TD 3 growing more organized

By: Dr. Jeff Masters , 8:01 PM GMT on July 22, 2010

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Tropical Depression Three is steadily organizing, and appears poised to become a much stronger storm than was forecast. Water vapor satellite loops show that the upper level low to the west of TD 3 that has been bringing high levels of wind shear to the storm is now moving faster to the west than predicted. This faster motion has resulted in a reduction in wind shear over TD 3, to a moderate 10 knots. Satellite images of TD 3 show that the storm is taking advantage of the lower shear by developing several low-level spiral bands to the north and east of the center. However, the center of circulation is still exposed to view, and dry air is still getting injected into the core of the storm from the southwest. The storm's heavy thunderstorms have not increased in intensity this afternoon, and the amount of heavy thunderstorm activity near the core of the storm is still limited. TD 3 will need to build more intense thunderstorms near its center before significant intensification can occur. TD 3 is a small storm, and surface observations in the Bahamas do not show the circulation very well. An outer rain band of TD 3 is now visible on Miami long-range radar, and a flood watch has been issued for all of South Florida. The Hurricane Hunters are in the storm at present, and have found top surface winds of 35 - 40 mph.


Figure 1. Afternoon satellite image of TD 3.

Track Forecast for TD 3
The storm is in a straightforward steering current environment, and TD 3 should progress steadily to the west-northwest through Sunday. This will bring the storm ashore over the Florida Keys or South Florida on Friday, and into the Gulf of Mexico on Saturday. The latest set of model runs from 8am EDT (12Z) foresee a track more to the north than the previous set of model runs. This increases the threat to the oil spill region, and I give a 40% chance that the oil spill region will see tropical storm force winds of 39 mph or higher this weekend. Oil recovery and relief well drilling operations should cease. If TD 3 makes a direct hit on the oil spill region as a tropical storm with 50 - 60 mph winds, it will likely drive a storm surge of 3 - 6 feet with high waves on top into the Louisiana marshlands, fouling a large area with oil. Oil would also penetrate into Lake Pontchartrain, which lies just two feet above sea level. However, the wave action of the storm will dilute the oil to some degree, which may limit the damage to the marshlands.

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 5 pm probabilities of various locations getting tropical storm force winds, 39 mph or higher:

Marathon 55%
Marco Island 43%
Miami 34%
New Orleans 33%
Galveston 13%

Intensity Forecast for TD 3
The primary detriment to development of TD 3 for the next three days will be the presence of the large upper-level low to its west. If the low remains in its present location, relative to TD 3, it will bring wind shear of about 10 knots to the storm. This will allow for steady intensification of perhaps 20 mph per day, and TD 3 could be a hurricane by Sunday at that pace. However, if the upper-level low slows down a bit, relative to TD 3, more shear and dry air will affect the storm, potentially weakening it. None of the computer models is calling for TD 3 to strengthen into a hurricane, but if the shear continues at 10 knots, I expect TD 3 will become a hurricane. My low-confidence intensity forecast gives TD 3 a 40% chance of becoming a hurricane. NHC is putting the odds of TD 3 being a hurricane at 2 pm Sunday at 15% with their 5pm advisory.

98L
An area of disturbed weather (98L) has developed in the Gulf of Mexico's Bay of Campeche. This system is under a low amount of shear, 5 - 10 knots, and probably does not have enough time to organize into a tropical depression before making landfall along the Mexican coast a few hundred miles south of the Texas border on Friday.

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 in the morning. ABC World News Tonight will probably show a sound bite I did for them today, on their 6:30pm broadcast.

Jeff Masters

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TS/03L/B
MARK
22.9N/74.5W
Member Since: July 15, 2006 Posts: 171 Comments: 53839
Shear continues to decrease by 20-40 knots.

Just updated:
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Move over high.
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Quoting Patrap:


I don't know if it's just my eye or it's actually happening but the convective storms on the Southwest corner of the COC seem to be stregnthening. As they do, they seem to be pulling the COC further North. If this is the case. The Forecast track may shift to the right a little bit which will put the Mississippi, Alabama and Northwest Florida Coasts in the path of what is now Tropical Storm Bonnie.
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I just want to make sure that everyone didn`t miss any of the 100s of post stating that we have BONNIE now!! roflmao
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Quoting Jeff9641:
Bonnie continues to build north. Seems a relocation to the NE is happening now. West Palm beach are you are not out of the woods. I suspect with these movement we will see watches and warnings extended to the Space Coast.


Yeah, waiting on that too Jeff... probably at 8pm or 11pm.
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AOI
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Quoting Jeff9641:
Bonnie continues to build north. Seems a relocation to the NE is happening now. West Palm beach are you are not out of the woods. I suspect with these movement we will see watches and warnings extended to the Space Coast.


You could be right. WPB could experience horribly devastating winds of 45 mph.
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"though the danger exists for the system to keep pumping heat and form its own upper environment"...

which, when considering the SST's...that's a spicy meataball!"....

and hence...my feeling Bonnie will form its own environment...somewhat be on the other side of the ULL..and simply follow it at a slower pace....

resulting in the ability of the system to explode to.....cat 3 or worse....
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Quoting Buhdog:
All the action is way north of the fcpts...

It never ceases in here to amaze me the stupid questions and statements by non regulars. People need to back off the bashing on Jeff too... my god, it has seemed North or north of what was expected all day!! Thank god this is approaching from the SE....


Thought I could get through this without opening my mouth but...I have to agree with you.

Most are here to learn BUT please just read all posts for several hours and you'll learn more and know what questions to ask! You'll know who is giving good info like StormW, Tampa, Drak, Pat and many others. Seeing the same questions and confusion 100 (1000) times a day - surface vs. flight level, mph vs. kts, do strong or weaker storms go north....

Nothing wrong with posting questions if you can't find the answers but the majority are answered ad nauseum on here during the course of a day. Just take the time to read and learn.

Back to lurking...
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Bonnie looks very disorganized. A decoupled center for sure. Good eye CCHS.
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Only a question.

Anyone else seeing a center reform further up to the NE around the new blow up of convection around 23.3N 75.1W?
Member Since: January 30, 2010 Posts: 0 Comments: 3259
956. redUK
Quoting Hurricanes101:


I agree with you

MLC looks to be headed north, LLC NW


Couldn't agree more.

Would'nt expect major intensification for 36hours (or never)
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Quoting patrikdude2:



plz stop with that
Member Since: May 21, 2006 Posts: 5091 Comments: 115107
Are the hurricane hunters moving into the center again? So that we can get another location?
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Quoting patrikdude2:


Thats where its starting to wrap around.
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000
WTNT63 KNHC 222222
TCUAT3
TROPICAL STORM BONNIE TROPICAL CYCLONE UPDATE...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032010
615 PM EDT THU JUL 22 2010

CORRECTED HEADER TO TROPICAL STORM BONNIE

...DEPRESSION BECOMES TROPICAL STORM BONNIE...

DATA FROM AN AIR FORCE HURRICANE HUNTER RECONNAISSANCE AIRCRAFT
DURING THE PAST HOUR INDICATE THAT SURFACE WINDS ASSOCIATED WITH
THE DEPRESSION HAVE INCREASED TO 40 MPH...65 KM/HR...AND THAT THE
DEPRESSION HAS BECOME A TROPICAL STORM.


SUMMARY OF 615 PM EDT...2215 UTC...INFORMATION
--------------------------------------------------
LOCATION...22.9N 75.4W
ABOUT 200 MI...320 KM SE OF NASSAU
ABOUT 415 MI...670 KM ESE OF KEY WEST FLORIDA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/HR
PRESENT MOVEMENT...NW OR 315 DEGREES AT 14 MPH...22 KM/HR
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES

$$
FORECASTER KIMBERLAIN/BEVEN

Member Since: July 15, 2006 Posts: 171 Comments: 53839
Quoting GetReal:


The beginnings of a CDO???


It is really starting to coalesce tightly. All of the convection seem to be wrapping tightly around the COC.
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Quoting TampaSpin:
Shear is impossible to forecast beyond 48hrs and that is not a certainty as evedent as to what happened today with the easing of the Shear today over Bonnie....Lets just watch and see how this plays out and be prepared if you are in the Areas of possible Landfall of whatever Storm Strenght it might be.
Sound Advice
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Quoting scott39:
Why has Bonnie lost alot of her convection?


Starting to make a come back!
Member Since: August 26, 2009 Posts: 0 Comments: 423
Atmosweather... This is the Southern Brevard County point forecast for Melbourne (SE of Orlando)... Friday: Scattered showers and thunderstorms, then showers likely and possibly a thunderstorm after noon. Some of the storms could produce gusty winds and heavy rain. Mostly cloudy, with a high near 90. Windy, with a east wind between 15 and 20 mph, with gusts as high as 30 mph. Chance of precipitation is 60%.
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Quoting IKE:
DATA FROM AN AIR FORCE HURRICANE HUNTER RECONNAISSANCE AIRCRAFT
DURING THE PAST HOUR INDICATE THAT SURFACE WINDS ASSOCIATED WITH
THE DEPRESSION HAVE INCREASED TO 40 MPH...65 KM/HR...AND THAT THE
DEPRESSION HAS BECOME A TROPICAL STORM.


Good...that should keep hurrikat off of here for awhile.


Amen, Ike.
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..DEPRESSION BECOMES TROPICAL STORM BONNIE...
6:15 PM EDT Thu Jul 22
Location: 22.9°N 75.4°W
Max sustained: 40 mph
Moving: NW at 14 mph
Min pressure: 1005 mb
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Quoting cchsweatherman:
Given the current and continued NW motion, latest satellite trends, recent hurricane hunter data, and observations, I would expect that the Tropical Storm Warning will be extended northward to Broward at the least later tonight.

Just noticed something new on satellite in the most recent imagery that it seems the mid-level and low level centers have decoupled.


I agree with you

MLC looks to be headed north, LLC NW
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Good evening.

Why is the NHC keeping Bonnie a 50 mph tropical storm for so long.
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The beginnings of a CDO???
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Forget all the "HYPE" This is what is expected in case you
live in South Florida.


Everyone Take Care and be safe!

Member Since: July 3, 2007 Posts: 0 Comments: 524
Hey everyone! My other computer has a virus so I have just been watching. How is everyone doing?
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Quoting Patrap:
Itsa BONNIE on the NOAA All Floater Page



And its continuing to strengthen.
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Those waves off Africa are really getting Torn Apart, WOW!
Member Since: August 26, 2009 Posts: 0 Comments: 423
Why has Bonnie lost alot of her convection?
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I feel the NHC and media is taking this too lightly.. things can change in a hurry.. and the mets should know that
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Shear is impossible to forecast beyond 48hrs and that is not a certainty as evedent as to what happened today with the easing of the Shear today over Bonnie....Lets just watch and see how this plays out and be prepared if you are in the Areas of possible Landfall of whatever Storm Strenght it might be.
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Neapolitan - post 793. Amen!

(I cut/pasted that one and saved as a doc - mind if I post it elsewhere as long as I attribute the source?)

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Given the current and continued NW motion, latest satellite trends, recent hurricane hunter data, and observations, I would expect that the Tropical Storm Warning will be extended northward to Broward at the least later tonight.

Just noticed something new on satellite in the most recent imagery that it seems the mid-level and low level centers have decoupled.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
X
Member Since: July 15, 2006 Posts: 171 Comments: 53839
Wonder what the NHC is looking for 60knot flight level winds lol
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NHC issuing advisories on TS BONNIE
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Quoting reedzone:
2-1-0


the days of 1-1-0 are gone now
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Quoting Levi32:
This is what can happen when a seemingly strong upper low is attacked by heat being pumped into the atmosphere by a tropical disturbance as the upper low backs away. TD 3 has warmed the upper environment enough to relax the shear for the moment, but its problems are not over. The big deep-layer ridge over the eastern US means that the strong easterly flow in the upper levels on its southern side will probably not allow outflow to get established in the northern semicircle of TD 3. The upper low may eventually pull away a little farther but won't be fully leaving TD 3 alone on its trek across the gulf. I still don't expect more than a weak TS from this, though the danger exists for the system to keep pumping heat and form its own upper environment. Right now the best conditions for development are still southeast of the system.

Its best chance for strengthening is right now while it's moving NW towards south Florida, as the upper low backing WSW puts it in a good position to ventilate it. TD 3 may not go through the straights, but it will be resuming a WNW track in the gulf and will be heading for Texas or Louisiana, not east of Louisiana like the models claimed yesterday.


Thanks Levi. :)
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921. IKE
DATA FROM AN AIR FORCE HURRICANE HUNTER RECONNAISSANCE AIRCRAFT
DURING THE PAST HOUR INDICATE THAT SURFACE WINDS ASSOCIATED WITH
THE DEPRESSION HAVE INCREASED TO 40 MPH...65 KM/HR...AND THAT THE
DEPRESSION HAS BECOME A TROPICAL STORM.


Good...that should keep hurrikat off of here for awhile.
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Get ready this one is going to ramp up quickly! We could see horribly devastating 45 mph winds in the Miami area in a worst case scenario.
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Bonnie is little but look at the visible and the large band forming to it's west, moisture to the west is increasing quickly. That's the magic of the gulf stream.Look for a surprise tonight. If not I'll agree it will be rough sledding after that for this storm but right now don't think so.
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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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