Tropical Depression Three forms

By: Dr. Jeff Masters , 3:42 PM GMT on July 22, 2010

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Tropical Depression Three has formed over the Bahama Islands, and appears poised to become Tropical Storm Bonnie later today. Satellite images of TD 3 show a modest area of heavy thunderstorms that have slowly increased in intensity and areal coverage this morning. The surface circulation center is exposed to view, thanks to strong upper-level winds out of the southwest that are creating about 20 knots of wind shear. This wind shear is due to the counter-clockwise circulation of air around a large upper-level low pressure system over Florida that is moving west at about the same speed TD 3 is. Water vapor satellite loops show a large area of dry air is associated with the upper-level low pressure system, and this dry air is hindering development of TD 3. The storm is attempting to wrap a curved band of clouds around its center, on its west side. If TD 3 is able to do this, the center will be protected from shear and dry air, and more significant strengthening can occur. Surface observations in the Bahamas and several nearby ships have shown top winds in TD 3 of up to 35 mph, so the storm is close to the 40 mph winds needed to be classified as a tropical storm.


Figure 1. Water vapor satellite image showing dry air (brown colors) associated with the upper-level low over Florida. Image credit: NOAA/NESDIS.

Track Forecast for TD 3
The storm is in a fairly straightforward steering current environment, and TD 3 should progress steadily to the west to west-northwest through Saturday. 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 2am EDT (6Z) had the advantage of having data from a flight of the NOAA jet last night, so we have higher confidence than usual in the track of TD 3 over the next two days. The location of TD 3's final landfall along the Gulf of Mexico coast has the usual uncertainties for 3 - 4 days, with the various models calling for landfall somewhere between the upper Texas coast and the Florida Panhandle coast. Given the uncertainties, the move halt operations in the Deepwater Horizon blowout recovery effort are probably wise.

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. As long as this low remains in its present location, relative to TD 3, it will bring wind shear of about 20 knots and dry air into the storm. This will limit the intensification potential of TD 3 to no more than about 10 - 15 mph per day. If the upper-level low slow down a bit, relative to TD 3, more shear will affect the storm, potentially weakening it. Conversely, if the upper-level low picks up speed and pulls away from TD 3, the storm may be able to intensify at a faster rate. None of the computer models is calling for that to happen, but it would not take much of an additional separation between TD 3 and the upper level low to substantially reduce shear and allow TD 3 to intensify into a hurricane on Saturday. I put the odds of TD 3 making it to hurricane strength in the Gulf of Mexico at 20%.

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 may barely 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 between 3 - 4 pm, when the Hurricane Hunters will be in the storm. I'll also speculate on the possible impact the storm will have on the oil spill region.

Jeff Masters

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This little bugger may be a big problem for someone down the road. It is VERY persistent... and systems that are persistent in the face of unfavorable conditions (which this one WAS in) become a problem when faced with favorable conditions... JMHO ;)
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Hey! they just dropped a 'sonde in the pond in the front of my Grandmother's house....

LOL

Well not quite - it's Exuma Sound. Guess they are checking out the further convection?

And is it me or are there 3 different aircraft currently flying this storm?
Member Since: October 25, 2005 Posts: 19 Comments: 20734
Quoting Orcasystems:

You have to look at surface not flight l... ahh forget it


they were surface, I know what to look for
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Quoting CybrTeddy:


He's a troll, a moron and a disgrace to himself. Hopefully, people just start ignoring him.
We members of the Lurking Morons Appreciating the Observations better known as the LMAO are hereby offended by that remark
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Patrap can you explain how to read the graphic you just posted?
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surface pressure is dropping consistently today
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Quoting cchsweatherman:


I am still sticking with my forecast from earlier with a moderate tropical storm making landfall in Southern Miami Dade county tomorrow afternoon.


That goes against the NHC and models in both track and intensity, but then again, any kid with a photo of the NHC for their avatar must know what they are doing. I'm just a monkey.
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Quoting MiamiHurricanes09:
Wobble? It's north of the cone and has been moving NW for a a couple hours. And of course when you know you are wrong you resort to my age. Typical.


u know more than half the ppl here
Member Since: July 21, 2010 Posts: 0 Comments: 1052
Quoting RitaEvac:
Pat is in fer some Cajun weather coming dat way.... gonna be on dirty side of ol Bonnie


Are you speeking Patish. LOL
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Quoting hurrkat05:
LOL YOU NOTICE WHAT THR NHC IS SAYING THE tropical depression WILL GO THROUGH THE FLORIDA STRAITS FRIDAY...KEY NAME HERE IS TROPICAL DEPRESSION..


Ummmm. Look at the forecast track by the nhc. Clearly a TS. .duhhhhhhhhhhhhh.....
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Quoting hurricane23:
No TS from iam finding on the recon obs...

VORTEX DATA MESSAGE AL032010
A. 22/19:20:30Z
B. 22 deg 25 min N
075 deg 07 min W
C. NA
D. 29 kt
E. 296 deg 22 nm
F. 024 deg 33 kt
G. 297 deg 24 nm
H. EXTRAP 1006 mb
I. 24 C / 183 m
J. 25 C / 217 m
K. 21 C / NA
L. NA
M. NA
N. 12345 / 01
O. 0.03 / 0 nm
P. AF306 02BBA INVEST OB 14
MAX FL WIND 33 KT NW QUAD 19:12:20Z
SLP EXTRAP FROM BELOW 1500 FT



Agreed, I dont see any TS winds.
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Quoting JamesSA:
But when a hurricane is moving in a straight line XTRP is ALWAYS right. ;-)
Exactly lol. and at the last moment, just before landfall the "xtap" is always right 100% of the time. But at that moment, you can just look out the window and say holy cr_p
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Quoting btwntx08:

just ingore him he is a really bad forecast hehe


btwntx: do you not know how to spell ignore?
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Hurrkat....if I recall....yesterday you said 97l was going to be dead today....changed your mind a little bit??
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guy on ABC25 in west palm just said unlike to be upgraded anytime soon
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Quoting Tazmanian:



are the hh in 98L too?


Maybe.
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Quoting extreme236:
I'd like to see a recon pass thru the NE quad where the strongest winds are. If were going to have a TS at 5 that's where they will find it.


Didn't they already do?
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Pat is in fer some Cajun weather coming dat way.... gonna be on dirty side of ol Bonnie
Member Since: July 14, 2008 Posts: 1 Comments: 9625
1552. Patrap
NEXRAD Radar
Miami, Velocity Azimuth Display Wind Profile Range 124 NMI

Member Since: July 3, 2005 Posts: 414 Comments: 125613
Quoting galvestonhurricane:


A wobble northwestward does not mean anything. Plus, he is only thirteen.
Wobble? It's north of the cone and has been moving NW for a a couple hours. And of course when you know you are wrong you resort to my age. Typical.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting btwntx08:

just ingore him he is a really bad forecast hehe


He is a Shout, Loud or a Scream Caster. One who must type in caps to think it makes them correct!
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Quoting Hurricanes101:


there were tons of obs earlier that were between 40-45mph


HH May consider it to be from thunderstorms not from the wind that is being made from the system itself
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Yall need to stop the arugeing.
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Soon to be "BONNIE" does not look very impressive currently.
The ULL should be keeping her in check and im thinking she
will possibly only maybe make maybe minimal TS strength at
best. 45-50kts possibly before she goes thru the straights
and into the Gulf as South Florida looks to be in good shape
on most of the new model runs, except for the obvious
potential threat to the Key's of course.

Stay Tuned!!!

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NEW BLOG
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there a lot od downcasting wishcasting and trollcasting going on today
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Quoting hurrkat05:
LOL YOU NOTICE WHAT THR NHC IS SAYING THE tropical depression WILL GO THROUGH THE FLORIDA STRAITS FRIDAY...KEY NAME HERE IS TROPICAL DEPRESSION..


That's because it's a TD right now, smart one.
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Quoting RainyEyes:


I am in Cape Coral....Howdy neighbor :)

Thank to those who have helped me understand btw :)
NW Cape Coral here
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1541. Torgen
Quoting tropicfreak:


Lower caps please!!!!


Some recognizable sentence structure and grammar wouldn't hurt either...
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Quoting Hurricanes101:


there were tons of obs earlier that were between 40-45mph

You have to look at surface not flight l... ahh forget it
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I'd like to see a recon pass thru the NE quad where the strongest winds are. If were going to have a TS at 5 that's where they will find it.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
The most Latitude it might gain before passing South of Florida is 24.5N
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Hurrkat.... we can all hear you! please stop using upper case text.
Member Since: September 18, 2007 Posts: 0 Comments: 1073
1536. Greyelf
Quoting cchsweatherman:


I am still sticking with my forecast from earlier with a moderate tropical storm making landfall in Southern Miami Dade county tomorrow afternoon.


Uh oh. You guys down there better get out teh additional shower curtain reinforcements.
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1535. hcubed
Quoting hurrkat05:
...98L LOOKS BETTER THEN THIS TRIOICAL DEPRESSION RIGHT NOW...


TRIOICAL?
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Intensifying ridge of high pressure over the SE US which will guide the system mainly WNW to landfall. On this track the storm will approach the SE TX/SW LA coast late Sunday night/early Monday morning. On this track adverse conditions will impact the entire oil spill area.
Member Since: July 14, 2008 Posts: 1 Comments: 9625
Quoting Seflhurricane:
no one is wishcasting look at the info before you open your mouth


A wobble northwestward does not mean anything. Plus, he is only thirteen.
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Quoting hurricane23:
No TS from iam finding on the recon obs...

VORTEX DATA MESSAGE AL032010
A. 22/19:20:30Z
B. 22 deg 25 min N
075 deg 07 min W
C. NA
D. 29 kt
E. 296 deg 22 nm
F. 024 deg 33 kt
G. 297 deg 24 nm
H. EXTRAP 1006 mb
I. 24 C / 183 m
J. 25 C / 217 m
K. 21 C / NA
L. NA
M. NA
N. 12345 / 01
O. 0.03 / 0 nm
P. AF306 02BBA INVEST OB 14
MAX FL WIND 33 KT NW QUAD 19:12:20Z
SLP EXTRAP FROM BELOW 1500 FT



there were tons of obs earlier that were between 40-45mph
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Quoting charlottefl:



I live in Southern Lee County near Bonita Springs. Grew up in Charlotte county..


I am in Cape Coral....Howdy neighbor :)

Thank to those who have helped me understand btw :)
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Quoting hurricane23:
No TS from iam finding on the recon obs...

VORTEX DATA MESSAGE AL032010
A. 22/19:20:30Z
B. 22 deg 25 min N
075 deg 07 min W
C. NA
D. 29 kt
E. 296 deg 22 nm
F. 024 deg 33 kt
G. 297 deg 24 nm
H. EXTRAP 1006 mb
I. 24 C / 183 m
J. 25 C / 217 m
K. 21 C / NA
L. NA
M. NA
N. 12345 / 01
O. 0.03 / 0 nm
P. AF306 02BBA INVEST OB 14
MAX FL WIND 33 KT NW QUAD 19:12:20Z
SLP EXTRAP FROM BELOW 1500 FT



A possibility.
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Quoting btwntx08:

just ingore him he is a really bad forecast hehe


It could be a she.
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I just took another gander at it and my eye still tells me it got Sarasota wrote all over it.
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Quoting galvestonhurricane:
Miami Hurricane: td 3 is not going to hit Miami. You need to stop wishcasting; we all know that you want a tropical storm or hurricane.
Never said it was going to hit Miami, I did say that it was going to hit southern Miami-Dade. Don't recall saying that it is going to be a hurricane either. So I also guess that CCHS is wishcasting too:

Quoting cchsweatherman:


I am still sticking with my forecast from earlier with a moderate tropical storm making landfall in Southern Miami Dade county tomorrow afternoon.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting TampaSpin:


NO he was not joking! It is a straight line average!


and Thanks for the heads up from your site very much appreciated.
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Quoting galvestonhurricane:
Miami Hurricane: td 3 is not going to hit Miami. You need to stop wishcasting; we all know that you want a tropical storm or hurricane.
no one is wishcasting look at the info before you open your mouth
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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.