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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Quoting caneswatch:


Where is the Euro track taking it?


Wouldn't you like to know? lol

Lets just say it effects someone in the CONUS. Trying to keep it cool here.
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Quoting NRAamy:
lurker....JFV/WS loves it....who else gets this much attention, bud?


dude this has been posted 3 times today..its gets old after a while.
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Quoting caneswatch:


Where is the Euro track taking it?


to JV.
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Quoting rwdobson:


This year, there has been a trough coming towards the E coast all summer...


I hope these troughs don't continue into the winter months..
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Pugnacious much?

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lurker....JFV/WS loves it....who else gets this much attention, bud?
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Quoting reedzone:
As with Bill, timing is crucial with 92L. If the trough came late or if 92L speeds up, we would be looking the EURO track. If the trough comes in fast or if 92L is slow, the trough will likely sweep it out to sea affecting no one, maybe Bermuda. This is still way too early to make tracks right now. Lets give 92L a few more days, possibly till the weekend before we make bold and confident statements.


Where is the Euro track taking it?
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639. Relix
I just want to know if it posses a threat to PR =(
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Quoting KarenRei:
Hey all, just checking in. What's up with that swirl just west of the CVs? Looks like there's lots of air in rotation.


Some of the models are calling for some development in that area soon; that msut be the energy they're calling for...
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hey guys, dont you think WS had enough humiliation for one day..give a guy a break. He may seem a little off the wall sometimes, but no one deserves this...
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As with Bill, timing is crucial with 92L. If the trough came late or if 92L speeds up, we would be looking the EURO track. If the trough comes in fast or if 92L is slow, the trough will likely sweep it out to sea affecting no one, maybe Bermuda. This is still way too early to make tracks right now. Lets give 92L a few more days, possibly till the weekend before we make bold and confident statements.
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Quoting StormChaser81:


Yup need to have some mass associated with for the coriolus effect to take it north.


And height; weaker storms are effected less. There's latitude too; storms south of 10N tend to be less effected or not at all...
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this has been the summer of the troughs,except for last week,the east coast has been near a trough or had a trough sitting right over it.
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Dude Florida is Safe...

not per our Bidet Blogger, JFV...
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Quoting Engine2:
Since the invest doesn't have a low level center of circulation to initiate on, the models are going to be all over the place. Just sit back watch and be vigilant thats all

That's what we do, right deuce?
Melb. FL Radar - this should clear out by launch time - let's not take any (major)lightning strikes!
Member Since: October 13, 2005 Posts: 4 Comments: 2156
Quoting Floodman:


OMG!

"Tower, this is PanAm flight 17; WTFO?"


LOL.roger, roger, over, over..airplane movie.
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Quoting canesrule1:
Your are incorrect in number one for the simple reason that 92L is not a hurricane. And number 2 is incorrect because it is a different jet stream that is supposed to dip and it is a matter of time to know if this will affect me in Florida or if it will actually recurve.

-CanesRule1.


Yup need to have some mass associated with for the coriolus effect to take it north.
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Quoting canesrule1:
Your are incorrect in number one for the simple reason that 92L is not a hurricane. And number 2 is incorrect because it is a different jet stream that is supposed to dip and it is a matter of time to know if this will affect me in Florida or if it will actually recurve.

-CanesRule1.
Quoting canesrule1:
Your are incorrect in number one for the simple reason that 92L is not a hurricane. And number 2 is incorrect because it is a different jet stream that is supposed to dip and it is a matter of time to know if this will affect me in Florida or if it will actually recurve.

-CanesRule1.


Well, that's the last time I answer any of
your questions.

yonzabam

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Quoting caneluver:
Why does there always seem to be a trough coming towards the E Coast when a Hurricane nears?


Why ask why? Im just thankful that there usually is
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Hey all, just checking in. What's up with that swirl just west of the CVs? Looks like there's lots of air in rotation.
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Quoting caneluver:
Why does there always seem to be a trough coming towards the E Coast when a Hurricane nears?


This year, there has been a trough coming towards the E coast all summer...
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Quoting canesrule1:
Well luckily, 92L is not a CAT 1, and according to satellite imagery 92L's convection is moving slightly north of west, not quite WNW in my opinion, more like WWNW.



Whaaaaaaaaaaaaaaaaaaaat??
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Quoting SavannahStorm:


Hope this isn't the case...
Well luckily, 92L is not a CAT 1, and according to satellite imagery 92L's convection is moving slightly north of west, not quite WNW in my opinion, more like WWNW.
606. Roger, Roger. What's your vector, Victor?

LOL
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Quoting reedzone:
Too early to say 92L will recurve, still days away from impacting land IF ANY. I said this with Bill when it was still east of the Leeward Islands but people said it was clearly going to go out to sea which in very little case, it did, but impacted Cape Cod, Bermuda, and Canada... Not a "fish" like storm in my opinion. I saw the models on 92L, still no defined circulation so all of the coastline from Florida to Maine needs to monitor 92L. It appears all models form something once it nears the Bahamas. All I'm gonna do like I did with Bill, is advise everyone in it's "possible" path to watch it and not worry until we know for a certainty it's coming there way.

exactly
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Quoting HIEXPRESS:

Yeah, I thought about that. What season?


Remember that trough that rolled through the Plains and Midwest was more like a May/June trough.
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Too early to say 92L will recurve, still days away from impacting land IF ANY. I said this with Bill when it was still east of the Leeward Islands but people said it was clearly going to go out to sea which in very little case, it did, but impacted Cape Cod, Bermuda, and Canada... Not a "fish" like storm in my opinion. I saw the models on 92L, still no defined circulation so all of the coastline from Florida to Maine needs to monitor 92L. It appears all models form something once it nears the Bahamas. All I'm gonna do like I did with Bill, is advise everyone in it's "possible" path to watch it and not worry until we know for a certainty it's coming there way.
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well im off to work, later guys
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An upper level trough is advecting towards the eastern seaboard and will likely create some degree of weakness.
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Quoting justalurker:


what the f**, over,


OMG!

"Tower, this is PanAm flight 17; WTFO?"
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Hope this isn't the case...
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Since the invest doesn't have a low level center of circulation to initiate on, the models are going to be all over the place. Just sit back watch and be vigilant thats all
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Quoting yonzabam:


1) Because that's what hurricanes do in that part of the world. They want to go north, then recurve. In order for this not to happen, the Bermuda High must be big and strong.

2) The abnormally strong trough that recurved Bill is still there. I think it might have something to do with the jet stream.
Your are incorrect in number one for the simple reason that 92L is not a hurricane. And number 2 is incorrect because it is a different jet stream that is supposed to dip and it is a matter of time to know if this will affect me in Florida or if it will actually recurve.

-CanesRule1.
Why does Nogaps have it going so far west?
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Quoting HIEXPRESS:

Yeah, I thought about that. What season?


what season?
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Quoting tornadodude:


funny thing, we had a tornado last week, a couple confirmed and several funnels, way to start off my college career lol

Yeah, I thought about that. What season?
Member Since: October 13, 2005 Posts: 4 Comments: 2156

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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.