About Jeff Masters
Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather
Disorganized Leslie headed towards Bermuda
By: Dr. Jeff Masters , 4:18 PM GMT on September 03, 2012
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
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
Category 6™
72. aislinnpaps
BigWes was on last night, had just got his power back on, was asking after you and if Nola Roux had had her pups.
71. sar2401
Maybe. It was in the tenth century, when there were pine forests and crops like barley and wheat were able to be grown there.
70. wxmod
I've started to invest in property there. Great golf course potential. I bought that whole swath you see in the satellite photo for pennies.
69. sar2401
Maybe Leslie will make landfall in Greenland...or Iceland. It's been a weird year so far. Speaking of weird, we are getting rain in Central AL today from the remnants of Isaac, located way up in southern Illinois. It looks like we could get more rain here from the remnants than we ever got from Isaac when he was a hurricane and only 250 miles from us.
68. wxmod
That's possible, but it might park on Bermuda and create quite a problem.
67. JrWeathermanFL
I have a feeling that greenland might actually be green one day
66. HurricaneDean07
I didn't look at the run. Just guessing.
65. HurricaneDean07
You should name each pup after a Storm name this season. and one of them needs to be named Isaac.
64. flcanes
or nadine?
63. flcanes
wow
62. HurricaneDean07
Michael follows Leslie?
61. sar2401
It sure seems like hurricanes this year are retaining their strength way further north than what would be expected. The SST's off the East Coast and Canada a higher than normal this year as well. If Leslie survives long enough to become a cat 2, and manages to move more west than predicted, it could be trouble for Nova Scotia again. Still, she has a lot of work to do if she's going to survive the shear, so we'll see.
60. flcanes
awe, those puppies were so cute
59. wxmod
58. sar2401
The kids look just like mom. :) So you were out from Wednesday through Saturday? Boy, I'm glad I live in my little house on wheels with a generator and battery bank. That must have been miserable, let alone the other damage. Good luck.
57. Patrap
FEMA has already Inspected our Home yesterday and we awaiting a Hotel Voucher for the "crew" here.
Thanx Aussie, G'night mate.
56. sar2401
Yeah, it could be another Helene thing if the predicted trough makes it all the way to Gulf, and it looks like it shouldn't be more than what Helene turned out to be. I hope not, Helene was a really irritating storm. :) I still haven't seen any models developing a system east of the Bahamas.
55. AussieStorm
Hey Pat, how are the pups. Glad your back, I hope your damage is fixed asap.
Cheers.
Goodnight
P.S Leslie will peak as a 90mph Cat 1 Hurricane North of Bermuda.
54. TropicalAnalystwx13
Ocean Heat Content is severely overrated on this blog. You realize Gordon and Kirk nearly became major hurricanes under 0 OHC, right?
53. wxmod
52. Patrap
A File Image, but a good one.
We got power Back round 4pm Saturday here Uptown.
Nola Roux and the "Pup's" delivered during the Hurricane.
51. Pirate999
Now
Scattered Clouds
Temperature 96.1 °F
Feels Like 138 °F
Wind(mph) 3.0
50. Tropicsweatherpr
Same track as Leslie.
49. sar2401
That trash bag look is fabulous. :) I'm amazed the lights stayed on as long as they did.
48. sar2401
Sorry, you are correct, she did have winds of 100 mph briefly before and after landfall. Let's hope Leslie manages to avoid the Gulf Stream this year.
47. Patrap
A-Ok Uptown.
Canal Street NOLA, Midnight Last Tuesday
46. TropicalAnalystwx13
I'm pretty sure the NHC would factor it into their forecast and in their discussion if they thought it would be as big of a problem as you're making it out to be.
45. AussieStorm
Leslie is predicted to travel 7.1degrees in 120hrs... which = 3.71mph. Think of all the up-welling.
Mind you, not much to up-well.
44. aislinnpaps
Not fun! I have a cousin from there, though she hasn't been back here to visit in about thirty years.
43. sar2401
Yes, Captain, we hardly knew ye....
Did anyone else notice in the 11 PM discussion of Leslie that the NHC officially used the word "blob"? I don't know if Grothar gave them a license for the word, but "blob" is now an official meteorological term. :)
42. weathermancer
Technically, Juan was a Cat. 2 storm. 2 minute sustained wind measurement.
41. GTcooliebai
40. GeoffreyWPB
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 04/1100Z TO 05/1100Z SEPTEMBER 2012
TCPOD NUMBER.....12-107
I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY: POSSIBLE 05/1800Z FIX
MISSION INTO TROPICAL STORM LESLIE NEAR 27.0N 63.3W.
39. Carnoustie
remnenets of Kirk are forecast to hit us here in Scotland over the next few days,60mph+ storm force winds.
38. sar2401
There are some similarities between Juan and Leslie. The thing to watch for is if Leslie shifts more to the west, develops into a cat 2, and passes Bermuda to the west. That could put her closer to or over the Gulf Stream, and allow her to remain a hurricane until she reached Nova Scotia. Even then, Nova Scotia wouldn't be likely to see more than a cat 1, as was the case with Juan. She's still a long way out and everything has to happen just right for a repeat of Juan. They'll just have to wait and watch.
37. weathermancer
Juan is still close in memory. Lost allot of trees here in coastal NS.
Landfall with Leslie or not, she will be generating tons of swells for days on end.
Either way... ocean SST's here this summer have been above normal for longer time period.
36. TropicalAnalystwx13
Not really.
35. aislinnpaps
My oldest son who lives behind me is disabled and lives in constant pain and often unable to get around. But if we had to use the generator, he would be the one to have to move it and work with it. My youngest son is a miracle child, born with multiple heart defects and not expected to live, but he is turning 20. BUT he can't be moving heavy things and heat gets to him fast. My daughter, daughter-in-law and I would do what we can, keeping the youngest son from feeling we aren't stopping him, but... It's a delicate balance I'd rather not have to deal with.
34. Tazmanian
yes lol
33. GTcooliebai
32. washingtonian115
31. aislinnpaps
Exactly. I have a generator, but also have a disabled son and it would be difficult for him.
30. CybrTeddy
KIRK IS NOT EXPECTED TO LIVE LONG AND PROSPER.
29. GTcooliebai
28. sar2401
Is this based on some model data or just a hunch?
27. aislinnpaps
Thanks, Sar. I have a good friend in Nova Scotia. They still talk about Juan.
26. washingtonian115
25. sar2401
Not the Doc, of course, but it's highly unlikely Leslie, if she ever reached cat 2, and if she ever reaches Canada, would still be a cat 2. If she was a strong cat 2 north of Bermuda, there's a chance she could be a cat 1, but even that looks doubtful to me. I'm still not convinced she ever gets to cat 2.
24. AussieStorm
dreaming
23. stillwaiting
22. CybrTeddy