Tropical Storm Bonnie Makes Her Debut

By: Dr. Jeff Masters , 4:32 AM GMT on July 23, 2010

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Hi everybody, this is Dr. Rob Carver filling in for Jeff on the late shift.

Based on information from Hurricane Hunters, the National Hurricane Center upgraded TD Three to Tropical Storm Bonnie. As of the 11PM EDT advisory, Bonnie was at 23.4N, 76.5W which is 285 miles southeast of Miami, Florida. Bonnie has maximum winds of 40 mph, a minimum central pressure of 1007 mb, and is moving to the northwest at 14 mph. Bonnie will pass over the Everglades/Florida Keys Friday and cross into the Gulf of Mexico Friday night/early Saturday morning. Tropical storm warnings are in effect for both Florida coasts south of Lake Okeechobee to Key West.


Fig. 1 IR satellite image of Tropical Storm Bonnie at 1216AM EDT.

Threats
NHC is expecting 2-4 inches of rain over south Florida due to Bonnie and 3-5 inches over the Bahamas. They are forecasting a storm surge of 1-2 feet. Tropical storm force winds are expected in the Bahamas starting Thursday night, and they are forecast to arrive in southern Florida Friday morning.

Impacts and Emergency Preparedness
As of 1130PDT EDT, the Key West NWS office is indicating that there are no evacuation orders in effect or planned for Monroe County (the Keys). Small craft are being advised to stay in port and be well secured to their docks. Two shelters will be opened, Key West High School and Stanley Switlik Elementary School in Marathon.

Most of the ships at the Deepwater Horizon oil spill site and other skimming ships have been ordered to seek safe harbor. In the statement, Adm. Allen said ships that operate the ROVs will be the last out and the first back to keep the wellhead observations going as long as possible.

Forecast/Model Assessment
The track models and ensemble models show remarkably good agreement for Bonnie's path across south Florida and towards southeast Louisiana. The current intensity forecast calls for Bonnie to maintain strong tropical storm force winds (40-50 knots) until it makes landfall in Louisiana, with a 15% chance of becoming a hurricane before then. However, the global models (GFS, Canadian GEM, NOGAPS) and the hurricane dynamical models (GFDL, Navy GFDL, and HWRF) do not intensify Bonnie at all. The statistical models (SHIPS and LGEM) support the intensity forecast.

I'm inclined to take the predictions of global and dynamical models with a large grain of salt. When I reviewed the latest model runs (18Z and 12Z), it was apparent that none of the models had a good initialization of Bonnie's structure. Bonnie has a relatively small circulation, so it's easy for the models' initialization to act like there isn't much of a storm there. Without accurate starting conditions, any model will have trouble producing an accurate forecast. NHC has a good summary of the different forecast models they use.

Next Update
Jeff will have an update sometime Friday morning.

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Quoting pfdfirefighter:
Gys what about the blow up of convection in the Bay of Campechee Spelling bites I know. People said something earlier about one of the models forecasting two storms, Just noticed the blow up and if the upper level low get west of it it may get pulled east back into th Gulf Of Mexico.
Dont kill me for the post just wanting others thoughts.


That tropical wave nearly developed into Colin and would have if it had another day over water. It is moving inland now and will continue westward into Mexico. It's a disastrous rain event for them yet again.
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Quoting nolauptowngirl:


Thank you!! I appreciate it! Not only have I caught the weather bug, but I teach Geology at a local comm. coll. and I've been showing this stuff (as I learn it myself) to my students.
Thanks again!


Glad I could help. I envy you in a way, I would love to teach. We have got to get on the ball again…science, engineering, etcetera. I find it quite disturbing that we have to give out visa’s every year to fill science and engineering jobs…enough ranting…again…if you need any help with GE let me know…especially if it will help you in the classroom.

v/r

Jon
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Westward Ho. Sorry still waiting for first band.
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144. 7544
do we see atleast 45mph from the hh ?
Member Since: May 6, 2007 Posts: 0 Comments: 6690
Anyone look at the weather stations in the Bahamas recently ? The only station reporting winds close to 30mph is one in North Bimini island (out of the East) which is the island closest to Fla probably at the northern edge of the "center". Can't find nary a west wind anywhere, so I am thinking it is probably now a TD if not close to having degenerated into an open wave based on what Levi just showed. I realize it is a small circulation, but it should show up on one of the islands.
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smiles :-)

Quoting xcool:
Goldenblack .:0
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Bonnie could already be at 60mph winds!
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139. xcool
Goldenblack .:0
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Quoting Levi32:


Yeah well it's been there a while and there is the faintest of reflections at the surface. If you remember 97L started out pretty close to this area and at one point it seemed like they were the same system but they were always separate. Bonnie is now more out in front so the distinction between the two is very evident now. It's weak but has time to drift....not an immediate threat but something to keep an eye on that is close to home.


My take on what happened is somewhat different, I was following the NHC surface analysis over days to see what was going on.

It seemed 97L started out as a tropical wave from Africa, which by the time it reached the Lesser Antilles, was getting enhanced by an ULL to its NW. Thunderstorms at the north end of the wave triggered a mid-level spin near PR on July 19. On July 20, the ULL turned southwestward, which intensified the shear. The tropical wave was seperated from its storms and mid-level spin due to the shear. The tropical wave continued uneventfully westward and away. The mid-level rotation and storm cluster left behind gained a surface trough near DR on July 21 in the NHC surface analyses (However, its possible that this surface trough was a northern fracture of the tropical wave). That surface trough & mid-level spin moved into the Bahamas on July 22, where they became Bonnie after the ULL moved westward and away.

Meanwhile, the anticyclone over/just east of 97L/Bonnie (it was usually lopped off to the east due to the shear from the ULL) triggered occasional storm flare ups on its divergent SE quadrant, like it is tonight over PR and DR. That seems to have triggered another weak mid-level spin. The differnce this time is there is no surface tropical wave (I belive Bonnie was a northern fracture of a tropical wave, this is not).
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Welcome EricSFL!
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136. xcool



flip-flopping.
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The surface COC is definitely exposed still and not under the convection IMO...take a look here and watch near 23.6N 77.2W.
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Looks like the center is going to pass just east of Andros, another track shift coming if it doesn't bounce back west.
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Quoting islandeye:
salutations all, tired of being a lurker...long-time fan of the blog, and am in the path of this one, so thought it'd be as good a time as any to say hello.


Welcome!
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Chief Met here in Mobile AL. said that conditions could become More favorable around Sat night going into Sunday in the GOM for Bonnie, but he is sticking with the official NHC forecast. This tells me the Gulf Coast is NOT in the ALL CLEAR with a 50/60mph landfall, until we see what happens. I was looking at the water vapor loop from 24 hours ago and Bonnie was almost lined up with the ULL in longitude, now there is almost a 10 degree longitude difference! How is the ULL going to influence Bonnie by the time she gets in the GOM by SAT? I dont understand the forecast with the ULL effecting Bonnie that much to the negative! This concerns me because I dont like an over commit forecast for a weak storm and then get underdelivered forecast of a Hurricane! Ok Levi you can straighten me out now! LOL
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Quoting cchsweatherman:
Hurricane Hunters have turned on SFMR instrument and recorded a 35 mph wind at 25.5 N and 79.8 W.


Well that's over land. Anyways night all.
Member Since: September 6, 2009 Posts: 2 Comments: 3710
xcool....I do not mean anything by this, I like your posts...

but doesn't the wording sometimes remind anyone of Captain Caveman? (Hanna Barbara cartoons).

Just a little late night insanity, again, nothing meant by it xcool.

Quoting xcool:


Bonnie LOOK GOOOOOD HMM
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129. xcool
7544 .JUST WAIT SHE GET GOM.
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I cant get over how tiny this storm is. Must be a record size.
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Why are they flying in at 10,000 ft? Expecting a much stronger storm?
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salutations all, tired of being a lurker...long-time fan of the blog, and am in the path of this one, so thought it'd be as good a time as any to say hello.
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Quoting Eagle101:


Goto this linkLink

Once there, you will find a link titled "Live Recon Data in Google Earth" and a link to a tutorial...when you click on the first link, assuming you have Google Earth loaded, it will automatically open for you. Please take the time to read the tutorial...it will explain everything. Let me know if you need any other help. Take care...

v/r

Jon


Thank you!! I appreciate it! Not only have I caught the weather bug, but I teach Geology at a local comm. coll. and I've been showing this stuff (as I learn it myself) to my students.
Thanks again!
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123. 7544
no sleep tonight lets hope she dosent stall
Member Since: May 6, 2007 Posts: 0 Comments: 6690
Hurricane Hunters have turned on SFMR instrument and recorded a 35 mph wind at 25.5 N and 79.8 W.
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Quoting HurricaneRoman:
lol! Now i'm more worried. If that is the case, watch Bonnie hit south florida with like 65/70 mph


Feasible. But, a 45-55MPH tropical storm is more likely.
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Quoting nolauptowngirl:


Orca - how do you get the forecast tracks on google earth? i'm not too savvy with it yet

Thanks in advance!


Goto this linkLink

Once there, you will find a link titled "Live Recon Data in Google Earth" and a link to a tutorial...when you click on the first link, assuming you have Google Earth loaded, it will automatically open for you. Please take the time to read the tutorial...it will explain everything. Let me know if you need any other help. Take care...

v/r

Jon
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117. 7544
hey xcool shes looking good tonight hmmmm something strange is going on
Member Since: May 6, 2007 Posts: 0 Comments: 6690
I'm tracking the Hurricane Hunter data tonight.
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115. xcool
nola BABYY
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Gys what about the blow up of convection in the Bay of Campechee Spelling bites I know. People said something earlier about one of the models forecasting two storms, Just noticed the blow up and if the upper level low get west of it it may get pulled east back into th Gulf Of Mexico.
Dont kill me for the post just wanting others thoughts.
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Oh, did anyone see this? 3-4-hour old ASCAT pass but Bonnie would have had to move nearly due north to be under the convective ball right now. The center isn't even that strongly closed

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112. xcool


Bonnie LOOK GOOOOOD HMM
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111. code1
Quoting atmosweather:


Hey code!!! Great to see you too! I'm trying to be more productive about getting on the blogs this season LOL!

I still think the LLC is not under the ball of convection, but the movement of the ULL is certainly trying to help Bonnie out...moving steadily W-ward.


More productive is great Atmos, Levi, ST, and others. Sure seems like old times here tonight reading back to prior blog. Old and new. What a sight this site has become! Even those of us who try or are made to leave come back. LOL Welcome to what should have been the original "Hotel California"! I'll be watching for yours and a few others updates Rich. The new tools since the first year are awesome, no? Ya'll all have a great night storm watching. I'll westcast/wishcast it away from FL. No wish for other states west of us, we just don't need it. I'm ready to share the love with the E. coast folks this year. Amen?
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lol! Now i'm more worried. If that is the case, watch Bonnie hit south florida with like 65/70 mph
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aight be back at 4am going to catch 2 hours of sleep
Member Since: July 21, 2010 Posts: 0 Comments: 1067
I gotta agree with this and several other posts. Look at the Blue Marble, zoom in one level, and animate. *It seems to be forming a tight CDO. *It's quite symmetrical. *It looks to have a closed circulation. *Several other TS in the past have blown up to hurricane strength as they pass over the Gulf Stream. IMHO the only thing going against Bonnie is its short time over the GS with its fast forward motion.
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105. 7544
whos posting the hh results i think they may up the winds on the next adv
Member Since: May 6, 2007 Posts: 0 Comments: 6690
Satellite presentation is steadily improving. Next 6 hours will tell the tale intensity wise for this storm IMO
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103. xcool
<<< HAVE BAD BAD FEEL :(
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Quoting cchsweatherman:
Bonnie's satellite appearance looks exactly like a hurricane symbol. lol


Funny how they can do that even when the center isn't under it lol.
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Recon is nearing Bonnie.
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Quoting atmosweather:


Yeah some of the dynamical models have consistently been pessimistic about Bonnie's strength through the GOM...the NAM and Euro in particular have continued to show a very weak low or even an open wave as Bonnie traverses the GOM.


Hope they're right. We'll be looking at the next one soon enough.
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btwntx08 .LOL YEP
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This storm truly is microscopic. look at the rainbow
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Quoting NCHurricane2009:


I did see that faint mid-level spin, that map you posted shows upper winds. The upper winds are divergent on the SE side of anticyclonic upper ridging over PR, DR, and Haiti, which triggered those storms. These storms tend to blow up, then die down (right now in a die down phase). There is no surface feature (tropcal wave, surface trough) to sustain that area or give it focus as a surface system (and most tropical cyclones all start as surface systems). So its going to be very difficult for this to develop.


They can surprise from time to time but for now unless the NHC sees somthing in it I'm not gonna pay much attention to it.
Member Since: September 6, 2009 Posts: 2 Comments: 3710

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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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