Tropical Depression Seven forms

By: Dr. Jeff Masters , 2:25 PM GMT on August 14, 2011

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The latest in our unusual number of weak tropical cyclones this season, Tropical Depression Seven, has formed to the southeast of Bermuda. Unless you live in Bermuda, TD 7 is not going to be a concern. Radar out of Bermuda shows an area of rain on the northern side of TD 7 beginning to approach the island, and rain from the storm will likely affect the island tonight and on Monday. TD 7 is not well-organized, and has only limited heavy thunderstorms, as seen on visible satellite images. While wind shear is a low 5 - 10 knots, dry air surrounds TD 7, and is keeping the storm from intensifying. None of the computer models foresee that TD 7 will ever become more than a weak tropical storm.


Figure 1. Morning satellite image of TD 7.

92L
TD 7 isn't the only system Bermuda needs to watch, Invest 92L is a day behind it, and will follow a path very similar to TD 7's. The disturbance will pass close to Bermuda on Tuesday, bringing the island a second round of tropical rains. However, Invest 92L is very disorganized, as seen on recent visible satellite loops. Dry air and close proximity to TD 7 will likely keep 92L from showing significant development over the next two days, with NHC giving the system just a 30% chance of developing into a tropical depression by Tuesday morning.

Elsewhere in the tropics
The disturbance midway between the Lesser Antilles Islands and the coast of Africa we've been tracking over the past few days, Invest 93L, has fallen apart and is no longer a threat to develop. This system will need to be watched once it enters the Caribbean later this week, though. None of the reliable models for predicting tropical cyclone formation predict development of this system or any new disturbances over the coming week.

Jeff Masters

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93L is really geting its act togeter this AM
Member Since: May 21, 2006 Posts: 5091 Comments: 115078
1774. SLU
It's back!

397

WHXX01 KWBC 151132

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS NATIONAL HURRICANE CENTER MIAMI FL

1132 UTC MON AUG 15 2011



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



DISTURBANCE INVEST (AL932011) 20110815 0600 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

110815 0600 110815 1800 110816 0600 110816 1800



LAT LON LAT LON LAT LON LAT LON

BAMS 13.3N 54.7W 13.8N 57.7W 14.2N 60.9W 15.0N 64.5W

BAMD 13.3N 54.7W 13.7N 57.7W 14.2N 60.6W 14.7N 63.6W

BAMM 13.3N 54.7W 13.8N 57.7W 14.3N 60.7W 15.0N 63.9W

LBAR 13.3N 54.7W 13.7N 58.2W 14.2N 61.8W 14.8N 65.6W

SHIP 20KTS 23KTS 28KTS 37KTS

DSHP 20KTS 23KTS 28KTS 37KTS



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

110817 0600 110818 0600 110819 0600 110820 0600



LAT LON LAT LON LAT LON LAT LON

BAMS 15.9N 68.2W 17.9N 75.4W 19.4N 81.0W 20.6N 85.2W

BAMD 15.4N 66.6W 17.1N 71.9W 18.6N 75.9W 20.0N 78.9W

BAMM 15.8N 67.2W 17.5N 73.1W 19.2N 77.8W 20.8N 81.5W

LBAR 15.5N 69.3W 16.8N 76.0W .0N .0W .0N .0W

SHIP 46KTS 62KTS 72KTS 79KTS

DSHP 46KTS 62KTS 72KTS 79KTS



...INITIAL CONDITIONS...

LATCUR = 13.3N LONCUR = 54.7W DIRCUR = 275DEG SPDCUR = 19KT

LATM12 = 12.9N LONM12 = 50.6W DIRM12 = 276DEG SPDM12 = 23KT

LATM24 = 12.5N LONM24 = 45.4W

WNDCUR = 20KT RMAXWD = 70NM WNDM12 = 20KT

CENPRS = 1010MB OUTPRS = 1013MB OUTRAD = 180NM SDEPTH = S

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN

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hey 93L welcome back
Member Since: May 21, 2006 Posts: 5091 Comments: 115078
Poll:
In the next advisory, Gert will be______.
A.60mph
B.65mph
C.70mph
D.Lower
E.Hurricane
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Quoting AtHomeInTX:


Good morning. A little cooler here this morning too. But the humidity is definitely not lower. Lol.

Orange County Airport
Lat: 30.07 Lon: -93.8 Elev: 13
Last Update on Aug 15, 6:15 am CDT

Fog/Mist

73 °F
(23 °C)
Humidity: 94 %
Wind Speed: Calm
Barometer: 29.93"
Dewpoint: 72 °F (22 °

C)
Visibility: 1.75 mi.

About the same here in the Piny Woods,still no rain,100 or better everyday.Evaporation rate 1.5" a day,Toledo Bend is dropping like a rock,new record low's each day.Not a wishcaster but sure could use a 93L.
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I see 93L has been reactivated.
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1768. SLU
My take on 93L is that the NHC will be more conservative with it as a result of its slow development and give it a yellow circle.
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Reactivated...

AL, 93, 2011081500, 131N, 528W, 20, 1012, DB
AL, 93, 2011081506, 133N, 547W, 20, 1010, WV
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Quoting islander101010:
not 10% even though?




whats see the the new two says in a few sac
Member Since: May 21, 2006 Posts: 5091 Comments: 115078
Quoting Tazmanian:
ex 93L has really came back too life this AM
not 10% even though?
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Quoting AtHomeInTX:


Good morning. A little cooler here this morning too. But the humidity is definitely not lower. Lol.

Orange County Airport
Lat: 30.07 Lon: -93.8 Elev: 13
Last Update on Aug 15, 6:15 am CDT

Fog/Mist

73 °F
(23 °C)
Humidity: 94 %
Wind Speed: Calm
Barometer: 29.93"
Dewpoint: 72 °F (22 °C)
Visibility: 1.75 mi.
73 get a jacket, it hasnt been 73 here since May :) Humidity here 71 percent due to high pressure stronger over my head.
Member Since: Posts: Comments:
Quoting Tazmanian:
ex 93L has really came back too life this AM
mhm
Member Since: June 17, 2011 Posts: 11 Comments: 6492
Quoting aislinnpaps:
Off to school, the kiddies await. Everyone have a wonderful first day of the work week. I have a feeling from reading back through the blog that I will come home this evening to 93L being baptized with a real name. Have a fun day all!Not all kiddies like going to public or private schools, some kiddies rather want non - formal education (as in homeschooling) because they want to stay with their mom, and - you know it.
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ex 93L has really came back too life this AM
Member Since: May 21, 2006 Posts: 5091 Comments: 115078
mjo
Member Since: June 17, 2011 Posts: 11 Comments: 6492
1759. Hugo7
interesting to see another low swinging back down like 94 did. 93 getting serious now.
Member Since: June 1, 2011 Posts: 0 Comments: 64
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Quoting aislinnpaps:
Off to school, the kiddies await. Everyone have a wonderful first day of the work week. I have a feeling from reading back through the blog that I will come home this evening to 93L being baptized with a real name. Have a fun day all!


Have a good day. :)
Member Since: Posts: Comments:
Quoting Tazmanian:
this is odd i seee they DEACTIVATE at 5:51AM but at 8:05AM they re activate it?

invest_DEACTIVATE_al922011.ren 6 KB 8/15/2011 5:51:00 AM


File:invest_al922011.invest 6 KB 8/15/2011 8:05:00 AM

That was my comment posted with style that i posted earlier i said it this:
Quoting Vincent4989:
i think its time to invest_DEACTIVATE_al922011.ren
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Quoting bohonkweatherman:
Good Morning to all, humidity lower this morning. Yes, less heat index. So far U.S.A. has been fortunate with no storms but there is a long way to go this Hurricane season.


Good morning. A little cooler here this morning too. But the humidity is definitely not lower. Lol.

Orange County Airport
Lat: 30.07 Lon: -93.8 Elev: 13
Last Update on Aug 15, 6:15 am CDT

Fog/Mist

73 °F
(23 °C)
Humidity: 94 %
Wind Speed: Calm
Barometer: 29.93"
Dewpoint: 72 °F (22 °C)
Visibility: 1.75 mi.
Member Since: Posts: Comments:
Member Since: October 9, 2008 Posts: 0 Comments: 8360
Off to school, the kiddies await. Everyone have a wonderful first day of the work week. I have a feeling from reading back through the blog that I will come home this evening to 93L being baptized with a real name. Have a fun day all!
Member Since: August 22, 2009 Posts: 0 Comments: 3125
06Z GFS has a CLASSIC East Coast Hurricane from Florida to NYC
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Quoting USAFwxguy:
93L is suffering from poor low lvl vort, but the negative vorticity in upper lvls is pretty nice.

850 (low lvl)


200 (upper lvl)


The negative vort at the 200 lvl could aid any development, as it will serve to allow escape of the latent heat drawn in at lower lvls. However, the lower lvls aren't spinning that well.


That's what I was wondering about. Thanks for posting those. :)
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1750. WxLogic
Quoting USAFwxguy:
93L is suffering from poor low lvl vort, but the negative vorticity in upper lvls is pretty nice.

850 (low lvl)


200 (upper lvl)


The negative vort at the 200 lvl could aid any development, as it will serve to allow escape of the latent heat drawn in at lower lvls. However, the lower lvls aren't spinning that well.


Indeed... current DMAX has been also helping it produce some convection.

Would be interesting to see if it's able to sustain those TSTM(s) to better assist on that LLC development and then have it work its say up to the mid levels by later today.

I would expect NHC to reinstate it if its able to main a decent convection for 24HR to 48HR.
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Quoting stormwatcherCI:
Maybe they still see a circulation with it. IDK.



may be and it has com back a little
Member Since: May 21, 2006 Posts: 5091 Comments: 115078
Quoting Tazmanian:
this is odd i seee they DEACTIVATE at 5:51AM but at 8:05AM they re activate it?

invest_DEACTIVATE_al922011.ren 6 KB 8/15/2011 5:51:00 AM


File:invest_al922011.invest 6 KB 8/15/2011 8:05:00 AM
Maybe they still see a circulation with it. IDK.
Member Since: October 9, 2008 Posts: 0 Comments: 8360
this is odd i seee they DEACTIVATE at 5:51AM but at 8:05AM they re activate it?

invest_DEACTIVATE_al922011.ren 6 KB 8/15/2011 5:51:00 AM


File:invest_al922011.invest 6 KB 8/15/2011 8:05:00 AM
Member Since: May 21, 2006 Posts: 5091 Comments: 115078
1746. WxLogic
Good Morning...

93L sure is looking quite healthier than these past days. So far NGP has been developing this system partially in the E Carib. Sea wither further development as it approaches W Carib.

If it develops then NAM would have done great with 93L as it develops it into a pretty strong TS to possibly HURR.
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Good Morning to all, humidity lower this morning. Yes, less heat index. So far U.S.A. has been fortunate with no storms but there is a long way to go this Hurricane season.
Member Since: Posts: Comments:
1743. SLU
Surface observations from Barbados indicate that a surface low could be forming with 93L. The air pressure in the vicinity of the system has dropped to 1009 - 1010mb according to reports from the buoy east of Martinique (41101).
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One question,

Any trace of Emily? :P
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93L seems to be headed toward the warm SST's ahead of it.The water is between 29-30 degree celcius.That is some hot water.It should get going once it gets in that bath tub.
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Quoting emguy:


Hi AtHomeInTX, The link below is a loop of the water vapor in the atmosphere. The browns are very dry air. You will notice the front band ahead of the wave is working through towards the Carribean like a snowplow. (best anology/explanation I can think of). Hope it is helpful.

Link to Loop


Great analogy. :) Thanks.
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1739. emguy
Quoting AtHomeInTX:


That's interesting. Thanks! Does anyone have a vort map they can put up? I can't find one. Of course I may be calling it the wrong thing. :)


Hi AtHomeInTX, The link below is a loop of the water vapor in the atmosphere. The browns are very dry air. You will notice the front band ahead of the wave is working through towards the Carribean like a snowplow. (best anology/explanation I can think of). Hope it is helpful.

Link to Loop
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Quoting islander101010:
i called a gilbert like track got called out on the blog the character is right. this one is three weeks to earlier than gilbert


If something develops here you could be right on with the track.
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Former 93L and Barbados

Last night was extremely hot and humid. Woken up this morning by continuously heavy rainfall and some thunder activity.
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Quoting emguy:


Whoops...was trying to answer someone on the devlopment of Ivan versus the current status of this wave. To the earlier poster I was responding to...Yes, Ivan was more developed at this point. Sorry if I confused anybody with this post.
LOL I realized it was me you were responding to. I don't recall what conditions were surrounding Felix at this point but it was in this area that he actually developed.
Member Since: October 9, 2008 Posts: 0 Comments: 8360
My goodness the temps outside are so nice in Mobile right now is 74.7 degrees.
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Quoting robert88:
Looks like x93L is about to hit some wonderful dry sinking air. If it stays an open wave it will just crash into CA like the EURO was showing. It needs to get going now.


Not inhibiting development, his anticyclone bodyguard is offering him free protection:
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i called a gilbert like track got called out on the blog the character is right. this one is three weeks to earlier than gilbert
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1732. emguy
Quoting emguy:
True, but Charley wasn't, nor were some of the others at this point. Was just making note of this, no 2 storms are ever alike.

On a more specific note regarding this wave...Yes...there is dry air in the eastern Carribean...However...there is a solid thunderstorm band ahead of it. That frontrunning band will continue moisten the environment just ahead of X93L in this scenario. A plus for potential development.


Whoops...was trying to answer someone on the devlopment of Ivan versus the current status of this wave. To the earlier poster I was responding to...Yes, Ivan was more developed at this point. Sorry if I confused anybody with this post.
Member Since: Posts: Comments:
Quoting emguy:
True, but Charley wasn't, nor were some of the others at this point. Was just making note of this, no 2 storms are ever alike.

On a more specific note regarding this wave...Yes...there is dry air in the eastern Carribean...However...there is a solid thunderstorm band ahead of it. That frontrunning band will continue moisten the environment just ahead of X93L in this scenario. A plus for potential development.


That's interesting. Thanks! Does anyone have a vort map they can put up? I can't find one. Of course I may be calling it the wrong thing. :)
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1730. emguy
True, but Charley wasn't, nor were some of the others at this point. Was just making note of this, no 2 storms are ever alike.

On a more specific note regarding this wave...Yes...there is dry air in the eastern Carribean...However...there is a solid thunderstorm band ahead of it. That frontrunning band will continue moisten the environment just ahead of X93L in this scenario. A plus for potential development.
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1729. SLU
Very favourable conditions exist for 93L now and there seems to be a low trying to form near 14n 56w but it lacks much vorticity.
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Quoting emguy:


Dry air shouldn't be a factor for this one right now...There is dry air ahead of it, but the wave is embedded in a core of deep moisture. Not an issue at this time.
Thanks Emguy.
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Conditions look favorable for 93L. It has a low shear environment ahead and an anticyclone over it. SAL is about the only nonfavorable situation but that will clear past the islands and the heat will go up.
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Quoting emguy:


Just a note...it is definately firing up and pulling in at the moment, but the general vorticity center would likely be SE of all the major convection. Lets just say somewhere around 13 N 56 W as a rough guess. It will require more time, but dry air is not an issue for this one. Good front running moisture of this one...we have seen this several times before. One of the most impressive storms was Ivan (2004), which had a solid dry air zone ahead of the system all the way at this point.
Good morning. Ivan was already a well developed system at this point though.
Member Since: October 9, 2008 Posts: 0 Comments: 8360
1725. emguy
Quoting mrsalagranny:
Is that 93L?


Yes...
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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.