Disorganized Leslie headed towards Bermuda

By: Dr. Jeff Masters , 4:18 PM GMT on September 03, 2012

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Tropical Storm Leslie continues to struggle with moderately high wind shear of 15 - 20 knots, due to strong upper-level winds out of the northwest. The shear is keeping heavy thunderstorms confined to the southeast quadrant of the storm. These thunderstorms are as far removed from the center as we've so far with Leslie, as seen on satellite loops. According to the latest SHIPS model forecast, the shear is expected to stay moderately high through Tuesday night, then drop to the low category, 5 - 10 knots, by Wednesday night. At that time, Leslie will be over warm ocean waters of 29°C, and the reduction in shear and warm waters should allow Leslie to intensify into at least a Category 1 hurricane by Friday, as predicted by most of the intensity forecast models. Intensification to a stronger storm may be hampered by its slow motion, which will cause Leslie to churn up cool water from the depths that will slow intensification. Once Leslie begins moving more quickly on Saturday, this effect will diminish, and Leslie could be at Category 2 strength on Saturday, as predicted by the HWRF and LGEM models. Steering currents for Leslie are expected to be weak on Tuesday - Friday, as Leslie gets stuck between two upper level lows. The latest guidance from our top computer continues to show Leslie making a very close pass by Bermuda on Saturday, and that island can expect a 3-day period of rough weather Friday through Sunday. Leslie will stay stuck in a weak steering current environment until a strong trough of low pressure approaches the U.S. East Coast on Saturday. This trough should be strong enough to pull Leslie quickly to the north on Saturday and Sunday, and Leslie may be close enough to the coast that the storm will make landfall in Canada on Monday, September 10. None of the reliable models have shown that a direct hit on New England will occur, but we can't rule that possibility out yet. The most likely long-term fate of Leslie will be for it to miss land entirely and brush by the coasts of Nova Scotia and Newfoundland, but any forecast of what a tropical cyclone might do a full seven days in advance is pretty speculative. Regardless, Leslie will bring an extended period of high waves to Bermuda, the U.S. East Coast, and Nova Scotia and Newfoundland this week. These waves will be capable of causing significant beach erosion and dangerous rip currents.


Figure 1. Morning satellite image of Tropical Storm Leslie. The low-level circulation center is fully exposed to view, thanks to strong northwest winds creating 15 - 20 knots of wind shear.

Invest 99L in the Central Atlantic
A small extratropical low pressure system that got cut off from the jet stream and is now spinning away in the Central Atlantic, near 26°N 42°W, (Invest 99L), is headed west at 10 mph, and has developed a small amount of heavy thunderstorm activity. This storm is not a threat to any land areas, and in their 8 am EDT Tropical Weather Outlook on Monday, NHC gave 99L a 30% chance of developing into a tropical cyclone by Wednesday morning.

Jeff Masters

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Quoting Grothar:


No, just joking.

Do they have kids of their own yet?
Do they call you the wise auld one?
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Quoting mtwhitney:
http://arctic.atmos.uiuc.edu/cryosphere/NEWIMAGES /a rctic.seaice.color.000.png

Half the arctic ice cap is gone. I wonder what weather will be like this winter. I wonder if civilization will last more than a few decades.


More like 2/3rds is gone, by area minimum anyway.

That grey line is the period average, not the period maximum, which was at the beginning.




Don't worry, the next super-eruption or cataclysmic meteor will fix SOME of what we've screwed up...
Member Since: January 25, 2012 Posts: 33 Comments: 1520
Quoting AussieStorm:

They still live at home???? My two are at school. Yr 1 and Yr 3.


No, just joking.
Member Since: July 17, 2009 Posts: 71 Comments: 27479
Not Good for S FL!!!
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Quoting Grothar:


Not a bad idea. Of course mine are 39 and 37, so it won't be easy.

They still live at home???? My two are at school. Yr 1 and Yr 3.
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Canadian sent a 954mb towards New England, plus since it was not the correct pressure intitialization, needs at least a -2mb correction.

Member Since: January 25, 2012 Posts: 33 Comments: 1520
Quoting cyberian:


Oh come on, how could should such a young chap such as yourself have children my age?


It's been so long, I forgot.
Member Since: July 17, 2009 Posts: 71 Comments: 27479
To the Port Light org.,I thank ya'll for what you do I got to see it 1st hand here in Hurley,MS at East Central HS.Thanks Doc for all you did.Mike
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Quoting Grothar:


Not a bad idea. Of course mine are 39 and 37, so it won't be easy.


Oh come on, how could should such a young chap such as yourself have children my age?
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Just walked along the oceanfront here on the Jersey Shore. The waves have picked up as predicted due to T.S. Leslie to our Southeast. The waves grew in size today, and are bigger tonight. If Leslie moves to the northwest, as the NHC cone is currently saying, before she decides what she will eventually do, I see days and days of increasing surf, growing in size due to the cyclone getting stronger, and moving waves from its right front quadrant towards the coast as it gets closer. According to this, we could see seas propagating from Leslie as a Category 1 and then a 2 for quite a bit of time before it moves on somehow. I think the fringe effects of Leslie could cause damage on the U.S. East Coast, even if it stays hundreds of miles offshore. What does anyone else think? Thanks.
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912. JLPR2
Quoting RTSplayer:


Gonna suck when that trough pulls away, because that ridge is going to try to build to the east, since Leslie is moving so slow anyway.

UKmet and NAM probably picking up on that, but those tracks don't exactly make sense either way, because if the high catches Leslie it would seem to turn due west...



Now that would suck...
Really complicated scenario setting up for Leslie.
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Quoting Grothar:


Not a bad idea. Of course mine are 39 and 37, so it won't be easy.


Yep, that will be a bit difficult.
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Quoting Abacosurf:
Surely you don't mean that...
Yeah, he does, and don't call him Shirley, LOL!!
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Member Since: July 15, 2006 Posts: 183 Comments: 57272
Quoting midgulfmom:
Awww Grother hope not....but a bit nostalgic ....my first storm (sniff sniff) lol


You remember that one? I missed it. I was in Norway and got my draft notice from here. LOL
Member Since: July 17, 2009 Posts: 71 Comments: 27479


Deja vu all over again...
Member Since: July 12, 2007 Posts: 0 Comments: 6069
Quoting MAweatherboy1:
The operational GFS is in excellent agreement with its ensemble members. I definitely feel it has the best handle on Leslie right now.



Expect a shift in the models in the morning.
Member Since: July 17, 2009 Posts: 71 Comments: 27479
Awww Grother hope not....but a bit nostalgic ....my first storm (sniff sniff) lol
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http://arctic.atmos.uiuc.edu/cryosphere/NEWIMAGES/a rctic.seaice.color.000.png

Half the arctic ice cap is gone. I wonder what weather will be like this winter. I wonder if civilization will last more than a few decades.
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Quoting cyberian:


Amen. Just sent 2 of mine to bed! I couldn't stand their bickering either.


Not a bad idea. Of course mine are 39 and 37, so it won't be easy.
Member Since: July 17, 2009 Posts: 71 Comments: 27479


remember its a six day forecast.
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Quoting KEEPEROFTHEGATE:
what i do now


Gave us information instead of opinion. Thanks
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The operational GFS is in excellent agreement with its ensemble members. I definitely feel it has the best handle on Leslie right now.

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Quoting AussieStorm:

This one, yes I did view the image on another tab.



Try more brighter colours.
Alright, I'll get new colors in next time.
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i hear the weatherh98 model is running
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Quoting KEEPEROFTHEGATE:


by 1000 1030 edt school tomorrow almost bedtime


Amen. Just sent 2 of mine to bed! I couldn't stand their bickering either.
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Quoting Bluestorm5:
Which one? And had you tried making the image bigger by clicking on "View Image"?

This one, yes I did view the image on another tab.



Try more brighter colours.
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Model raw /adjusted

12z Euro 916mb / 911mb
18z GFDL 955mb / 952mb
18z HWRF 944mb / 946mb
18Z GFDL 972mb / 962mb


avg raw: 947mb
avg adj: 943mb

Without Euro:

avg raw: 957mb
avg adj: 953mb
Member Since: January 25, 2012 Posts: 33 Comments: 1520
Quoting snowboy:


ich bin nur selten hier..


Schade. Kom fter
Member Since: July 17, 2009 Posts: 71 Comments: 27479
Quoting midgulfmom:
that blocking high(s)....they can do some crazy moves like a pinball machjne sometimes. Betsy '65 made a loop de loop! Answered though....thanks Grother, enjoy your posts:)


Thanks, mom. By the way. I just happen to have Betsy's track available, hoping someone would bring it up.

Deja vu?

Member Since: July 17, 2009 Posts: 71 Comments: 27479
Quoting RTSplayer:


Gonna suck when that trough pulls away, because that ridge is going to try to build to the east, since Leslie is moving so slow anyway.

UKmet and NAM probably picking up on that, but those tracks don't exactly make sense either way, because if the high catches Leslie it would seem to turn due west...



GFS 180hrs...


ECMWF 192hrs...


HWRF 111hrs. Look in Leslie, I see Bermuda... ouch



40-45ft significant wave height.


Also note how Leslie's wave effect most of the N ATL
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THE only thing that takes away from this blog are cry baby post.whaa,whaa,whaa.
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Quoting Grothar:


I've been posting these all day, you mean you just noticed? :)



ich bin nur selten hier..
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Quoting Grothar:


You mean the astute observation of the blog arguments or the blocking high expected over Leslie? It's hard to tell. Geoff and I get a little diverted when the adults are having a dispute.
that blocking high(s)....they can do some crazy moves like a pinball machjne sometimes. Betsy '65 made a loop de loop! Answered though....thanks Grother, enjoy your posts:)
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lol
Member Since: July 15, 2006 Posts: 183 Comments: 57272
Quoting KEEPEROFTHEGATE:
what i do now


Nothing, but you do it better than anybody.
Member Since: July 17, 2009 Posts: 71 Comments: 27479
Quoting CaicosRetiredSailor:



adults?

where?


by 1000 1030 edt school tomorrow almost bedtime
Member Since: July 15, 2006 Posts: 183 Comments: 57272


Pretty Looking weird storm
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Quoting trHUrrIXC5MMX:


any guess on landfall intensity?


I think the EURO was going pretty strong with it (as a major), and the GFS was as well. I'm not entirely sure, though, because I haven't looked any model runs today.
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Quoting CaicosRetiredSailor:



adults?

where?


Good one.
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Quoting snowboy:
models runs are trending west for Leslie, and landfall somewhere along the North American east coast is looking more likely


I've been posting these all day, you mean you just noticed? :)

Member Since: July 17, 2009 Posts: 71 Comments: 27479
Quoting AussieStorm:


Until you get back on blog topic/Weather related, your going on my ignore list. I hope you stop cause I don't want to do this, you forced my hand.

For those that missed it, here is a Video that Patrap took during Isaac.

Nice. Looking for my Wilma video.
Member Since: August 2, 2011 Posts: 0 Comments: 2110
Quoting Grothar:


What a guy!
what i do now
Member Since: July 15, 2006 Posts: 183 Comments: 57272
Quoting Bluestorm5:
Which one? And had you tried making the image bigger by clicking on "View Image"?


I don't have that option. :O
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Quoting Hurricane12:


That's scary, too, because it's forecast to possibly become a major within the next few days.


any guess on landfall intensity?
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Thanks JLPR2! Image makes that perfectly clear....just glad no Betsy '65 loop.
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Quoting Grothar:


You mean the astute observation of the blog arguments or the blocking high expected over Leslie? It's hard to tell. Geoff and I get a little diverted when the adults are having a dispute.



adults?

where?
Member Since: July 12, 2007 Posts: 0 Comments: 6069
Just a little off topic... I found these TWC pics I had saved on my old PC...


2006 version of Isaac...such an old graphic


2010 Earl...that is a different map from what I have seen.
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Quoting AussieStorm:

Nice graphic but you need to change your colours, they are not clear as to which colour they are.
Which one? And had you tried making the image bigger by clicking on "View Image"?
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Quoting snowboy:
models runs are trending west for Leslie, and landfall somewhere along the North American east coast is looking more likely


That's scary, too, because it's forecast to possibly become a major within the next few days.
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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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