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 ConchHondros:
My daughter just text messaged me, asked what I was doing...told her...she replied OMG, WTFO..what is the BFD with that lamo site anyway? Flood, rare...translation??


Translation ??. She thought she was texting someone other than her father.
Member Since: August 19, 2006 Posts: 0 Comments: 15748
Link shuttle visability
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Quoting Grothar:


Hey Allstar, you have helped me many times before. I have never posted an image before. I am trying to show the South Florida Water Management Department image of tropical storm forecasts which shows 92L. It is really a very interesting site. Just can't do it. HELP!!!


You need to send the photo through an image hosting site. The SFWMD does not allow direct image placement.
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Aaa...I see, well...I would smash her phone with a hammer, because I cant afford a ticket to New Zealand to whack her...but then again I cant afford to replace her iphone...I could take it away...but she would put everyone within a 20 mile radius through hell until she got it back...oh wtf..16 is the new 30...right?
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Quoting Acemmett90:

i afraied of what you will do when i tell you what it means
lmao= laughing my a$$ off
WTF= what the F%^&
not sure on the other one


BFD= Big F***ing Deal, I'm afraid...
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Quoting ConchHondros:
My daughter just text messaged me, asked what I was doing...told her...she replied OMG, WTFO..what is the BFD with that lamo site anyway? Flood, rare...translation??

complete sentence..

oh my god, what the F%^%, OVER, what is the big f%$% deal with that lame site
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Quoting futuremet:
474

B..but...I wanna know....where is it gonna hit?!?!?!?!?!?!?


Ok I don't know exactly where it will hit, but I can tell you IF it hits the US it will be an east coast storm. The carolinas, GA and possibly FL bears watching with 92L.
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AL 92 2009082418 BEST 0 170N 580W 20 1010 DB
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Quoting ConchHondros:
My daughter just text messaged me, asked what I was doing...told her...she replied OMG, WTFO..what is the BFD with that lamo site anyway? Flood, rare...translation??


And I quote:

"Oh, my god, what the f@*k...what is the big f@*king deal with that lamo site anyway?"
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Quoting AllStar17:


Please post it again, it did not work.


Hey Allstar, you have helped me many times before. I have never posted an image before. I am trying to show the South Florida Water Management Department image of tropical storm forecasts which shows 92L. It is really a very interesting site. Just can't do it. HELP!!!
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Quoting usa777:
Anyone have any idea of which of the models performed best on "bill"??? Thanks in advance.


Here is one site that tracks performance, however I don't know what their criteria are or how they complile the stats. I have seen others that don't agree with their data. Also, since the info from the NHC on the ECMWF model is not released it is difficult to determine it's performance other than a gut feel.
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.
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Quoting Acemmett90:

i afraied of what you will do when i tell you what it means
lmao= laughing my a$$ off
WTF= what the F%^&
not sure on the other one


BFD= BIG F$#%% DEAL
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480. IKE
Space shuttle takes off at 1:36 am EDST tomorrow morning. All systems are go for now.
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474

B..but...I wanna know....where is it gonna hit?!?!?!?!?!?!?
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My daughter just text messaged me, asked what I was doing...told her...she replied OMG, WTFO..what is the BFD with that lamo site anyway? Flood, rare...translation??
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Member Since: June 29, 2009 Posts: 13 Comments: 5300
Quoting SaoFeng:
Hows the shear over the SW Caribbean disturbance?



Very low but, it does not matter its going inland and into the Pacific soon.
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Hows the shear over the SW Caribbean disturbance?
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Quoting Grothar:
http://xlr8.sfwmd.gov/portal/page?_pageid=2854,19644915,2854_19644936:2854_19645022:2854_19645029&a mp;_da d=portal&_schema=PORTAL

This just came out. Hope I did it correctly.


Please post it again, it did not work.
Member Since: June 29, 2009 Posts: 13 Comments: 5300
Quoting usa777:
Anyone have any idea of which of the models performed best on "bill"??? Thanks in advance.


ECMWF!!!
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Anyone have any idea of which of the models performed best on "bill"??? Thanks in advance.
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Quoting btwntx08:

yep


isnt this the wave that gfs shows in 144 hr to be going towards california coast?


Link
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12Z ECMWF
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Quoting TampaSpin:
The ULL is actually helping to vent 92L.


1 Tim

The diffluent flow aloft caused by the ULL is helping this system to maintain its convection. This is why convection has not decreased despite diurnal minimum. However, the ULL is also making it difficult for it effectively coalesce. Albeit a ULL does help convection, but an upper level anticyclone is best for tropical cyclone, because it provides good divergence with a lack of shear. But, this is exactly what is going to happen, when the degenerating trough over the eastern U.S. start to split in about 24hrs. As the detached trough propagates southward, it will help ventilate the area to the east--creating an upper anticyclone. This will provide ideal conditions for tropical cyclogenesis.
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Quoting Grothar:


We all feel it is impolite to write in languages other than English on this blog because it is mostly English speaking people.


Thanks for that! Much appreciated! :)
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Quoting TampaSpin:
The ULL is actually helping to vent 92L.
I'll agree to that for the N, but seems to be impinging on the western semi-circle.
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Quoting btwntx08:

incorrect
Your turn SQUAWK !
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http://xlr8.sfwmd.gov/portal/page?_pageid=2854,19644915,2854_19644936:2854_19645022:2854_19645029&_da d=portal&_schema=PORTAL

This just came out. Hope I did it correctly.
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Shear now decreasing over 92L
Member Since: June 29, 2009 Posts: 13 Comments: 5300
CSU and the NHC need to compare notes.


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Quoting caneluver:


I am coming to get you Allstar....


LMAO !!!
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Quoting SQUAWK:


He is just trying to get his numbers up so people will think he really has something going on at his blog. Then they see what is there and discover what he really is.
Thanks, you're right. Having worked with computers for 52 years I have learned to recognize that kind of action! I would just ignore but that does little to help when others just quote him. Besides, he sometimes has things of interest to the whole blog and I wouldn't want to miss them! I'm a lurker, not much for making invalid contributions!
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The ULL is actually helping to vent 92L.
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453. IKE
Quoting btwntx08:
aoi in sw carb looking good too


Looks like that AOI is moving slightly south of west and may head N 2 the east-Pac.
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Quoting 7544:
92l looking better this hour it just may do it before wends imo


Still being pretyy heavily sheared though; at this rate it won't last until the shear starts to ease
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450. 7544
92l looking better this hour it just may do it before wends imo
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Oh Danny Boy....
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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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