Leslie headed towards Bermuda; Tropical Storm Michael forms

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

Share this Blog
41
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 487 - 437

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26Blog Index

Quoting GTcooliebai:
Oh look at Tues. cool front clearing the area? Maybe look for some upper 60s away from the coast and in our northern counties.
geez we could use a GOOD cold front huh..whew its hot out there today
Member Since: Posts: Comments:
Quoting RTSplayer:


The surge was measured above sea level...

The surge at Waveland and Biloxi broke Camille's records by several feet, and may have been higher than official numbers, but NHC threw out one of the buoy readings near Waveland.


Costliest U.S. Atlantic hurricanes
Cost refers to total estimated property damage
Rank Hurricane Season Damages
1 Katrina 2005 $108 billion
2 Ike 2008 $29.5 billion
3 Andrew 1992 $26.5 billion
4 Wilma 2005 $20.6 billion


Even if you inflation adjust Andrew's damage, Katrina still beats it by a factor of about 2.5...after hitting LESS populated areas...
Andrew was a small storm with stronger winds, Katrina was a big storm with stronger surge and slightly weaker winds. Andrew could've been as bad as Katrina if it was little bigger and 5-10 mph stronger.
Member Since: Posts: Comments:
Quoting LargoFl:
looks like it, mixed in with a weak cool front

it is moving towards Florida, right?
Member Since: Posts: Comments:
It looks to me as though Leslie is done with her bipolar "I mean business/nah, nevermind" night/day shenanigans. She looks like she's kicking it into next gear, and perhaps prove the models right a bit ahead of schedule.
This could be very bad news.

And Michael is doing precisely what I thought he would; the same as Chris, Gordon, and Kirk before him... it seems the northerly storms always tend to do really well. There's less dry air further north, and the warmer SSTs definitely extend further and further north each year, it seems. I'm guessing he will continue the trend of hurricanes far north of the MDR.
Member Since: August 26, 2008 Posts: 0 Comments: 564
Quoting GetReal:


Blob formerly known as Isaac is moving rather quickly south back into N. GOM.

Ain't nothing gettin past TX's atmosphere.
Member Since: Posts: Comments:
Quoting LargoFl:
.............they upped weekend rain chances...........
Oh look at Tues. cool front clearing the area? Maybe look for some upper 60s away from the coast and in our northern counties.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Member Since: Posts: Comments:
Quoting CCkid00:

is this the remnant of isaac?
looks like it, mixed in with a weak cool front
Member Since: Posts: Comments:
Quoting ncstorm:


maybe I am reading too much into this but this trough is supposed to be strong and pull Leslie to the north..I have seen "weak".."faster" and "low confidence" in two discussions about this trough..lets hope the models dont do a windshield wiper effect..
Also have to remember if it takes the left side of the cone the Northeast coastline juts out, particularly Cape Cod, so the impacts might be more than surf there, could have a chance of TS force conditions, and Leslie is a big storm.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Bermuda closest approach pressure forecast.

model raw / adjusted

12z Euro 939mb / 937mb


The others all ended up in the 965mb range if I remember correctly, so at least the Euro is moving more in line with the consensus or average of the other 3 best models....
Member Since: January 25, 2012 Posts: 33 Comments: 1520
.............they upped weekend rain chances...........
Member Since: Posts: Comments:
Quoting RitaEvac:
Every time I read Michael, I think I'm being directed to, then have to realize nobody is calling my name.


Lol. I know a bunch of Michaels (probably like everyone). Takes time to think of all of them whenever the storm is mentioned here.
Member Since: Posts: Comments:
Quoting TropicalAnalystwx13:

What does a phoenix have to do with anything?

Bcuz he's weird xD
JK
Member Since: Posts: Comments:
Quoting LargoFl:

is this the remnant of isaac?
Member Since: Posts: Comments:
Did someone have the nerve to bring up Isabel?.
Member Since: Posts: Comments:


I spy...
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting PalmBeachWeather:
Yep.........Good to know they are people just like us.......And maybe the would like a Bud Light sometimes too


Did someone say Bud Light? :)
Member Since: Posts: Comments:
Quoting GTcooliebai:
What part of Southwest FL. are you located, I'm going to assume closer to the coast because it has been raining in the interior.




Yeah, Cape Coral here so only about 6 miles from Gulf as the crow flies, if that much. Been seein' beautiful t-storms last couple afternoons far to the south, maybe down around Marco, and sometimes in the interior, but nothin' over me. Grass started drying up again yesterday.... :-(
Member Since: Posts: Comments:
Quoting Bluestorm5:
Andrew was really bad at landfall and was even worse than Katrina, but it was in a small area since Andrew was a small storm and Katrina was a massive storm. Also, Katrina did 25 foot surge over wide area and in area that are below sea level. Andrew did worse damage, but Katrina damage was by far more widespread. They are equally as bad IMO.


The surge was measured above sea level...

The surge at Waveland and Biloxi broke Camille's records by several feet, and may have been higher than official numbers, but NHC threw out one of the buoy readings near Waveland.


Costliest U.S. Atlantic hurricanes
Cost refers to total estimated property damage
Rank Hurricane Season Damages
1 Katrina 2005 $108 billion
2 Ike 2008 $29.5 billion
3 Andrew 1992 $26.5 billion
4 Wilma 2005 $20.6 billion


Even if you inflation adjust Andrew's damage, Katrina still beats it by a factor of about 2.5...after hitting LESS populated areas...
Member Since: January 25, 2012 Posts: 33 Comments: 1520
Every time I read Michael, I think I'm being directed to, then have to realize nobody is calling my name.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting GetReal:


Blob formerly known as Isaac is moving rather quickly south back into N. GOM.

What's that spin in the central-south GOM?
Member Since: Posts: Comments:
More MDR activity expected in the next couple of weeks.



Link
Member Since: April 29, 2009 Posts: 75 Comments: 14071
Micheal trying to pull a Kirk/Gordon..
Member Since: Posts: Comments:
Quoting OracleDeAtlantis:
It's a little creepy ...






What does a phoenix have to do with anything?
Member Since: July 6, 2010 Posts: 113 Comments: 31554
Quoting islander101010:
mini.tw.in.central.gulf

can you post a link please? thanks!
Member Since: Posts: Comments:
Quoting Bluestorm5:
TS Leslie better not do "Isabel"....



ISABEL Graphics Archive
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Question, The storm that is going to drop down into the gulf and maybe cross florida, will this bring a good soaking to the central fl area--east coast?
Member Since: Posts: Comments:
Quoting Bluestorm5:
TS Leslie better not do "Isabel"....



yeah, lets hope not!
Member Since: Posts: Comments:
Quoting Bluestorm5:
TS Leslie better not do "Isabel"....


NO
Member Since: Posts: Comments:
Quoting GTcooliebai:
Best thing to do is keep an eye on it, observing the recent trends with storms such as Isaac shows that the trend in the models would be towards the west and not east, due to the weaker troughs that have been observed this year.


maybe I am reading too much into this but this trough is supposed to be strong and pull Leslie to the north..I have seen "weak".."faster" and "low confidence" in two discussions about this trough..lets hope the models dont do a windshield wiper effect..
Member Since: Posts: Comments:
mini.tw.in.central.gulf
Member Since: September 11, 2010 Posts: 1 Comments: 4362
Quoting OrchidGrower:
Wow!- Is rainy season over already for Southwest Florida?? It's been a week with no rain (and not even a lot of clouds) at my place, and every day the Weather Channel forecast changes its mind about day-after-tomorrow and replaces the little t-storm logo with a p-cloudy logo.

Geesh, we just left a drought when Deb got here; do we hafta go back to drought already?!
What part of Southwest FL. are you located, I'm going to assume closer to the coast because it has been raining in the interior.

Member Since: August 31, 2009 Posts: 0 Comments: 5628
Former Isaac gonna merge with heat low in gulf and go back to NOLA and Patrap gonna have more puppies.
Member Since: Posts: Comments:
TS Leslie better not do "Isabel"....

Member Since: Posts: Comments:


Blob formerly known as Isaac is moving rather quickly south back into N. GOM.
Member Since: Posts: Comments:
Quoting sar2401:


It will take some refinement and work to be able to calculate things like total kinetic energy in real time, but I think it's a good start. BTW, the NHC is not going to like this idea. From Wikipedia:

"In 2009, the NHC made moves to eliminate pressure and storm surge ranges from the categories, transforming it into a pure wind scale, called the Simpson Hurricane Wind Scale (Experimental) [SSHWS].[5] The new scale became operational on May 15, 2010.[6] The scale excludes flood ranges, storm surge estimations, rainfall, and location, which means a Category 2 hurricane which hits a major city will likely do far more cumulative damage than a Category 5 hurricane that hits a rural area.[7] The agency cited various hurricanes as reasons for removing the "scientifically inaccurate" information, including Hurricane Katrina (2005) and Hurricane Ike (2008), which both had stronger than estimated storm surges, and Hurricane Charley (2004), which had weaker than estimated storm surge.[8]"

http://en.wikipedia.org/wiki/Saffir%E2%80%93Simps on_Hurricane_Scale


So... why did the NHC do that, and are the people who did that still in charge of the NHC?
Member Since: Posts: Comments:
Wow!- Is rainy season over already for Southwest Florida?? It's been a week with no rain (and not even a lot of clouds) at my place, and every day the Weather Channel forecast changes its mind about day-after-tomorrow and replaces the little t-storm logo with a p-cloudy logo.

Geesh, we just left a drought when Deb got here; do we hafta go back to drought already?!
Member Since: Posts: Comments:
Quoting PensacolaDoug:



Hope itt doesnt go Humberto on us!
Certainly can't be ruled out as it spends 3 days over water.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Quoting TropicalAnalystwx13:
Tropical Storm Marco's tropical storm force winds extended out 30 miles from the center of the storm.

Tropical Storm Michael's tropical storm force winds extend out 35 miles from the center of the storm.

Ooh..

MICHEAL MUST SHRINK!
Member Since: Posts: Comments:
Tropical Storm Marco's tropical storm force winds extended out 30 miles from the center of the storm.

Tropical Storm Michael's tropical storm force winds extend out 35 miles from the center of the storm.

Ooh..
Member Since: July 6, 2010 Posts: 113 Comments: 31554
Quoting ncstorm:
So along with my NWS, the HPC is stating low confidence about the trough..oh brother..

THE FINAL
AFTERNOON ISSUANCE PREFERS A LAGGED-AVERAGE APPROACH WHICH USES 30
PERCENT EACH 00Z GFS/ECMWF AND 20 PERCENT EACH 12Z
GFS/ECMWF...WHICH OFFERS A BALANCE OF CONTINUITY...NUDGING TOWARD
THE LATEST GUIDANCE...AND HIGHER MAINTAINING AMPLITUDE. AS SHOULD
BE EXPECTED...CONFIDENCE IS BELOW AVERAGE. THE FINAL RESULT
PRODUCES A PROGRESSIVE LONGWAVE TROUGH OVER THE NORTHWEST AROUND
DAYS 6-7/MON-TUE...AND A WEAKER/FASTER CLOSED LOW TRAVERSING THE
EAST COAST DAYS 5-7 COMPARED TO EARLIER ISSUANCES. GIVEN THAT THE
ANTICIPATED PATTERN APPEARS UNRESOLVED...FUTURE SOLUTION CHANGES
ARE ANTICIPATED...WHICH MAY SUPPORT ADDITIONAL CHANGES TO THE
MEDIUM RANGE PERIOD FORECAST OVER THE NEXT COUPLE DAYS.



Isn't that what is usually posted prior to the storm track changing to your location.
Member Since: Posts: Comments:
Quoting ncstorm:
So along with my NWS, the HPC is stating low confidence about the trough..oh brother..

THE FINAL
AFTERNOON ISSUANCE PREFERS A LAGGED-AVERAGE APPROACH WHICH USES 30
PERCENT EACH 00Z GFS/ECMWF AND 20 PERCENT EACH 12Z
GFS/ECMWF...WHICH OFFERS A BALANCE OF CONTINUITY...NUDGING TOWARD
THE LATEST GUIDANCE...AND HIGHER MAINTAINING AMPLITUDE. AS SHOULD
BE EXPECTED...CONFIDENCE IS BELOW AVERAGE. THE FINAL RESULT
PRODUCES A PROGRESSIVE LONGWAVE TROUGH OVER THE NORTHWEST AROUND
DAYS 6-7/MON-TUE...AND A WEAKER/FASTER CLOSED LOW TRAVERSING THE
EAST COAST DAYS 5-7 COMPARED TO EARLIER ISSUANCES. GIVEN THAT THE
ANTICIPATED PATTERN APPEARS UNRESOLVED...FUTURE SOLUTION CHANGES
ARE ANTICIPATED...WHICH MAY SUPPORT ADDITIONAL CHANGES TO THE
MEDIUM RANGE PERIOD FORECAST OVER THE NEXT COUPLE DAYS.

Best thing to do is keep an eye on it, observing the recent trends with storms such as Isaac shows that the trend in the models would be towards the west and not east, due to the weaker troughs that have been observed this year.
Member Since: August 31, 2009 Posts: 0 Comments: 5628
Quoting Bluestorm5:
Andrew was really bad at landfall and was even worse than Katrina, but it was in a small area since Andrew was a small storm and Katrina was a massive storm. Also, Katrina did 25 foot surge over wide area and in area that are below sea level. Andrew did worse damage, but Katrina damage was by far more widespread. They are equally as bad IMO.
I agree Bluestorm.... The problem was the "water" with Katrina
Member Since: Posts: Comments:
Reference Andrew, a tornado is pretty small also, unless it passes over your house. That being said Andrew was a kick ass ginormous tornado.
Member Since: Posts: Comments:
Quoting CybrTeddy:


Actually, it was 125mph Category 3.

Actually during it's landfall near Buras-Triumph, it was a Cat 4 with winds I believe of 140 mph.
Member Since: Posts: Comments:
Quoting LargoFl:
72 hours we got a Low in the gulf



Hope itt doesnt go Humberto on us!
Member Since: Posts: Comments:
So along with my NWS, the HPC is stating low confidence about the trough..oh brother..

THE FINAL
AFTERNOON ISSUANCE PREFERS A LAGGED-AVERAGE APPROACH WHICH USES 30
PERCENT EACH 00Z GFS/ECMWF AND 20 PERCENT EACH 12Z
GFS/ECMWF...WHICH OFFERS A BALANCE OF CONTINUITY...NUDGING TOWARD
THE LATEST GUIDANCE...AND HIGHER MAINTAINING AMPLITUDE. AS SHOULD
BE EXPECTED...CONFIDENCE IS BELOW AVERAGE. THE FINAL RESULT
PRODUCES A PROGRESSIVE LONGWAVE TROUGH OVER THE NORTHWEST AROUND
DAYS 6-7/MON-TUE...AND A WEAKER/FASTER CLOSED LOW TRAVERSING THE
EAST COAST DAYS 5-7 COMPARED TO EARLIER ISSUANCES. GIVEN THAT THE
ANTICIPATED PATTERN APPEARS UNRESOLVED...FUTURE SOLUTION CHANGES
ARE ANTICIPATED...WHICH MAY SUPPORT ADDITIONAL CHANGES TO THE
MEDIUM RANGE PERIOD FORECAST OVER THE NEXT COUPLE DAYS.

Member Since: Posts: Comments:
Quoting BA:
RE: "swirly thing in center of GOM"

So I guess cloaked space ships aren't completely invisible after all, they affect the weather around them.


Kirk making a re-appearance in a cloaked cling on vessel? The cloaked cyclone, you read it here first!
Member Since: Posts: Comments:

Viewing: 487 - 437

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.