barbados in the Lesser Antilles Islands. This wave has not gotten any better organized during the past 12 hours, as seen in the latest Satellite imagery. The wave is under about 10 knots of wind shear. The shear is forecast to remain below 10 knots through Tuesday, and there is some favorable anticyclonic outflow at high levels, and 97L has a good chance of developing into a tropical depression by Tuesday. At that point, the future evolution of the storm depends strongly on how far north it is. If 97L moves northwest over Puerto Rico on Wednesday, as the GFDL and some of the global models predict, it may encounter a zone of high wind shear associated with the bottom part of a trough of low pressure positioned to the north of Puerto Rico. This shear should keep the storm from becoming a hurricane. If 97L stays on a more west-northwest track and penetrates into the Caribbean Sea south of Puerto Rico, as predicted by the simpler BAMM model, the storm is likely to encounter less shear, and could grow into a hurricane. Regardless, 97L will bring heavy rain and gusty winds to most of the Lesser Antilles Islands tonight through Tuesday.

Links to follow for 97L
Martinique radar
Barbados weather
Guadaloupe weather
Martinique weather
St. Lucia weather


Figure 1. Microwave image from 4:46 pm EDT today showing low-level spiral bands starting to form on the west side of 96L. Image credit: Navy/NRL.

Far Atlantic disturbance 96L
A tropical wave "96L" in the far eastern Atlantic, about 650 miles southwest of the Cape Verdes Islands, has gotten more organized during the past 24 hours, as seen in the latest Satellite imagery. The circulation associated with the wave is unusually large. The storm will be a little slow to get going, since the storm is so far south. At the storm's current latitude--6 degrees north of the Equator--it cannot leverage the earth's spin very much to help spin up the huge circulation it has. Despite it's close proximity to the Equator, low-level spiral bands have already formed, as seen in recent microwave satellite images (Figure 1). The wave is under about 10 knots of wind shear. The shear is forecast to remain below 10 knots through Wednesday, and there is some favorable anticyclonic outflow at high levels. There is a good chance 96L will become a hurricane late this week, as forecast by the SHIPS intensity model. The Lesser Antilles Islands should anticipate the possibility that this will be a hurricane by the time it reaches the islands seven days from now, although it could miss to the north. It is possible 96L will encounter a zone of high wind shear beginning four days from now. The HWRF model develops 96L into a 55-mph tropical storm by Tuesday, then weakens the system the remainder of the week. The GFDL model does not develop 96L at all.

I'll edit this blog tonight to include the evening QuikSCAT pass, if it hits 96L. Otherwise, I'll be back Monday morning--and maybe I'll even talk about our one active storm, Jerry!

Jeff Masters

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861. weathers4me
4:34 PM GMT on September 24, 2007
OMG!! 96 is going to be a monster. The question is, will it feed the fish or feed on the US? Any thoughts on long term steering patterns?
Member Since: May 24, 2007 Posts: 0 Comments: 118
860. Eyewall911
2:43 PM GMT on September 24, 2007
my-oh-my 96L has to have the biggest circulation I have ever seen!!! Don't think shear will do anything to this monster. Can we all say annular hurricane?
859. sngalla
2:40 PM GMT on September 24, 2007
New blog up.
Member Since: February 18, 2003 Posts: 57 Comments: 5363
858. NEwxguy
2:38 PM GMT on September 24, 2007
Very appropriate for football analogy on a Monday morning
Member Since: September 6, 2007 Posts: 881 Comments: 15820
857. quackquack
2:37 PM GMT on September 24, 2007
96 looks very impressive to my novice eye.Glad it is way to the East of us.
856. CJ5
2:36 PM GMT on September 24, 2007
Morning all!

94L at 21.7/92.8 looks a a little better this am. Its movement seems to be WNW and I wouldn't expect it to be much if anything, though it has become better defined so with the way the season has gone I would be careful to not take my eyes of it.

96L at 9.4/31.7 looks better than any of the others. As long as it stays S of 20 it shouldn't experience much shear along its trek. I don't see any of the models developing this above a TS in the next 96hrs which I am not sure I agree with. They are in fairly good agreement on its track through that period. It depends on which model to believe when it comes to late steering. It appears that in 72hrs or so it is very possible for it to begin a more N-NW track and a fish is possible. I tend to think a more WNW-NW track and the US still in the cone.

97L at 12.4/58.9 looks pretty good this am also. It should begin to move into heavy shear w/tendancies increasing and models show that the shear will stay high along the N Islands and the DR. If this holds its going to have a tough time interacting with the shear and land. I believe a track towards DR is likely but around 72hrs it could begin a more N-NW turn as well. If some of the models hold it to could swing enough N to be a fish. I am not so sure. This one will have to pull an Ingrid, IMHO, to be a concern for the US.

These are just my thoughts today...not to be used for life or death planning.
Member Since: July 4, 2007 Posts: 0 Comments: 1755
855. IKE
2:36 PM GMT on September 24, 2007
97L will have some strong air defense (shear) to work into. Good safetys and corners could keep this attack at bay; but, has rotation, anticyclone. It'll have to keep a good, slow and steady running game plan to keep the drive up.

I guess it's not time to punt yet with 97L.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
854. moonlightcowboy
2:34 PM GMT on September 24, 2007
http://cimss.ssec.wisc.edu/tropic2/real-time/temp/image.gif

97L will have some strong air defense (shear) to work into. Good safetys and corners could keep this attack at bay; but, has rotation, anticyclone. It'll have to keep a good, slow and steady running game plan to keep the drive up.
Member Since: July 9, 2006 Posts: 184 Comments: 29610
853. HTownJitters
2:33 PM GMT on September 24, 2007
96L looks like it wants to set some records. I don't know what the stats are for farthest east major-cane, farthest south major-cane, or farthest east cat-5, but it is rapidly developing banding on all sides. If that continues, it will get strong fast. Hopefully a fish storm!
Member Since: August 31, 2007 Posts: 0 Comments: 97
852. woodlandstx
2:33 PM GMT on September 24, 2007
local NWS forecast discussion here in HOU predicts that the ULL over brownsville will move north taking the shear and dry air north by evening. Will this pull 94L onto the upper tx cst tomorrow? Also, cold front coming down with dry line in wst tx moving east. is it just me, or do you guys think that models will have much difficulty getting this right?
851. Wots
2:32 PM GMT on September 24, 2007
Good morning everyone.
First post, been visiting WU for years now, trying to learn. I īd like to thank you all, because questions and answers both teach what to look at. I donīt live in the tropics, but through all the info I gather here, I understand better my own weather.
I have also a question. Watching 97L it seems to me there are 2 COCs, one at 58 W and another, smaller at 47 W 15 N Is thas possible?
Member Since: September 13, 2007 Posts: 0 Comments: 17
849. NEwxguy
2:30 PM GMT on September 24, 2007
Hi,all,
Been away all weekend,and I come back and see invests all over the place.
Member Since: September 6, 2007 Posts: 881 Comments: 15820
848. txag91met
2:28 PM GMT on September 24, 2007
by 48 hours the shear will weaken and 94L will likely become a tropical storm.
Member Since: January 30, 2005 Posts: 6 Comments: 750
847. LakeShadow
2:28 PM GMT on September 24, 2007
Ok, since its up to my imagination as to where Jerry came from...here is what I think happened..
A large family of whales got into some bad kelp and had a case of collective gas. The methane rose through the atmosphere quickly, creating a small surface low that in turn developed for a smidge, long enough to be classified as a STS and was therefore named Jerry...
am I right?
Member Since: August 10, 2007 Posts: 3 Comments: 2134
846. sporteguy03
2:27 PM GMT on September 24, 2007
Fish Sticks
Member Since: July 7, 2005 Posts: 0 Comments: 5350
845. JupiterFL
2:24 PM GMT on September 24, 2007
Whats up Littlefish. Top of the mornin to ya.
Member Since: August 10, 2005 Posts: 0 Comments: 2146
844. IKE
2:21 PM GMT on September 24, 2007
Posted By: nrtiwlnvragn at 9:20 AM CDT on September 24, 2007.
No recon today. 97L put off untill tomorrow. All recon for 94L canceled.

Link


I thought they would pay a visit to 97L today...more crow.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
843. LakeShadow
2:21 PM GMT on September 24, 2007
"my prediction is 94L is dead and the cowboys are going all the way!!!!"
denial...its so sad... :o)

just joshin...darn cowboys stole 2 of our SB victories...
Member Since: August 10, 2007 Posts: 3 Comments: 2134
842. littlefish
2:20 PM GMT on September 24, 2007
Glad I'm nowhere near 96L. That looks like a monster waiting to happen. Soon.
841. nrtiwlnvragn
2:20 PM GMT on September 24, 2007
No recon today. 97L put off untill tomorrow. All recon for 94L canceled.

Link
Member Since: September 23, 2005 Posts: 14 Comments: 11211
840. SomeRandomTexan
2:19 PM GMT on September 24, 2007
Patrap---

What are the chances now of 94L developing?
Member Since: August 30, 2007 Posts: 0 Comments: 1857
839. cattlebaroness
2:18 PM GMT on September 24, 2007
So in looking at the image Patrap just posted, is 94 becoming less organized as it moves north? Trying to learn, what I am seeing. TIA
838. Squid28
2:18 PM GMT on September 24, 2007
Thanks for the response, if they decide to run the models again, how long till we start to see them come out?
Member Since: May 23, 2006 Posts: 0 Comments: 343
837. littlefish
2:18 PM GMT on September 24, 2007
96L looks like a gorilla about to take steroids, nice symmetry and convection. Just needs a tight LLC to suction in all that convection.
836. beell
2:16 PM GMT on September 24, 2007
hey sj-say fish,fish,fish-take three swigs of cold medicine, repeat as required-see ya pal.
Member Since: September 11, 2007 Posts: 143 Comments: 16720
834. LakeShadow
2:15 PM GMT on September 24, 2007
ooh I see it...the COC on 94l its getting even more prominent by the minute, jpritch. Doesn't look like wind shear is affecting it, one bit!
Member Since: August 10, 2007 Posts: 3 Comments: 2134
833. beell
2:14 PM GMT on September 24, 2007
We may be fortunate in that the also N/S aligned CONUS trof will stay that way and continue moving W to E. If it starts to "lay over" and get more zonal then that might open up a bit more GOM to the east for this thing to play in.
OK really gotta go before i am unemployed.
Member Since: September 11, 2007 Posts: 143 Comments: 16720
832. StormJunkie
2:13 PM GMT on September 24, 2007
Morning mlc, bl, and all :~)

Plenty to keep us busy for the next week or two.

Back to work for me. See y'all in a couple of hours.

Quick Links-Easily navigate forecast models, imagery, marine data, wind data, and preparedness info.
Member Since: August 17, 2005 Posts: 26 Comments: 16842
831. Patrap
2:13 PM GMT on September 24, 2007
GOM AVN Infrared Loop

Link
Member Since: July 3, 2005 Posts: 426 Comments: 128632
829. seminolesfan
2:12 PM GMT on September 24, 2007
Hey thel; looks like our two posts fit together pretty well. lol
Member Since: June 14, 2006 Posts: 0 Comments: 2108
828. woodlandstx
2:11 PM GMT on September 24, 2007
floater designated for 94L
827. thelmores
2:10 PM GMT on September 24, 2007
Member Since: September 8, 2005 Posts: 0 Comments: 3805
826. seminolesfan
2:10 PM GMT on September 24, 2007
Posted By: Squid28 at 2:04 PM GMT on September 24, 2007.
Where is the "center" of 94L in relation to the convective blowup?


The low level circ on VIS is to the SW of the most intense convection on IR.




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825. beell
2:08 PM GMT on September 24, 2007
i like da way you think mlc.
Member Since: September 11, 2007 Posts: 143 Comments: 16720
824. jpritch
2:08 PM GMT on September 24, 2007
Squid, you can see the center in that last image Patrap posted. It's the eye-like feature in the lower southwest part of the storm.
Member Since: June 28, 2007 Posts: 0 Comments: 291
823. thelmores
2:07 PM GMT on September 24, 2007
looks like some nice convection firing up to the
N,NE and W of 94L's LLC......
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822. moonlightcowboy
2:07 PM GMT on September 24, 2007
Beell, just thinking the same thing. That could mean a tug towards the ncentral GOM I think.
Member Since: July 9, 2006 Posts: 184 Comments: 29610
821. IKE
2:07 PM GMT on September 24, 2007
Posted By: Squid28 at 9:04 AM CDT on September 24, 2007.
Where is the "center" of 94L in relation to the convective blowup?


Partially exposed to the south and west of the convection.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
820. LakeShadow
2:06 PM GMT on September 24, 2007
Bears need a new QB...Cowboys are on a roll.

come play Bflo Bills, cowboys and bears will seem like a probowl team

Anyone? Jerry? do I just use my imagination?
Member Since: August 10, 2007 Posts: 3 Comments: 2134
819. beell
2:05 PM GMT on September 24, 2007
94l
lower level steering was SE to NW yesterday, but it looks like the CONUS trof will pick this thing up or at least move it more N than anything. But then were looking at a system getting squeezed between the trof to the west and the N/S aligned upper ridge to the east.
Member Since: September 11, 2007 Posts: 143 Comments: 16720
818. Squid28
2:04 PM GMT on September 24, 2007
Where is the "center" of 94L in relation to the convective blowup?
Member Since: May 23, 2006 Posts: 0 Comments: 343
817. IKE
2:04 PM GMT on September 24, 2007
Bears need a new QB...Cowboys are on a roll.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
816. IKE
2:03 PM GMT on September 24, 2007
Memo to NHC...96L needs upgrading!
Member Since: June 9, 2005 Posts: 23 Comments: 37858
815. Txwxchaser
2:03 PM GMT on September 24, 2007
thought my first didn't post...i said it twice...uncalled for!
Member Since: September 13, 2007 Posts: 0 Comments: 312
813. Patrap
2:02 PM GMT on September 24, 2007
GOM Visible Loop


Link
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812. IKE
2:01 PM GMT on September 24, 2007
94L does seems to be moving WNW...with the convection to it's north and NE. Shear has relaxed some...still at 20 knots to it's west and NW.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
811. Crawls
2:01 PM GMT on September 24, 2007
I realize that whether 94 develops into anything significant is still "up in the air" but, by the looks of the current steering, is it a reasonable conclusion that the LA coast will be affected - even if it is just a lot of rain?
Member Since: August 17, 2007 Posts: 0 Comments: 272

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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