Leslie headed towards Bermuda; Tropical Storm Michael forms

By: Dr. Jeff Masters , 3:01 PM GMT on September 04, 2012

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Tropical Storm Leslie continues to suffer from 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. Satellite loops show that Leslie has almost no heavy thunderstorm activity near its center, and the storm is crawling north at walking pace, 3 mph. Leslie's slow forward speed means that the storm is staying over the cold water stirred up by the storm's winds, inhibiting intensification. 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 Thursday afternoon. At that time, Leslie will be over warm ocean waters of 29 - 30°C, and the reduction in shear and warm waters should aid intensification. However, Leslie's motion will continue to be slow, keeping the storm over its cool water wake, and keeping any intensification slow. Once Leslie begins moving more quickly on Saturday, this effect will diminish, and Leslie could be at Category 2 strength on Sunday morning, as indicated in the official NHC forecast. Steering currents for Leslie are expected to be weak through Friday, as Leslie is stuck between two upper level lows. The latest guidance from our top computer models continues to show Leslie making a very close pass by Bermuda on Saturday. Leslie is a huge storm, and tropical storm-force winds are expected to extend outward from its center 250 miles by Friday. Bermuda is likely to see a 48-hour period of tropical storm-force winds beginning Friday night that lasts until Sunday night. The official NHC forecast shows Leslie nearly making a direct hit on Bermuda, but the uncertainty in 4-day NHC forecasts is around 200 miles. Thus, the latest 11 am EDT NHC wind probability forecast calls for just a 12% chance of hurricane force winds on Bermuda on Saturday. Nevertheless, Leslie is capable of bringing an extended period of hurricane-force winds lasting six or more hours to Bermuda Saturday night through Sunday morning, should a direct hit materialize.


Figure 1. Morning satellite image of Tropical Storm Leslie. The low-level circulation center has very little in the way of heavy thunderstorms surrounding it, thanks to strong northwest winds creating 15 - 20 knots of wind shear.

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 Nova Scotia or Newfoundland, 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 storm may also miss land entirely, and brush by the coasts of Nova Scotia and Newfoundland. Large swells from Leslie reached Cape Hatteras, North Carolina last night, and will begin pounding the entire Eastern Seaboard today through Sunday. These waves will be capable of causing significant beach erosion and dangerous rip currents. The Hurricane Hunters are scheduled to make their first flight into Leslie on Wednesday afternoon.


Figure 2. Morning satellite image of Tropical Storm Michael.

Tropical Storm Michael forms in the Central Atlantic
Tropical Storm Michael has formed in the Central Atlantic on Monday, but is not destined for fame. Satellite loops show that this is a very small tropical cyclone, and the storm is well away from any land areas. Michael is under moderately high shear of 15 - 20 knots, and this shear is forecast to remain at 15 - 20 knots through Wednesday. Since Michael is such a small storm, just a modest increase in shear could destroy it. But if Michael survives until Thursday, when shear is expected to fall to the low range, it has the opportunity to strengthen.

Michaels's formation on September 4 puts 2012 in third place for earliest formation date of the season's thirteenth storm. The record is held jointly by 2005, which had Hurricane Maria form on September 2, and 2011, which had Tropical Storm Lee form on September 2 (there was an unnamed tropical storm that year before Lee.) None of the models show that Michael will threaten any land areas. Michael is a classic example of the type of storm that likely would have been missed before the advent of satellites, since the storm is small, far from land, and may be short-lived.

Jeff Masters

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150 hr
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Quoting Grothar:


I bet Morse Code would drive you to distraction. j/k

.-- .... .- - . ...- . .-. -.. --- -.-- --- ..- -- . .- -. ..--..
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114 hrs. better run for Bermuda as the center would pass about 2 or 3 degrees to the right of them.

Member Since: August 31, 2009 Posts: 0 Comments: 5628
138 hr
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Quoting louisianaweatherguy:
Bob Breck (New Orleans Fox8 weather) showed VIPIR model picking up on the blob drifting into the gulf turning into a TS/Hurr and going into Tampa Bay this weekend... interesting...

...KEEP IN MIND that the VIPIR model has been very much correct for most of the season (including Debby from the very beginning)
Can you provide a link to that model? TIA
Member Since: August 31, 2009 Posts: 0 Comments: 5628
96 Hours
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Quoting AegirsGal:
Isaac is dead, there will be no zombie storm, and no phoenix rising from the proverbial ashes.

Does it suck for those who were impacted by Isaac to have to deal with more rain? Yes.

Each tropical cyclone is different, and cannot be compared to any other, either in track or intensity.

Will there be similarities? Yes, since they are all tropical cyclones.


I agree that Isaac is gone..however the weather I've seen today is definitely healthy in nature...
Also if this turns into a GOM problem, expect some crow recipes.. :)
Ok..Back to lurking mode..
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880. beell
Quoting pcola57:


Please don't be too hasty w/him..he may (like myself) have a handicapp


orabrokenspacebar
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Quoting want2lrn:
I was curious if there were any sites that showed "future" fronts for conus similar to the ones that show canes?


check your mail buddy
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Quoting hunkerdown:

what is your issue with the "." between each word???

Also, who is Issacc?? Come on, how hard is it to spell these names correctly...you aren't even close.


I bet Morse Code would drive you to distraction. j/k
Member Since: July 17, 2009 Posts: 71 Comments: 26517
Quoting louisianaweatherguy:
Bob Breck (New Orleans Fox8 weather) showed VIPIR model picking up on the blob drifting into the gulf turning into a TS/Hurr and going into Tampa Bay this weekend... interesting...

...KEEP IN MIND that the VIPIR model has been very much correct for most of the season (including Debby from the very beginning)


No shite? I saw that VIPIR model while watching local coverage on my DirecTV. Thought it was pretty cool!
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Quoting HurricaneHunterJoe:
Has the ever been a Cat5 Hurricane as small as Marcos/Michael?
only cat 4 Cyclone tracy I think in 1974.
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66 Hours
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Isaac is dead, there will be no zombie storm, and no phoenix rising from the proverbial ashes.

Does it suck for those who were impacted by Isaac to have to deal with more rain? Yes.

Each tropical cyclone is different, and cannot be compared to any other, either in track or intensity.

Will there be similarities? Yes, since they are all tropical cyclones.
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Why do I get the feeling that if Michael becomes a hurricane he would influence the steering of Leslie?

GFS 72. hrs:

Member Since: August 31, 2009 Posts: 0 Comments: 5628
I was curious if there were any sites that showed "future" fronts for conus similar to the ones that show canes?
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Bob Breck (New Orleans Fox8 weather) showed VIPIR model picking up on the blob drifting into the gulf turning into a TS/Hurr and going into Tampa Bay this weekend... interesting...

...KEEP IN MIND that the VIPIR model has been very much correct for most of the season (including Debby from the very beginning)
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Quoting LostTomorrows:
It seems that, although Leslie's convection isn't as impressively doom-like as other nights, she is seeming to actually organize, rather than just keep up with an LLC that wanted to get rid of her. I have a feeling she will be on a strengthening trend very shortly.


Agreed. The convection around the center seems more banded, rather than resembling a shapeless blob as in previous days.
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Quoting pcola57:


Please don't be too hasty w/him..he may (like myself) have a handicapp

Apologies to him/her, you and others on how it came off...but...the "." between each word is annoying to read. As for the spelling of Isaac, it has been mentioned on this blog sooo many times that people should see the correct spelling envisioned permanently. I can understand a typo but that misspelling was way beyond a typo.
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Has the ever been a Cat5 Hurricane as small as Marcos/Michael?
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For animation, see blog entry.
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Quoting wxchaser97:

This whole year has been challenging, storms have not liked us WU bloggers. This is like the 4th or 5th storm to stall and these high latitude storms also have been becoming hurricanes.
So true, I accept the challenge, it is the challenges and frustration that makes us learn more about the complexity of meteorology and to me what makes tracking these storms so fun, so many possibilities yet one ultimate outcome.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
TS.Leslie's travel-speed between it's 2 most recent positions was 1.55mph(2.49km/h)
4Sept.06pm's 25.1n62.6w has been re-evaluated&altered
5Sept.12am's 25.0n62.6w-25.1n62.7w are now the most recent positions
All times in GMT
Derived from NHC_ATCF data for TropicalStormLeslie at 2Sept.6pm
KXFL-PalmCoast :: BDA-Bermuda

The longer kinked line traces Leslie's path on its 4th day as a TropicalStorm
The longer kinked line traces Leslie's path on its 5th day as a TropicalStorm
Note the difference in the distances traveled by Leslie on its 4th and 5th day as a TropicalStorm.
4th day: 204miles(329kilometres) @ ~8.5mph(13.7km/h)
5th day : 88miles (141kilometres) @ ~3.7mph ( 5.9km/h)
The southernmost dot on the longest line is TS.Leslie's most recently reported position

The longest line is a straightline projection through TS.Leslie's 2 most recent positions to it's closest approach to Bermuda
4Sept.12am: TS.Leslie had been headed for passage 276miles(443kilometres)ESEast of Bermuda
4Sept.06am: TS.Leslie had been headed for passage 340miles(548kilometres)ESEast of Bermuda
4Sept.12pm: TS.Leslie had been headed for passage 126miles(202kilometres)East of Bermuda
4Sept.06pm: TS.Leslie had been headed for passage 86miles(139kilometres)WSWest of Bermuda
5Sept.12am: TS.Leslie was heading for passage 238miles(383kilometres)SWest of Bermuda

Copy&paste kxfl-29.404n81.094w, 31.196n60.17w, 30.299n59.418w, 32.387n62.5w, 31.7323n66.211w, 32.281n64.887w-bda-32.368n64.647w, 21.3n60.9w- 22.1n61.4w- 22.8n61.6w- 23.4n62.2w- 23.6n62.7w, 23.6n62.7w- 23.8n62.8w- 24.1n62.7w- 24.5n62.5w- 24.8n62.5w, 24.8n62.5w-25.0n62.6w, 25.0n62.6w-25.1n62.7w, 25.0n62.6w-29.885n67.781w, 32.281n64.887w-29.885n67.781w into the GreatCircleMapper for a larger map and other information
The previous mapping for comparison
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Quoting hunkerdown:

what is your issue with the "." between each word???

Also, who is Issacc?? Come on, how hard is it to spell these names correctly...you aren't even close.


Please don't be too hasty w/him..he may (like myself) have a handicapp
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oh.well.....crippled.just.like.issacc
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Quoting islander101010:
yellow.over.crippled.issacc

what is your issue with the "." between each word???

Also, who is Issacc?? Come on, how hard is it to spell these names correctly...you aren't even close.
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860. FOREX
Quoting DFWjc:
Does anyone know if leftovers of Isaac is moving back into the gulf?


the low is actually leaving southwest Georgia and is maybe a few hours away from being in the Gulf, where it should sit for a few days before being picked up towards theNortheast this weekend.
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.
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1. AN AREA OF LOW PRESSURE OVER CENTRAL ALABAMA IS EXPECTED TO MOVE GENERALLY SOUTHWARD INTO THE NORTH-CENTRAL GULF OF MEXICO DURING THE NEXT DAY OR SO. ENVIRONMENTAL CONDITIONS APPEAR MARGINALLY CONDUCIVE FOR SLOW DEVELOPMENT OF THIS DISTURBANCE ONCE IT MOVES OVER WATER. THIS SYSTEM HAS A LOW CHANCE...10 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

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Quoting DFWjc:
Does anyone know if leftovers of Isaac is moving back into the gulf?
Some going there, some on the way to New England.
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.
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Quoting wxchaser97:

Depending on how much moister and thunderstorms it can wrap-up, I think a few inches could be in store. Now I really have to/am going to bed, night all.
tHANKS AND GOOD NIGHT
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Quoting Funication:



372 Hours?is too far away Models are good with 144-168 hours... other than that is speculation
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Quoting MississippiBoy:
one more ? how much rain can we expect here on the coasts of LOU,MS,AL?

Depending on how much moister and thunderstorms it can wrap-up, I think a few inches could be in store. Now I really have to/am going to bed, night all.
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Quoting MississippiBoy:
where would it go inland at and how big?

I think in the Norther to Central Peninsula and around the same size as now. Rain and flooding would be this TD/TS's main threats, maybe if it spends some more time over water a moderate TS. I'll happily accept if I'm wrong and learn from my mistakes.
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It seems that, although Leslie's convection isn't as impressively doom-like as other nights, she is seeming to actually organize, rather than just keep up with an LLC that wanted to get rid of her. I have a feeling she will be on a strengthening trend very shortly.
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huge 922 mb low there
Member Since: April 23, 2011 Posts: 104 Comments: 14873
one more ? how much rain can we expect here on the coasts of LOU,MS,AL?
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Quoting NoloContendere:
Not to worry, it's been lower than that even in my lifetime. I can remember when the submarine Skate surfaced at the North Pole in 1958. If you want to worry about something, worry about global cooling and whether we're heading for a Dalton or Maunder type solar minimum. Think cold.



Lower in your lifetime? Are you a couple of million years old? There are some oldies here and I'm no spring chicken but nobody makes these kinds of claims. I'm afraid I'll need to see documentation.

The Skate surfaced through the ice not in an ice-free Arctic Ocean. This is clearly stated in the Wikipedia entry on the vessel. The vessel got citations for operating successfully for thousands of miles under the pack ice.

"Thinking cold" will not be very effective, IMHO.
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Quoting wxchaser97:

I don't think it would get much stronger than a weak TS.
where would it go inland at and how big?
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I'm off for the night, once again it will be interesting to see if Leslie can hold the convection together and what Michael looks like in the morning, good night.
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Convection is waning a little on Leslie.

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Quoting MississippiBoy:
how strong do ya'll think the distrubed weather will get in the gulf before cold front picks it up?

I don't think it would get much stronger than a weak TS.
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Quoting DFWjc:
Does anyone know if leftovers of Isaac is moving back into the gulf?

Well, part of Isaac(mostly just his MLC) is moving back into the GOM with some other energy. There it is expected to organize and become a TD and even a TS, which would be named Nadine.
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Quoting NoloContendere:
Not to worry, it's been lower than that even in my lifetime. I can remember when the submarine Skate surfaced at the North Pole in 1958. If you want to worry about something, worry about global cooling and whether we're heading for a Dalton or Maunder type solar minimum. Think cold.

Oh the sun........and what we have yet to learn. Quite literally mind boggling.
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how strong do ya'll think the distrubed weather will get in the gulf before cold front picks it up?
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Quoting GTcooliebai:
So now Michael is stationary, I think that is like 4 storms that have done that this year. Steering currents have been complex this year and I think it is because of the amount of ULLs and weaker troughs that are unable to pick these storms up and send them OTS or in Isaac's case send him quickly across America.

This whole year has been challenging, storms have not liked us WU bloggers. This is like the 4th or 5th storm to stall and these high latitude storms also have been becoming hurricanes.
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837. DFWjc
Does anyone know if leftovers of Isaac is moving back into the gulf?
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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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