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 FloridaTigers:
17 years ago today, Andrew came by.
17 years ago today I learned that cat-5-hurricanes form and strike whether there is an El-Nino or not.I also learned that a good size chunk of the Everglades and the southern tip of Florida won,t look the same as it did for a long-long time.
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Quoting IKE:


Pretty good consensus....


If you discount NOGAPS and CMC, ya. All of the GFS based models are in pretty good consensus.
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545. IKE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC
255 PM EDT MON AUG 24 2009

LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 255 PM SUN...A TROPICAL WAVE MOVES INTO THE BAHAMAS
WEDNESDAY THEN DEVELOPS INTO A LOW AND LIFTS NORTH NORTHEAST
THURSDAY AND FRIDAY...PASSING JUST EAST OF CAPE HATTERAS ON
SATURDAY.
THE 12Z GFS HAS THIS AS A RATHER SIGNIFICANT FEATURE.
FOR ITS AFFECTS ON OUR WEATHER I WILL FOLLOW THE HPC SOLUTION
WHICH IS MUCH LESS AMPLIFIED. ON SUNDAY THE LOW WILL BE OFF TO THE
NORTHEAST WITH A COLD FRONT APPROACHING FROM THE WEST. FOR NOW
WILL CARRY SLIGHT CHANCE POPS THURSDAY AND FRIDAY...THEN CHANCE
SATURDAY AND SUNDAY.
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I see we have 92L. Model forecasting this thing to stay off the coast of possible threaten the middle atlantic states.
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CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

1907 UTC MON AUG 24 2009



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



DISTURBANCE INVEST (AL922009) 20090824 1800 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

090824 1800 090825 0600 090825 1800 090826 0600



LAT LON LAT LON LAT LON LAT LON

BAMS 17.0N 58.0W 18.9N 61.7W 21.2N 64.9W 23.1N 67.2W

BAMD 17.0N 58.0W 19.0N 60.4W 21.0N 62.6W 22.9N 64.4W

BAMM 17.0N 58.0W 18.8N 61.1W 20.8N 63.7W 22.4N 65.6W

LBAR 17.0N 58.0W 18.6N 61.0W 20.4N 63.8W 22.0N 66.4W

SHIP 20KTS 23KTS 30KTS 36KTS

DSHP 20KTS 23KTS 30KTS 36KTS



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

090826 1800 090827 1800 090828 1800 090829 1800



LAT LON LAT LON LAT LON LAT LON

BAMS 25.0N 69.4W 28.5N 72.6W 31.5N 73.9W 35.4N 71.8W

BAMD 24.4N 65.9W 26.5N 68.5W 28.1N 70.2W 30.9N 71.0W

BAMM 23.9N 67.4W 26.3N 70.4W 28.6N 72.1W 32.1N 71.6W

LBAR 23.4N 68.5W 25.7N 71.5W 27.7N 72.9W 30.2N 72.6W

SHIP 44KTS 56KTS 67KTS 75KTS

DSHP 44KTS 56KTS 67KTS 75KTS



...INITIAL CONDITIONS...

LATCUR = 17.0N LONCUR = 58.0W DIRCUR = 290DEG SPDCUR = 20KT

LATM12 = 15.9N LONM12 = 54.0W DIRM12 = 289DEG SPDM12 = 20KT

LATM24 = 14.6N LONM24 = 50.0W

WNDCUR = 20KT RMAXWD = 0NM WNDM12 = 20KT

CENPRS = 1010MB OUTPRS = 1012MB OUTRAD = 200NM SDEPTH = M

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN
Member Since: July 15, 2006 Posts: 174 Comments: 54372
542. IKE
Quoting nrtiwlnvragn:


Pretty good consensus....
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Quoting IKE:


I don't see much at 17N and 58W.

I take that back.... I zoomed in at those coordinates and caught WSJFV trying to drag 92L west with a rope.


I think I went cross-eyed but I see it.
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Quoting HIEXPRESS:


Heads I win, Tails you lose.


haha love it, well im sitting in my dorm listening to the Purdue band play, they are practicing.
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I'm out for a while......going on a 50mile bike ride....see you all later.....hope i don't get wet......LOL
Member Since: September 2, 2007 Posts: 178 Comments: 20443
tropical wave exiting african coast maybe another significant hurricane expected to track west towards the islands of the lesser antilles
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12E in the EPAC. In fact, TAFB gave it a T3.0/45 knots estimate, so its probably close to, if not at TS strength.

EP, 12, 2009082418, , BEST, 0, 162N, 1167W, 30, 1005
Member Since: August 2, 2007 Posts: 19 Comments: 19234
We now have storm #12 in the East Pacific

08/24/2009 07:26PM 54,422 aep122009.dat.gz
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Quoting StSimonsIslandGAGuy:
All models seem to take whatever 92L turns into towards NC or out to sea.


Heads I win, Tails you lose.
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92L tracks moving left right......it makes no difference what the models say until something starts to really develop.....models are pure guess until development occurs.
Member Since: September 2, 2007 Posts: 178 Comments: 20443
Quoting TheCaneWhisperer:



Should 92L develop, it's going to be a challenging forecast down the line.


The Trof that influenced Bill's track has closed off again, and, I can see how the current models seem to favor movement towards the Carolinas but a lot will depend on how far West the A-B high is able to build back again by the time 92L starts approaching the Bahamas in a few days.........It's all about timing if the sheer does not finish it off.
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Quoting TexasHurricane:
Hello all...

Just checking in for the day. I saw that our AOI is now at an orange....(which I am sure yall know that already)

This area in the Carribean looks interesting as well. Anyone think this will be an AOI (yellow,orange or red circle) soon?

Tell you what TexasHurricane,If that blob in the S.W. Caribbean were to stay where it is until tomorrow,we would have more than a red circle down there.
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529. GBlet
My dad spent 5 years hauling flat glass from Texas to Florida After Andrew.
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Quoting TheCaneWhisperer:



Should 92L develop, it's going to be a challenging forecast down the line.


It will be... this is one of those situation where you see erratic motion (e.g. loops, etc...) at one point or the other.
Member Since: August 14, 2008 Posts: 4 Comments: 4977
17 years ago today, Andrew came by.
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526. IKE
Quoting nrtiwlnvragn:
SHIPS (Using BAMM for track) has shear drop after 18 hours over 92L.


Interesting... SHIPS takes it is to 72.3W and that's when it's at 30.2N or east of Jacksonville,FL. It takes it NNE after that. Trough may kick this on out...time will tell.
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do you think 92L will track up to the NE Contus?
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Quoting AllStar17:


All you do is click on "Image" above the post box. Then right click on the image you want to post and click view image in new window, copy the URL, and paste the URL into the "URL box" (the first one that appears) when you click on image. Then click OK twice (dont bother to worry about the width or length of your image), and it should appear in the posting box, then click post.


Thanks! do I get to use the phrase "My bad" which I just learned, on this one?
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Quoting WxLogic:


We'll see how the rest of the runs tonight and tomorrow do... the Cut-Off low strength and location should be able to dictate how far W 92L will go.



Should 92L develop, it's going to be a challenging forecast down the line.
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Quoting AllStar17:
Latest Best Track Posistion for 92L


lol!!! I guess you'll need to pay now...
Member Since: August 14, 2008 Posts: 4 Comments: 4977
SHIPS (Using BAMM for track) has shear drop after 18 hours over 92L.
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Quoting futuremet:
12Z ECMWF 96hrs.

The track has shifted slightly left again...



We'll see how the rest of the runs tonight and tomorrow do... the Cut-Off low strength and location should be able to dictate how far W 92L will go.
Member Since: August 14, 2008 Posts: 4 Comments: 4977
Latest Best Track Posistion for 92L
Member Since: June 29, 2009 Posts: 13 Comments: 5313
Quoting kmanislander:


Different times I guess. Sounded like a case of soap and water with the toothbrush !.


No toothbrush though...yeah I did that when she was young...16 on up...I think they take "how to cuss like a Marine" as a prerequisite for english comp2
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515. Relix
Now 17N looks more dangerous for the northern antilles. =P
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Quoting futuremet:
12Z ECMWF 120hrs.

The track has shifted slightly left again...




Based on current intensity, position and heading it seems as if the NoGaps has the most reasonable solution at this time heading WNW.


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Interesting cluster in the SW Caribbean.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
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??


I can see her point of view. It is kind of like Revenge of the Nerds around here.
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92L looks pretty impresive on visible. Most models are taking it to South Carolina.
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510. IKE
Quoting TheCaneWhisperer:


Brought it down to 17N I see. 18.2 seemed rather high.


I don't see much at 17N and 58W.

I take that back.... I zoomed in at those coordinates and caught WSJFV trying to drag 92L west with a rope.
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good afternoon all! i just got back from my first day of classes at Purdue, and now i have some down time before i go to work
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Quoting Floodman:


LOL...I would have thought so too, kman...my 19 year old texts me like occasionally though very much in the same vein...


Different times I guess. Sounded like a case of soap and water with the toothbrush !.
Member Since: August 19, 2006 Posts: 0 Comments: 15842
Quoting Floodman:


LOL...I would have thought so too, kman...my 19 year old texts me like occasionally though very much in the same vein...


just call the hurricane hunters to go pick her up and drop her in the middle of 92L
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Hello all...

Just checking in for the day. I saw that our AOI is now at an orange....(which I am sure yall know that already)

This area in the Carribean looks interesting as well. Anyone think this will be an AOI (yellow,orange or red circle) soon?

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Afternoon Folks....Nice and Quiet in the tropics and the only place in the MDR with significant sheer is right around 92L and in the Eastern Caribbean....Very low off Africa, in the Gulf, and in the Southern-Western Caribbean but nothing there expect for the cluster of showers apparently headed towards the E-pac as noted by Ike earlier. This is a good thing actually and morning/evening temps in North Florida been feeling like "fall" the past few days........No one knows how the season ends up but with 16 days to go to the historical peak, it is still too early to suggest that things will remain quiet in the long-term (next two weeks). My biggest question is "where" as opposed to when.
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12Z ECMWF 96hrs.

The track has shifted slightly left again...



model page
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Quoting TheCaneWhisperer:


You need to send the photo through an image hosting site. The SFWMD does not allow direct image placement.


Just remove the "s" from https and it works.
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Quoting kmanislander:


Translation ??. She thought she was texting someone other than her father.


LOL...I would have thought so too, kman...my 19 year old texts me like occasionally though very much in the same vein...
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Quoting nrtiwlnvragn:
AL 92 2009082418 BEST 0 170N 580W 20 1010 DB


Brought it down to 17N I see. 18.2 seemed rather high.
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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!!!


All you do is click on "Image" above the post box. Then right click on the image you want to post and click view image in new window, copy the URL, and paste the URL into the "URL box" (the first one that appears) when you click on image. Then click OK twice (dont bother to worry about the width or length of your image), and it should appear in the posting box, then click post.
Member Since: June 29, 2009 Posts: 13 Comments: 5313
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: 15842

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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.