Bill is gone; Invest 92 pops up

By: Dr. Jeff Masters , 2:08 PM GMT on August 24, 2009

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Hurricane Bill is no more. The hurricane swept past Canada's Nova Scotia province Sunday afternoon, then made landfall early this morning in southeastern Newfoundland as a borderline tropical storm/Category 1 hurricane. Bill's waves claimed two lives over the weekend, a 54-year old swimmer that drowned in Florida, and a 7-year old girl in Maine that got swept into the sea by a big wave. The first death of the 2009 Atlantic hurricane season occurred on August 16, when a swimmer drowned in the rough surf from Tropical Storm Claudette at Pananma City Beach, FL.

Nova Scotia misses a direct hit
The center of Bill scooted parallel to the coast of Nova Scotia Sunday afternoon, and never quite came onshore. Since the storm's forward speed was so rapid--about 35 mph--this resulted in a highly asymmetric wind distribution. Since the top winds of a hurricane include the forward motion of the storm, Bill's top winds of 85 mph observed in the offshore, right front quadrant of the storm meant that the winds on the weak side of the storm, over Nova Scotia, were 85 mph minus 35 mph, or just 50 mph. Winds along most of the coast stayed below 39 mph, the borderline for tropical storm-force winds. The strongest winds measured in Canada were at Sable Island, which lies 150 miles offshore of Nova Scotia. Winds on the island hit 61 mph, gusting to 77 mph, between 4 - 5 pm ADT Sunday afternoon. A few islands along the Nova Scotia coast, such as Beaver Island and Hart Island, reported sustained winds of 39 - 40 mph. The big story for Nova Scotia was the waves from Bill. Buoy 44258 at the mouth of Halifax Harbor recorded significant wave heights of 29.5 feet and maximum wave heights of 49 feet as Bill passed 50 miles offshore. The buoy recorded top sustained winds of 35 mph, gusting to 51 mph. The waves combined with a 1.5 - 3 foot storm surge flooded many coastal roads. Buoy 44150, about 160 miles offshore of of the southwest tip of Nova Scotia, was in the east eyewall of Bill between 10 - 11 am ADT, and reported sustained winds of 62 mph, gusting to 85 mph, with significant wave heights of 44 feet. The buoy recorded a maximum wave height of 87 feet, according to Environment Canada. The highest official rain report on Nova Scotia was 2.6" (65 mm) at Yarmouth. Rainfall cause some localized flooding and road damage. Bill's winds cut power to about 40,000 people at the height of the storm. At Peggys Cove, three men were hit by a giant wave but were not hurt. A gift shop and attached home in the village were swept off of their foundation.

Newfoundland gets hit, but damage is minor
The southeast corner of Newfoundland took a direct hit from Bill. The storm made landfall early this morning as a borderline tropical storm/Category 1 hurricane. Top winds on the island were measured at Cape Race, which recorded sustained winds of 58 mph, gusting to 76 mph, between 1:30 and 2:30 am NDT. A storm surge of 1.2 meters (4 feet) was estimated by Environment Canada for Placentia Bay where Bill made landfall. Damage was minor on Newfoundland, with no major flooding reported. Bill dumped up to three inches of rain on Newfoundland.


Figure 1. The eye of Hurricane Bill on August 19 at 2157 UTC, from a NOAA P-3 Hurricane Hunter aircraft flying at 10,000 feet. Photo credit: Jack Parrish of NOAA's Aircraft Operations Center.

Kelvin-Helmholtz instability waves in the eye of Bill
Flight Director Jack Parrish of NOAA's Aircraft Operations Center snapped a cool photo in the eye of Hurricane Bill on Friday, showing the existence of a Kelvin-Helmholtz instability wave (Figure 1). The photo was taken on August 19 at 2157 UTC, from a NOAA P-3 Hurricane Hunter aircraft flying at 10,000 feet. The photo is taken looking WNW towards the eyewall. The towering clouds of the eyewall extend up to 50,000 - 55,000 feet in the photo, and the ocean surface is not visible, due to stratocumulus clouds covering the bottom of the eye. The center of the photo shows that the top of one of these stratocumulus clouds has a feature that looks like a breaking wave in the ocean. Well, that is an example of a breaking wave in the atmosphere known as a Kelvin-Helmholtz instability wave. The atmosphere behaves as a fluid, and thus has wave-like motions. When there is a sudden change of wind speed along the top of a cloud (wind shear), the flow can become unstable and cause breaking waves to form. One can see Kelvin-Helmholtz in the sky several times per year, and several alert wunderphotographers have uploaded photos of these waves over the years. However, it is uncommon to see these waves in the stratocumulus clouds covering the eye of a hurricane.


Figure 2. Water vapor satellite image for 8:15 am EDT 8/24/09. A tropical wave is approaching the Northern Lesser Antilles Islands, but is running into high wind shear from an upper-level cold low to the west of it. Image credit: NOAA/SSD.

Tropical wave approaching Lesser Antilles becomes Invest 92
A tropical wave with a moderate amount of shower activity is moving west-northwest at 20 - 25 mph and is approaching the northern Lesser Antilles Islands. This wave was designated "Invest 92" (92L) by NHC this morning. The wave is under about 20 - 30 knots of wind shear due the strong upper-level winds from the west. These winds are being created by the counter-clockwise flow of air around an upper-level cold-cored low north of Puerto Rico (Figure 2). This low is expected to move west-southwest and slowly weaken over the next two days, allowing shear to drop to the moderate 10 - 20 knot range beginning Tuesday night, according to the SHIPS model. By Wednesday, the upper low is predicted to be weak enough and far enough away from 92L that it will have a chance to develop. Most of the models show some degree of development of 92L by Thursday, when it is expected to be a few hundred miles off the coast of South Carolina. This wave could turn northward and give a wet weekend to New England, though it is too early to be confident of this. NHC is giving 92L a low (less than 30% chance) of developing into a tropical depression by Wednesday morning. The upper-level low will create plenty of wind shear and dump cold, dry air into 92L over the next two days, so Wednesday is probably the earliest we can expect the system to begin organizing into a tropical depression.

Several models predict the development of a tropical wave coming off the coast of Africa late this week.

I'll have an update Tuesday.

Jeff Masters

Beach Wall wave 1 (BeachBecky)
Waves from Hurricane Bill crashing on the sea wall during high tide in Lynn, MA
Beach Wall wave 1
Hurricane Bill Waves Day 2 # 9 (RIWXPhoto)
Hurricane Bill Waves Day 2 # 9
Kelvin-Helmholtz Instabilities (btangy)
Kelvin-Helmholtz Instabilities to the S of Boston. Wavy like pattern in clouds is caused by a difference in winds between the cloud layer and the layer just above (called wind shear). The manifestation of this at the top of the altostratus deck is quite a beautiful and rare sight!
Kelvin-Helmholtz Instabilities

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848. iluvjess
10:26 PM GMT on August 24, 2009
I forsee the models nudging left some on 92. Nothing extreem like a Texas landfall, but inching left for the next 24 hours or so.
847. Tazmanian
10:25 PM GMT on August 24, 2009
talk about a fast spin up i dont think TD 12E is a TD any more i think we have are next E PAC name storm

Member Since: May 21, 2006 Posts: 5091 Comments: 115454
846. TheDawnAwakening
10:25 PM GMT on August 24, 2009
That was an interesting post about Hurricane Bill and Bob about being disappointed hurricanes. Hurricane Bill was a disaster averted by mother nature. Nature had simply evened the playing field. The eastern CONUS trough was a day early which allowed Bill to become sheared and pushed out to sea. The trough was neutral to possibly negative as it pulled eastward. It could have been a situation of Katrina in NO. Why do I say this? Like New Orleans in 2005, Cape Cod, MA only has one way out and would take several days worth of preparation to prepare for a hurricane making landfall on the South Coast of New England. Hurricane Katrina spared New Orleans because of undergoing an EWRC in time right before landfall. This period of the EWRC allowed the very little effects the trough had on her to affect her and allow her winds to weaken enough from causing a much bigger and more catastrophic landfall. The superdome of NO had experienced wicked wind damage on the roof, but Katrina could have been stronger, so nature evened the playing field a little in time right at landfall. With Hurricane Bill, he was large enough to not allow him to strengthen rapidly like I believed he had the chance to do so. A further westward track would have allowed a large hurricane a better chance to affect New England a category three or four hurricane. This would have been a big disaster. RTE 6 on Cape Cod, MA is the only road out of Cape Cod, MA. We would need several days to get out of dodge before a major hurricane came up the coast. The earlier arrival of the trough by a day allowed wind shear to not allow Bill to strengthen quickly. I am just saying that Cape Cod, MA is lucky that we were spared and the trough saved our area from Hurricane Bill.
Member Since: October 21, 2008 Posts: 248 Comments: 3970
845. Dakster
10:24 PM GMT on August 24, 2009
Going by what has happened in recent previous seasons. (I know this is bad, as past performance doesn't gaurantee future performance)

It seems like multiple Hurricanes take roughly the same path throughout the season. Notice I did not say ALL OF THEM DO, just that numerous ones do. For example last years straight west runs across the Atlantic and into Mexico, and in 2004 and 2005 , the multiple Florida strikes.

So, Ike, you comment on Bill Part 2 seems very reasonable to me at the moment, going by nothing but historical reference at the moment.
Member Since: March 10, 2006 Posts: 0 Comments: 10760
844. mobilegirl81
10:24 PM GMT on August 24, 2009
I noticed that the GFS shows a third storm developing off africa and moving toward the CONUS. My thinking is the beginning MJO upward/Negative NAO being responsible for an upward swing.imo
Member Since: August 31, 2008 Posts: 0 Comments: 833
843. largeeyes
10:24 PM GMT on August 24, 2009
Eastern NC weather guys are downplaying it as an increased risk of showers and t-storms this weekend.
Member Since: August 22, 2006 Posts: 0 Comments: 1462
841. CatastrophicDL
10:22 PM GMT on August 24, 2009
Thanks for the explanation Drak!
Member Since: September 3, 2007 Posts: 3 Comments: 1519
840. Drakoen
10:20 PM GMT on August 24, 2009
Quoting CatastrophicDL:

I was referring to the 12Z CMC, NOGAPS and ECMWF.


The CMC and NOGAPS foresee the most strengthening with the system which would induce a more poleward movement. The thing is regardless of how strong this is, if it bypass the first trough then it will be under a ridge (ECMWF/UKMET)which could allow it to come further west. Then there is the issue of how strong the trough is behind the ridge. Whether it comes in flat or whether ti comes in deep. The models foresee a closed upper cyclone or mid level trough forming in the GOM which I believe will protect the GOM states with the exception of Florida. Everyone from Florida northward should monitor the progression of this system.
Member Since: October 28, 2006 Posts: 57 Comments: 30816
839. CatastrophicDL
10:20 PM GMT on August 24, 2009
Atmo, The water temps might not be great, but 93L it has a strong anti-cyclone above it and great convergence and divergence. Good for strengthening.
Member Since: September 3, 2007 Posts: 3 Comments: 1519
838. BenBIogger
10:18 PM GMT on August 24, 2009
ECMWF Forecast 500mb
120 Hours
Member Since: March 19, 2009 Posts: 0 Comments: 1421
837. IKE
10:17 PM GMT on August 24, 2009
18Z GFS.......has 92L pulling a Bill part 2.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
835. CatastrophicDL
10:16 PM GMT on August 24, 2009
Quoting Drakoen:


If you are referring to the BAMM guidance then there is really no argument. The cannot see such a dynamic change in the steering currents as some of the higher resolution models can.

I was referring to the 12Z CMC, NOGAPS and ECMWF.
Member Since: September 3, 2007 Posts: 3 Comments: 1519
834. atmoaggie
10:15 PM GMT on August 24, 2009
Quoting AllStar17:
LOL, talk about uncertainty in the forecast!

So if the spread were evenly distributed in opposite directions, do the automated algorithms generating an ensemble mean churn out that it is just going to not move and be a permanent feature?
Member Since: August 16, 2007 Posts: 6 Comments: 12463
833. IKE
10:14 PM GMT on August 24, 2009
Quoting GeoffreyWPB:
Pacific bound..



Finally...a system that moves west as it makes landfall. WSJFV would love 93L.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
832. hydrus
10:13 PM GMT on August 24, 2009
Quoting JupiterFL:


wrobble, wrobble
Shake it, Shake it
Yes,Danny will be larger than three typhoon Tips.
Member Since: September 27, 2007 Posts: 1 Comments: 22585
830. atmoaggie
10:13 PM GMT on August 24, 2009
Quoting Vortex95:


Unless somthing happens in steering soon. It could turn into somthing in the EPAC.

I don't know that the SSTs really are in it's favor until it does get into EPAC.



A little better there:
Member Since: August 16, 2007 Posts: 6 Comments: 12463
829. CatastrophicDL
10:13 PM GMT on August 24, 2009
Quoting mobilegirl81:
Where is 93L expected to move?
All steering layers have it moving west unless it drifts north, gets super strong and then it might go north.
Member Since: September 3, 2007 Posts: 3 Comments: 1519
828. Grothar
10:12 PM GMT on August 24, 2009
Quoting Seastep:


Grothar - still trying, huh? :)

If you right-click the image itself, and "copy image location" and then past that without the "s" it will work. Should look like this:

http://my.sfwmd.gov/sfwmd/common/images/weather/plots/storm_92.gif

The 92 would be 93 for 93L.


Noticed that did ya!!!! My wife is laughing so hard in the background, she informed me I should switch to astronomy and just go out and look at the stars. What I am really trying to post is the track on 93L. Help me out here, Seastep. Could you post it for me and say this is what Grothar was attempting to post. Who knows, it might get a laugh (like someone else in the room here!!!!)
Member Since: July 17, 2009 Posts: 71 Comments: 27208
827. GeoffreyWPB
10:12 PM GMT on August 24, 2009
Pacific bound..

Member Since: September 10, 2007 Posts: 0 Comments: 11538
826. Drakoen
10:11 PM GMT on August 24, 2009
Quoting CatastrophicDL:
Drak, the most of 12Z models incl. the ECMWF show a US landfall. The 18Z models are much further east. Is this because of the "complex situation" you were talking about?


If you are referring to the BAMM guidance then there is really no argument. The cannot see such a dynamic change in the steering currents as some of the higher resolution models can.
Member Since: October 28, 2006 Posts: 57 Comments: 30816
825. AllStar17
10:11 PM GMT on August 24, 2009
LOL, talk about uncertainty in the forecast!
Member Since: June 29, 2009 Posts: 13 Comments: 5315
824. atmoaggie
10:10 PM GMT on August 24, 2009
Quoting Tazmanian:



read the post few commets down and you find it

Sry, Taz, dry mockery of the 3 full copies we have is what that was.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
823. Tazmanian
10:09 PM GMT on August 24, 2009
Quoting atmoaggie:
Could someone please post the Special TWO?



read the post few commets down and you find it
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
821. 7544
10:09 PM GMT on August 24, 2009
Quoting Vortex95:


Unless somthing happens in steering soon. It could turn into somthing in the EPAC.


well i guess its safe to use the word west for 93l lol
Member Since: May 6, 2007 Posts: 0 Comments: 6874
820. CatastrophicDL
10:09 PM GMT on August 24, 2009
Drak, the most of 12Z models incl. the ECMWF show a US landfall. The 18Z models are much further east. Is this because of the "complex situation" you were talking about?
Member Since: September 3, 2007 Posts: 3 Comments: 1519
819. Seastep
10:09 PM GMT on August 24, 2009
Gotta run. BBL.
Member Since: September 9, 2008 Posts: 6 Comments: 3414
818. mobilegirl81
10:09 PM GMT on August 24, 2009
Where is 93L expected to move?
Member Since: August 31, 2008 Posts: 0 Comments: 833
816. Drakoen
10:08 PM GMT on August 24, 2009
Quoting atmoaggie:
Could someone please post the Special TWO?


I need to see it at least 20 times to be satisfied
Member Since: October 28, 2006 Posts: 57 Comments: 30816
815. Drakoen
10:07 PM GMT on August 24, 2009
The UKMET model tracks the system just east of Florida
Member Since: October 28, 2006 Posts: 57 Comments: 30816
813. atmoaggie
10:07 PM GMT on August 24, 2009
Could someone please post the Special TWO?
Member Since: August 16, 2007 Posts: 6 Comments: 12463
812. mobilegirl81
10:07 PM GMT on August 24, 2009
Going into phase II of tropical atlantic activity I see.
Member Since: August 31, 2008 Posts: 0 Comments: 833
811. Tazmanian
10:06 PM GMT on August 24, 2009
guys 93L need to be watch it can spin up vary fast
Member Since: May 21, 2006 Posts: 5091 Comments: 115454
810. Drakoen
10:06 PM GMT on August 24, 2009
Quoting Drakoen:


Every 3 hours


It's a pretty good product and you can run a loop on it.
Member Since: October 28, 2006 Posts: 57 Comments: 30816
809. Seastep
10:06 PM GMT on August 24, 2009
Quoting Grothar:
http://xlr8.sfwmd.gov/portal/page?_pageid=2854,19644915,2854_19644936:2854_19645022:2854_19645029&a mp;_da d=portal&_schema=PORTAL


Grothar - still trying, huh? :)

If you right-click the image itself, and "copy image location" and then past that without the "s" it will work. Should look like this:

http://my.sfwmd.gov/sfwmd/common/images/weather/plots/storm_92.gif

The 92 would be 93 for 93L.
Member Since: September 9, 2008 Posts: 6 Comments: 3414
808. VAbeachhurricanes
10:06 PM GMT on August 24, 2009


plz no...... :( i know its a model but that scares me.
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807. Drakoen
10:05 PM GMT on August 24, 2009
Quoting futuremet:


How often is it updated?


Every 3 hours
Member Since: October 28, 2006 Posts: 57 Comments: 30816
806. breald
10:05 PM GMT on August 24, 2009
Quoting klaatuborada:
My local newspaper printed an article where someone called Hurricane Bill and Hurricane Bob "disappointing" hurricanes. Link

I sent this today as a letter to the Editors. I wonder if they'll print it.

Dear Sirs:

RE: August 23, 2009 article "Hurricane Bill restricts Cape and Islands recreation"

I take issue with the comments of Mr. Mitrokostas re: Hurricane Bob being a "disappointing" hurricane. Perhaps where Mr. Mitrokostas was, Bob was "disappointing", but from where I was I was scared and Hurricane Bob was more than "power outages" and "wind outside". Bob's storm surge was significant, and several areas in Rhode Island, Buzzards Bay, Cape Cod and Martha's Vineyard reported extensive wind and storm-surge damage not seen since Hurricane Carol in 1954. Hurricane Bob left eighteen people dead and $2.8 billion dollars in damage. In Falmouth the Admiralty Apartments had the roof blown off. In Provincetown 38 boats were sunk by the high storm surge with wind causing building damage as well. Motels lost their roofs in Yarmouth and Truro. Route 6A and all of the Cape were littered with downed trees and power lines and people's lives were disrupted for weeks. This storm did not hit us directly and was only a Cat 2 when it hit, but "disappointing"?

What is a "disappointing hurricane"? One that doesn't cause billions of dollars in damage? Does a hurricane like Katrina have to hit Cape Cod in order for people to respect the power of these storms? I think the miracle of Hurricane Bill is that it only caused 3 deaths, and missed so many people and places that would have been devastated by a direct hit. I for one was not "disappointed" but happy that it passed us by. I know people who have been in Category 4 and 5 hurricanes, and they paint a picture more horrifying than anything I can imagine. It's not an exciting thing when a major storm system is headed for the Cape. It's a scary thing, and should be. Let's all be careful what we wish for. And kudos to the officials that took this storm seriously; closing the beaches saved lives. If Bill had taken a slight turn Westward it would have been a much different scenario. My thanks to the NHC and NOAA for their great work.

Sincerely

Me


Good response. I hope they print it.
Member Since: May 28, 2008 Posts: 38 Comments: 5303
805. Eagle300
10:04 PM GMT on August 24, 2009
Quoting 7544:


yeap it cold happen here as we blog its really bursting out at this hour and might be leaving the ull it was attached to i think


Thanks.
I have been under the impression that ULL create a high shear environment so if the ULL is moving away that would relax the shear, right?

and ULL is upper level low, where as a tropical cyclone is a LLL,
lower level low? =)
804. futuremet
10:03 PM GMT on August 24, 2009
Quoting Drakoen:
Low level vorticity product from PSU:



How often is it updated?
Member Since: July 19, 2008 Posts: 43 Comments: 4051
803. Grothar
10:03 PM GMT on August 24, 2009
http://xlr8.sfwmd.gov/portal/page?_pageid=2854,19644915,2854_19644936:2854_19645022:2854_19645029&_da d=portal&_schema=PORTAL
Member Since: July 17, 2009 Posts: 71 Comments: 27208
802. litestar
10:03 PM GMT on August 24, 2009
To Keeper of the Gate Can you tell me if weather over South Fla. Will clear by midnight? thank you Star.
801. 7544
10:03 PM GMT on August 24, 2009
hmm a orange and yellow in less than 12 hours could we see one more circle pop up somewhere
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Member Since: July 17, 2009 Posts: 71 Comments: 27208

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