A weakening Bill generating a major wave event for Bermuda and the U.S. coast

By: Dr. Jeff Masters , 2:29 PM GMT on August 21, 2009

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Wind shear and dry air are weakening Hurricane Bill, which may no longer be a major hurricane. However, the hurricane is still large enough and strong enough that it will generate a major wave event for much of the Western Atlantic. Visible and infrared satellite imagery show that the hurricane is no longer as symmetric as it once was, with a squashed oval shape to its cloud pattern. Upper-level cirrus clouds are restricted on the storm's southwest side, indicating that upper-level winds from the southwest are shearing the storm. The University of Wisconsin CIMSS wind shear analysis shows about 10 - 15 knots of southwesterly wind shear impacting Bill. Satellite intensity estimates of Bill's strength show essentially no change since 2am EDT this morning, and Bill is at the borderline of becoming a Category 2 hurricane. There are currently no Hurricane Hunter aircraft in Bill, and the next mission is scheduled for 2pm EDT this afternoon.

Wind shear is forecast to remain low to moderate, 5 - 15 knots, for the next two days, and it is possible Bill may see a relaxation of the wind shear affecting it, allowing some re-intensification today. Sea Surface Temperatures (SSTs) will be plenty warm today, as Bill traverses a region of ocean with SSTs near 29°C. Total ocean heat content is steadily declining, though, as the warm waters Bill is currently traversing do not extend to great depth. By Saturday, SSTs decline to 27.5°C, and intensification becomes less likely.


Figure 1. Visible satellite image of Bill at from Friday morning 8/21/09. Bill had an oval shape, and was missing upper-level cirrus clouds on the southwest side, indicating that wind shear from strong upper-level southwesterly winds was affecting it.

The computer model track forecasts for Bill have been very consistent the past two days, giving confidence that the trough of low pressure developing along the U.S. East Coast this weekend will turn Bill to the north then northeast as expected. Both Nova Scotia and Newfoundland, Canada can expect tropical storm conditions from Bill, which should be rapidly weakening on Sunday afternoon when it makes its closest pass to Nova Scotia. Category 1 hurricane conditions are possible on Nova Scotia if Bill makes a direct hit there. Cape Cod and eastern Maine may receive sustained winds of 35 mph from Bill, just below tropical storm force, but the chance of a direct hit by Bill are slim.

Bill's waves
Hurricane Bill is generating huge waves, thanks to its enormous size and major hurricane intensity. Output from NOAA's Wavewatch III model suggests that significant wave heights near Bill's center will peak at 50 feet by Saturday. Large swells from Bill have reached Bermuda, and are generating waves of 10 - 20 feet in the offshore waters. The Bermuda Weather Service predicts seas will increase to 20 - 30 feet on Saturday as Bill makes its closest approach to the island.

In the U.S., Bill's swells will reach New York's Long Island on this afternoon, and seas will build to 7 - 10' on Saturday and 12 - 16' on Sunday in the near shore waters. By tonight, Bill's swells will be affecting the entire U.S. East Coast from Florida to Maine. Maximum sea heights in near shore waters over the weekend will be about 6 - 8' from Florida to South Carolina, 11 - 14' along the North Carolina coast, 8 - 11' along the mid-Atlantic coast, and 11 - 14' along the coast of Maine. The highest waves along the U.S. coast will occur at Cape Cod, Massachusetts, where waves of 18 - 23' are being forecast by NOAA for Sunday. Bill's high waves will likely cause millions of dollars in coastal erosion damage and create very dangerous rip currents and swimming conditions along the coast.

CloudSat slices through Bill
The CloudSat satellite, launched in 2006, carries the first satellite-based millimeter wavelength cloud radar. It is the world's most sensitive cloud-profiling radar, more than 1000 times more sensitive than current weather radars. It collects data about the vertical structure of clouds, including the quantities of liquid water and ice, and how clouds affect the amount of sunlight and terrestrial radiation that passes through the atmosphere. The satellite has a narrow field of view, so can image only a small portion of the planet each day. About once per year, CloudSat happens to slice through the eye of an Atlantic hurricane. This happened Wednesday, when CloudSat caught a remarkable view of Hurricane Bill (Figure 2).


Figure 2. Top: conventional 89 GHz microwave "radar in space" image of Hurricane Bill on Wednesday, 8/19/09, from the AMSR-E instrument on the Aqua spacecraft. Bottom: cross section through Bill's eye taken at the same time from the CloudSat cloud radar instrument. The CloudSat pass occurs along the red line in the top image. The CloudSat pass runs from south (left side of CloudSat image) to north (right side of CloudSat image). At the time of the image, Hurricane Bill was strengthening into a Category 4 hurricane (135 knot winds, 947 mb pressure), while completing an eyewall replacement cycle. In the 89 GHz Microwave image, half of the eyewall is already completed (half red circle on right side of the image). In the CloudSat image, the southern eyewall shows weak echoes at the low levels, and slopes outward with height. The northern eyewall is much more intense, and a core of high reflectivity echoes extends high into the troposphere, to 16 km altitude, forming a "hot tower". These "hot towers" a characteristic of intensifying hurricanes. Interestingly, the hot tower is tilted into the eye, so that the eyewall does not slope outward with height along the northern eyewall. This is not the typical behavior of a hurricane, and may be due to the unusual strength of the hot tower. Cirrus clouds with a base at 8.5 km can be seen to the south of the hurricane in the CloudSat image. The thin grey line at 5 km marks the 0°C temperature line. Ice particles falling inside the hurricane melt at an altitude just below the 0°C line, creating a "bright band" of orange echoes throughout most of the hurricane. Image credit: NASA/Colorado State University.

Elsewhere in the tropics
There are no threat areas in the Atlantic worth mentioning today. The GFS model calls for a tropical cyclone to develop just off the coast of Africa about seven days from now.

I'll have an update Saturday.

Jeff Masters

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I am completely new to this and any knowledge I have of weather is related to a half year of high school meterology sum 19 years ago is please pardon some of my questions. Question 1. Will the trough continue out to sea with bill pushing him to his destruction, or could bill recoupe and come back around as happen in year or two ago?
Question 2. There was mention earlier in the week that there was a likelylhood of a future event in the next 7-10 days off the cost of Africa, how accurate are those predictions?

Again thanks for your tolerance with a non-expert. Some background on me I've been in Emergency Services for 18 years. The company I am with is frequently sent to diasters created by hurricanes. Most of our deployments are two weeks, so weather has been important in planning for my family while I am deployed hence my renewed interest in off shore weather.
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Afternoon all,
Is Bill spawning a twin?



if so, JFVWS will be the midwife....
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Bill only has to go 3deg further to get to 70West anthing further west without a move More NOrth will bring New England back into play.....Not seen that move north yet Unless the last LOOP is the turn.....

Member Since: September 2, 2007 Posts: 178 Comments: 20439
254. jeffs713

Excellent Avatar (I haven't chosen one because I am a procrastinator.) Blame it on this Blog -- hmmm, need to add that to the Class Action Suit. I will shut up now and go back to lurking because newbies should shut up and not be trolls. Thanks to all for the really great graphics this morning...I'm learning despite the liquid refreshments on the keyboard. TGIF -- it's 5 o'clock somewhere. Take care and stay safe.
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look around 33W and 13N, i think this might be our next invest:

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Quoting AwakeInMaryland:


LMAO: Warning to other newbies: Do not drink coffee, coke, or alcoholic beverages over your keyboard while reading this blog.


give this a try, not only is it waterproof but dishwasher safe....

http://www.sealshield.com/
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Ya'll are killin me..LOL...This blog is so entertaining...
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Quoting 21N71W:
Afternoon all,
Is Bill spawning a twin?

maybe shedding some fat
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273. 7544
Quoting cyclonekid:
What do you mean?


lookat the blob that just split from bill and going south to the est

Link
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For a Good chuckle,..read this article on the USS New Orleans by Dan Baum,,..and you'll come across my Description and Quote from here,..down in the Story..


March 13, 2007
A Boatload of Money


By Dan Baum

The federal government has spent a boatload of money on something called New Orleans. It happened without much public debate—and, when it turned out that doing a good job would cost nearly twice as much as originally planned, Congress shrugged and wrote a check.
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Quoting 21N71W:
Afternoon all,
Is Bill spawning a twin?
What do you mean?
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Quoting FirstCoastMan:
Colorado State University is calling for above normal activity for the Atlantic over the next 15 days


Looks like it . . .

Link
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jognorth
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Quoting jeffs713:

Very true. Especially when someone is on a roll (like Press is today).

And I can speak from earlier experience (earlier this season, in June, I think) that Margaritas do NOT feel good when someone makes you laugh and the margarita comes out of your nose.
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Afternoon all,
Is Bill spawning a twin?
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lined up for miles to come.......
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Good Day! Bill is now going Northward, so Bermuda should only get outer bands. I do see several waves coming of the African coast that should be monitored, imo.
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Quoting bowldwelller:
patrap:

LPD18 was the USS New Orleans. World Trade Center steel was used in LPD21, USS New York. The company I used to work for installed the decks and fire supression and detection systems in all the LPD series boats.


I know..I was here for the USS New Orleans Commissioning in 2007,..and was even Quoted that Day in the New Yorker.
Some Boot reporter here musta wrote that one up..also I corrected his construction Cost,..He had it as 1.2 Million ..I sent them a Lil correction.

I figured someone might notice,..and you sure did. Thanx
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Quoting hydrus:
Good Morning TampaSpin-The disturbance I was watching yesterday looks more interesting today.This is the weather system that hunker down said did not exist.


Yep i know! It has a chance at an Invest within 48hrs
Member Since: September 2, 2007 Posts: 178 Comments: 20439
260. JLPR
looking better than yesterday



I kept talking about this low but not many people cared =P
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Quoting P451:


I don't know if that's Ana anymore I think she's long gone. As to what's there I don't see anything but a highly sheared wave.



j/k I know..just trying to be funny, back on topic
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253. i think this captures your sentiment...

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Cool article in our local paper this week on the 1943 storm that hit Galveston Bay. Basically no one knew it was coming due to blackouts on the coast. U-boats offshore, etc. Cat. 2 storm. Caught everyone by surprise.
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"I can't help but marvel at the size of that thing."

...it I had a nickel for every time I've heard that...
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Quoting TampaSpin:


If you like that one.....Try some of this i have...
Good Morning TampaSpin-The disturbance I was watching yesterday looks more interesting today.This is the weather system that hunker down said did not exist.
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Quoting AwakeInMaryland:


LMAO: Warning to other newbies: Do not drink coffee, coke, or alcoholic beverages over your keyboard while reading this blog.

Very true. Especially when someone is on a roll (like Press is today).

And I can speak from earlier experience (earlier this season, in June, I think) that Margaritas do NOT feel good when someone makes you laugh and the margaritas comes out of your nose.
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I can't help but marvel at the size of that thing.

As I've mentioned before, I'm a newbie and this is the first big storm I've really followed in detail, and it's just so bizarre to me that this invisible, nebulous trough is going to save the NE USA.

I look at the satellite photos of Bill and I'm like "AAAAAH! OH NO! IT'S COMING THIS WAY OH NOES". And of course, it isn't; it's going to swerve tidily away from the coast. I've only been living by the coast for a few years now, and it's so weird that this sort of thing was going on under my nose and I never paid attention to it before.

I will keep a close watch on this blog for the rest of the season. Thank you for all your great info, everyone.
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patrap:

LPD18 was the USS New Orleans. World Trade Center steel was used in LPD21, USS New York. The company I used to work for installed the decks and fire supression and detection systems in all the LPD series boats.
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I been lurking for a long time , finally created an account. Gotta admit , this board is quite hilarious.
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Quoting jeffs713:

Looks kinda elongated.


Elongated, but seems like a circulation nonetheless, with our AOI at 30 W.
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Quoting Browardjon:


Lol, spilled coke on mine last week. im feeling a lawsuit coming on.


Excellent -- Class Action Suit! Count me in!
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bit off topic.

does anyone have here a link to the first official recorded hurricane?
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Quoting presslord:
JFVWS: "I'm so depressed I'm suicidal...Bill turned right...so there won't be massive property damage and loss of life!!!"


Take some Valium. If you can try to wait, I'm very sure within the next 10yrs your depression will end. PLease try to hold on till then!.....LOL
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243. 7544
wave 32 w 92l soon

look how this blob just split off from bill going south hmmm could this also develope
Link
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Quoting AllStar17:
Circulation?

Looks kinda elongated.
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Quoting AwakeInMaryland:


LMAO: Warning to other newbies: Do not drink coffee, coke, or alcoholic beverages over your keyboard while reading this blog.


Lol, spilled coke on mine last week. im feeling a lawsuit coming on.
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That eye is starting to look a little less ragged:

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 21 AUG 2009 Time : 151500 UTC
Lat : 27:48:32 N Lon : 66:03:31 W


CI# /Pressure/ Vmax
5.6 / 956.5mb/104.6kt


Final T# Adj T# Raw T#
(3hr avg)
5.6 5.9 5.9

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Quoting midgulfmom:
Good Morning. AllStar17 your graphics are great! Will just be lurking for a bit. Thanks.


Thanks!
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232. never get out of the boat......



LOL
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Good Morning. AllStar17 your graphics are great! Will just be lurking for a bit. Thanks.
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Quoting presslord:
JFVWS: "How do y'all like my cute fishy shower curtain?"


LMAO: Warning to other newbies: Do not drink coffee, coke, or alcoholic beverages over your keyboard while reading this blog.
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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.