90L in the Gulf disorganized; Leslie and Michael weaken

By: Dr. Jeff Masters , 4:27 PM GMT on September 07, 2012

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A partial remnant of Hurricane Isaac off the coast of Louisiana, Invest 90L, was almost torn apart last night by wind shear, but is making a bit of a comeback today. Visible satellite loops and surface observations from buoys and oil rigs in the Gulf show that 90L has an sloppy, elongated surface circulation. The area covered by heavy thunderstorms is relatively modest, and has been pushed to the south side of the circulation center by strong northerly winds that are creating a high 20 knots of wind shear. There is a large amount of dry air that surrounds 90L on all sides that is interfering with development. A hurricane hunter aircraft scheduled to investigate 90L today was cancelled, and has been rescheduled for Saturday afternoon.


Figure 1. Visible satellite image of Invest 90L taken at 11:58 am EDT Friday September 7, 2012.

Forecast for 90L
Wind shear over 90L is predicted to stay in the moderate to high range, 15 - 20 knots, through Saturday morning, then drop to the low range Saturday afternoon through Sunday. Ocean temperatures in the Gulf are 28.5° - 29°C, which is plenty warm enough to support formation of a tropical storm. 90L is essentially stationary this morning, but should begin a slow motion to the east-northeast tonight, in response to the steering flow from a trough of low pressure and its associated surface cold front approaching the Gulf Coast from the northwest. This trough should be capable of pulling 90L to a landfall along the Florida Panhandle or west coast of Florida by Sunday morning. In their 8 am Tropical Weather Outlook, NHC gave 90L a 20% chance of developing into a tropical depression by Sunday morning. I put these odds higher, at 30%.

Leslie weakens to a tropical storm
Tropical Storm Leslie continues to remain nearly stationary to the south of the island of Bermuda, and a NOAA hurricane hunter aircraft found this morning that Leslie had weakened below hurricane strength, to a 70 mph tropical storm. An ocean probe launched by the aircraft found that the ocean temperatures at one location in Leslie were 24.5°C, a full 5°C (8°F) drop from when the storm first reached the area two days ago. Moderate wind shear of 10 - 20 knots due to strong upper-level winds out of the west continue to drive dry air to Leslie's west into the core of the storm. The combined effect of shear and cool waters have eroded away Leslie's core, and the storm has no eyewall, as seen on satellite loops. A NOAA hurricane hunter aircraft will be in the storm tonight, and an uncrewed NASA Global Hawk aircraft finished an HS3 Hurricane Research Mission into Leslie this morning.


Figure 2. Hurricane Leslie as seen by NASA's Aqua satellite at 10:45 am EDT Thursday, September 6, 2012. At the time, Leslie was a Category 1 hurricane with 75 mph winds. Image credit: NASA.

Forecast for Leslie
A strong trough of low pressure approaching the U.S. East Coast should make Leslie start moving to the north at 5 mph by Saturday morning. The models have stayed with their more eastwards solution to Leslie's track, which keeps the threat of Bermuda receiving hurricane-force winds relatively low, since the island is expected to be on the weak (left) side of the storm. If the official NHC forecast verifies, tropical storm-force winds will just graze Bermuda Sunday morning through Sunday evening. According to the latest SHIPS model forecast, the shear is expected to fall to the low category, 5 - 10 knots, by Friday night. Leslie is over warm ocean waters of 29 - 30°C, and once the storm moves away from the large pool of cool waters it has stirred up, the reduction in shear and warm waters should allow the storm to intensify to at least a Category 1 hurricane by Sunday. The latest 11 am EDT NHC wind probability forecast calls for a 30% chance that Leslie will be a Category 2 or stronger hurricane Sunday morning at 8 am EDT, when the storm will be beginning its closest pass to Bermuda. Leslie is a huge storm, and tropical storm-force winds are expected to extend outward from its center 200 - 220 miles by Sunday.

Most of the models indicate Leslie is likely to make landfall in Newfoundland, Canada on Tuesday night or Wednesday morning. However, the models have been trending more to the east with Leslie's track in recent runs, and given the uncertainty in 4-day hurricane forecasts, the storm could very well miss the island, passing to the northeast. Large swells from Leslie are pounding the entire Eastern Seaboard, and are creating beach erosion and dangerous rip currents.


Figure 3. Hurricane Michael as seen by NASA's Aqua satellite at 12:20 pm EDT Thursday September 6, 2012. At the time, Michael was a Category 3 hurricane with 115 mph winds. Image credit: NASA.

Hurricane Michael weakens to Category 2
The only major hurricane of the 2012 Atlantic hurricane season, Hurricane Michael, has weakened, and is now a Category 2 storm with 105 mph winds. Satellite loops show that Michael is still an impressive storm with a well-developed eye, but the storm is not as symmetric, and the eye no longer as distinct as was the case yesterday. Michael is far out over the open Atlantic, and none of the models show that Michael will threaten any land areas during the coming seven days.

Elsewhere in the Atlantic
Most of the reliable computer models are predicting that a new tropical wave moving off the coast of Africa today will develop into a tropical depression by the middle of next week. This wave is predicted to exit Africa too far north to threaten the Lesser Antilles Islands.

Jeff Masters

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Quoting CaribBoy:


Go to hell Pre 91L fish


I've read many of your complaints about you not getting any rain and not having the "joy or excitement" of having a storm come your way. Caution: BE CAREFUL WHAT YOU WISH FOR! A nice juicy big one may just decide to pay you a visit. I hope that if/when it comes it does not find you hiding under your bed.

Just to let you know: Your complaints don't bother me though. Keep looking for the prize. I'm looking too, we need rain here in Antigua.
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anyone think todays squall line thats gonna come threw south new jersey much later today (tomorrow ha) will be worse then the derencho? here in the atlantic city area thats talked about much more then any other storm espically "thunder storm" in quite a while..lots of damage and all that bad stuff..dont need another day like that.....BUT im off tomorrow so bring it on
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697. wxmod
Quoting spathy:


Its understandable.
I have a habit of killing a blog.
You know leaving people speechless.
When they have no rebuttal to direct reality,as opposed to pie in the sky hope and change.


Satellite photos aren't pie in the sky. I think it's going to be interesting times ahead for all of us, not comfortable, but interesting. I just wonder how the people who said 'we can't afford to fix climate change' are going to tell their kids when climate disaster comes.
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Good night folks.. see you tomorrow for another boring day in the tropics (yes tropics as Leslie and Michael are not in the tropics!!!)
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Quoting KoritheMan:


No. The synoptic flow is much more progressive with this front than the one that spawned Nate last year. It won't just stall.
Oh ok.thanks Kori :).
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691. wxmod
Quoting LBAR:


What's going on in the Southern Hemisphere?


There are a lot more people and there is a lot more carbon dioxide and soot in the northern hemisphere.
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Quoting allancalderini:
I have a question could that cold front leave a piece of energy in the gulf and develop into something?


No. The synoptic flow is much more progressive with this front than the one that spawned Nate last year. It won't just stall.
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Quoting CaribBoy:
Everything is dead : MDR + BLOG and the GFS ONLY SEES FISHES WOW WHAT A BORING SEASON!
I like fish storms they are better than the ones that make landfall and kill people imo.
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Quoting CaribBoy:
Everything is dead : MDR + BLOG and the GFS ONLY SEES FISHES WOW WHAT A BORING SEASON!


Everybody's busy playing with the...

BEST GOOGLE DOODLE EVER!!!

Seriously. There are Tribbles!
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I have a question could that cold front leave a piece of energy in the gulf and develop into something?
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Quoting CaribBoy:
Everything is dead : MDR + BLOG and the GFS ONLY SEES FISHES WOW WHAT A BORING SEASON!


It's not dead if I'm here.
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Everything is dead : MDR + BLOG and the GFS ONLY SEES FISHES WOW WHAT A BORING SEASON!
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Well business is closed for the NE islands...
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Quoting Gearsts:
Recurves everywhere! So i guess we will stay super dry in september lol


And I guess that's a good thing lol
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Where is that damn ridge that was in place for Ernesto and the other 2 !
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Hmmmm... looks as though Leslie is making a nice comeback. I guess she'll be a hurricane again tomorrow.
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Quoting Tropicsweatherpr:
Saved image.



Go to hell Pre 91L fish
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Quoting JLPR2:


I can live with no storms, but the dryness and hot weather is annoying me. :|


100% agree. I'm depressed as our region (NE Caribbean) is experiencing a severe drought since early august. I guess EL NINO is responsible for something. I hate EL NINO!!
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676. LBAR
Quoting wxmod:
Record year. Let's hope the ice comes back. I wish the oil and coal people would be a lot more helpful.



What's going on in the Southern Hemisphere?
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Quoting Chicklit:

Too far north?


dissipated.

am done for the day.
goodnight.
anyway, happy for nigel.
wow, jamaica beat usa!
and on the heels of the great olympic victories...
well done!


LOOOL AT 90L
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674. JLPR2
Quoting Gearsts:
Recurves everywhere! So i guess we will stay super dry in september lol


I can live with no storms, but the dryness and hot weather is annoying me. :|
Member Since: September 4, 2007 Posts: 7 Comments: 8499
00Z GFS is still boring your the islands
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Quoting JLPR2:
September 21st, Georges 14th anniversary in Puerto Rico.

If "Oscar" where hundreds of miles to the south, it would be deja-vu. XD

Recurves everywhere! So i guess we will stay super dry in september lol
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Quoting txjac:
Come on Florida, Louisiana, Mississippi and Alabama foks ...share some rain with Texas ...makes 90L come our way ...dont need it to pull to the NE
We've got the fans out, trying to blow it your way!!
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668. JLPR2
September 21st, Georges 14th anniversary in Puerto Rico.

If "Oscar" where hundreds of miles to the south, it would be deja-vu. XD

Member Since: September 4, 2007 Posts: 7 Comments: 8499
667. wxmod
Quoting spathy:


And just think about the fact that if you(Gov) took all the taxable income from the demeaned "rich" You could not balance the budget and then you would have nothing left to tax in the next years.

Doesnt seem like a good way to secure revenue for a cleaner future.

Spending and spending priorities have any meaning?

Just what is more important?
A cleaner planet or all the other things that our Gov is doing that even the rich cant pay for?

And once the rich have given everything.
What do we do next year, and how does being broke pay for anything down the road?


I agree with you, but then again, I'll probably tell the next person who disagrees with you that I agree with them too!
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I'm turning in for the night as I need as much sleep as possible for today's weather. Good night and stay safe everyone!
Member Since: March 16, 2012 Posts: 127 Comments: 7927
At 174 hrs, Nadine is really recurving and Oscar/TD will not recurve as much. Another wave comes off Africa and would probably be Patty.
Member Since: March 16, 2012 Posts: 127 Comments: 7927
Winds finally easing over southeast Australia

After copping a battering over the last few days from wind gusts as strong as 159km/h(99mph), conditions are finally set to ease across southeastern Australia.

Winds are significantly lighter across South Australia, Tasmania and Victoria today after a week that saw strong winds bring down trees and powerlines. Tasmania is the only state still under a severe weather warning today. The warnings that were in place for New South Wales and Victoria were cancelled this morning as a high pressure system strengthens over the region.

Strong winds continued last night, with Mount Boyce in the Blue Mountains recording a wind gust of 117km/h(73mph). Hogan Island, off the Victoria mainland managed to register a gust of 159 km/h(99mph) on Friday afternoon. These were the strongest winds in over a year for both locations.

Wind wasn't the only feature for the southeast, with heavy rain and snow falling in parts of New South Wales, Victoria and Tasmania.

Western parts of Tasmania saw the heaviest falls. Roseberry picked up 37mm(1.45in) which was their highest September fall since 2009. South Queenstown and Strathgordon both recorded 35mm(1.37in).

In Victoria, the West and South Gippsland and North East were the wettest places. Balook had one of the highest falls with 34mm(1.33in), the heaviest for September in three years. Elsewhere, Traralgon South and Upper Lang Lang both had 32mm(1.25in).

The heavy rain may have dampened the moods of some, although it was sure to lift spirits for skiiers and snowboarders heading to the resorts this weekend.

After a warm week, the Alps were lucky enough to pick up some solid snowfalls. Overnight the New South Wales resorts reported 30-35cm(11.8in- 13.7in) and the Victorian resorts up to 20cm(7.8in). This was on top of the 10-20cm(3.9in-7.8in) from the previous day. Fresh snowfalls coupled with clearing conditions should make for a great spring weekend on the slopes.

A high will bring clearer skies and lighter winds across most of the nation's southeast by Sunday, with Tasmania looking forward to calmer conditions on Monday.

After some morning showers, both Melbourne and Hobart can expect a mostly sunny day on Sunday, with top temperatures of 18 and 17 degrees Celsius respectively. Sydney will be sunny all day, reaching a pleasant high of 21 degrees Celsius.


%uFFFD Weatherzone 2012
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661. JLPR2
GFS says: Nadine and Oscar.

Member Since: September 4, 2007 Posts: 7 Comments: 8499
Quoting TropicalAnalystwx13:
Good night guys. I'll be back tomorrow mid-morning (definitely sleeping in) to cover the Severe Weather outbreak, TS Leslie, Hurricane Michael, and the new African wave.


Night TA, tomorrow/today will be a crazy day with the tropics and severe weather. Blog will be in full sing tomorrow. If I could only sleep in, tomorrow will be a very busy day for me.
Member Since: March 16, 2012 Posts: 127 Comments: 7927
Good night guys. I'll be back tomorrow mid-morning (definitely sleeping in) to cover the Severe Weather outbreak, TS Leslie, Hurricane Michael, and the new African wave.

Member Since: July 6, 2010 Posts: 113 Comments: 31463
657. wxmod
Quoting spathy:


I love ya Sky.
Thanks for continuing your point.

I Was just poking fun.
I am true to form as you. :O)


I don't see Dems or Repubs doing anything about carbon dioxide or soot. The difference seems to be this. Repubs are less likely to own up to their contribution to the problem. Can't fix carbon dioxide and soot if some of us refuse to see the problem. We all have to solve it together. Half of us just cant do the job.
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LOL <- funny joke, no offence intended.


Homes damaged, trees down as winds tear across NSW

Gusting winds have brought down trees and damaged roofs across New South Wales.

The wild afternoon culminated in Sydney in a large traffic snarl caused by a bus fire on a major road.

The State Emergency Service is working through 180 calls for assistance to secure roofs and remove trees and branches brought down by the winds.

Areas from the southern border through Sydney to the Hunter have been affected.

Before the winds began easing the driver of a double decker bus was forced to pull over on Southern Cross Drive, in eastern Sydney, when his bus caught fire.

The driver was not hurt and had no passengers but the blaze speak quickly into nearby parkland.

The rapid knock-on effect on the eastern distributor and the Harbour Tunnel meant even fire trucks could not get through.

Firefighters had to go in on foot and use a hydrant for water to put out the blaze.


%uFFFD ABC 2012
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Quoting Chicklit:

Looks that way, doesn't it Aussie?

Sure does, and it looks like it will effect much more people than the others earlier your summer.
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653. Skyepony (Mod)
Quoting spathy:


Are you highlighting the Democrat electorate that uses all that energy?

And then demands that others conserve!!!!

Forgive me I could not resist!


My bad..totally should have posted the other end of the storm..it's a big one.

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taste of fall
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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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