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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We need a good rain maker in the GOM. nothing major!
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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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Nobody can ruin my day!!!! My youngest went off to college this weekend...The nest is empty!!!!!!!!!!! All is right with God's world!!!!!!!!!!!!!!!!!
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Quoting aquak9:


nope, can't see'm.


me either
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Quoting aquak9:


nope, can't see'm.


sarcasm much lol
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Quoting BahaHurican:
Reminder: Hebert's box is not a magical forecasting item. It is a statistical tool.


You have to google "magical box" to find out about the forecasting tool.
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Quoting tornadodude:
ok... are my messages showing?


nope, can't see'm.
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Quoting cajunmoma:


I hope that is the case atmo...because the GFS has gone wild! and those last few storms, seem to have aim on the GOM. of course i am no expert, but it seems when they are that far south, they always come visit us...fingures crossed that stay far away.
I think it is safe to say that we really don,t need any storms in the gulf,especially around the Texas and LA.coasts.
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ok... are my messages showing?
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Quoting stormsurge39:
I read before that if a storm passes thru the herbet(i tried)box,that 72% of the time they have hit FL.
NO! 72 percent of the storms that hit Florida, first went through at least one of the boxes, which is very different from 72 percent of the storms that went through the box hit Florida; big difference! A lot of Florida storms never hit the boxes, however a lot have, but more importantly, hitting the boxes doesn't tell us where the storm will go. Confusing yes, but wording is extremely important here.
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Quoting TampaSpin:


He lives somewhere in the Carolina's.........LMAO

You just set off his text message alert jingle. 2 Carolinas in a row set off his house alarm.

Oops, sorry, Press.
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the eastern fifth of one of the carolinas, i believe
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Quoting largeeyes:
Presslord, where do you live again? New Bern, NC here.


He lives somewhere in the Carolina's.........LMAO
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984. bwat
Quoting BahaHurican:
Reminder: Hebert's box is not a magical forecasting item. It is a statistical tool.


Amen
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Reminder: Hebert's box is not a magical forecasting item. It is a statistical tool.
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quick question- how do i post pictures?
thanks
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"fleeing" the fifth...as opposed to "pleeing" the fifth...
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(ducks and runs as empty fifths come flying thru air)
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Quoting largeeyes:
Presslord, where do you live again? New Bern, NC here.


Charleston...Johns island...I love New Bern...

Aqua...behave...
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977. bwat
2 of them: http://en.wikipedia.org/wiki/Hebert_box
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How many Hebert Boxes are there?
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Quoting hydrus:
That is rather slippery of you agent starling.

Watch that movie a couple of times?

And, Dr. M, and I am sure a few others, made mention of a coming quiet period.

Previous post went the Japanese small engine repair blog, I guess. (Sorry if doubles)

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Quoting emeraldcoast:
Quoting presslord:

clearly...it's gonna pass through the Youknowwhat Box...

Question: what's the Youknowwhat Box and what's the significance of passing through it ?


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Presslord, where do you live again? New Bern, NC here.
Member Since: August 22, 2006 Posts: 0 Comments: 1462
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Quoting atmoaggie:

StormW and I both saw the MJO moving out of our domain and were hopeful it would be quiet. Then, it came back and with a forecast to begin a large spike about 6 days ago. Spike hasn't happened yet and might not happen at all. Obviously in a transition of sorts and GFS has no idea.
That is rather slippery of you agent starling.
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Quoting atmoaggie:

StormW and I both saw the MJO moving out of our domain and were hopeful it would be quiet. Then, it came back and with a forecast to begin a large spike about 6 days ago. Spike hasn't happened yet and might not happen at all. Obviously in a transition of sorts and GFS has no idea.


I hope that is the case atmo...because the GFS has gone wild! and those last few storms, seem to have aim on the GOM. of course i am no expert, but it seems when they are that far south, they always come visit us...fingures crossed that stay far away.
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Quoting stormsurge39:
When is the trough suppose to come down and start turning possible Danny


so wait, the trough is gonna help? not push it away?
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When is the trough suppose to come down and start turning possible Danny
Chocolate and Caramel everywhere. Makes storm sticky.

Gee, how many times do these guys have to be hit before they are willing to share some obs with us?

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966. JLPR
Quoting Relix:


Hey... I wouldn't mind it! Besides it would be a fun day. A minor storm passing at 20MPH over us. Gives us a free day and some enjoyment, and flooding problems should be minor. PERFECT!!


XD lol
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965. Relix
Quoting JLPR:


well I cant believe what im saying but a day off would be great
now I need to punish myself for that xD


Hey... I wouldn't mind it! Besides it would be a fun day. A minor storm passing at 20MPH over us. Gives us a free day and some enjoyment, and flooding problems should be minor. PERFECT!!
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evening all, whats poppin in the tropics?
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Quoting hydrus:
Someone on this blog said that the MJO was going to help suppress tropical cyclone development in September.

StormW and I both saw the MJO moving out of our domain and were hopeful it would be quiet. Then, it came back and with a forecast to begin a large spike about 6 days ago. Spike hasn't happened yet and might not happen at all. Obviously in a transition of sorts and GFS has no idea.
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Google "Hebert Box"...then just forget it...
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960. bwat
Quoting emeraldcoast:
Quoting presslord:

clearly...it's gonna pass through the Youknowwhat Box...

Question: what's the Youknowwhat Box and what's the significance of passing through it ?


heres a good site to answer your question.
http://en.wikipedia.org/wiki/Hebert_box
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LOL atmo!!!
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ABNT20 KNHC 242331
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON AUG 24 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

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.



ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BRENNAN
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Quoting emeraldcoast:
Quoting presslord:

clearly...it's gonna pass through the Youknowwhat Box...

Question: what's the Youknowwhat Box and what's the significance of passing through it ?
dont open that can of worms
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I read before that if a storm passes thru the herbet(i tried)box,that 72% of the time they have hit FL.
Quoting hydrus:
Someone on this blog said that the MJO was going to help suppress tropical cyclone development in September.


Well the forecast seems to change everyday so who knows.
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hhmm interesting!!

Link

the GFS has totally gone wild with development.
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952. JLPR
Quoting Relix:


17N would spell trouble for us at PR =)


well I cant believe what im saying but a day off would be great
now I need to punish myself for that xD
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Quoting presslord:

clearly...it's gonna pass through the Youknowwhat Box...

Question: what's the Youknowwhat Box and what's the significance of passing through it ?
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950. Relix
Quoting stormsurge39:
Relix on the Sat Animation, 92L LOOKS like its trying to get its act together around 60W and 17n


17N would spell trouble for us at PR =)
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Quoting extreme236:


Well with more MJO action here soon we could see more convection develop with it.
Someone on this blog said that the MJO was going to help suppress tropical cyclone development in September.
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Quoting extreme236:


Well with more MJO action here soon we could see more convection develop with it.

Not sure that is going to happen.
Big time whiff by GFS on that for the last 5 days. Fine by me!

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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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