Bonnie weakens to a tropical depression
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
Reader Comments
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Thanks. Was wondering why it didn't see Bonnie and yet it looks like they had the end of the track and strength correct. Cmc didnt do bad either. Except of course over doing the strength. The gfs never seems to see anything this season.
http://www.nco.ncep.noaa.gov/pmb/nwpara/analysis/carib/gfs/18/index_ten_l_loop.shtml
Interesting week ahead?
We defiantly needs to watch this wave over the next couple of days. I'm too lazy to check but are any other models predicting development? We Also need to watch the area around Bermuda as Levi mentioned earlier.
"Well I believe you may get your headlines, Mr. Ismay"
+1 KOTG , I still think climatology, upper atmospheric conditions and SST rules the roost in terms of predicting and forcasting cyclones or developing ones, yet there is plenty that is unknown. It's Nature's secret!
Most are just trying get under your skin by going against this season's thinking. I still expect an above average season but not 20 storms or more.
Lol. Nevermind my statement about the GFS.
Good post!
I fell into that trap myself yesterday, responding to idiots that were clearly just trying to rile me up.
I probably even ended up on some ignore lists myself.
Call me Bruce, really. :)
True dat!
And just Poof.
Disappear..
Just Like Dat.
"Snap's finger's"..
Snap!
The beer is too cold,
The daquiris too fruitiful
GFS naturally does better with CV systems, we'll have to watch this as well. VERY long range however.
You don't need a global ACE that high to necessarily correspond to a hyperactive season in the Atlantic. The global ACE this year will remain generally low yes, because the Pacific basins will be below normal and the Indian looked about normal in its first season peak with 3 storms. The Atlantic contributes only a small amount to the global ACE, largely because of the west Pacific, which you mentioned, which is the ACE powerhouse of the world.
We're going into a very cold plunge right now globally with this La Nina and cold PDO lining up. 2005 had high ACE because the Pacific hurricane seasons were both near-normal along with the above-normal Atlantic because we were in a warm PDO with lots of heat to share. 1998 didn't go as cold as fast during the summer, and waited until later for the La Nina to really take over that winter. Look at where the ACE graph is by 1999....way down there.
The fact is that the overall global pattern is going to be different over the next couple decades than at any time during the graph you posted. A cold PDO like this can generate a really low global ACE because of the lack of heat, but what heat is available is all bundled up in the Atlantic, where tropical activity usually sees bursts. That is the place to go for global tropical activity this year. Atlantic is the focus-point.
It saw Bonnie's ULL pretty well if you ask me. It also saw the next one in line developing over Hispaniola.
:]
Oh boy. Big Sigh.
Black hole or the dreaded "Blog Hole"?
Parallel GFS not showing development.
Operational GFS is showing development, however it takes it over the northern Antilles as a sharply inverted tropical wave.
Operation GFS 144 hours.
NOGAPS showing weak development but it is very south.
NOGAPS 144 hours
LMAO!! +1 best post of the evening, need a little humor to lighten up the spirits along with the Coors light of course!
A hint at things to come.
I meant it didn't show a tropical storm. At least I don't think it did. But yes I was following pre-Bonnie for a while now. And the next one also. CMC been iffy about it but has been showing both for a while too. :)
Huge amount of heat and not a lot of shear over the Atlantic Basin through the heart of the season...something always gives in that situation.
Watch the tracks. We've seen the two main ones for the season. IMHO
Yes
So they might not know that you have them on ignore?? Unless you say Poof of course..
I was going to post that XD
And I was going to say that is as real as the patience and harmony that characterizes this blog. XD
Issued at 07:33 JST 24 Jul 2010
Occurred at (JST) Latitude
(degree) Longitude
(degree) Depth Magnitude Region Name
07:08 JST 24 Jul 2010 6.7N 123.5E 590km 7.1 Philippines and its Vicinity
The sad part is, that's the day after my birthday. :(
2010 July 23 22:08:11 UTC
Versión en Español
* Details
* Summary
* Maps
* Scientific & Technical
* Tsunami
Earthquake Details
* This event has been reviewed by a seismologist.
Magnitude 7.3
Date-Time
* Friday, July 23, 2010 at 22:08:11 UTC
* Saturday, July 24, 2010 at 06:08:11 AM at epicenter
* Time of Earthquake in other Time Zones
Location 6.708°N, 123.479°E
Depth 604.5 km (375.6 miles)
Region MORO GULF, MINDANAO, PHILIPPINES
Distances 100 km (65 miles) SW of Cotabato, Mindanao, Philippines
120 km (75 miles) S of Pagadian, Mindanao, Philippines
155 km (95 miles) E of Zamboanga, Mindanao, Philippines
915 km (570 miles) SSE of MANILA, Philippines
Location Uncertainty horizontal +/- 4.5 km (2.8 miles); depth +/- 6.7 km (4.2 miles)
Parameters NST= 93, Nph= 93, Dmin=235.6 km, Rmss=0.83 sec, Gp= 22°,
M-type=teleseismic moment magnitude (Mw), Version=7
Source
* USGS NEIC (WDCS-D)
Event ID us2010zbbz
What does this tell us? The heat pumped into the tropics by the El Nino this past winter is not just going to go away. With the Pacific shut down the heat has to be released somewhere else. It has been all bundled up in the Atlantic which is why we've been seeing the record SSTs and very low surface pressures, the lowest found on the globe right now relative to normal. That heat has to go somewhere to balance the earth's energy budget. The La Nina gives the atmosphere a mechanism with which to deal with that excess heat, and that mechanism is tropical cyclones.
Rita wasn't a Cape Verde but the GFS had the TX/LA coast landfall nailed 5 days out. Obviously not many people believed it, hence the TEXODUS. :) But no I'm not advocating basing your preps on any model 5 days out.
Wowiee, now that's a blast from the past request.
While not heavy rain, Bonnie has brought steady drips to my area. It's been steady since about 11:30 am here.
WEPA42 PHEB 232301
TIBPAC
TSUNAMI BULLETIN NUMBER 001
PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS
ISSUED AT 2301Z 23 JUL 2010
THIS BULLETIN APPLIES TO AREAS WITHIN AND BORDERING THE PACIFIC
OCEAN AND ADJACENT SEAS...EXCEPT ALASKA...BRITISH COLUMBIA...
WASHINGTON...OREGON AND CALIFORNIA.
... TSUNAMI INFORMATION BULLETIN ...
THIS BULLETIN IS FOR INFORMATION ONLY.
THIS BULLETIN IS ISSUED AS ADVICE TO GOVERNMENT AGENCIES. ONLY
NATIONAL AND LOCAL GOVERNMENT AGENCIES HAVE THE AUTHORITY TO MAKE
DECISIONS REGARDING THE OFFICIAL STATE OF ALERT IN THEIR AREA AND
ANY ACTIONS TO BE TAKEN IN RESPONSE.
AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS
ORIGIN TIME - 2251Z 23 JUL 2010
COORDINATES - 6.5 NORTH 123.6 EAST
DEPTH - 581 KM
LOCATION - MINDANAO PHILIPPINES
MAGNITUDE - 7.3
EVALUATION
A DESTRUCTIVE TSUNAMI WAS NOT GENERATED BASED ON EARTHQUAKE AND
HISTORICAL TSUNAMI DATA.
THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT UNLESS
ADDITIONAL INFORMATION BECOMES AVAILABLE.
THE JAPAN METEOROLOGICAL AGENCY MAY ALSO ISSUE TSUNAMI MESSAGES
FOR THIS EVENT TO COUNTRIES IN THE NORTHWEST PACIFIC AND SOUTH
CHINA SEA REGION. IN CASE OF CONFLICTING INFORMATION... THE
MORE CONSERVATIVE INFORMATION SHOULD BE USED FOR SAFETY.
THE WEST COAST/ALASKA TSUNAMI WARNING CENTER WILL ISSUE PRODUCTS
FOR ALASKA...BRITISH COLUMBIA...WASHINGTON...OREGON...CALIFORNIA.
...SP...
well it seems based on the pattern at the end of the model that the system would go on a more nw motion after last image. This will change frequently if this system even develops at all. This far out in 2007 it had what would become hurricane dean making landfall on the east coast and it ended up making landfall in i think guatemala or belize
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