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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1048. centex
Where is that wave which Doc mentioned for later in the week?
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My only comment about 93l is that if it had been going NW instead of W, we would have a lot of very interested people in here...

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According to NHC, 93L is now broad area of LP. That's the next step. 2AM or 8AM could post orange circle. :(
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1044. KEEPEROFTHEGATE (Mod)
250

WHXX01 KWBC 250044

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

0044 UTC TUE AUG 25 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) 20090825 0000 UTC



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

090825 0000 090825 1200 090826 0000 090826 1200



LAT LON LAT LON LAT LON LAT LON

BAMS 17.8N 59.9W 20.2N 63.6W 22.7N 66.2W 25.0N 68.6W

BAMD 17.8N 59.9W 19.8N 62.2W 21.9N 64.3W 23.8N 66.1W

BAMM 17.8N 59.9W 19.5N 62.8W 21.3N 65.2W 22.9N 67.1W

LBAR 17.8N 59.9W 19.6N 62.9W 21.4N 65.4W 23.0N 67.6W

SHIP 20KTS 24KTS 29KTS 36KTS

DSHP 20KTS 24KTS 29KTS 36KTS



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

090827 0000 090828 0000 090829 0000 090830 0000



LAT LON LAT LON LAT LON LAT LON

BAMS 27.2N 70.4W 30.9N 72.3W 34.4N 71.8W 38.5N 66.8W

BAMD 25.3N 67.9W 27.6N 70.5W 30.1N 71.3W 34.2N 69.0W

BAMM 24.4N 68.9W 26.7N 71.7W 29.1N 72.6W 32.1N 71.5W

LBAR 24.4N 69.3W 26.2N 71.4W 27.8N 72.7W 29.8N 73.5W

SHIP 44KTS 56KTS 66KTS 72KTS

DSHP 44KTS 56KTS 66KTS 72KTS



...INITIAL CONDITIONS...

LATCUR = 17.8N LONCUR = 59.9W DIRCUR = 290DEG SPDCUR = 20KT

LATM12 = 16.5N LONM12 = 56.0W DIRM12 = 288DEG SPDM12 = 20KT

LATM24 = 15.2N LONM24 = 52.0W

WNDCUR = 20KT RMAXWD = 50NM WNDM12 = 20KT

CENPRS = 1012MB OUTPRS = 1013MB OUTRAD = 120NM SDEPTH = M

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



$$

NNNN
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Quoting TampaSpin:
JUst update the site to include the latest on 92L and 93L. WE need to really watch 92L as North Carolina could really be under the spot light.


Thanks for the new update Tim.

I almost didn't recognize you with the new avatar. lol
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Quoting StormW:
Evening!


Evenin' Storm.
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1040. JLPR
92L is a open wave that looks good xD
once 92L gets a LLC then we can discuss where it is going until then lets just watch it
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting StormW:


They musta been on my blog earlier. LOL!


If they weren't, they should've been! Always good to see you Senior Chief!
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Quoting DestinJeff:


I like!
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1037. centex
Quoting DestinJeff:
Well I don't think they just draw a line, I think it's a program which just extrapolates the current movement, so a very simple model.
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Quoting Tazmanian:
this in


24/2345 UTC 19.4N 59.4W TOO WEAK 92L -- Atlantic
24/2345 UTC 11.2N 81.9W TOO WEAK 93L -- Atlantic


Dvorak numbers are kinda useless for 92L right now since it has no center.
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1034. VARob
Evening StormW
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this in


24/2345 UTC 19.4N 59.4W TOO WEAK 92L -- Atlantic
24/2345 UTC 11.2N 81.9W TOO WEAK 93L -- Atlantic
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1029. centex
Why have the models for 92L not been updated to 8PM?
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1028. VARob
Quoting sebastianflorida:
The only sure prediction right now is that this blog will be very busy starting tommorow, a lot of westcasters, floridacasters, and wish casters, and some trolls.


You forgot Fishcasters...sayin!
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1027. JLPR
92L doesnt have a LLC yet



and it has been there for 24hrs
its taking its time apparently =P
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Hopefully we on the east coast will have no worries with 92. Everytime I come to this site and read the blogs the storms stay well away from NC. I am hoping my streak stays intact and nobody has to deal with anything.


When I was younger and didn't own a house I thought they were cool. Hurrican Fran came up the mouth of the cape fear and we lost power for two weeks. Trees down everywhere and about 15k worth of damage to my folks house. I no longer think they are cool.
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1025. KEEPEROFTHEGATE (Mod)


xx/xx/92L
MARK
18.3N/56.4W
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NASA Launch Blog is Active

NASA TV

"On Schedule" for 1:36:05 AM EST Launch
Member Since: October 13, 2005 Posts: 4 Comments: 2156
Looks like it is organizing, imo:

92L has a much better chance to develop then 93L. More water, more favorable conditions in the next 48 hours, and warmer, deeper water along forecast track. Shear is beginning to slacken over the eastern extent of the heavy thunderstorm activity already showing signs of getting organized with the northern extent of the shower activity.
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NHC thinks that it will have a better chance as time goes by..

SHOWERS AND THUNDERSTORMS REMAIN DISORGANIZED IN ASSOCIATION WITH A
TROPICAL WAVE INTERACTING WITH AN UPPER-LEVEL LOW ABOUT 300 MILES
EAST-NORTHEAST OF THE LEEWARD ISLAND. UPPER-LEVEL WINDS MAY BECOME
MORE FAVORABLE
FOR SLOW DEVELOPMENT OF THIS SYSTEM OVER THE NEXT
COUPLE OF DAYS AS IT MOVES TOWARD THE WEST-NORTHWEST AT AROUND 25
MPH. THERE IS A MEDIUM CHANCE...30 TO 50 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.
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1020. bwat
Quoting AstroHurricane001:

Yeah...both models pass the storm over Cape Hatteras too.


Im from the NC coast, but really thinking this will be no more than a tropical rainstorm. One can only hope.
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One reason NHC circled / declared 93L is because it's far enough away from Central America to get to TS status before crossing the ithmus. Doesn't seem hugely likely that will happen, but still.....
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93L has virtually no chance to develop...its going to be in the EPAC in about 36-48 hours, and there it has a good chance to develop.
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1017. KEEPEROFTHEGATE (Mod)
taz the shear is to slacken off some over 92l by tomorrow late afternoon as for area in carb 93l thats heading to epac
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Quoting MelbourneTom:


I agree, the models are seeing someting to spin up for 92L but I just do not see it happining in this shear. Path of movement is probably good but nothing building soon.


Again, shear is going to decrease as the ULL moves out of the picture.
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Opps that should be KOG. my other half is talking as i and typing
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Quoting Tazmanian:
92L is RIP its under 30kts of wind shear going to 40kt soon and it stays like that all the way up the E cost

Link



now for 93L this is the storm we need too watch it uder 5 to 10kt of wind shear and it vary low this could went it spin up fast


Uh no. 92L is going to be in a more favorable environment. Your using a current shear map.
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Quoting presslord:
Don't forget the Carolinacasters...

Yeah...both models pass the storm over Cape Hatteras too.
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Quoting Tazmanian:
92L is RIP its under 30kts of wind shear going to 40kt soon and it stays like that all the way up the E cost

Link



now for 93L this is the storm we need too watch it uder 5 to 10kt of wind shear and it vary low this could went it spin up fast


I agree, the models are seeing someting to spin up for 92L but I just do not see it happining in this shear. Path of movement is probably good but nothing building soon.
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KOP will be watching and learning from your knowledge. It helps when there are people on here have the insight you and a few others on here have. It makes all the b/s a little easier to deal with. appreciate your input and opinions
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Quoting tornadodude:
ok... are my messages showing?


I like your handle name.
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Don't forget the Carolinacasters...
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12z CMC goes crazy with 92L and passes it directly over New York, while NOGAPS passes it east of the city. Link
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Quoting Vortex95:


Did she go to Carolina University?


I dunno where he went...just delighted he's gone...tho I recall 2 years ago when his sister left, by the end of the first week I was missin' her...
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92L is RIP its under 30kts of wind shear going to 40kt soon and it stays like that all the way up the E cost

Link



now for 93L this is the storm we need too watch it uder 5 to 10kt of wind shear and it vary low this could went it spin up fast
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Quoting BahaHurican:
Just another reminder. Storms passing through Hebert's box #1 are highly likely to impact locations such as St. Kitts, Antigua, Guadalupe, the upper Netherlands Antilles, and the Virgin Islands.

Storms passing through Hebert's box #2 will often impact the Caymans and in all likelihood Cuba.

[indistinct "Charlie Brown adult" voice in background]

What? This is supposed to be about Florida? What are you talking about? The obvious impacts are right there! There's nothing about Florida on this map.

[indistinct "Charlie Brown adult" voice in background]

Oh. Didn't know Hebert was a Floridacaster.

[ahem] And are also likely to hit Florida.
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The only sure prediction right now is that this blog will be very busy starting tommorow, a lot of westcasters, floridacasters, and wish casters, and some trolls.
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1003. KEEPEROFTHEGATE (Mod)
Quoting texascoastres:
We need a good rain maker in the GOM. nothing major!
let see if i can spin some thing up for ya
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Quoting TampaSpin:


LOL wait till you get the Bill tho.....LOL



Trust me...it's worth every penny...
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Quoting presslord:
Nobody can ruin my day!!!! My youngest went off to college this weekend...The nest is empty!!!!!!!!!!! All is right with God's world!!!!!!!!!!!!!!!!!


LOL wait till you get the Bill tho.....LOL
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why?
Member Since: June 28, 2006 Posts: 25 Comments: 8357
We need a good rain maker in the GOM. nothing major!
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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.