Dr. Jeff Masters' WunderBlog

Bill is gone; Invest 92 pops up

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

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

Hurricane Bill Waves Day 2 # 9 (RIWXPhoto)

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!

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1453. F5Tornado 4:47 AM GMT on August 25, 2009
HI all, I will be here to talk in about two hours. I am currently busy, but I would like to talk about the atlantic invest at around 1a.m. MST. Thanks, I had better not hog the comments.

1454. JLPR 4:53 AM GMT on August 25, 2009
well since not much is going on here im going to bed too lets see how 92L looks tomorrow =P Member Since: September 4, 2007 Posts: 36 Comments: 5223

1455. KEEPEROFTHEGATE (Mod) 5:02 AM GMT on August 25, 2009
iam out as well later all Member Since: July 15, 2006 Posts: 143 Comments: 40528

1456. TampaSpin 5:02 AM GMT on August 25, 2009
Launch trend is improving Member Since: September 2, 2007 Posts: 175 Comments: 19747

1457. JRRP 5:02 AM GMT on August 25, 2009
see you later... Link Member Since: August 16, 2007 Posts: 0 Comments: 4309

1458. bingcrosby 5:03 AM GMT on August 25, 2009
Weather seems to be improving slightly near the shuttle. Just a matter of timing. Member Since: August 14, 2008 Posts: 0 Comments: 137

1459. bluenosedave 5:13 AM GMT on August 25, 2009
Quoting bingcrosby: Weather seems to be improving slightly near the shuttle. Just a matter of timing. Whoooeeee. This one is gonna be close. Very dynamic weather situation. I'm crossing my fingers. Member Since: August 26, 2006 Posts: 0 Comments: 323

1460. litestar 5:16 AM GMT on August 25, 2009
well looks like a scrub .. 24 hour turn around..an here we go again.....

1461. bingcrosby 5:19 AM GMT on August 25, 2009
Weather should be clearing up 7 minutes prior to launch. Sounds as though they can't tell whether they lost some helium. Possible instrumentation problem? Member Since: August 14, 2008 Posts: 0 Comments: 137

1462. LightningCharmer 5:22 AM GMT on August 25, 2009
Green on ceilings and visabilities. Lightning from phase-two to phase-one. Member Since: September 1, 2007 Posts: 0 Comments: 1111

1463. bingcrosby 5:27 AM GMT on August 25, 2009
Scrubbed. Thanks Bill. Member Since: August 14, 2008 Posts: 0 Comments: 137

1464. LightningCharmer 5:28 AM GMT on August 25, 2009
Red on flight-precip, cumulus, anvil, etc. Scrub for today. Member Since: September 1, 2007 Posts: 0 Comments: 1111

1465. whitewabit (Mod) 5:28 AM GMT on August 25, 2009
Just scrubed the launch... Member Since: August 17, 2005 Posts: 322 Comments: 24090

1466. bluenosedave 5:28 AM GMT on August 25, 2009
Launch scrubbed due to weather. Trying again tomorrow. Member Since: August 26, 2006 Posts: 0 Comments: 323

1467. LightningCharmer 5:31 AM GMT on August 25, 2009
01:10:22 EDT rescheduled launch time tomorrow. Member Since: September 1, 2007 Posts: 0 Comments: 1111

1468. boyzNme 5:31 AM GMT on August 25, 2009
Shuttle launch just scrubbed due to weather. They are going to try again tomorrow. I don't understand all of their jargon, but they are going for "24, 0105". I guess they mean 24 hours from now. NasaTV will start broadcasting tomorrow nights launch at 830pm and they just confirmed that launch will be rescheduled to 1:10AM Wed. I don't know who gave the link for NasaTv, but thanks! Member Since: August 29, 2008 Posts: 5 Comments: 58

1469. snotly 5:33 AM GMT on August 25, 2009
silly earthlings. Member Since: August 27, 2005 Posts: 0 Comments: 668

1470. chucky7777 5:35 AM GMT on August 25, 2009
dang Shuttle launch scrubbed due to weather.i was looking forward to seeing it go up from my house,although it is only a red dot as i live way away from the Cape. Member Since: October 19, 2005 Posts: 0 Comments: 174

1471. LightningCharmer 5:37 AM GMT on August 25, 2009
Quoting boyzNme: Shuttle launch just scrubbed due to weather. They are going to try again tomorrow. I don't understand all of their jargon, but they are going for "24, 0105". I guess they mean 24 hours from now. NasaTV will start broadcasting tomorrow nights launch at 830pm and they just confirmed that launch will be rescheduled to 1:10AM Wed. I don't know who gave the link for NasaTv, but thanks! You're welcome. Someone else may have provided a link as well. Blogger, Codaflow, works in the NASA pressroom at the Cape, and was providing good information. Member Since: September 1, 2007 Posts: 0 Comments: 1111

1472. 7544 5:52 AM GMT on August 25, 2009
new cmc goes a little further west with 92l is the front due to stall out over cent fla Member Since: May 6, 2007 Posts: 0 Comments: 5925

1473. boyzNme 5:59 AM GMT on August 25, 2009
Quoting LightningCharmer: You're welcome. I have never listened to NasaTV and I look forward to another attempt tomorrow night. Here's hoping it is nice & clear so we can see it from SFL!! Many thanks for the link and to Codaflow for the insight. Member Since: August 29, 2008 Posts: 5 Comments: 58

1474. msphar 6:42 AM GMT on August 25, 2009
So is there any thing of interest weatherwise out to the East of the islands ? Looks to my inexpert eyes that things will be quiet for the next several days out in the MDR. This season will be hardpressed to meet the forecast of the season predictions made by the pros unless things pick up a bit. Member Since: August 20, 2006 Posts: 0 Comments: 258

1475. KoritheMan 6:45 AM GMT on August 25, 2009
Quoting msphar: So is there any thing of interest weatherwise out to the East of the islands ? Looks to my inexpert eyes that things will be quiet for the next several days out in the MDR. This season will be hardpressed to meet the forecast of the season predictions made by the pros unless things pick up a bit. Only threat is 92L. Member Since: March 7, 2007 Posts: 408 Comments: 15433

1476. msphar 6:48 AM GMT on August 25, 2009
92L is already beyond my area of concern. Hence my focus on the MDR. I hope 92L doesn't grow but that is not where my concerns lie. Member Since: August 20, 2006 Posts: 0 Comments: 258

1477. KoritheMan 7:30 AM GMT on August 25, 2009
Quoting msphar: 92L is already beyond my area of concern. Hence my focus on the MDR. I hope 92L doesn't grow but that is not where my concerns lie. In that case, the GFS continues to hint at the possibility of tropical cyclogenesis with a tropical wave in the EATL a week or so from now. Member Since: March 7, 2007 Posts: 408 Comments: 15433

1478. F5Tornado 8:24 AM GMT on August 25, 2009
This blog site seems too quiet, Ill start a conversation and Ill be available untill 3 a.m. Mountain Time. Ill be back with the tropical invest, and what everyone is refering to as a NASA mission. BRB

1479. HIEXPRESS 8:27 AM GMT on August 25, 2009
:( Member Since: October 13, 2005 Posts: 4 Comments: 2153

1480. F5Tornado 8:36 AM GMT on August 25, 2009
Tomorrow at eleven 1:10 EDT or did it already happen? ONe of NASA's sites states that the launch will be tomorrow, yet anther states that it will be today. Can I get help on this?

1481. F5Tornado 8:40 AM GMT on August 25, 2009
No wait, scratch that, NASA sayed that the launch was scrubbed today as a result of thunderstorm activity. Another try is scheduled tomorrow same time.

1482. F5Tornado 8:43 AM GMT on August 25, 2009
Great picture though.

1483. IpswichWeatherCenter 9:11 AM GMT on August 25, 2009
Great Bill is headed straight for me crys Member Since: April 27, 2008 Posts: 29 Comments: 2097

1484. HadesGodWyvern 9:20 AM GMT on August 25, 2009
National Hurricane Center Tropical Cyclone Advisory #3 TROPICAL CYCLONE IGNACIO (EP122009) 9:00 AM UTC August 25 2009 ============================= At 6:00 AM UTC, Tropical Storm Ignacio (1004 hPa) located at 18.1N 118.5W or 565 west-southwest of Southern Tip of Baja California Peninsula has sustained winds of 35 knots with gusts of 45 knots. The cyclone is reported as moving west-northwest at 10 knots. Gale-force Winds ================ 45 NM from the center Forecast and Intensity ====================== 12 HRS: - 18.7N 119.9W - 40 knots (Tropical Storm) 24 HRS: - 19.7N 122.0W - 45 knots (Tropical Storm) 48 HRS: - 23.0N 125.0W - 40 knots (Tropical Storm) 72 HRS: - 26.5N 128.5W - 30 knots (Tropical Depression) Member Since: May 24, 2006 Posts: 43 Comments: 36686

1485. HadesGodWyvern 9:20 AM GMT on August 25, 2009
Central Pacific Hurricane Center Tropical Cyclone Advisory #12 TROPICAL CYCLONE HILDA (EP112009) 9:00 AM UTC August 25 2009 ============================= At 6:00 AM UTC, Tropical Storm Hilda (1001 hPa) located at 14.8N 147.9W or 510 southeast of Hilo Hawaii has sustained winds of 50 knots with a gust of 60 knots. The cyclone is reported as moving west at 8 knots. Gale/Storm-force Winds ================== 65 NM from the center Forecast and Intensity ====================== 12 HRS: - 14.7N 149.1W - 55 knots (Tropical Storm) 24 HRS: - 14.6N 150.6W - 55 knots (Tropical Storm) 48 HRS: - 14.2N 153.4W - 60 knots (Tropical Storm) 72 HRS: - 14.3N 156.2W - 65 knots (SSHS-1 Cyclone) Member Since: May 24, 2006 Posts: 43 Comments: 36686

1486. HadesGodWyvern 9:20 AM GMT on August 25, 2009
India Meteorological Department 8:30 AM IST August 25 2009 =============================== A low pressure area has formed over northwest Bay of Bengal and adjoining coastal Orissa. Member Since: May 24, 2006 Posts: 43 Comments: 36686

1487. IpswichWeatherCenter 9:21 AM GMT on August 25, 2009
Quoting HadesGodWyvern: Central Pacific Hurricane Center Tropical Cyclone Advisory #12 TROPICAL CYCLONE HILDA (EP112009) 9:00 AM UTC August 25 2009 ============================= At 6:00 AM UTC, Tropical Storm Hilda (1001 hPa) located at 14.8N 147.9W or 510 southeast of Hilo Hawaii has sustained winds of 50 knots with a gust of 60 knots. The cyclone is reported as moving west at 8 knots. Gale/Storm-force Winds ================== 65 NM from the center Forecast and Intensity ====================== 12 HRS: - 14.7N 149.1W - 55 knots (Tropical Storm) 24 HRS: - 14.6N 150.6W - 55 knots (Tropical Storm) 48 HRS: - 14.2N 153.4W - 60 knots (Tropical Storm) 72 HRS: - 14.3N 156.2W - 65 knots (SSHS-1 Cyclone) ooh a Hurricane in Cpac. Member Since: April 27, 2008 Posts: 29 Comments: 2097

1488. HadesGodWyvern 9:22 AM GMT on August 25, 2009
right overland U.K. in the coming hours Member Since: May 24, 2006 Posts: 43 Comments: 36686

1489. IpswichWeatherCenter 9:27 AM GMT on August 25, 2009
Quoting HadesGodWyvern: right overland U.K. in the coming hours I can already feel it. Instead of a rather humid day, their a chill in the air. Winds are about 10 mph sustained, with cloud and a few small showers. Member Since: April 27, 2008 Posts: 29 Comments: 2097

1490. InTheCone 10:14 AM GMT on August 25, 2009
Morning All - ECMWF shows 92l going up the east coast and now has a CATL low at the end of its run, getting VERY interesting out there.... ECMWF Also shows 93l becoming a storm in the Pacific! Member Since: September 1, 2007 Posts: 0 Comments: 1979

1491. WPBHurricane05 10:21 AM GMT on August 25, 2009
Whoa...I miss 1 day from this blog and I miss a lot. Space shuttle, 92L, 93L, another one in the MDR next week. Member Since: July 31, 2006 Posts: 56 Comments: 7928

1494. zebralove 10:38 AM GMT on August 25, 2009
thanks so much for the links, I am one that is always asking for links now I have months worth of trying to figure it all out now. Watch my brain grow! Quoting TampaSpin: Anyone that needs nearly anything as for as Models can find it on the Home page of WeatherUnderground. You can also try StormJunkie.com as he has a tab with all kinds of links. I also have a tab on my site that has nearly everything you need as Links to find nearly everything.... StormJunkie.com under the tab quick links TampaSpinsWeather.webs.com under the tab weather links Hope this helps some as many ask about where to find things. Member Since: July 27, 2009 Posts: 3 Comments: 94

1495. AllStar17 10:41 AM GMT on August 25, 2009
Blog very quiet right now.....I see not much change with 92L, and 93L is about to move over land. I still say Hawaii should not take their eye of Hilda yet. Even the CPHC says it is too early to say whether or not the NGFDL and the NOGAPS could be right. If they were Hawaii would be looking at a Cat. 1/2 landfalling Hurricane from Hilda (if those tracks verified) I'll be back later today. Member Since: June 29, 2009 Posts: 13 Comments: 5135

1497. extreme236 10:43 AM GMT on August 25, 2009
Just stopping in for a bit this morning. Still expecting gradual development of 92L during the next day or so. Also expecting EPAC development of 93L, and the 00Z ECMWF had a storm forming as it moves into the CATL a bit later in the period. Member Since: August 2, 2007 Posts: 19 Comments: 19234

1499. Cavin Rawlins 10:59 AM GMT on August 25, 2009
Good Morning all Tropical Invests 92L and 93L Member Since: July 24, 2005 Posts: 407 Comments: 19076

1500. WxLogic 11:01 AM GMT on August 25, 2009
Good morning... Member Since: August 14, 2008 Posts: 4 Comments: 4667

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