Dr. Jeff Masters' WunderBlog

High wind shear ripping into 97L

Posted by: Dr. Jeff Masters, 1:49 PM GMT on July 20, 2009

A strong tropical wave (97L) a few hundred miles east of Barbados in the Lesser Antilles Islands has grown less organized today as it tracks west at 15 - 20 mph. The wave is moving underneath an upper-level trough of low pressure, which is bringing 30 knots of wind shear to 97L. While there is a respectable amount of heavy thunderstorm activity associated with 97L, there is no longer any low-level spiral banding or rotation of the cloud pattern. This morning's QuikSCAT pass at 5:35 am EDT showed sustained winds of 35 mph a few hundred miles east of Barbados, but there was no surface circulation evident. The islands of Barbados, St. Vincent and the Grenadines, St. Lucia, and Martinique can expect heavy rain and wind gusts to 50 mph as 97L moves through the Lesser Antilles Islands this afternoon and tonight, but 97L will not become a tropical depression.

Wind shear along the path of 97L is forecast to remain in the high 25 - 35 knot range for at least the next three days. This should prevent further development of 97L, and I expect the disturbance will be gradually torn apart during the next few days. The National Hurricane Center gives 97L a low (less than 30% chance) of developing into a tropical depression in the next 48 hours. None of the computer models are forecasting any tropical storm development over the next seven days.

Figure 1. Current satellite image of African wave 97L.

I'll have an update Tuesday morning. As 97L moves through the islands, you may want to follow local observations there using our wundermap for the region.

Jeff Masters

Categories: Hurricane

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1551. mikatnight 11:02 PM GMT on July 20, 2009
Member Since: October 18, 2005 Posts: 0 Comments: 1973

1552. cchsweatherman 11:04 PM GMT on July 20, 2009
Gotta say that from the Southwest Atlantic down through the Caribbean and Central America, it just looks like a massive mess. Not much organization is happening due to all whole complex trough pattern. Even though I'm not going to rule out something developing, in looking at satellite imagery and upper level conditions, its seeming quite unlikely that we will see development. Just seems like things have become too complex and too hostile for much to happen. Just going to sit back and enjoy the messy show that Mother Nature has been and continues to put on. Member Since: April 14, 2007 Posts: 8 Comments: 4926

1553. Makoto1 11:05 PM GMT on July 20, 2009
Quoting Weather456: 18Z Global models ability to develop tropical cyclones and extratropical cyclones. Most models continuing to develop some of the energy from 97L as it interacts with a frontal feature. CPD thinks its going to be warm-core. Shear on friday expected to be around 10 knots north of the Bahamas. Just out of curiosity more than anything, a good bit of my family is on vacation in Connecticut this coming week.. Should I be watching that area off the southeast closely in case something tries to move up that way?

1554. IKE 11:05 PM GMT on July 20, 2009
Quoting extreme236: Not to mention how boring it is. If its gonna form, just form already, don't make us go through a week of it poofing and reviving off and on. It is rather tiresome. Looks like another front may move through the SE USA this coming weekend....from the Birmingham,AL. extended discussion.... "THE LONG WAVE PATTERN IS EXPECTED TO STRENGTHEN ONCE AGAIN OVER THE WEEKEND. ANOTHER FRONT COULD MOVE THROUGH LATE SATURDAY INTO SUNDAY."..... Looks like I'm protected through the rest of July.... Member Since: June 9, 2005 Posts: 23 Comments: 37044

1556. BurnedAfterPosting 11:06 PM GMT on July 20, 2009
bestill my heart, looks like QS will finally hit 97L lol

1558. Drakoen 11:06 PM GMT on July 20, 2009
Quoting IKE: It is rather tiresome. Looks like another front may move through the SE USA this coming weekend....from the Birmingham,AL. extended discussion.... "THE LONG WAVE PATTERN IS EXPECTED TO STRENGTHEN ONCE AGAIN OVER THE WEEKEND. ANOTHER FRONT COULD MOVE THROUGH LATE SATURDAY INTO SUNDAY."..... Looks like I'm protected through the rest of July.... Yay! Member Since: October 28, 2006 Posts: 57 Comments: 29010

1559. IKE 11:06 PM GMT on July 20, 2009
Quoting cchsweatherman: Gotta say that from the Southwest Atlantic down through the Caribbean and Central America, it just looks like a massive mess. Not much organization is happening due to all whole complex trough pattern. Even though I'm not going to rule out something developing, in looking at satellite imagery and upper level conditions, its seeming quite unlikely that we will see development. Just seems like things have become too complex and too hostile for much to happen. Just going to sit back and enjoy the messy show that Mother Nature has been and continues to put on. I agree with you. It's just not conducive right now in those areas. Maybe I'll be wrong. Member Since: June 9, 2005 Posts: 23 Comments: 37044

1560. Tazmanian 11:06 PM GMT on July 20, 2009
Quoting jasoniscoolman09: thats old Member Since: May 21, 2006 Posts: 5088 Comments: 111354

1561. stormpetrol 11:07 PM GMT on July 20, 2009
97L looks like a rooster that had just took a good beating, let's see if it can make a comeback. Member Since: April 29, 2007 Posts: 0 Comments: 6400

1563. Drakoen 11:07 PM GMT on July 20, 2009
Quickscat pass will show an open wave. No need for a pass with such a disorganized system. Member Since: October 28, 2006 Posts: 57 Comments: 29010

1564. moonlightcowboy 11:07 PM GMT on July 20, 2009
Quoting IKE: Looks to me like the Caribbean is just off-limits for now.... Ike, I think you're right. Definitely right, right now. All of the tropics, except the cATL look hostile; but, there's this wierd looking setup looking like it's trying to form in the Caribbean - the anticyclone climbing up from SA, the trough lifting out from the islands, the eConus front getting pushed out by the deep trough behind it - and, it looks as if the cCaribbean could clear somewhat in 12-48 hours...???? Hhhhmmm, maybe it's time for coffee or a cocktail. WATER VAPOR LOOP Member Since: July 9, 2006 Posts: 179 Comments: 28121

1565. Patrap 11:08 PM GMT on July 20, 2009
Potty mouth,..bad Drak..be careful. The Powers that be arent intimidated. Member Since: July 3, 2005 Posts: 371 Comments: 111516

1566. BurnedAfterPosting 11:09 PM GMT on July 20, 2009
Quoting Drakoen: Quickscat pass will show an open wave. No need for a pass with such a disorganized crappy system. 4 hours ago you were very interested in the west winds that were being reported in the Islands, now you have taken a complete 180 and are calling this system dead I dont get it

1567. extreme236 11:10 PM GMT on July 20, 2009
Quoting Patrap: Potty mouth,..bad Drak..be careful. The Powers that be arent intimidated. Didnt know saying crap makes you a potty mouth lol Member Since: August 2, 2007 Posts: 19 Comments: 19234

1568. TampaSpin 11:10 PM GMT on July 20, 2009
Nothing like a 30mile bike ride in 90deg heat and then a whiskey sour slouchy....Priceless! Member Since: September 2, 2007 Posts: 175 Comments: 19747

1569. stormpetrol 11:11 PM GMT on July 20, 2009
wave at 6N/31.5W looks much more interesting on the quikscat Member Since: April 29, 2007 Posts: 0 Comments: 6400

1571. Drakoen 11:11 PM GMT on July 20, 2009
Quoting BurnedAfterPosting: 4 hours ago you were very interested in the west winds that were being reported in the Islands, now you have taken a complete 180 and are calling this system dead I dont get it I was interested but certainly was not bought. And yes I do think it is RIP. I'll pencil that in. If I am wrong you can feed me my crow and call me whatever you want. Member Since: October 28, 2006 Posts: 57 Comments: 29010

1572. Cavin Rawlins 11:12 PM GMT on July 20, 2009
Quoting Makoto1: Just out of curiosity more than anything, a good bit of my family is on vacation in Connecticut this coming week.. Should I be watching that area off the southeast closely in case something tries to move up that way? You continue to monitor anc check back every now and again but don't get too excited about it for: 1) We can't guarantee development and 2) Most of the models keep the system offshore. 3) relatively fast moving system Other than your local weather, this should not be a vacation buster. I hope they have a great time up there. Member Since: July 24, 2005 Posts: 407 Comments: 19076

1573. Tazmanian 11:13 PM GMT on July 20, 2009
i am now calling this a moderate El Nino Member Since: May 21, 2006 Posts: 5088 Comments: 111354

1574. extreme236 11:12 PM GMT on July 20, 2009
Quoting stormpetrol: wave at 6N/31.5W looks much more interesting on the quikscat Likely too far south for any immediate development. Member Since: August 2, 2007 Posts: 19 Comments: 19234

1575. futuremet 11:12 PM GMT on July 20, 2009
Quoting BurnedAfterPosting: 4 hours ago you were very interested in the west winds that were being reported in the Islands, now you have taken a complete 180 and are calling this system dead I dont get it Because the COC is west of all the convection. If it wrap itself with some convection, then it will have to be watch as shear decreases. Furthermore, 500mb vorticity has be weakened, and displaced northeastward due to shear. This why I think consolidation is likely tomorrow. Member Since: July 19, 2008 Posts: 43 Comments: 4049

1576. Drakoen 11:12 PM GMT on July 20, 2009
I never vehemently say a system is dead. I look a lot of things and then determine that. Member Since: October 28, 2006 Posts: 57 Comments: 29010

1577. BurnedAfterPosting 11:12 PM GMT on July 20, 2009
Quoting Drakoen: I was interested but certainly was not bought. And yes I do think it is RIP. I'll pencil that in. If I am wrong you can feed me my crow and call me whatever you want. I dont believe in crow, if you are wrong you are wrong, its no big deal I am just curious how you could do a complete 180 in just 4 hours

1578. extreme236 11:13 PM GMT on July 20, 2009
Quoting Tazmanian: i am now calling this a moderate El Nino I doubt its moderate with those SOI numbers. I'd still say its rather weak at this point. Member Since: August 2, 2007 Posts: 19 Comments: 19234

1579. Makoto1 11:13 PM GMT on July 20, 2009
Quoting Weather456: You continue to monitor anc check back every now and again but don't get too excited about it for: 1) We can't guarantee development and 2) Most of the models keep the system offshore. 3) relatively fast moving system Other than your local weather, this should not be a vacation buster. I hope they have a great time up there. Ah, thanks. That's what I wanted to hear, lol.

1580. reedzone 11:13 PM GMT on July 20, 2009
Models support energy from 97L developing near the Bahamas in a few days. I'm not RIPing 97L, I never RIPed it yet, still staying strong. Member Since: July 1, 2008 Posts: 13 Comments: 7247

1581. moonlightcowboy 11:14 PM GMT on July 20, 2009
Quoting Tazmanian: i am now calling this a moderate El Nino Good post, TAZ. Thanks. I don't think the NINO is going to be as pronounced as has been suggested earlier. WTG, dude! Good call! Member Since: July 9, 2006 Posts: 179 Comments: 28121

1583. jeffs713 11:14 PM GMT on July 20, 2009
1562. Quoting him telling him to go away will just encourage him. Just press the magical "Ignore User" button, and be blissful in knowing that whatever drivel he posts, you can't see it. Also... DON'T FEED THE TROLLS! Member Since: August 3, 2008 Posts: 15 Comments: 5722

1584. Drakoen 11:14 PM GMT on July 20, 2009
Quoting BurnedAfterPosting: I dont believe in crow, if you are wrong you are wrong, its not big deal I am just curious how you could do a complete 180 in just 4 hours I didn't do a 180 and you are calling out the wrong person. You're still new here. I 180 implies that my thoughts have become opposite of what I said earlier today and that is not the case. I said there was only a 30% chance of survival which means I gave it a 70% chance of being put to death. Member Since: October 28, 2006 Posts: 57 Comments: 29010

1585. reedzone 11:15 PM GMT on July 20, 2009
Quoting Tazmanian: i am now calling this a moderate El Nino Looks like 2004... please don't bash me lol Member Since: July 1, 2008 Posts: 13 Comments: 7247

1586. IKE 11:15 PM GMT on July 20, 2009
What will the NHC say about our week long invest? They may say it's become more disorganized... Member Since: June 9, 2005 Posts: 23 Comments: 37044

1587. Cavin Rawlins 11:15 PM GMT on July 20, 2009
The atmopsheric effects of our El Nino is not well estbalised yet Member Since: July 24, 2005 Posts: 407 Comments: 19076

1588. Patrap 11:16 PM GMT on July 20, 2009
Quoting IKE: What will the NHC say about our week long invest? They may say it's become more disorganized... Member Since: July 3, 2005 Posts: 371 Comments: 111516

1589. BurnedAfterPosting 11:16 PM GMT on July 20, 2009
Quoting Drakoen: I didn't do a 180 and you are calling out the wrong person. You're still new here. I 180 implies that my thoughts have become opposite of what I said earlier today and that is not the case. I said there was only a 30% chance of survival which means I gave it a 70% chance of being put to death. ok maybe not a total 180, but you did go from being interested in the observations and gave the impression that you didnt think this was dead, now you are saying it is dead

1590. Drakoen 11:16 PM GMT on July 20, 2009
Quoting reedzone: Looks like 2004... please don't bash me lol This is not a El Nino Modoki. This is a regular El Nino characterized by plaguing wind shear and subsidence. Member Since: October 28, 2006 Posts: 57 Comments: 29010

1591. Drakoen 11:17 PM GMT on July 20, 2009
Quoting BurnedAfterPosting: ok maybe not a total 180, but you did go from being interested in the observations and gave the impression that you didnt think this was dead, now you are saying it is dead I was just wondering where they came from. Based on what I see it is dead. Member Since: October 28, 2006 Posts: 57 Comments: 29010

1592. LPStormspotter 11:18 PM GMT on July 20, 2009
Quoting IKE: Poll question..... Do you want 97L to get ripped apart, aka..sheared to death, and end it's misery and the blogs? (1)Yes. (2)There's still hope. Don't pull the plug yet. (3)No. A valiant comeback will be made tonight while we're sawing logs. This baby could survive 80 knots of shear! 2 for sure Member Since: July 17, 2008 Posts: 0 Comments: 378

1593. BurnedAfterPosting 11:19 PM GMT on July 20, 2009
Quoting Drakoen: I was just wondering where they came from. Based on what I see it is dead. Ok fair enough

1594. KoritheMan 11:19 PM GMT on July 20, 2009
I would be more concerned about possible tropical cyclogenesis occurring across the Bahamas over the next few days, as models indicate generally favorable upper-level winds in that area. I know this has been mentioned several times today by 456 and others, I'm just saying that this area is far more likely to develop, particularly in the short-term. Member Since: March 7, 2007 Posts: 409 Comments: 15445

1595. Drakoen 11:19 PM GMT on July 20, 2009
At least I am willing to stick my neck out. I wonder how many of you can play this game and pick B. 97L A) Die soon B) Become Ana Member Since: October 28, 2006 Posts: 57 Comments: 29010

1596. moonlightcowboy 11:20 PM GMT on July 20, 2009
...detente! Aaahhh...good going, fellas! Member Since: July 9, 2006 Posts: 179 Comments: 28121

1597. Ossqss 11:20 PM GMT on July 20, 2009
Quoting Patrap: Very nice Patrap, that item has a quarter slot in it! Now we know the budget at the NHC is gettin tight when they have to insert a quarter to use the yellow crayola ,LoL Member Since: June 12, 2005 Posts: 6 Comments: 8154

1598. IKE 11:21 PM GMT on July 20, 2009
Quoting Drakoen: At least I am willing to stick my neck out. I wonder how many of you can play this game and pick B. 97L A) Die soon B) Become Ana A.... Member Since: June 9, 2005 Posts: 23 Comments: 37044

1599. futuremet 11:21 PM GMT on July 20, 2009
Quoting Drakoen: At least I am willing to stick my neck out. I wonder how many of you can play this game and pick B. 97L A) Die soon B) Become Ana lol I rather synthesize both.... Ayyyybeeee I cannot vaguely say A, because I know for a fact that wind shear will drop to marginal levels tomorrow. I cannot say B, because the atmospheric dynamics do not fully favor tropical cyclogenesis. I will draw my conclusion tomorrow; making any assumptions now is futile. Member Since: July 19, 2008 Posts: 43 Comments: 4049

1600. Patrap 11:21 PM GMT on July 20, 2009
LOL..nothing like watching individuals create so much Havoc over something they have ZERO control over. A few Psychologist from the VA watch this Blog and believe me,..they have a good amount of fun with it too. Member Since: July 3, 2005 Posts: 371 Comments: 111516

1601. moonlightcowboy 11:21 PM GMT on July 20, 2009
Quoting Drakoen: At least I am willing to stick my neck out. I wonder how many of you can play this game and pick B. 97L A) Die soon B) Become Ana "B", Drak, I'm with it. But, I may change my mind in the a.m. LOL Member Since: July 9, 2006 Posts: 179 Comments: 28121

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