Bill is gone; Invest 92 pops up

By: Dr. Jeff Masters , 2:08 PM GMT on August 24, 2009

Share this Blog
3
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 248 - 198

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33Blog Index

from previous blog...
Quoting StormW:


Thanks Oz!

Have a safe journey back.


Thanks Storm...been interesting, delightful, intense, restful, and safe...so far!
Member Since: Posts: Comments:
Quoting TheCaneWhisperer:


I've been watching all AM at work to see if Katrina's eyewall would take shape of either a triangle, square, pentagon, or hexagon. In the last few hours, I've noticed the eyewall had a triangle shape. The current IR image doesn't show it.
This is known as mesovortices, and very strong hurricanes have been known to show these eyewalls. A well documented Hurricane Isabel in Sept 2003 had satellite imagery of a well formed "starfish pattern" of the eye.
It appears Katrina's eye isn't so interesting at the moment, but considering she just keeps getting stronger by the hour, maybe she'll give us an interesing eye formation later on.

Source


I was aware of the situation with Isabel, but wasn't she a LOT more powerful than Vamco was during that shot? I guess the mesovortices can create all types of eye shapes...
Member Since: Posts: Comments:
Quoting btwntx08:

i dont see any spin there


just paranoia than, just ignore..thanks for clarifying!!
Member Since: Posts: Comments:
Quoting Floodman:


No worries...I was just trying to make sure that the forecasting weaknesses at this time scale and with a storm of that low strength were clear...

Your wife calls you a troll, huh? That's sort opf a term of endearment, you reckon? LOL


Not likely! She learned that word from this blog and now says it in 3 languages. Now back to the weather. What is the little dot to which everyone is referring. Any current data which would inidicate as to when they expect formation, if any?
Member Since: July 17, 2009 Posts: 71 Comments: 26475
Quoting Floodman:


Okay, ignore the WUmail I just sent you...LOL


Yeah, I got a phone call right about that time....that's all. I'll have one for you later! :)
Member Since: Posts: Comments:
gonna take about 3 days storm for 92l to get it together already approaching first 24 got 48 more to go
Member Since: July 15, 2006 Posts: 173 Comments: 54352
well done p451.

Member Since: Posts: Comments:
Quoting pearlandaggie:


i didn't realize an eye that resembles a pentagon is indicative of a deadly storm!


I've been watching all AM at work to see if Katrina's eyewall would take shape of either a triangle, square, pentagon, or hexagon. In the last few hours, I've noticed the eyewall had a triangle shape. The current IR image doesn't show it.
This is known as mesovortices, and very strong hurricanes have been known to show these eyewalls. A well documented Hurricane Isabel in Sept 2003 had satellite imagery of a well formed "starfish pattern" of the eye.
It appears Katrina's eye isn't so interesting at the moment, but considering she just keeps getting stronger by the hour, maybe she'll give us an interesing eye formation later on.

Source
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
Hey Floodman :) How are ya?


Not too bad, all things considered...and for you? The sun still shining on you?
Member Since: Posts: Comments:
210. P451

Just been lurking but had to chime in, that was hilarious!
Member Since: Posts: Comments:
NASA's STS-128 Launch Blog

Join us here as we count down the final hours before space shuttle Discovery and the STS-128 crew lift off from NASA's Kennedy Space Center in Florida on this mission to the International Space Station. Launch is scheduled for 1:36 a.m. EDT on Tuesday.

"From our blog console at Kennedy's Launch Control Center, we'll take you inside the countdown as launch time approaches. Our live coverage of the STS-128 countdown and launch begins Monday, Aug. 24 at 8:30 p.m. EDT."
Member Since: Posts: Comments:
235. IKE
Eastern trough on the 12Z GFS @ 144 hours...

Member Since: Posts: Comments:
Quoting pearlandaggie:


I resemble that remark! LOL

BTW, you didn't have to rephrase your comment as mine was directed toward the misunderstanding about Pearland, Texas, not "the Carolina". But, it seems that remark could work for both situations! LOL


Okay, ignore the WUmail I just sent you...LOL
Member Since: Posts: Comments:
231. Relix
Quoting Floodman:


That red dot is actually an indication of a higher, colder cloudtop...not a possible COC


Ding! Ding! Ding! Thank you =)
Member Since: August 3, 2006 Posts: 0 Comments: 2725
Quoting Floodman:


Nope, just commenting on the fact that you're apparently from Pearland and you're an Aggie (both of which are jokes BTW...I know lots of smart folks from Pearland and a lot of smart folks who graduated from Aggie schools...)

On the other hand, I am having to explain myself...LOL

Just joking, pearland!


I resemble that remark! LOL

BTW, you didn't have to rephrase your comment as mine was directed toward the misunderstanding about Pearland, Texas, not "the Carolina". But, it seems that remark could work for both situations! LOL
Member Since: Posts: Comments:
Quoting P451:
Ah, what the hell...I had a few minutes to kill.



That's awsome, you forgot hot air coming from ws mouth.
Member Since: Posts: Comments:
Quoting P451:
Ah, what the hell...I had a few minutes to kill.


and hence the flush model has been exposed
Member Since: July 15, 2006 Posts: 173 Comments: 54352
you know what makes that photo even more funny?....the fact that JFV will LOVE it!!!!!!!

;)
Member Since: Posts: Comments:
Quoting P451:
Ah, what the hell...I had a few minutes to kill.



LOL...OMG that challenges #67 for POD (Post of the Day).

Member Since: Posts: Comments:
any body notice the a small spin in center of mexico below the BOC..heading to the gulf..maybe i'm seeing things now..sorry if wrong. just curious that's all.
Member Since: Posts: Comments:
Howdy, StSimon!
Member Since: Posts: Comments:
223. IKE
Quoting P451:
Ah, what the hell...I had a few minutes to kill.



LOL!
Member Since: Posts: Comments:
Quoting P451:
Ah, what the hell...I had a few minutes to kill.



LOL!
Member Since: Posts: Comments:
Quoting Relix:




Guess that red dot could be the future center?


That red dot is actually an indication of a higher, colder cloudtop...not a possible COC
Member Since: Posts: Comments:
Quoting pearlandaggie:
aren't the Carolinas right next to the Dakotas? LOL


...just stirrin' the pot :)


Stir the pot a littlemore with this

The Carolinas is a term used in the United States to refer collectively to the states of North and South Carolina. The Carolinas were known as the Province of Carolina during America's colonial period, from 1663–1710. Prior to that, the land was considered part of the Colony and Dominion of Virginia, from 1609–63.
The province, named "Carolina" to honor King Charles I of England, was divided into South Carolina and North Carolina in 1729, although the actual date is the subject of debate.[1]
Member Since: July 17, 2009 Posts: 71 Comments: 26475
Quoting P451:
Ah, what the hell...I had a few minutes to kill.



MUAHAHAHAHAHAHA!

Now that's funny, I don't care who you are
Member Since: Posts: Comments:
Quoting P451:
Ah, what the hell...I had a few minutes to kill.



lmao!!!
Member Since: Posts: Comments:
Quoting P451:
Ah, what the hell...I had a few minutes to kill.



LMAO!
Member Since: Posts: Comments:
Quoting pearlandaggie:


i didn't realize an eye that resembles a pentagon is indicative of a deadly storm!



Aren't we particular this morning. The pentagon shape comes from mesovortices in the eyewall, typically found in intense cyclones.

Eyewall mesovortices

Eyewall mesovortices are small scale rotational features found in the eyewalls of intense tropical cyclones. They are similar, in principle, to small "suction vortices" often observed in multiple-vortex tornadoes. In these vortices, wind speed can be up to 10% higher than in the rest of the eyewall. Eyewall mesovortices are most common during periods of intensification in tropical cyclones.

Eyewall mesovortices often exhibit unusual behavior in tropical cyclones. They usually rotate around the low pressure center, but sometimes they remain stationary. Eyewall mesovortices have even been documented to cross the eye of a storm. These phenomena have been documented observationally,[15] experimentally,[16] and theoretically.[17]

Eyewall mesovortices are a significant factor in the formation of tornadoes after tropical cyclone landfall. Mesovortices can spawn rotation in individual thunderstorms (a mesocyclone), which leads to tornadic activity. At landfall, friction is generated between the circulation of the tropical cyclone and land. This can allow the mesovortices to descend to the surface, causing large outbreaks of tornadoes.
Member Since: Posts: Comments:
Quoting Grothar:


Hey there, Floodman, I am not defending myself here, I just asked what Allstar's opinion was on the previously observed thinking in the track. I hope you did not infer otherwise. It is bad enough my wife refers to me as a troll. I would not want to be conceived as such here. By the way I enjoy your blogs. If you read my blogs; I ask more questions than I answer and I try to word them in a manner which is not speculative, since my English is not always that good.


No worries...I was just trying to make sure that the forecasting weaknesses at this time scale and with a storm of that low strength were clear...

Your wife calls you a troll, huh? That's sort opf a term of endearment, you reckon? LOL
Member Since: Posts: Comments:
92L/XX/XX
MARK
16.6N/56.1W
Member Since: July 15, 2006 Posts: 173 Comments: 54352
Quoting IKE:
12Z GFS.....doesn't do much with 92L.


Not at all... definitely a lot of rain.. but that's about it.
Member Since: Posts: Comments:
208. Relix
Quoting JLPR:
wow 92L and its looking impressive
I wasnt expecting it would look so good by now =S




Guess that red dot could be the future center?
Member Since: August 3, 2006 Posts: 0 Comments: 2725
Quoting Floodman:


Point well taken, press, and I apologize...it's a bad habit of those of us in the rest of the country to make statements that take in both states, north and south and call them the "Carolinas"...kind of like people calling New Orleans "Nyu Orleenz"...
Or calling North America and South America ( The Americas).
Member Since: Posts: Comments:
guys what is 92L current location
Member Since: Posts: Comments:
CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

1327 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 1200 UTC



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

090824 1200 090825 0000 090825 1200 090826 0000



LAT LON LAT LON LAT LON LAT LON

BAMS 16.5N 56.0W 19.0N 60.0W 21.8N 63.8W 24.7N 66.4W

BAMD 16.5N 56.0W 18.4N 58.7W 20.3N 61.2W 22.1N 63.3W

BAMM 16.5N 56.0W 18.4N 59.3W 20.4N 62.3W 22.3N 64.5W

LBAR 16.5N 56.0W 18.3N 59.2W 20.2N 62.1W 21.8N 64.7W

SHIP 20KTS 24KTS 30KTS 36KTS

DSHP 20KTS 24KTS 30KTS 36KTS



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

090826 1200 090827 1200 090828 1200 090829 1200



LAT LON LAT LON LAT LON LAT LON

BAMS 27.2N 68.9W 31.4N 71.0W 33.6N 70.0W 34.2N 68.5W

BAMD 23.6N 64.9W 25.2N 67.5W 25.7N 69.5W 25.8N 71.6W

BAMM 23.9N 66.4W 26.5N 69.4W 27.8N 70.7W 28.8N 72.0W

LBAR 23.4N 66.9W 25.7N 69.8W 26.9N 71.0W 28.6N 71.4W

SHIP 43KTS 52KTS 61KTS 72KTS

DSHP 43KTS 52KTS 61KTS 72KTS



...INITIAL CONDITIONS...

LATCUR = 16.5N LONCUR = 56.0W DIRCUR = 290DEG SPDCUR = 20KT

LATM12 = 15.2N LONM12 = 52.0W DIRM12 = 289DEG SPDM12 = 20KT

LATM24 = 14.0N LONM24 = 48.0W

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: 173 Comments: 54352
At what level in the clouds does an eyewall begin to form (High or Low)?
Member Since: Posts: Comments:
203. JLPR
wow 92L and its looking impressive
I wasnt expecting it would look so good by now =S
Member Since: September 4, 2007 Posts: 36 Comments: 5223
Quoting SavannahStorm:
I will be buying up coastal property on the new "Gulf of the Carolinas"


They'd just divide that up too.
Member Since: Posts: Comments:
Quoting pearlandaggie:
190. what? now I'M responsible for general ignorance of geography? LOL

there ya go...i modified the post for clarity! LOL


Nope, just commenting on the fact that you're apparently from Pearland and you're an Aggie (both of which are jokes BTW...I know lots of smart folks from Pearland and a lot of smart folks who graduated from Aggie schools...)

On the other hand, I am having to explain myself...LOL

Just joking, pearland!
Member Since: Posts: Comments:
TO: Canewhisperer

Thank you for the answer. It makes sense now.
Member Since: July 17, 2009 Posts: 71 Comments: 26475
Quoting TheCaneWhisperer:


That was fast. Vamco had the deadly pentagon shaped eye this morning.


i didn't realize an eye that resembles a pentagon is indicative of a deadly storm!
Member Since: Posts: Comments:

Viewing: 248 - 198

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33Blog Index

Top of Page

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.

Local Weather

Mostly Cloudy
58 °F
Mostly Cloudy