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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Oh Danny Boy....
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Quoting TheSuperCane:
Good evening everyone

it´s my first post. I´m from Germany and interested in tropical storms and the impacts of them with europe.

I think, if the shear, produced by the upper level low will decrease tomorrow, 92L will develope quite qickly. Sure the track is hard to predict at the moment, cause nobody knows, whre the LLC will devolope.

(Sorry for my bad english)

Greets



Welcome, there are many people on this post who speak German. If you have any questions you may contact them directly for clarification by clicking on their name. We all feel it is impolite to write in languages other than English on this blog because it is mostly English speaking people. We correspond privately in repect to others. It is a lot of fun and there are some very informative people on this blog
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Quoting earthlydragonfly:


Dont forget to wish cast it to Florida
If Florida is even remotely involved forecast-wise then it should be obvious that the ENTIRE GOM is most certainly at risk.
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Quoting PortABeachBum:

Comments listed on your two comments pages starting with


"8. btwntx08 9:06 PM GMT on August 07, 2008 ..."

thru

"155. btwntx08 9:56 PM GMT on August 07, 2008 ..."

are all yours and all contain NOTHING.



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.
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Vortex and Jeff, how do you generate these graphics?
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Quoting HurricaneKyle:


TampaSpin had Claudette dead on. He said there was a SFC circulation developing on 91L, he was dead on right, the next TWO raised it to 'Red'.


Thanks Kyle.....RAre is just busting my chops....LOL
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Quoting KEEPEROFTHEGATE:
1000 drones on roof ready for take off phase one seed phase two float in water to transfer surface reading from seeding report data to flush model for stormtops detailed forcast

lol

red circle by 2am


I think we should call in Bill Gates for this one... Deep cool water upwelling is the key. and a couple of hundred trillion dollars
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438. IKE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
139 PM EDT MON AUG 24 2009

.SYNOPSIS...
WEAK HIGH PRESSURE WILL BUILD NORTH OF THE REGION THROUGH MIDWEEK.
LOW PRESSURE WILL DEVELOP OFF THE SOUTHEAST U.S. COAST BY LATE
WEEK...THEN WILL MOVE NORTHEAST OF THE AREA THIS WEEKEND.

FRI THROUGH SUNDAY...MODELS CONTINUE TO ADVERTISE TROPICAL LOW PRES
IN SOME FORM WILL PASS N OF THE BAHAMAS FRI THEN STEER N AND
EVENTUALLY NE ALONG THE GULF STREAM EARLY SAT AND WELL NE OF OUR
REGION OVER THE WEEKEND.
WE HAVE FORECAST CHANCE POPS FRI INTO
SAT...THEN SLIGHT CHANCE POPS ON SUNDAY. FORECAST TEMPERATURES
FAIRLY CLOSE TO CLIMO THROUGHOUT.

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Quoting btwntx08:
398: blog is fine what are u looking at....at the bottom is 92L if u didn't know ask more questions on my blog like that will make me ingore you but not for right now at least

Comments listed on your two comments pages starting with


"8. btwntx08 9:06 PM GMT on August 07, 2008 ..."

thru

"155. btwntx08 9:56 PM GMT on August 07, 2008 ..."

are all yours and all contain NOTHING.

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435. LBAR
Quoting IKE:
I don't see how 92L gets an orange circle, but they are the experts, so I'll take their word at it.


ULL is moving away...shear should be decreasing. I'm nervous for the SC coast...although a tropical storm dropping some rain wouldn't be a bad thing by any means.
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Quoting DestinJeff:


Dont forget to wish cast it to Florida
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1000 drones on roof ready for take off phase one seed phase two float in water to transfer surface reading from seeding report data to flush model for stormtops detailed forcast

lol

red circle by 2am
Member Since: July 15, 2006 Posts: 171 Comments: 53839
Quoting IKE:


Apparently so. I guess this force...er, Farce, will knock down the 30 knots of westerly shear blowing over this bad-boy.


It lifts out in 48 hours or so:



If it hangs on that long the shear will ease...it better be moving nearly due west by then though; after 72 hours it builds back in again
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429. Relix
Quoting TheCaneWhisperer:


I think that is the best guess position if I had to pin a tail on an oversize donkey, err, umm?


Yeah I understand this. I had the possible center at 17.8 or around that.
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Just joking BTW. I would love to have all the tools that they do to pick up on cyclone formation.
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Quoting IKE:


Apparently so. I guess this force...er, Farce, will knock down the 30 knots of westerly shear blowing over this bad-boy.
covert seeding program is about to be initated on 92L
Member Since: July 15, 2006 Posts: 171 Comments: 53839
Quoting Relix:
They initialized 92L at 18.2N? Wow that's pretty much a lot to the N. Guess the northward islands are really safe from this one.


I think that is the best guess position if I had to pin a tail on an oversize donkey, err, umm?
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424. IKE
Quoting TheCaneWhisperer:


Told ya man! It will all make sense in the morning, there using the Farce.


Apparently so. I guess this force...er, Farce, will knock down the 30 knots of westerly shear blowing over this bad-boy.
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Quoting TheCaneWhisperer:


Told ya man! It will all make sense in the morning, there using the Farce.


LOL
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422. Relix
They initialized 92L at 18.2N? Wow that's pretty much a lot to the N. Guess the northward islands are really safe from this one.
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Quoting IKE:


And that gets an orange circle?



Told ya man! It will all make sense in the morning, there using the Farce.
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Quoting Txstorm09:
New to the blog and trying to learn. What direction is 92L moving?


WNW or thereabouts
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Data slow to come out on 92L. Seems to be moving along now.
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New to the blog and trying to learn. What direction is 92L moving?
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Quoting DestinJeff:
JFVWS:





LMAO... This one made my day...
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Quoting IKE:
I don't see how 92L gets an orange circle, but they are the experts, so I'll take their word at it.


After the amazing job they did with Bill, I have huge confidence in the NHC.
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413. IKE
Quoting TheCaneWhisperer:
24/1745 UTC 18.2N 58.8W TOO WEAK 92L -- Atlantic


And that gets an orange circle?

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Quoting rareaire:
TAMPA is not really very good at this weatheur forcastin but to call him a troll is kinda harsh!


TampaSpin had Claudette dead on. He said there was a SFC circulation developing on 91L, he was dead on right, the next TWO raised it to 'Red'.
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24/1745 UTC 18.2N 58.8W TOO WEAK 92L -- Atlantic
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TAMPA is not really very good at this weatheur forcastin but to call him a troll is kinda harsh!
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Quoting IKE:
I don't see how 92L gets an orange circle, but they are the experts, so I'll take their word at it.



They have secret planes going out tonight, it will make sense in the morning.
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Quoting AllStar17:


Please do not quote caneluver, he is a troll.


Even trolls can be right about something...sorry caneluver....LOL
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402. IKE
I don't see how 92L gets an orange circle, but they are the experts, so I'll take their word at it.
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There they go.
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400. IKE
They found the right crayon...

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Quoting NRAamy:



Yellow alert for JFV's john....


LMAO
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Quoting btwntx08:

u doubled posted please get rid of one please thanks
How about going to your own page and doing a little housework. Double post ! LOL!
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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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