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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264 hrs.

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Quoting wxchaser97:

Its the end of Bermuda as we know it. Anyway what the Euro shows is hopefully over done but it would still be a cat4 hurricane at the very least.


For heaven's sake. Firstly, intensity models never get it right. Secondly, Bermuda's been there for a long time and has been hit by many hurricanes. The average speed of landfalling hurricane has been 102 mph. Hurricane Fabian, in 2003, was a strong category 3 when it made almost a direct hit on Bermuda, with wind of 120 mph sustained and 165 mph in gusts. Even if, God forbid, Bermuda got hit by a cat 4, the island is not going be demolished down to nothing but coral. It's posts like some of these that really make us look like doomcasters.
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Quoting KEEPEROFTHEGATE:


the island would be stripped clean
so that nothing remains
but the dirt and water
and maybe not even the dirt
but bare rock


This would not happen. If Bermuda got hit with a Cat 4 there would be severe damage to vegetation, major structural damage would only occur to structures that were low lying and on the immediate coast. Very few structure set back from the coast would be destroyed however there would be some structural failure of roofs but even these will be minimal. Maximum loses would be around US $300 million with US $100 million in insured loses, US $100 million in uninsured losses and US $100 million in infrastructure damages.
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Quoting Grothar:


I know Nuuuuuuthing!! Just keep watching the EURO.
What do you think about the wave in the central Atlantic?.I know the models don't develop it.But I still think it has a chance.
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Quoting HurricaneHunterJoe:


Any blatant implications from that Most Wise One?


I know Nuuuuuuthing!! Just keep watching the EURO.
Member Since: July 17, 2009 Posts: 71 Comments: 26123
Off topic...Sad...

'Green Mile' star Michael Clarke Duncan dies at age 54
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Quoting washingtonian115:
Like Earl.Seriously though in order for Leslie to become a cat 5 she would have to quickly start organizing.Since she is also large it'll take a while for her to consolidate.


It already looks like she's trying... the gal has her own ideas. A lot of the cyclones this year are pretty twisted jokers: Debby, Ernesto, Isaac... Leslie the next Fabian? Considering her size and what's being predicted, she could very easily be worse. =(
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So far finding only 2 webcams on Bermuda.... still searching.
Member Since: August 2, 2011 Posts: 0 Comments: 1918
will have too see what are storm looks like in the AM all so are center is starting too be cover overe


Member Since: May 21, 2006 Posts: 5091 Comments: 115081
Quoting unknowncomic:
Buoy north of Leslie she will pass near on friday already 16ft waves. Latest GFS also show a direct hit to Bermuda.
Conditions at 41049 as of
2150 GMT on 09/03/2012:
Unit of Measure: Time Zone:

Click on the graph icon in the table below to see a time series plot of the last five days of that observation.
5-day plot - Wind Direction Wind Direction (WDIR): ESE ( 110 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 19.4 kts
5-day plot - Wind Gust Wind Gust (GST): 23.3 kts
5-day plot - Wave Height Wave Height (WVHT): 16.1 ft


I hope TWC send a corresponsal and show live the pass of Leslie over Bermuda
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Im not liking some of the model shifts west for Leslie. I live here in Richmond VA.. Remember Isabel just tore this state up in 2003. let's hope it chugs along in the Atlantic as a fish.
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Link
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180 hrs. Leslie will absorb whatever comes off the Southeast coast and both will be scooped up by the trough which will make for a beautiful extratropical storm:

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Quoting ncstorm:


Lets hope not..a Cat 4/5 will make its own steering..
Like Earl.Seriously though in order for Leslie to become a cat 5 she would have to quickly start organizing.Since she is also large it'll take a while for her to consolidate.
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Quoting sar2401:


You mean the hurricane from 1932? Where did you see that this was promoted from a cat 3 to cat 4? I can't find anything about it. I can't imagine the NHC doing this.

Link
Yes 1932
The Atlantic Tracks File is an ASCII (text) file containing the 6-hourly (0000, 0600, 1200, 1800 UTC) center locations (latitude and longitude in tenths of degrees) and intensities (maximum 1-minute surface wind speeds in knots and minimum central pressures in millibars) for all Tropical Storms and Hurricanes from 1851 through 2002. More information on this file is found in NOAA Technical Memorandum NWS NHC 22 "A Tropical Cyclone Data Tape for the North Atlantic Basin, 1886-1983: Contents, Limitations, and Uses" by Brian R. Jarvinen, Charles J. Neumann, and Mary A. S. Davis.

It weakens to cat 3 hurricane as it moved over the island, but when it made landfall it was classified as cat 4
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Gets me, the Euro and GFS usually low-ball long range intensity forecasts, so what are we supposed to make of a Cat 5 forecast on the Euro?!

Wait for consistency and verify from other models.

I think it's somehow picking up on some of Isaac's left-over energy and incorporating it in Leslie.
Member Since: January 25, 2012 Posts: 33 Comments: 1520
Quoting beell:


Looks a little shear-y, Baha.
Hey beell... as in shearing something, or being sheared?
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Quoting CybrTeddy:


Those wave heights are incredible, I have never seen that for a tropical cyclone. Leslie is going to be an absolutely massive hurricane if the models verify.


How long have you been watching this?


Katrina had dominant wave heights of 17 METERS, over 50ft.


Ivan may have had an isolated wave over the central Gulf which was as high as 90feet, based on a damage report on a oil platform.
Member Since: January 25, 2012 Posts: 33 Comments: 1520
189 JLPR2:
Here is a pretty non-tropical system.

In just the right spot to become the 949millibar Cyclone that GFS was predicting a couple of days ago.
Major sea-ice melt from a powerful,well-covered ArcticCyclone; then another smaller, less reported ArcticCyclone did noticeable damage to the sea-ice extent.
Another major ArcticCyclone to finish off the ArcticMeltSeason?
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Quoting washingtonian115:
I don't think Leslie will be a cat 5...The ECWMF is over doing intensity IMO.The wave in the central Atlantic still continue to hold it's own.I see T.D 13 has formed.


Lets hope not..a Cat 4/5 will make its own steering..
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Member Since: July 15, 2006 Posts: 171 Comments: 53811
Buoy north of Leslie she will pass near on friday already 16ft waves. Latest GFS also show a direct hit to Bermuda.
Conditions at 41049 as of
2150 GMT on 09/03/2012:
Unit of Measure: Time Zone:

Click on the graph icon in the table below to see a time series plot of the last five days of that observation.
5-day plot - Wind Direction Wind Direction (WDIR): ESE ( 110 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 19.4 kts
5-day plot - Wind Gust Wind Gust (GST): 23.3 kts
5-day plot - Wave Height Wave Height (WVHT): 16.1 ft
Member Since: August 2, 2011 Posts: 0 Comments: 1918
Quoting allancalderini:
Could td 13 be michael at the 11pm update?

There is a good possibility, but we will have to wait and see how it looks like at 10-11pm.
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I don't think Leslie will be a cat 5...The ECWMF is over doing intensity IMO.The wave in the central Atlantic still continue to hold it's own.I see T.D 13 has formed.
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Quoting windshear1993:
omggg how do you post pictures


Click on the pic you want to post with the right site of your mouse. Copy the URL in the pop-up-menue which appears. Paste it on WU after clicking on "Image" in the free space. Sorry if unclear, but I'm German ;-)
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Quoting KEEPEROFTHEGATE:


the island would be stripped clean
so that nothing remains
but the dirt and water
and maybe not even the dirt
but bare rock

Its the end of Bermuda as we know it. Anyway what the Euro shows is hopefully over done but it would still be a cat4 hurricane at the very least.
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Quoting wxmod:


This stuff doesn't matter. Fact is: Arctic ice VOLUME has been decimated. Your calculations only obscure that fact.


I'm not just interested in the sea ice summer minimum.

That's extremely short-sighted, as the warming actually only just BEGINS when summer sea ice ends...


I'm interested in figuring out realistically,w ith all negative feed backs considered, when meltdowns occur in various months: September, August, October, July, December, June; probably in that order for having at least one day being Ice free.


Getting February through May ice free will take quite a while longer, but considering the exponential melting also applies to winter time ice, it will eventually happen, although the coefficient is itself decreasing at some limit due to permanent darkness during the winter months, etc; It's exactly half the summer melt rate growth, to within margin of error of measurement anyway.



My calculation doesn't obfuscate anything, because all of the trend lines from each statistic should converge to zero on a single year, for both summer time minimum and winter maximum, or at least a spread of 1 to 3 years with 95% confidence, when margin of error is taken into consideration.



There is so much focus on the first summer time meltdown that people forget Global Warming does not stop with the ice melting seasonally, nor does it stop with the ice melting totally.

It will actually only stop when convection increases so high that clouds offset the decrease in albedo from melted ice, plus the CO2, which is going to be quite a very, very hot ride for some folks. It may not even be physically possible to stop if CO2 and other greenhouse gases get pushed too high.
Member Since: January 25, 2012 Posts: 33 Comments: 1520
Quoting allancalderini:
Could td 13 be michael at the 11pm update?



will see
Member Since: May 21, 2006 Posts: 5091 Comments: 115081
Quoting allancalderini:
Could td 13 be michael at the 11pm update?

Possibly. Depends on how it looks like by then.
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490. beell
Quoting BahaHurican:
Afternoon, all. I'm noticing that ULL right over us... I have to since it has been bringing some hefty downpours all day...

Any chance of it building downard? It's been sitting there for a while...


Looks a little shear-y, Baha.
Member Since: September 11, 2007 Posts: 142 Comments: 16607
Could td 13 be michael at the 11pm update?
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Quoting ncstorm:


I didnt even run the loop all the way for the Swell..last frame-just incredible..


Leslie broke the ocean...
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The disturbance in the central Atlantic...

...TROPICAL WAVES...

THE TROPICAL WAVE MOVING ACROSS THE CENTRAL TROPICAL ATLC
CONTINUES TO BE DIFFICULT TO PIN DOWN. AS OF 1200 UTC...THE WAVE
AXIS IS ANALYZED FROM 18N35W TO 12N37W. HOWEVER...MODEL GUIDANCE
AND LIMITED OBSERVATIONS NEAR THIS SYSTEM INDICATED NO CYCLONIC
CURVATURE NEAR THE WAVE AXIS...NOR AT 700 MB LEVEL WHERE
CYCLONIC CURVATURE SHOULD BE BEST PRONOUNCED. IT IS LIKELY THAT
THIS WAVE BECAME EMBEDDED IN THE MONSOONAL GYRE DESCRIBED BELOW
...AS SEVERAL EARLIER SCATTEROMETER PASSES ONLY INDICATED
SURFACE TURNING ASSOCIATED TO THE MONSOON TROUGH AXIS.
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Quoting wxchaser97:

Lets all hope so because if the Euro is right then, bye bye Bermuda.


the island would be stripped clean
so that nothing remains
but the dirt and water
and maybe not even the dirt
but bare rock
Member Since: July 15, 2006 Posts: 171 Comments: 53811
well its like this. never underestimate a tropical system. i dont
Member Since: April 26, 2006 Posts: 5 Comments: 3126

Very broad inflow.
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omggg how do you post pictures
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Quoting CybrTeddy:


Those wave heights are incredible, I have never seen that for a tropical cyclone. Leslie is going to be an absolutely massive hurricane if the models verify.


It's going to be interesting what Leslie is like when a possible recon mission goes in on Wednesday.
Member Since: September 10, 2007 Posts: 0 Comments: 11151
Quoting CybrTeddy:


Those wave heights are incredible, I have never seen that for a tropical cyclone. Leslie is going to be an absolutely massive hurricane if the models verify.


I didnt even run the loop all the way for the Swell..last frame-just incredible..

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http://www.google.com/imgres?um=1&hl=en&sa=N&biw=13 34&bih=589&tbm=isch&tbnid=6Vso5hwkSJ6UBM:&imgrefur l=http://julieannamos.hubpages.com/hub/Hurricane-D og&imgurl=http://s3.hubimg.com/u/1462378_f520.jpg& w=520&h=408&ei=yipFUOzYNoXW9QSQy4DgBQ&zoom=1&iact= hc&vpx=269&vpy=267&dur=870&hovh=199&hovw=254&tx=13 0&ty=74&sig=113304317007294587058&page=1&tbnh=123& tbnw=157&start=0&ndsp=21&ved=1t:429,r:8,s:0,i:101
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Quoting CybrTeddy:


Those wave heights are incredible, I have never seen that for a tropical cyclone. Leslie is going to be an absolutely massive hurricane if the models verify.

true dat
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Quoting ncstorm:




this looks like the Atlantic Ocean blew up


Those wave heights are incredible, I have never seen that for a tropical cyclone. Leslie is going to be an absolutely massive hurricane if the models verify.
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Quoting RTSplayer:


Map says sub-880 is possible, but highly, highly unlikely.

It would be incredibly explosive intensification to pull that one off.


Very scary thought
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Quoting TropicalAnalystwx13:

I fixed it, Taz. We get busy trying to update the ACE page, timeline, timeline page, current storm information section, and even articles (when one is warranted). Just bare with us...any mistakes you guys see will be corrected promptly.

Also it says Kirk was only 90 mph..
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http://upload.wikimedia.org/wikipedia/commons/e/ee/ Dog_1950_track.png
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Afternoon, all. I'm noticing that ULL right over us... I have to since it has been bringing some hefty downpours all day...

Any chance of it building downard? It's been sitting there for a while...
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Quoting stormpetrol:
I wonder if 12N/33W will get a yellow circle at 8pm, it looks better than TD13.


Hi Stormpetrol
I was wondering the same thing until I read todays NHC 2 pm discussion,they mention 'no cyclonic signature associated with the wave, embedded in the monsoon trough' to this effect......
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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.