High wind shear dominates the Atlantic

By: Dr. Jeff Masters , 1:48 PM GMT on October 05, 2006

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There are two areas of heavy thunderstorms over the Atlantic worth mentioning today. One area, over the southern Gulf of Mexico, is under 20-30 knots of vertical wind shear (Figure 1). Wind shear is expected to increase to very high levels over the Gulf over the next week (Figure 2), and there will be no tropical development there. The second area is between the Bahamas and Bermuda. Wind shear is also a high 20-30 knots in this region, and is expected to remain at about this level over the next few days. QuikSCAT imagery from this morning shows some winds of tropical storm strength, but no evidence of a surface circulation or even a wind shift in this area. Some of the computer models are forecasting that a low pressure system will develop in this area sometime in the next week, but it appears that this low will probably be extratropical.

Next week, we'll have to keep an eye on the Caribbean. Wind shear is expected to drop to low levels (Figure 2), and any tropical waves or cold fronts that move into the region might have the potential to develop. However, I'm not expecting any development.

Figure 1. Wind shear from 8am EDT today, as forecast by last night's 00Z (8pm EDT) GFS model run. The red areas show areas less than 16 knots of wind shear, which are favorable for tropical storm formation. The wind units are in meters per second; a rough rule of thumb is that 1 m/s = 2 knots. The high levels of wind shear over most of the tropical Atlantic is typical of what we see in October during an El Nino year.


Figure 2. Seven-day wind shear forecast for 8am EDT Wed October 11, as forecast by last night's 00Z (8pm EDT) GFS model run. The red areas show areas less than 16 knots of wind shear, which are favorable for tropical storm formation. The wind units are in meters per second; a rough rule of thumb is that 1 m/s = 2 knots. While most of the tropical Atlantic is expected to be under high wind shear, a "hole" in the shear is expected to open over the Caribbean.

Jeff Masters

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569. Skyepony (Mod)
1:53 PM GMT on October 06, 2006
About time they slapped an invest on that..If invest are to help warn the ships...Ships have been avoiding that area for 2 days now...

Found the probibilities of development graphic most interesting. Of all the areas, it says watch that newly blown up Caribbean blob...

Member Since: August 10, 2005 Posts: 162 Comments: 37498
568. sandcrab39565
1:45 PM GMT on October 06, 2006
Rand, look at the goes east IR winds going west and winds going east quite a show.lol
Member Since: June 25, 2006 Posts: 36 Comments: 9972
567. ricderr
1:39 PM GMT on October 06, 2006
ok..let me try.....
well my bloggers..
the navy needs to get their head out of the foggers...
all this ueless investing...
is as bad as the foolish wishcasting...
Member Since: June 27, 2006 Posts: 672 Comments: 21444
566. sandcrab39565
1:34 PM GMT on October 06, 2006
mouseture? lol
Member Since: June 25, 2006 Posts: 36 Comments: 9972
564. thelmores
1:23 PM GMT on October 06, 2006
"Posted By: ricderr
ok..so chances are...we have a subtropical system going n/e and shear will keep it from forming...can i play gulfscotman and say it's a waste of resources and funding?"

well, you can..... but you can't hit it straight on..... you have to mix in some philosophy and poetry, and then a little attitude! LOL
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563. sandcrab39565
1:22 PM GMT on October 06, 2006
Good morning all seems we have a bit of activity this am.
Member Since: June 25, 2006 Posts: 36 Comments: 9972
562. WPBHurricane05
1:21 PM GMT on October 06, 2006
well i must get off, time for brunch, you have fun talking about the tropical/subtropical/non-tropical thingy
Member Since: July 31, 2006 Posts: 56 Comments: 8112
561. WPBHurricane05
1:19 PM GMT on October 06, 2006
not that I have see, the only mousture have been with the ocean breeze, that has been causing isolated but heavy showers here in West Palm
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560. ricderr
1:17 PM GMT on October 06, 2006
now.....will it increase the moisture for florida?
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559. WPBHurricane05
1:16 PM GMT on October 06, 2006
or I could be wrong and the LLC is in the middle of area 1 and 2
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558. WPBHurricane05
1:15 PM GMT on October 06, 2006


I still have area 1 and 2 on that image.
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557. ricderr
1:13 PM GMT on October 06, 2006
ok..so chances are...we have a subtropical system going n/e and shear will keep it from forming...can i play gulfscotman and say it's a waste of resources and funding?
Member Since: June 27, 2006 Posts: 672 Comments: 21444
554. thelmores
1:05 PM GMT on October 06, 2006
dangit, i had multiple choice test! LOL

I choose 1...... i have a 50% chance, but get it wrong 90% of the time! LOL
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553. thelmores
1:03 PM GMT on October 06, 2006
nope..... not even north! :D
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552. WPBHurricane05
1:03 PM GMT on October 06, 2006
Which one is the LLC, area 1 or 2?
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550. thelmores
1:02 PM GMT on October 06, 2006


looks like bermuda should soon start feeling the "effects" of 99L soon......



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548. ricderr
1:01 PM GMT on October 06, 2006
rand....is that a i want to make a loop model forecast?
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545. Patrap
12:56 PM GMT on October 06, 2006
Atlantic Buoy...Link
Member Since: July 3, 2005 Posts: 421 Comments: 127702
543. thelmores
12:54 PM GMT on October 06, 2006


definately not your "standard" tropical system, in fact, i wonder if it has much if "any" tropical characteristics at the moment....

maybe it is trying to "transition" as we speak, thus the invest.........
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542. WPBHurricane05
12:53 PM GMT on October 06, 2006
I say shear is high, with no change in sight.
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541. ricderr
12:52 PM GMT on October 06, 2006
ok....sub tropical heading ne.....and shear...high?..low?....steady..increasing...decreasing?
Member Since: June 27, 2006 Posts: 672 Comments: 21444
540. WPBHurricane05
12:49 PM GMT on October 06, 2006
well jeez nuetercane isnt a term anymore

neutercanes, but this term was quickly discontinued the following year in 1973.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
539. nash28
12:49 PM GMT on October 06, 2006
Not really a limb though. It will get picked up with the cut off low and quickly move NE out to sea. But hey, at least we have "something" to study:-)
Member Since: July 11, 2005 Posts: 190 Comments: 16972
538. thelmores
12:48 PM GMT on October 06, 2006
hey nash, don't go out on a limb! NE.... LOL

doesnt appear very menaing at the moment..... does take up quite a bit of real-estate though! :)
Member Since: September 8, 2005 Posts: 0 Comments: 3805
537. Patrap
12:47 PM GMT on October 06, 2006
Kinda like this one in 2000...Link
Member Since: July 3, 2005 Posts: 421 Comments: 127702
535. WPBHurricane05
12:47 PM GMT on October 06, 2006
Me found the LLC, i will have to say NE, now to answer question 2, how about non-tropical??
Member Since: July 31, 2006 Posts: 56 Comments: 8112
534. Patrap
12:46 PM GMT on October 06, 2006
Subtropical Storms...Link
Member Since: July 3, 2005 Posts: 421 Comments: 127702
533. WPBHurricane05
12:45 PM GMT on October 06, 2006
I'm still on part 1, where is the LLC, cant acquire the correct motion without a LLC.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
532. weatherguy03
12:45 PM GMT on October 06, 2006
Subtropical as it hook up with Cut-Off Low. Here are the current model runs:

Member Since: July 5, 2005 Posts: 592 Comments: 29704
531. Patrap
12:43 PM GMT on October 06, 2006
Invest ...a subject for This am....lets get the numbers..LOL!
Member Since: July 3, 2005 Posts: 421 Comments: 127702
530. Patrap
12:44 PM GMT on October 06, 2006
can you say ..NEUTERCANE!
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529. nash28
12:43 PM GMT on October 06, 2006
I'm gonna say NE on this one guys.
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528. WPBHurricane05
12:43 PM GMT on October 06, 2006
just a joking ricder
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527. ricderr
12:43 PM GMT on October 06, 2006
ok...next debatable point.....tropical or subtropical?
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526. ricderr
12:42 PM GMT on October 06, 2006
West-SouthEast
...ummm.....wpb....help me on that one please
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525. WPBHurricane05
12:41 PM GMT on October 06, 2006
looks like the direction is West-SouthEast
Member Since: July 31, 2006 Posts: 56 Comments: 8112
524. Patrap
12:41 PM GMT on October 06, 2006
Shes got good lick to her shoulder ..And hes got the Headache..So ..he& her coming home.Then Im taking the 2 to the Hospital across the street from Here.HOspital just acquired by Oschner..they bought up 5 locally.Including the one in town that had all the deaths..Memorial.,after Katrina
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522. WPBHurricane05
12:40 PM GMT on October 06, 2006
Member Since: July 31, 2006 Posts: 56 Comments: 8112
521. nash28
12:40 PM GMT on October 06, 2006
Hey Rand. Just wondering about you:-)
Member Since: July 11, 2005 Posts: 190 Comments: 16972
520. ricderr
12:40 PM GMT on October 06, 2006
ok......an invest.......let's get the direction argument out of the way first....chime in with your traveling direction
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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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