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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Still Positive.

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.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
MOST OF THE LONG RANGE GUIDANCE AS WELL AS THE GLOBAL ENSEMBLES
AND GFS ENSEMBLES ARE IN FAIRLY GOOD AGREEMENT DIGGING A BROAD LONG
WAVE TROUGH INTO NEW ENGLAND BY THURSDAY THEN SHIFTING IT EAST AND
PERHAPS CLOSING OFF NEAR THE DAVIS STRAIT...BETWEEN GREENLAND AND
CANADA...WITH A BLOCKING RIDGE DEVELOPING EAST OF GREENLAND BY
FRIDAY. IF BLOCKING OCCURS THEN THE UPPER LEVEL FLOW WILL LIKELY
BECOME MORE AMPLIFIED LATER IN THE PERIOD ACROSS THE NORTHERN
CONTIGUOUS 48 STATES.

THERE ARE SIGNS MORE CANADIAN SHORT WAVE ENERGY WILL FORM A BROAD
UPPER TROUGH ACROSS THE GREAT LAKES BY THIS WEEKEND...ALLOWING FOR
HEIGHTS TO TEMPORARILY RISE ALONG THE EASTERN SEABOARD. HOWEVER
THERE IS SOME UNCERTAINTY REGARDING THE AMPLITUDE AND POSITIONING OF
THE UPPER LEVEL TROUGH AT THIS TIME.

10pm thinking nws taunton mass
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Quoting VAbeachhurricanes:


any chnace i can see it from here?
are you in Virginia Beach ? If so, I hope you have a really good telescope :)
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Quoting AussieStorm:
Good Afternoon all.
What's new?
two new invests! lol
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Good Afternoon all.
What's new?
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Quoting hunkerdown:

you can read about all the models here:

http://www.nhc.noaa.gov/modelsummary.shtml
then i would say HWRF, SHIPS, NOGAPS
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Quoting hunkerdown:
If all goes as planned:

With the countdown moving backward as planned, the seven astronauts who will fly Discovery to the International Space Station have begun the ride from their quarters at NASA’s Kennedy Space Center to Launch Pad 39A. A team of technicians will help them strap into their seats and get ready for launch at 1:36 a.m. EDT.


any chnace i can see it from here?
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Quoting kmanislander:
I like the REBAR model. Use lots in your walls to ensure adequate resistance to hurricane force winds.
I hear its good with lightning too if you have it mounted on your roof...
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1289. geepy86
Quoting StormW:
1271. geepy86 10:13 PM EDT on August 24, 2009
what time is the shuttle suppose to go?


1:36 a.m.

Thank you
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STORMW

You are appreciated too!!!! :)
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Actually, 92L doesn't remind me of pre-Noel as much as pre-Hanna in a sense. Similar ULL situation and location.
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Quoting extreme236:


That model is crap.
how bout the UKMET?
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Quoting canesrule1:
no how about the UKMET instead of the LBAR?

you can read about all the models here:

http://www.nhc.noaa.gov/modelsummary.shtml
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1283. KEEPEROFTHEGATE (Mod)
Quoting Chicklit:

Hi Keeper.

That looks about where LBAR has an L as of 8 p.m.
hello chicklit ya we are pretty close
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Quoting canesrule1:
im currently using the LBAR model.


That model is crap.
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I like the REBAR model. Use lots in your walls to ensure adequate resistance to hurricane force winds.
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1280. surfmom
Quoting kmanislander:

There will likely be at least one and if so CAT 5 on the cards


well, you caught my eye with this Kman.

& you know I won't forget -- LOL
after last year I pay mind to your sensibilities
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Quoting Stormchaser2007:


Well the LBAR was initialized with the correct position so its better than the HWRF.
no how about the UKMET instead of the LBAR?
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Quoting HIEXPRESS:
1229. hunkerdown 10:02 PM
Quoting litestar:
need to know? at midnight will north brevard Co Fla be clear of clouds,rain,lighting... PLEASE answer>>>> melbourne radar clutter..cant see any thing...help Star

for the shuttle launch ?

I'm betting on it. Heading out now in the boat to watch.

Awww...lucky you. I was just in Melbourne on business this evening. An associate said he was taking someone to Canaveral to watch the launch (scheduled for 1:38 a.m.).
They're always spectacular at night!
Hope visability is good.
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Quoting geepy86:
what time is the shuttle suppose to go?
If all goes as planned:

With the countdown moving backward as planned, the seven astronauts who will fly Discovery to the International Space Station have begun the ride from their quarters at NASA’s Kennedy Space Center to Launch Pad 39A. A team of technicians will help them strap into their seats and get ready for launch at 1:36 a.m. EDT.
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Quoting canesrule1:
well other than the CLIP model i am using the LBAR model.


"LBAR does not perform well whenever there is significant vertical wind shear"
Link
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Quoting canesrule1:
well other than the CLIP model i am using the LBAR model.
I hope you are pulling our legs, if not you need to do some homework on the models. you are picking the losers:

Limited Area Sine Transform Barotropic (LBAR) Model

LBAR is a simple two-dimensional dynamical track prediction model. It solves the shallow-water wave equations initialized with vertically averaged (850-200 hPa) winds and heights from the GFS global model. An idealized symmetric vortex and a constant wind vector (equal to the initial storm motion vector) are added to the GFS global model analysis to represent the TC circulation. The model equations are solved using a spectral sine transform technique over an area near the TC. The lateral boundary conditions are obtained from the GFS forecast. LBAR includes no horizontal gradients in temperature (and as a consequence, no vertical wind shear), making the LBAR a relatively poor performer beyond 1-2 days or outside of the deep tropics.
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Quoting hunkerdown:
I would suggest a quick change...it will be hard for someone to take your opinions seriously if you base them on the Clipper
im currently using the LBAR model.
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Quoting AllStar17:


? What one?
u spelled Hispaniola it is spelled Hispañiola, not a big problem.
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1271. geepy86
what time is the shuttle suppose to go?
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Quoting canesrule1:
well other than the CLIP model i am using the LBAR model.


Well the LBAR was initialized with the correct position so its better than the HWRF.
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Quoting canesrule1:
i know, for right now that is what im using, i will probably change my mind.
I would suggest a quick change...it will be hard for someone to take your opinions seriously if you base them on the Clipper
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Quoting hunkerdown:
because it is a statistical model based on climatology, it is not a forecast model
well other than the CLIP model i am using the LBAR model.
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1229. hunkerdown 10:02 PM
Quoting litestar:
need to know? at midnight will north brevard Co Fla be clear of clouds,rain,lighting... PLEASE answer>>>> melbourne radar clutter..cant see any thing...help Star

for the shuttle launch ?

I'm betting on it. Heading out now in the boat to watch.
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Everything that I have oberved being said on the blog and from other sources, it sounds like we will probably see Fred, Grace, and Henry ?
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Quoting canesrule1:
UKMET and ECMWF links please, thank you.


HERE you go.
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Quoting Stormchaser2007:


Its a climatological model.
you beat me to the response :)
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Mostly a lurker here, but while we are at it, I'd like to thank StormW as well for his professionalism and expertise he brings to this blog. Thanks again Storm!
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Quoting dcoaster:


I sure hope that wasn't put on TV with that horrid spelling error...


? What one?
Member Since: June 29, 2009 Posts: 13 Comments: 5313
Quoting KEEPEROFTHEGATE:


xx/xx/92L
MARK
18.9N/60.1W

Hi Keeper.

That looks about where LBAR has an L as of 8 p.m.
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Quoting Stormchaser2007:


Its a climatological model.
i know, for right now that is what im using, i will probably change my mind.
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Quoting Drakoen:




Can't get the picture(s), any other way they can be shown?
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Quoting canesrule1:
why do u say that, huh?
because it is a statistical model based on climatology, it is not a forecast model
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1256. KEEPEROFTHEGATE (Mod)


a little sea breeze going on with some small clusters of convection still firing moving wnw from e se if ya get a chance to clear it will be brief
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1255. Drakoen
Quoting canesrule1:
UKMET and ECMWF links please, thank you.


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Quoting AllStar17:


I sure hope that wasn't put on TV with that horrid spelling error...
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Quoting canesrule1:
why do u say that, huh?


Its a climatological model.
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The HWRF is way too far to the north as well
Member Since: June 29, 2009 Posts: 13 Comments: 5313
Quoting Drakoen:


The GFS is too far north. At this time, I agree with the ECMWF and UKMET solution.
UKMET and ECMWF links please, thank you.
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1250. geepy86
bin in and out. did jfv/ws get banned again?
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Quoting StormW:


And you are appreciated!


Awwwww, thanks STORMW :) SO ARE YOU!!!!
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Quoting Drakoen:


The GFS is too far north. At this time, I agree with the ECMWF and UKMET solution.


OK.
Member Since: June 29, 2009 Posts: 13 Comments: 5313

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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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