Bonnie weakens to a tropical depression

By: Dr. Jeff Masters , 23. heinäkuuta 2010 klo 20:40 (GMT)

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Tropical Depression Bonnie is nearing the end of its traverse of South Florida, and passage over land has significantly disrupted the small storm. Satellite images show almost no heavy thunderstorms near Bonnie's center of circulation, and the center is now exposed to view. Radar-estimated rainfall from the Key West radar shows that Bonnie dumped very little rain on South Florida--maximum rainfall amounts from the storm were about four inches over a small region southwest of Miami. Water vapor satellite loops show that Bonnie is embedded in a large area of dry air, thanks to an upper level low to the west over the Gulf of Mexico. This low has brought an increasing amount of wind shear to Bonnie today, and shear has increased from 20 knots this morning to 25 knots this afternoon. Surface observations in South Florida currently don't show any tropical storm force winds. Bonnie's top winds today were at Fowey Rocks, which had sustained winds of 46 mph, gusting to 53 mph, at 10:45 am EDT.


Figure 1. Satellite image of Bonnie from NASA's MODIS instrument, taken at 17:10 UTC July 23, 2010. Image credit: NASA/.

Track Forecast for Bonnie
The latest set of model runs from 8am EDT (12Z) are very similar to the three previous sets of runs, and this degree of consistency gives me confidence that Bonnie will stay within the cone of uncertainty depicted on the track forecast images. The projected track will take Bonnie over the oil spill region, and the storm's strong east to southeasterly winds will begin to affect the oil slick on Saturday morning. Assuming Bonnie doesn't dissipate over the next day, the storm's winds, coupled with a likely storm surge of 2 - 4 feet, will drive oil into a substantial area of the Louisiana marshlands. However, the current NHC forecast has Bonnie making landfall in Louisiana near 9pm CDT Saturday night. According to the latest tide information, this will be near the time of low tide. This will result in much less oil entering the Louisiana marshlands than occurred during Hurricane Alex in June. That storm brought a storm surge of 2 - 4 feet and sustained winds of 20 - 30 mph that lasted for several days, including several high tide cycles. The latest oil trajectory forecasts from NOAA (Figure 2) predicts potential oil impacts along a 150-mile stretch of Louisiana coast on Sunday.


Figure 2. Oil Trajectory forecast for Sunday for the Deepwater Horizon oil spill. Image credit: NOAA.

Intensity Forecast for Bonnie
Bonnie has been disrupted by its passage over land, and it will take at least six hours for the storm to reorganize once it moves over the warm waters of the Gulf of Mexico tonight. This process will be hindered by the large upper-level low to its west. If the low remains in its present location, relative to Bonnie, it will bring high wind shear of about 20 - 30 knots to the storm. This will allow for only slow intensification, or may even destroy Bonnie. Bonnie is unlikely to intensify to more than a 50 mph tropical storm, and I give a 30% chance it will dissipate over the Gulf of Mexico before making landfall. The GFDL model predicts Bonnie could hit the Gulf Coast as a 50 mph tropical storm, but the other major models such as the HWRF, GFS, ECMWF, and NOGAPS show a much weaker storm. I don't give Bonnie any chance of becoming a hurricane. NHC is putting the odds of Bonnie being a hurricane at 2 pm Saturday at 4% (5pm advisory.)

If you are wondering about the specific probabilities of receiving tropical storm force winds at your location, I recommend the wind probability product from NHC. The latest probabilities of various locations getting tropical storm force winds, 39 mph or higher, from the 5pm EDT advisory:

Buras, LA 30%
New Orleans 28%
Mobile, AL 37%
Pensacola, FL 30%

Resources for the BP oil disaster
Map of oil spill location from the NOAA Satellite Services Division
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's interactive mapping tool to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

Next update
I'll have an update Saturday morning.

Jeff Masters

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2211. earthlydragonfly
24. heinäkuuta 2010 klo 13:08 (GMT)
NEW BLOG
Member Since: 1.07.2005 Posts: 10 Comments: 1681
2210. hunkerdown
24. heinäkuuta 2010 klo 13:08 (GMT)
Quoting IKE:


I've seen that exact statement about 1,000 times this season.


then you haven't spent enough time here, its been said easily 10,000 times this month.
Member Since: 15.08.2008 Posts: 0 Comments: 2515
2209. earthlydragonfly
24. heinäkuuta 2010 klo 13:07 (GMT)
NEW BLOG
Member Since: 1.07.2005 Posts: 10 Comments: 1681
2208. AussieStorm
24. heinäkuuta 2010 klo 13:05 (GMT)
Quoting KYDan:
She does not want to go away quietly.


typical woman... lol... jks
Member Since: 30.09.2007 Posts: 9 Comments: 15749
2207. Hardcoreweather2010
24. heinäkuuta 2010 klo 13:03 (GMT)



Member Since: 24.01.2010 Posts: 0 Comments: 529
2206. AussieStorm
24. heinäkuuta 2010 klo 13:03 (GMT)
Quoting FLdewey:
Mesoanalysis shows some serious activity down in das Goolf de Cooba.





**The image above does not reflect the views of ANY reputable agency... there is no need panic **

I wonder if that will soak up the oil? how about putting him down the oil well and see if he can plug it cause BP ain't done it yet.
Member Since: 30.09.2007 Posts: 9 Comments: 15749
2205. KEEPEROFTHEGATE (Mod)
24. heinäkuuta 2010 klo 13:03 (GMT)
Member Since: 15.07.2006 Posts: 163 Comments: 52257
2204. earthlydragonfly
24. heinäkuuta 2010 klo 13:02 (GMT)
Quoting StormW:
Nice visible of naked Bonnie

VISIBLE LOOP


Sir that was off topic and you have been reported..

LOL

Morning Senior Chief Caster!
Member Since: 1.07.2005 Posts: 10 Comments: 1681
2203. tkeith
24. heinäkuuta 2010 klo 13:01 (GMT)
Quoting StormW:
Nice visible of naked Bonnie

VISIBLE LOOP
That is a good view...
Member Since: 1.11.2004 Posts: 25 Comments: 8912
2202. WDEmobmet
24. heinäkuuta 2010 klo 13:01 (GMT)
bonnie on visible clearly shows naked swirl...last two frames
Member Since: 3.02.2010 Posts: 0 Comments: 723
2201. Orcasystems
24. heinäkuuta 2010 klo 13:01 (GMT)


AOI

AOI

AOI

AOI

Landfall Points

TS BUSTED FORECAST ALIBI
Member Since: 1.10.2007 Posts: 81 Comments: 26493
2200. earthlydragonfly
24. heinäkuuta 2010 klo 13:00 (GMT)
Quoting CybrTeddy:


That was the wave that became Bonnie..


Wow that smile was a sign after all.. Maybe it was the tropics smiling at us because it knew it was messing with us and creating all the hub-bub...
Member Since: 1.07.2005 Posts: 10 Comments: 1681
2199. KYDan
24. heinäkuuta 2010 klo 13:00 (GMT)
She does not want to go away quietly.

Member Since: 6.07.2010 Posts: 0 Comments: 100
2197. CybrTeddy
24. heinäkuuta 2010 klo 12:59 (GMT)
Quoting Twinkster:
18z


00z


06z


all show cape verde hurricane forming first week of august. This far out it is not good for track but it the consistency increases the likelihood that cyclogenesis may occur by the cape verde islands the first week of august


That is completely possible and needs to be watched.
Member Since: 8.07.2005 Posts: 259 Comments: 23012
2196. CybrTeddy
24. heinäkuuta 2010 klo 12:58 (GMT)
Quoting earthlydragonfly:
Heck I never connected it.. I just pop in and out.. It could have been but I dont know for sure.




That was the wave that became Bonnie..
Member Since: 8.07.2005 Posts: 259 Comments: 23012
2195. tkeith
24. heinäkuuta 2010 klo 12:57 (GMT)
Do y'all have basements in LA?

we call em coffer dams...
Member Since: 1.11.2004 Posts: 25 Comments: 8912
2194. earthlydragonfly
24. heinäkuuta 2010 klo 12:56 (GMT)
Quoting HurricaneSwirl:


From the looks of it it may actually go to the east of the oil spill.. which would be a best case scenario. Looks to me it may be an open wave at landfall, plus it'll push the oil away from the coast (but not that far, it's a 1013 low). Everyone wins!


The only problem I see is the fact that the work had to stop to begin with... From what the local news said it will take at least a week for them to get all the pieces back in place just to get back where they where before the evac. Everyone here knows what can happen in a week. especially since IMO tropical formations tend to follow each other... Kind of like the first one creates a wake for the other...
Member Since: 1.07.2005 Posts: 10 Comments: 1681
2192. tkeith
24. heinäkuuta 2010 klo 12:53 (GMT)
Quoting HurricaneSwirl:


From the looks of it it may actually go to the east of the oil spill.. which would be a best case scenario. Looks to me it may be an open wave at landfall, plus it'll push the oil away from the coast (but not that far, it's a 1013 low). Everyone wins!
looks that way to me too.
Member Since: 1.11.2004 Posts: 25 Comments: 8912
2191. earthlydragonfly
24. heinäkuuta 2010 klo 12:52 (GMT)
Quoting KEEPEROFTHEGATE:
get it right he's not mexican hes the big cuban



So Gulf de Cuban??
Member Since: 1.07.2005 Posts: 10 Comments: 1681
2190. HurricaneSwirl
24. heinäkuuta 2010 klo 12:52 (GMT)
Quoting Hardcoreweather2010:
It's headed for the Oil Rig! Hopefully Tony Hayward is on his yact vacationing near it :)



From the looks of it it may actually go to the east of the oil spill.. which would be a best case scenario. Looks to me it may be an open wave at landfall, plus it'll push the oil away from the coast (but not that far, it's a 1013 low). Everyone wins!
Member Since: 7.07.2008 Posts: 2 Comments: 3237
2189. tkeith
24. heinäkuuta 2010 klo 12:52 (GMT)
Quoting FLdewey:
Mesoanalysis shows some serious activity down in das Goolf de Mexican





**The image above does not reflect the views of ANY reputable agency... there is no need panic **
when are gonna they send the HH's in dewey?
Member Since: 1.11.2004 Posts: 25 Comments: 8912
2188. KEEPEROFTHEGATE (Mod)
24. heinäkuuta 2010 klo 12:50 (GMT)
Quoting FLdewey:
Mesoanalysis shows some serious activity down in das Goolf de Mexican


get it right he's not mexican hes the big cuban
Member Since: 15.07.2006 Posts: 163 Comments: 52257
2186. RedStickCasterette
24. heinäkuuta 2010 klo 12:48 (GMT)
Quoting earthlydragonfly:


Sure blame me... LOL


Haha the smiley looked so neat on the red ESL site.
Member Since: 20.07.2010 Posts: 0 Comments: 377
2185. earthlydragonfly
24. heinäkuuta 2010 klo 12:47 (GMT)
Quoting RedStickCasterette:


Im telling you that was her. I saved the progressive pix on my other laptop. If I can save the harddrive, I will show you. I thought it was so cool, so I followed her. Later she looked like a troll with a sword. Like she had a battle to attend.

Haha sounds nuts, but I have the pix, when I can get to them. But yeah think you started it...


Sure blame me... LOL
Member Since: 1.07.2005 Posts: 10 Comments: 1681
2184. earthlydragonfly
24. heinäkuuta 2010 klo 12:45 (GMT)
Quoting Hardcoreweather2010:
It's headed for the Oil Rig! Hopefully Tony Hayward is on his yact vacationing near it :)



LOL funny but he wouldnt want to get any of that dark stuff on his hull...
Member Since: 1.07.2005 Posts: 10 Comments: 1681
2183. RedStickCasterette
24. heinäkuuta 2010 klo 12:45 (GMT)
Quoting earthlydragonfly:
Heck I never connected it.. I just pop in and out.. It could have been but I dont know for sure.




Im telling you that was her. I saved the progressive pix on my other laptop. If I can save the harddrive, I will show you. I thought it was so cool, so I followed her. Later she looked like a troll with a sword. Like she had a battle to attend.

Haha sounds nuts, but I have the pix, when I can get to them. But yeah think you started it...
Member Since: 20.07.2010 Posts: 0 Comments: 377
2182. Hardcoreweather2010
24. heinäkuuta 2010 klo 12:43 (GMT)
It's headed for the Oil Rig! Hopefully Tony Hayward is on his yact vacationing near it :)

Member Since: 24.01.2010 Posts: 0 Comments: 529
2181. earthlydragonfly
24. heinäkuuta 2010 klo 12:42 (GMT)
Quoting RedStickCasterette:


I had been watching the Walmart smiley since you or someone posted it one night. Saved the pix on my laptop that is toast. Anyway, watched her all the way. Halfway, she looked like a troll, it was freaky.
Heck I never connected it.. I just pop in and out.. It could have been but I dont know for sure.


Member Since: 1.07.2005 Posts: 10 Comments: 1681
2179. Twinkster
24. heinäkuuta 2010 klo 12:42 (GMT)
18z


00z


06z


all show cape verde hurricane forming first week of august. This far out it is not good for track but it the consistency increases the likelihood that cyclogenesis may occur by the cape verde islands the first week of august
Member Since: 7.06.2007 Posts: 4 Comments: 937
2178. GainesvilleGator
24. heinäkuuta 2010 klo 12:42 (GMT)
ULLs in the left half of the Atlantic basin and dry air between the Lessor Antilles & Africa. I guess this is not that all unusual for July. Keep in mind that June & July are pretty dead months for tropical development.

I do expect a busy Aug, Sep, & Oct and 15 or more named storms this season. I think 20 named storms at this point would be a big reach.
Member Since: 11.09.2005 Posts: 4 Comments: 744
2177. RedStickCasterette
24. heinäkuuta 2010 klo 12:41 (GMT)
Quoting breald:


Because the peak of the season does not start until Aug thru Sept. Things will ramp up.


Oh I believe that 100%. If it doesn't them so be it.
Member Since: 20.07.2010 Posts: 0 Comments: 377
2176. WeatherNerdPR
24. heinäkuuta 2010 klo 12:40 (GMT)
Are models predicting any development?
Member Since: 7.07.2010 Posts: 0 Comments: 5521
2175. tkeith
24. heinäkuuta 2010 klo 12:40 (GMT)
Quoting kingy:
although the storm amounted to minimal problems what about the oil splurge that will come with the waves ?

New Orleans, Louisiana (Airport)
Updated: 44 min 58 sec ago
84 °F
Overcast
Humidity: 82%
Dew Point: 78 °F
Wind: 5 mph from the NNW

Pressure: 30.04 in (Rising)
Heat Index: 95 °F

if that wind direction stays like it is, it would help

Member Since: 1.11.2004 Posts: 25 Comments: 8912
2173. RedStickCasterette
24. heinäkuuta 2010 klo 12:39 (GMT)
Quoting earthlydragonfly:


you think the walmart wave was Bonnie? or the wave behind it?


I had been watching the Walmart smiley since you or someone posted it one night. Saved the pix on my laptop that is toast. Anyway, watched her all the way. Halfway, she looked like a troll, it was freaky.
Member Since: 20.07.2010 Posts: 0 Comments: 377
2172. breald
24. heinäkuuta 2010 klo 12:38 (GMT)
Quoting RedStickCasterette:


How so you know things will ramp up?


Because the peak of the season does not start until Aug thru Sept. Things will ramp up.
Member Since: 28.05.2008 Posts: 38 Comments: 5303
2170. RedStickCasterette
24. heinäkuuta 2010 klo 12:37 (GMT)
Quoting reedzone:


np, I try to use facts and stuff to back up my statements.


I know that, as a lurker for many years, so just wanted to see if you could say why, how, etc.

You have come a long way...not that I know anything lol. I just read. Now I talk. LOL.
Member Since: 20.07.2010 Posts: 0 Comments: 377
2169. kingy
24. heinäkuuta 2010 klo 12:37 (GMT)
although the storm amounted to minimal problems what about the oil splurge that will come with the waves ?
2168. earthlydragonfly
24. heinäkuuta 2010 klo 12:37 (GMT)
Quoting RedStickCasterette:


That ULL was amazing to watch, for me. Never thought anything would take down the Walmart wave.


you think the walmart wave was Bonnie? or the wave behind it?
Member Since: 1.07.2005 Posts: 10 Comments: 1681
2167. tkeith
24. heinäkuuta 2010 klo 12:36 (GMT)
mornin dewey -_-

where's yer tie?
Member Since: 1.11.2004 Posts: 25 Comments: 8912
2165. reedzone
24. heinäkuuta 2010 klo 12:36 (GMT)
Quoting RedStickCasterette:


I believe what you are saying. I just wanted to hear it from you!


np, I try to use facts and stuff to back up my statements.
Member Since: 1.07.2008 Posts: 13 Comments: 7334
2164. RedStickCasterette
24. heinäkuuta 2010 klo 12:35 (GMT)
Quoting earthlydragonfly:
What is going on with all the ULL. I dont remember a time when there seemed to be so many in the tropics interacting with each other. Is it the time of year (before CV starts)?


Or is this a greater scale type of event happening.... Like Dr. Masters said in one of his global warming blogs. Yes the earth may be heating up and that would mean higher temps all around the world and in the oceans.... BUT this will create more sheer and (i dont remember if he said this) maybe more SAL?


OH and Good morning... (pistons are firing today sorry in advance)


That ULL was amazing to watch, for me. Never thought anything would take down the Walmart wave.
Member Since: 20.07.2010 Posts: 0 Comments: 377
2163. WxLogic
24. heinäkuuta 2010 klo 12:34 (GMT)
Good morning...
Member Since: 14.08.2008 Posts: 4 Comments: 4881
2162. WeatherNerdPR
24. heinäkuuta 2010 klo 12:33 (GMT)
Quoting DestinJeff:


Is he talking about Al?

O_o Seeing that sketch is disturbing.
Member Since: 7.07.2010 Posts: 0 Comments: 5521

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About JeffMasters

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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