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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Thank God Bonnie will not have a lot of time, she is winding up fast on the visible. I know I'm jumping the gun with the name but I bet it gets one by or before 5.
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Im getting the barbs now.. winds about 45mph at the surface
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1751Z

34.9 knots (~ 40.1 mph)
Tropical Storm
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668. xcool
<< slidell la here too lol
Member Since: September 26, 2009 Posts: 2 Comments: 15671
Quoting gumboyaya:
Re 611
Hey StormW,

I'm in Slidell, LA--Pass Christian's in my backyard or I'm in their backyard depending upon how you look at things. How much closer are you thinking? I'm thinking we'll get a good smack. . . How much of a smack do you think we'll get?


Howdy neighbor! :)
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39 knot winds by SFMR
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Recon already found 45mph uncontaminated SFMR winds.

000
URNT15 KNHC 221751
AF306 02BBA INVEST HDOB 22 20100722
174230 2311N 07549W 6246 04104 0136 031 -137 066013 014 /// /// 03
174300 2309N 07548W 6517 03760 0140 052 -124 074013 014 /// /// 03
174330 2307N 07546W 6930 03255 0147 078 -111 079016 017 /// /// 03
174400 2305N 07545W 7308 02808 0139 105 -094 068016 016 /// /// 03
174430 2303N 07544W 7588 02495 0143 123 -078 066021 022 /// /// 03
174500 2301N 07543W 7972 02080 0141 150 -059 071023 025 /// /// 03
174530 2259N 07542W 8309 01715 0126 174 -034 076025 026 /// /// 03
174600 2257N 07542W 8500 01532 0133 182 -045 066028 029 /// /// 03
174630 2258N 07544W 8871 01157 0139 193 003 070033 034 /// /// 03
174700 2259N 07543W 9239 00799 0128 205 029 062031 031 /// /// 03
174730 2257N 07542W 9538 00509 0116 219 047 055032 033 /// /// 03
174800 2256N 07540W 9733 00338 0117 229 062 053030 031 /// /// 03
174830 2255N 07539W 9785 00286 0112 233 074 053032 033 040 002 03
174900 2254N 07538W 9689 00375 0113 228 085 052032 032 039 003 00
174930 2253N 07537W 9765 00302 0110 234 094 051032 034 039 002 00
175000 2251N 07536W 9765 00301 0108 235 101 048031 032 038 003 00
175030 2250N 07535W 9767 00298 0107 234 107 043029 031 037 002 03
175100 2249N 07534W 9772 00293 0107 235 113 047032 033 036 003 00
175130 2248N 07533W 9765 00298 0105 233 117 045032 033 034 002 03
175200 2246N 07532W 9771 00292 0104 232 121 045032 033 035 001 00
Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting sebastianflorida:
2pm advisory hit. there's a .4 degree shift to the north. and a .1 degree shift to the west. starting to believe that northerly shift by 5pm.



You mean a .1 degree shift to the East, check your facts again!
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661. Skyepony (Mod)
TD3 does look well north of the forecast points..
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35kt uncontaminated right after they turned on the SFMR


175200 2246N 07532W 9771 00292 0104 +232 +121 045032 033 035 001 00
Member Since: September 23, 2005 Posts: 14 Comments: 11165
Re 611
Hey StormW,

I'm in Slidell, LA--Pass Christian's in my backyard or I'm in their backyard depending upon how you look at things. How much closer are you thinking? I'm thinking we'll get a good smack. . . How much of a smack do you think we'll get?
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Quoting StonedCrab:


Where are you getting the data from?
The kmz (Google Earth) file has quit passing the dropsondes. Thx


Live Recon Data
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still not getting any wind barb readings.
Member Since: September 6, 2009 Posts: 2 Comments: 3720
655. xcool
td3 move wnw .
Member Since: September 26, 2009 Posts: 2 Comments: 15671
Already recording tropical storm force winds.
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More moisture is exiting the Cuba north coast and will be feeding Bonnie now!
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Quoting cchsweatherman:
Hurricane Hunters are descending now and have begun taking in data for Tropical Depression 3.


Where are you getting the data from?
The kmz (Google Earth) file has quit passing the dropsondes. Thx
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Quoting MiamiHurricanes09:
03L looking impressive on rainbow with the banding.


Has recon reached 03L yet? I wanna see what they find.
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Hello everyone..i'm in SW LA and I am not liking the track it's on right now....Do yall think this track will change??? TIA :)
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Forecast for Metropolitan Miami Dade Hide
Updated: 12:08 PM EDT on July 22, 2010
Tropical Storm Wind Warning in effect until 2 am EDT Saturday...
Member Since: September 6, 2009 Posts: 2 Comments: 3720
For those who want to know how the ULL is moving relative to TD3, I have compared the water vapor loop from 12 hours ago with the most recent, and marked the position of both systems. Here are the results:



So it appears to me that the ULL is indeed, for the time being at least, moving faster than TD3, and sinking southward.
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645. Skyepony (Mod)
AF306 is descending into the storm...
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Hurricane Hunters are descending now and have begun taking in data for Tropical Depression 3.
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Quoting Hurricanes101:


coordinates are 22.3N 74.9W

based on that the convection is over the center


Seeing if you were paying attention. Good proof reader. LOL
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Quoting xcool:
NOW BACK TO WNW
2pm advisory hit. there's a .4 degree shift to the north. and a .1 degree shift to the west. starting to believe that northerly shift by 5pm.

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based on that ASCAT, 98L will likely run out of time
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639. myway
Quoting hurricanedave:
NHC just changed track now into ft lauderdale



Poof!!!
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03L looking impressive on rainbow with the banding.

Member Since: September 2, 2009 Posts: 130 Comments: 21193
Quoting MiamiHurricanes09:
You mean the ULL?


Thanks, fixed it in my original post LOL!
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well i have learned my lesson with wobbles from alex. alex would make a huge long lasting wobble and get right back on track with nhc. you see i'm a worry caster:) if something has any chance at all of coming here(La.)i get worried, and start thinking that every northern wobble is a change in direction and i go into questioning of the nhc.lol! right now i just want to see if the ull in front of t.d.3 will move away or not. if it moves you will see me start asking a lot of questions:)
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Recon's checking out COC.. they should head north into the thunderstorms. IMO they'll find some 35 knot winds there..
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Quoting Drakoen:
98L has sloppy circulation



Not surprising...
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Quoting neonlazer:
I am not sure what is wrong with it right now. I don't think anyone has been able to see the mission going to 03L


All Im getting is the 30 min Observations. No Dropsonde info since it crossed over FL
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Quoting Grothar:
If the coordinates of 22.2N and 78.9W are correst, the strong convection has not wrapped around the center yet. It appears that it is trying. How will the jump of the center to the NE affect the current track??????



coordinates are 22.3N 74.9W

based on that the convection is over the center
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Quoting angiest:


But will (Mitch Landrieu?) be any better?
yes...imo
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Re: Post 572.....Remove it.
.
The worst thing that anyone can do is to post something that the NHC says...that's not the truth.
.
If I had anything to say in the matter, and I do, this is an offense to be met with more than a 24hr. ban.
Member Since: August 3, 2005 Posts: 10 Comments: 5588
Quoting StormW:
000
WTUS82 KKEY 221535
HLSKEY

URGENT - IMMEDIATE BROADCAST REQUESTED
TROPICAL DEPRESSION THREE LOCAL STATEMENT
NATIONAL WEATHER SERVICE KEY WEST FL
1135 AM EDT THU JUL 22 2010

...TROPICAL STORM WARNING ISSUED FOR THE FLORIDA KEYS...

.AREAS AFFECTED...
THIS LOCAL STATEMENT PROVIDES IMPORTANT INFORMATION AND
RECOMMENDED ACTIONS FOR PEOPLE AND MARINERS IN THE FLORIDA KEYS
OF MONROE COUNTY AND ADJACENT COASTAL WATERS.

.WATCHES/WARNINGS...
A TROPICAL STORM WARNING IS IN EFFECT FOR THE FOLLOWING
LOCATIONS...MONROE UPPER KEYS...MONROE MIDDLE KEYS AND MONROE
LOWER KEYS.

FOR MARINE INTERESTS...A TROPICAL STORM WARNING IS IN EFFECT FOR
ALL OF FLORIDA KEYS COASTAL WATERS.

.STORM INFORMATION...
AT 11 AM EDT...THE CENTER OF TROPICAL DEPRESSION THREE WAS
LOCATED NEAR LATITUDE 21.9N...LONGITUDE 75.0W. THIS WAS ABOUT
460 MILES EAST-SOUTHEAST OF KEY WEST. THE MOTION WAS TO THE WEST
NORTHWEST AROUND 15 MPH. MAXIMUM SUSTAINED WINDS ARE 35 MPH.

.SITUATION OVERVIEW...
BREEZY TO WINDY CONDITIONS WILL CONTINUE ACROSS THE FLORIDA KEYS AND
SURROUNDING WATERS FROM LATE THIS AFTERNOON THROUGH EARLY FRIDAY
MORNING. TROPICAL STORM FORCE CONDITIONS ARE POSSIBLE IN THE ATLANTIC
WATERS ADJACENT TO THE FLORIDA KEYS EARLY FRIDAY MORNING...AND THEN
IN THE FLORIDA KEYS LATER FRIDAY MORNING.

.PRECAUTIONARY/PREPAREDNESS ACTIONS...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
RESIDENTS AND BOATERS IN THE FLORIDA KEYS SHOULD COMPLETE
PREPARATIONS FOR TROPICAL STORM CONDITIONS AS EARLY AS POSSIBLE.

&&

.NEXT UPDATE...
THE NEXT LOCAL STATEMENT CONCERNING THE IMPACTS OF TROPICAL
DEPRESSION THREE TO THE FLORIDA KEYS WILL BE ISSUED BY THE
NATIONAL WEATHER SERVICE IN KEY WEST SHORTLY. IT WILL PROVIDE
ADDITIONAL IMPORTANT DETAILS REGARDING TROPICAL DEPRESSION THREE
AND ITS POTENTIAL IMPACT ON THE FLORIDA KEYS.

FLZ076>078-221730-
/O.NEW.KKEY.TR.W.1003.100722T1535Z-000000T0000Z/
MONROE UPPER KEYS-MONROE MIDDLE KEYS-MONROE LOWER KEYS-
1135 AM EDT THU JUL 22 2010

...TROPICAL STORM WARNING IN EFFECT...

...NEW INFORMATION...
A TROPICAL STORM WARNING HAS NOW BEEN ISSUED. A MORE DETAILED
STATEMENT WILL FOLLOW SHORTLY.

$$

GMZ031>033-052>054-072>075-221730-
/O.NEW.KKEY.TR.W.0001.100722T1535Z-000000T0000Z/
FLORIDA BAY-GULF SIDE OF THE LOWER KEYS OUT 20 NM-
GULF WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE 20 TO 60 NM OUT-
OCEAN REEF TO CRAIG KEY OUT 20 NM-
CRAIG KEY TO THE WEST END OF THE 7 MILE BRIDGE OUT 20 NM-
WEST END OF THE 7 MILE BRIDGE TO KEY WEST OUT 20 NM-
OCEAN REEF TO CRAIG KEY 20 TO 60 NM OUT-
CRAIG KEY TO THE WEST END OF THE 7 MILE BRIDGE 20 TO 60 NM OUT-
WEST END OF THE 7 MILE BRIDGE TO KEY WEST 20 TO 60 NM OUT-
KEY WEST TO 20 NM WEST OF DRY TORTUGAS OUT 60 NM-
1135 AM EDT THU JUL 22 2010

...TROPICAL STORM WARNING IN EFFECT...

...NEW INFORMATION...
A TROPICAL STORM WARNING HAS NOW BEEN ISSUED. A MORE DETAILED
STATEMENT WILL FOLLOW SHORTLY.

$$

04/JACOBSON
Am ready in Key West for some rain and wind.
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Quoting Hurricanes101:
so much for 2010 being a bust lmao


OMG..
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yes, getting rid of Nagen was a great move but I am sure he would be all over this if another storm were to hit NOLA. LOL
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Quoting naynaysnanny1:

and we can all say AMEN that he's not the mayor here anymore


But will (Mitch Landrieu?) be any better?
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Quoting Grothar:
If the coordinates of 22.2N and 78.9W are correst, the strong convection has not wrapped around the center yet. It appears that it is trying. How will the jump of the center to the NE affect the current track??????

Problably not much difference as the ridge will strengthen back and cause it to go WNW
Member Since: July 5, 2008 Posts: 0 Comments: 254

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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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