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High wind shear dominates the Atlantic

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

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

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

What about Nova?

Jesus Patrap that's awful!
Were the kittens there too?
She musta just left ric's. Are you going to hold him libel?
Saturn SL-1 with SUV then house
OK, let me get this straight, some lady hit your car, and than hit a house??
just got off phone..Teresa was making left turn..and SUV went inside her turn to pass..lost control..hit freaking house...she transported after falling out getting out of truck..Teresa Nova..& Jr..safe..unhurt...Mirror missing on Saturn..with some scraping & other door damage...Phew...haste from stupidity=Butthead...
well thats good to here everyone is ok
Yup..Thanks for the concern...Woman transported like I said..witnessess left Buisness cards..State Police in Route..local Sheriff cant do report cause State Highway..Patrap Jrs.Got a Headache.He was sleeping with pillow up against his window.Pictures taken....Jeezus..at least Daughter coming home from Dominican...today.She misses all the xcitement living in the city proper...
well, looks like we have 99L this mornning.....

99L

HOPE EVERYBODY HAS A GOOD WEEKEND! :)
well jeez that might make it on the 10:00 news!
99L is over the Bahamas I see.
oh good grief pat, you JUST got done saying it was quiet out there....jo
99L winds are at 25 MPH
Woman has broken leg...Her boyfriend shows up...Says to teresa..shes always leaving for work when its time to be there..LOL...THis is a given.She lucky just to Break leg.Yesterday..Get this..Tragedy.On I-12 yesterday aft,local fireman in pickup with un-secured xtension ladder in Truck driving on Interstate.Ladder pops out..18wheeler avoids by swerving into oncoming westbound traffic..plows over 3 in a Lexus SUV..2 Killed 1 seriously injured....crazy.
I'm glad your family is ok Patrap.

And, we have an invest to chat over. Where's Rand. This should make his day.
99LINVEST.20kts-1012mb-296N-700W

jeez patrap talk about crazy stuff!
dang pat......a bit of excitement...hope all is well with jr.....glad others are ok...and may she have great insurance
Way ahead of ya Nash! I was working on it when Thel mentioned it.
ok......an invest.......let's get the direction argument out of the way first....chime in with your traveling direction
Hey Rand. Just wondering about you:-)
It might even be safe to discuss this Invest Nash....doesn't look to be heading West! LOL!
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
looks like the direction is West-SouthEast
West-SouthEast
...ummm.....wpb....help me on that one please
ok...next debatable point.....tropical or subtropical?
just a joking ricder
I'm gonna say NE on this one guys.
can you say ..NEUTERCANE!
Invest ...a subject for This am....lets get the numbers..LOL!
Subtropical as it hook up with Cut-Off Low. Here are the current model runs:

I'm still on part 1, where is the LLC, cant acquire the correct motion without a LLC.
Subtropical Storms...Link
Me found the LLC, i will have to say NE, now to answer question 2, how about non-tropical??
I doubt Tropical Nash.
Kinda like this one in 2000...Link
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! :)
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:-)
well jeez nuetercane isnt a term anymore

neutercanes, but this term was quickly discontinued the following year in 1973.
ok....sub tropical heading ne.....and shear...high?..low?....steady..increasing...decreasing?
I say shear is high, with no change in sight.


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.........
UPPER-LEVEL WINDS ARE FORECAST TO REMAIN
UNFAVORABLE FOR TROPICAL CYCLONE DEVELOPMENT.
Atlantic Buoy...Link
Patrap - OUCH -you take care of them. Those "day after the collision" aches and pains are never fun. Glad to hear they were unscathed - sorry about the mirror on the Saturn - my mirror on the Malibu was removed by one OOPS - the wayward horse - she thought it was a scratching post and they are tested for "horse shoulder scratching". It didn't withstand the pressure.
rand....is that a i want to make a loop model forecast?
Well that sure ain't West y'all!


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



LOL...I was holding off waiting for that comment Ric!
Which one is the LLC, area 1 or 2?
nope..... not even north! :D
dangit, i had multiple choice test! LOL

I choose 1...... i have a 50% chance, but get it wrong 90% of the time! LOL
Dang Thel....that's tough.
"ricderr at 1:01 PM GMT on October 06, 2006.

rand....is that a i want to make a loop model forecast?"

don't EVEN go there, loops-are-NOT-us ric jo
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?


I still have area 1 and 2 on that image.
or I could be wrong and the LLC is in the middle of area 1 and 2
now.....will it increase the moisture for florida?
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
well i must get off, time for brunch, you have fun talking about the tropical/subtropical/non-tropical thingy
Good morning all seems we have a bit of activity this am.
"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
the only mousture

I only get mouseture when my hand sweats!
mouseture? lol
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...
Rand, look at the goes east IR winds going west and winds going east quite a show.lol
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...