Tropical Storm Bonnie Makes Her Debut

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

Share this Blog
0
+

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.

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: 497 - 447

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 | 30Blog Index

Member Since: Posts: Comments:
495. IKE
00Z ECMWF
Member Since: Posts: Comments:
Quoting MiamiWarnings:
tim you ahve us in suspense here, where were they fofund?


There weren't any LOL. Here are the latest obs. The SFMR instrument has been malfunctioning throughout the mission...so flight level winds are the most reliable measure and none above 40 kts have been found.
Member Since: Posts: Comments:
493. xcool
Link

go here rader
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Looking at upper level steering (both speed and direction) vs. lower level steering, I think it's just possible that the upper circ will be catching up soon. This is as of 3 hours ago, and 850 and 500 vort were well stacked ... don't know how they are doing atm. No vort up at 200 yet.

Look at upper level winds vs. lower level winds

Hopefully that will get updated soonish.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
EURO shows ZIPPO...NADA

NIGHT!!!
Member Since: Posts: Comments:
484. 7544
472. TampaSpin 3:01 AM EDT on July 23, 2010
Recon just found 60mph winds .....

Member Since: May 6, 2007 Posts: 0 Comments: 6874
483. xcool
1celia70 lmao
Member Since: Posts: Comments:
Quoting TampaSpin:
Recon just found 60mph winds .....


Flight level or surface? Flagged or no?
Member Since: Posts: Comments:
Quoting atmosweather:


For at least the next 2-3 days...it is always going to be moving along the southern periphery of the strong deep layer ridge to the N.


Yeah, I saw that ridge. Those isobars are pretty tight. Well, I guess we just wait and see. I'm looking at the Sats and she's looking even more elongated than she did a couple of hours ago.
Member Since: Posts: Comments:
Quoting TampaSpin:
Recon just found 60mph winds .....


LOL good try!
Member Since: Posts: Comments:
Quoting TampaSpin:
Recon just found 60mph winds .....
maybe there was a power surge in the blow dryer...lol
Member Since: Posts: Comments:
Quoting robert88:
Alex was a beautiful storm. I just hate tracking these Anas Hannas etc. lol It was a blessing for the GOM with that ULL so close by.


Then why claim that we haven't had a decent hurricane yet?
Member Since: Posts: Comments:
Quoting weatherwart:


How long will those easterly winds stick around, do you think?


0z GFS indicates that conditions should improve soon. But if she doesn't slow down, that's no good, either.
Member Since: Posts: Comments:
Just finished my first blog for TampaSpin's site.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Quoting weatherwart:


How long will those easterly winds stick around, do you think?


For at least the next 2-3 days...it is always going to be moving along the southern periphery of the strong deep layer ridge to the N.
Member Since: Posts: Comments:
Recon just found 60mph winds .....
Member Since: Posts: Comments:
471. 7544
when the warning and watches go down ill say u are all right untill then i think bonnie will still be there in the mornig sorry cant join the rip croud maybe after dmax but not now sit wait and watch to close now
Member Since: May 6, 2007 Posts: 0 Comments: 6874
Alex was a beautiful storm. I just hate tracking these Anas Hannas etc. lol It was a blessing for the GOM with that ULL so close by.
Member Since: Posts: Comments:
Quoting alfabob:
Am I missing something? IR just shows a more organized system, the ULL is affecting Bonnie less then previously, shear is down, and it has plenty of warm water still to cover. It's been lacking upper divergence but if the system doesn't start to decay soon, I think it will be intensifying. I'm tracking it from Miami to Fort Myers, then back into the GOM.


You've looked at everything but the overall circulation. Notice anything along the south side? Get back to me when you do.
Member Since: Posts: Comments:
Quoting TampaSpin:
Levi might wanna wake up until Recon finishes......LOL...just kidding....LOL


LOL...they are heading up the eastern side of the circulation about 70-80 miles NE of the center...nothing special in terms of winds. Hopefully they are going to run through the center again and into the SW quadrant...I want to see what they find. I really believe this is no longer a closed low.
Member Since: Posts: Comments:
465. IKE
A little slow on the movement NHC. She'll be passing Miami by around 8 am, unless she slows down....



Member Since: Posts: Comments:
Quoting KoritheMan:


Well, SSTs aren't the problem. It's as atmos said, low-level easterlies are ripping straight through her ill-defined surface circulation.


How long will those easterly winds stick around, do you think?
Member Since: Posts: Comments:
Quoting btwntx08:
robert88 has long term memory loss lol cause alex was great


I just don't think people realize the ignorance in some of their statements...

Referring to robert88 by the way, not you.
Member Since: Posts: Comments:
Quoting IKE:
Bumbling Bonnie.

Estimated (by SFMR or visually) Maximum Surface Wind: 22kts (~ 25.3mph)

My blow dryer puts out more wind.


LOL
Member Since: Posts: Comments:
Based on the RECON center fix...the NHC's current track looks remarkably good right now. All of the rainbands and gusty winds are N of the center but the actual LLC is right on track with the NHC's 11PM forecast. It should continue moving WNW-ward and move through the N-ern Keys.
Member Since: Posts: Comments:
Quoting TampaSpin:
Levi might wanna wake up until Recon finishes......LOL...just kidding....LOL


What do you think of her, Tim?

Under the same impression as the general lot of us are? Namely, that she lacks a well-defined surface circulation, and consequently, is no longer a tropical cyclone?
Member Since: Posts: Comments:
458. xcool
wow time to rip her.lolol
Member Since: Posts: Comments:
Levi might wanna wake up until Recon finishes......LOL...just kidding....LOL
Member Since: Posts: Comments:
Quoting weatherwart:


I was thinking the same thing. Once she crosses over the Keys or southern Florida, then it's a lot of very warm open Gulf. Who knows at that point?


Well, SSTs aren't the problem. It's as atmos said, low-level easterlies are ripping straight through her ill-defined surface circulation.
Member Since: Posts: Comments:
Quoting robert88:
So far getting toward the end of July is the month of ULL's and dry air. Wonder how long until we get a decent TS or cane? Negative upward motion is spreading into the Atlantic now until almost mid August.


Alex wasn't decent?
Member Since: Posts: Comments:
TropicalStorm Bonnie was^heading for a Flamingo,Florida landfall in ~9hours after having made landfall upon SouthAndrosIsland,Bahamas
(Straightline^projection using its last 2 positions. Take with HUGE grain of salt)
Copy&paste 22.7N75.4W, 23.1N75.9W, 23.4N76.5W-23.8N77.5W, 23.8N77.5W-25.1N80.9W, BIX, TAM, 18.5N87W, 28.7N88.4W into the GreatCircleMapper
Shortest red line denotes the movement between last two positions. Below the map shows:
TS.Bonnie had a heading of 293.7degrees (1.2degrees north of WestNorthWest) while traveling
a distance of 69miles(~111kilometres) over 3hours at a speed of 23mph(~37k/h), and was
232miles(~374kilometres) away from the mainland coast in the direction of its heading.

^ Straightline projections are not forecasts of what will happen in the future,
especially not for TropicalCyclones. They aftcast what has already happened.
* DeepwaterHorizon is marked at 28.7N88.4W
Member Since: Posts: Comments:
Quoting KoritheMan:


It should be noted that this is notoriously the case for developing tropical cyclones. 2001's Chantal, 2004's Earl, and 2009's Ana all fell prey to this phenomenon.

Bonnie might regenerate in the Gulf though as the upper flow improves.


I was thinking the same thing. Once she crosses over the Keys or southern Florida, then it's a lot of very warm open Gulf. Who knows at that point?
Member Since: Posts: Comments:
Quoting KoritheMan:
Still not seeing any westerly winds on satellite imagery. She's having trouble maintaining sufficient low-level convergence, due to her fast forward speed.


It should be noted that this is notoriously the case for developing tropical cyclones. 2001's Chantal, 2004's Earl, and 2009's Ana all fell prey to this phenomenon.

Bonnie might regenerate in the Gulf though as the upper flow improves.
Member Since: Posts: Comments:
Quoting IKE:
Bumbling Bonnie.

Estimated (by SFMR or visually) Maximum Surface Wind: 22kts (~ 25.3mph)

My blow dryer puts out more wind.


She's decoupled as she can be right now and with the strong easterlies pushing the LLC away from the mid level energy it's not looking good for her. There are still zero reports or indications of westerly winds either from imagery, ASCAT, RECON or surface obs. She could easily have lost her closed circulation.
Member Since: Posts: Comments:

Viewing: 497 - 447

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 | 30Blog 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.