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Little change to TD 7; 93L may develop off the coast of Africa

By: Dr. Jeff Masters , 1:57 PM GMT on August 10, 2012

Tropical Depression Seven continues westward across the central tropical Atlantic with little change in appearance. Looking remarkably like the tropical depression that became Tropical Storm Ernesto last week, TD 7 has a limited region of heavy thunderstorms, as seen on satellite loops. A large amount of dry air to the west and north is visible on water vapor satellite loops, and this dry air is interfering with TD 7's heavy thunderstorms. Wind shear is a light 5 - 10 knots, which is favorable for intensification. Ocean temperatures are 26.5°C, which is a bit on the cool side, but these temperatures are 0.5° warmer than on Thursday. Winds at the Middle Atlantic buoy 41041 peaked at 29 mph, gusting to 38 mph, at 1:50 am EDT this Friday morning, when the center of TD 7 passed about 40 miles to the south. TD 7 will pass about 60 miles south of buoy 41040 near midnight tonight. The first hurricane hunter mission into TD 7 is scheduled for Saturday morning.


Figure 1. Morning satellite image of TD 7.

Forecast for TD 7
TD 7 formed about 400 miles east-northeast of where Ernesto became a tropical depression, as seen on our wundermap. Atmospheric and oceanic conditions are currently quite similar to what Ernesto experienced, and I expect TD 7 will struggle with dry air like Ernesto did. The SHIPS model predicts that shear will remain light through tonight, then rise to the moderate range on Saturday, when the storm will encounter upper-level southwesterly winds associated with a trough of low pressure. However, ocean temperatures will warm to 28°C, which may partially counteract the increase in shear, as far as maintaining a favorable environment for development. Dry air and shear may be significant enough to destroy TD 7 on Sunday, as predicted by the GFS and ECMWF models. These models tried to kill off Ernesto in a similar situation last week, so I am inclined to believe TD 7 will survive for the coming five days, but struggle. The official NHC forecast of a 45 mph tropical storm moving through the Lesser Antilles Islands Saturday night and Sunday is a reasonable one.


Figure 2. Morning satellite image of Invest 93L.

93L
A strong tropical wave in the far Eastern Atlantic that emerged off the coast of Africa Thursday night was designated Invest 93L by NHC. In their 8 am Tropical Weather Outlook, NHC gave 93L a 50% chance of becoming a tropical depression by Sunday morning. Satellite loops show a pronounced spin to the atmosphere at mid levels, but little in the way of heavy thunderstorm activity. The latest Saharan Air Layer Analysis from the University of Wisconsin shows that while the atmosphere immediately surrounding the disturbance is moist, there is a large area of dry air from the Sahara to the west and north. This dry air will be a significant impediment to development during the coming week. The ECMWF model shows some weak development of 93L over the coming week, and predicts a general west-northwesterly track. The storm may be something Bermuda needs to be concerned about in eight or so days.

I'll have a new post this afternoon.

Jeff Masters


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

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723. aspectre
9:34 PM GMT on August 10, 2012
10August12pmGMT's 13.7n480w was re-evaluated&altered at ~1pmGMT
10August06pmGMT's 13.6n48.6w-13.7n50.9w are now the most recent positions
(Vectors and straightline projections have been corrected from the previous mapping)
Derived from (NHC) ATCF data for TropicalDepressionSeven for 10August6pmGMT:
MinimumPressure remained 1009millibars
MaxSusWinds held at 30knots(35mph)56km/h
Vector changed from 270.3°West@25.8mph(41.5km/h) to 272.8°West@25.8mph(41.5km/h)

POS-Trinidad :: GND-Grenada :: BGI-Barbados :: SLU-St.Lucia

The easternmost dot on the connected;omes is where 92L became AL07
The next dot to the right is where AL07 became TD.7
The easternmost dot on the longest line is TD.7's most recent position

The longest line is a straightline projection through TD.7's 2 most recent positions to its closest approach (within 18miles or 29 kilometres) to a coastline
9August6pmGMT: TD.7 had been headed for passage over GrantleyAdamsInternationalAirport (bottomBGIblob)
10August12amGMT: TD.7 had been headed for passage over Bathsheba (middleBGIblob)
10August6amGMT: TD.7 had been headed for passage over HighCliffPoint (topGNDdumbbell)
10August12pmGMT: 10August12pmGMT: TD.7 was heading for passage over LittleBay (topBGIblob)
10August6pmGMT: TD.7 was heading for passage over LinnisPoint,Dennery(town) in ~23hours from now (when this comment was posted)

Copy&paste pos-10.595n61.023w, bgi-13.09n59.457w-13.198n59.488w-13.31n59.579w, gnd-12.191n61.602w,slu,axa, 13.7n41.7w-13.7n42.9w, 13.7n42.9w-13.7n44.6w, 13.7n44.6w-13.6n46.3w, 13.6n46.3w-13.6n48.6w, 13.6n48.6w-13.7n50.9w, 13.6n48.6w-13.89n60.883w into the GreatCircleMapper for a larger-scale map and other information
The previous mapping for comparison
Member Since: December 31, 1969 Posts: Comments:
722. HurricaneHunterJoe
8:48 PM GMT on August 10, 2012
Quoting washingtonian115:
I don't want to discuss politics on a WEATHER BLOG!!!!!.Their is plenty other blogs to discuss this.I want to talk about weather.I have to hear my husband,dad,mother,and brothers and sisters discuss politics on the regular bases along with my co-workers.So please take it some where else.....We know politics affect us.But this isn't the place to discuss especially when their's several tropical entities out there...


Here Here Im with you on this one!!

+1000
Member Since: December 31, 1969 Posts: Comments:
721. redwagon
8:16 PM GMT on August 10, 2012
Quoting ncstorm:
two surface lows near florida

If we could beg, borrow or steal a decent anti-cyclone over the GOM it would make use of all the moisture thrashing about. Anything for even clouds, if we can't have rain....
Member Since: December 31, 1969 Posts: Comments:
720. jascott1967
8:14 PM GMT on August 10, 2012
Quoting Jedkins01:


Stop fussing about politics and stick to weather, the other major sources are no better, just from a different end of the political spectrum.



+1000

Quickest way to get banned from this site is by talking politics. jrweatherman should not have started this garbage.
Member Since: December 31, 1969 Posts: Comments:
719. jascott1967
8:11 PM GMT on August 10, 2012
Quoting CrozetDutch:
Fox News : masters in psychology to snow millions of viewers. Propaganda channel superieure with mixes of lies and half-truths (selectively chosen) to beat democrats to pulp and idolize rightwing tea baggers and "republicans" 24/7. The most malignant cancer ever on the airwaves. One cannot call it journalism. No surprise as the boss is Roger Ailes, decades long GOP propagandist-in-chief.


Do you know what that term means, or could mean? I'm only asking because one definition of it is a vulgar slur that could get you banned from this site. I won't report you (I still believe in freedom of speech) but others may and have the right to try because of the site rules.
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718. ncstorm
8:08 PM GMT on August 10, 2012
Member Since: December 31, 1969 Posts: Comments:
717. ncstorm
8:08 PM GMT on August 10, 2012
two surface lows near florida
Member Since: December 31, 1969 Posts: Comments:
716. hericane96
8:03 PM GMT on August 10, 2012
found this on the weather channal explaning whats in the western caribbean.


An upper-level trough which brought heavy rain to the northern Caribbean islands, and whose strong high-altitude winds "sheared" the remnants of Florence, has now, on its southern periphery, contributed to the formation of a concentrated area of convection (thunderstorms) over the western Caribbean. Satellite loops show that cluster of tstorms spinning, i.e. what meteorologists call a "mesoscale convective vortex" (MCV) has formed, which can sometimes lead to surface low pressure forming. That's what happened with the recent tropical storm wannabe in the Bahamas and Florida. On the other hand, such features can dissipate after a few hours. We'll watch to see what this one does.
Member Since: December 31, 1969 Posts: Comments:
715. kwgirl
7:58 PM GMT on August 10, 2012
Quoting PalmBeachWeather:
Last year "they" were saying they were excellent to eat... Now I have heard "please be careful eating them"
Like any reef fish, they could have cigutera (SP?), which is very painful if you ingest fish with the bacteria (I think it's a bacteria). You can get it from snapper, grouper any reef fish. Mostly in the Caribbean, people get it from Barracuda. They prey on reef fish so they accumulate more. Just eat the little fish.:)
Member Since: December 31, 1969 Posts: Comments:
714. wunderkidcayman
7:56 PM GMT on August 10, 2012
Quoting BahaHurican:
[-] the posts. Works most of the time.

It's only been there for a couple days, no matter how lonw it seems... lol

I thought they were poisonous...

How come it's only wrong to forecast a storm getting close to the Caymans when you're from the Caymans???

uh...
just sayin?
...

you know so when I forecast it its wrong I don't think so
Member Since: December 31, 1969 Posts: Comments:
713. wunderkidcayman
7:54 PM GMT on August 10, 2012
I say TS watches for the Islands of Barbados, St. Vincet, St. Lucia, Martinique, Dominica and Guadeloupe at 5pm advisory
Member Since: December 31, 1969 Posts: Comments:
712. MiamiSurvivor
7:54 PM GMT on August 10, 2012
Quoting kwgirl:
Fort Jefferson is in the Dry Tortugas, about 70 miles west of Key West. It is a National Park, but the Government doesn't have the money to repair it. One of the curtain walls is falling down. They get hit with a lot of hurricanes out there. It is beautiful. Google it!


When I was a kid (early teen) I spent a week down there, camped on the beach, the Fort was my playground, the ocean my swimming pool. I understand they have roped off a lot of it now, for many reasons, to protect it. It is a very special place, and it would be a shame if the storms damaged it.
Member Since: December 31, 1969 Posts: Comments:
711. BahaHurican
7:53 PM GMT on August 10, 2012
Quoting Bluestorm5:
The big problem with political trolls is that some of them are "tropical experts" that likes to discuss politics as well. I just can't put them on ignored list in the case that this person is legal and not a troll.
[-] the posts. Works most of the time.

Quoting LargoFl:
..ive been watching that for days now, its a tropical wave that stalled there for what seems like a week now, there IS a watch for it there..still purple so far
It's only been there for a couple days, no matter how lonw it seems... lol

Quoting PalmBeachWeather:
Last year "they" were saying they were excellent to eat... Now I have heard "please be careful eating them"
I thought they were poisonous...

Quoting xtremeweathertracker:
My forecast of TD7....NOT OFFICIAL!!!
img src="Photobucket">
How come it's only wrong to forecast a storm getting close to the Caymans when you're from the Caymans???

uh...
just sayin?
...
Member Since: December 31, 1969 Posts: Comments:
710. Jedkins01
7:47 PM GMT on August 10, 2012
Quoting CrozetDutch:
Fox News : masters in psychology to snow millions of viewers. Propaganda channel superieure with mixes of lies and half-truths (selectively chosen) to beat democrats to pulp and idolize rightwing tea baggers and "republicans" 24/7. The most malignant cancer ever on the airwaves. One cannot call it journalism. No surprise as the boss is Roger Ailes, decades long GOP propagandist-in-chief.


Stop fussing about politics and stick to weather, the other major sources are no better, just from a different end of the political spectrum.
Member Since: December 31, 1969 Posts: Comments:
709. Jedkins01
7:44 PM GMT on August 10, 2012
I finally got my first good storm since Monday, got nailed with plenty of heavy rain and most of all a great light show with numerous hits close to me.

Despite the fact that below average coverage was expected into to the weekend, I guess we are finally going to be headed back to where we should, which is great because August has started way too dry after having so much rain in June and July over much of the area
Member Since: December 31, 1969 Posts: Comments:
708. kwgirl
7:34 PM GMT on August 10, 2012
Quoting BahaHurican:
This was the place in the Keys, right? Think I read a Nnevada Barr novel set there....
Fort Jefferson is in the Dry Tortugas, about 70 miles west of Key West. It is a National Park, but the Government doesn't have the money to repair it. One of the curtain walls is falling down. They get hit with a lot of hurricanes out there. It is beautiful. Google it!
Member Since: December 31, 1969 Posts: Comments:
707. BahaHurican
7:34 PM GMT on August 10, 2012
Quoting VAbeachhurricanes:


LOL cause it bashes a liberal its nonsense? I love how thats uncalled for, but if you come in here and bash Romney and Bain its fair game and no one peeps about it.
Actually, I don't need any of it here... lots of wx to talk about these days.
Member Since: December 31, 1969 Posts: Comments:
706. Msdrown
7:30 PM GMT on August 10, 2012
Quoting LargoFl:
BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
156 PM CDT FRI AUG 10 2012

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
HANCOCK COUNTY IN SOUTHERN MISSISSIPPI...
THIS INCLUDES THE CITY OF DIAMONDHEAD...
SOUTH CENTRAL PEARL RIVER COUNTY IN SOUTHERN MISSISSIPPI...

* UNTIL 245 PM CDT

* AT 152 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
EXCESS OF 60 MPH. THESE STORMS WERE LOCATED ALONG



22/TD


Yes, as you say its been booming here all morning and my weather alert has been going off every 5 min.
Member Since: December 31, 1969 Posts: Comments:
704. tedauxie
7:26 PM GMT on August 10, 2012
Quoting barbamz:
Did you read his memories on Katrina? Impressive.
http://28storms.com/about/

I just read Jason's memoirs of Katrina. They are more than just impressive. I teared-up when I finished reading the piece.

If the lad ever tires of met, he could have a helluva future as a writer.
Member Since: December 31, 1969 Posts: Comments:
703. HuracanTaino
7:26 PM GMT on August 10, 2012
Quoting WxGeekVA:


Agreed on both parts.
Might lose some of its punch while crossing the hostile zone, but would rise again like his predessor, good old Ernesto in the western Carobbean but in a more northern track of course...,
Member Since: December 31, 1969 Posts: Comments:
702. wunderkidcayman
7:25 PM GMT on August 10, 2012
wow looks like TD 7 is a stronger system it not even reached the bouy yet already seing pressure drop to 1012mb and still falling with wind at 19kts
bouy Station 41040 located at 14.477 N 53.008 W (14%uFFFD28'38" N 53%uFFFD0'28" W)

the TD is at 13.7N 50.9W

Link
Member Since: December 31, 1969 Posts: Comments:
700. 954FtLCane
7:23 PM GMT on August 10, 2012
Quoting LargoFl:
..yes i see that..supposed to move over florida this weekend..by me they have it at 50% for the weekend into monday i think

I hope you're right. I'll take rain over oppressive heat anytime!
Member Since: December 31, 1969 Posts: Comments:
699. BahaHurican
7:22 PM GMT on August 10, 2012
Quoting MississippiWx:
Well, looks like mcluvin accomplished his/her goal of riling up/trolling the blog. Look at all the responses. Lol.
We're bored while waiting to see what happens next w/ our three systems... lol

Quoting HurricaneDean07:

Really?
Are you really kidding?
Or are you just "Kidding" because you got bashed for calling this season a "Bust" by about 7 People...
I think he actually was just kidding... really.... lol

Quoting jrweatherman:
For those who can't handle the truth - I've got more:)
Just not in the WX blog, please. You will get banned if u keep it up. Look: pple have been told not to talk about the OLYMPICS in this blog... what makes u think politics is ok??? Sheesh...
Member Since: December 31, 1969 Posts: Comments:
698. VirginIslandsVisitor
7:21 PM GMT on August 10, 2012
Quoting PalmBeachWeather:
SS , Looks a a problem that is going to be tough to stop... Very nasty fish


We're also losing the battle here in the Virgin Islands with the Lion Fish. Nasty, nasty critters. Seems you can't snorkel anywhere without seeing one now.

Lindy
Member Since: December 31, 1969 Posts: Comments:
697. Msdrown
7:20 PM GMT on August 10, 2012
Quoting SFLWeatherman:
Big Rain coming in to S FL now



You posted earlier that something off to the SE was suppose to cross fla into the GOM. Is this it?
Member Since: December 31, 1969 Posts: Comments:
695. jeffs713
7:18 PM GMT on August 10, 2012
Quoting VAbeachhurricanes:


LOL cause it bashes a liberal its nonsense? I love how thats uncalled for, but if you come in here and bash Romney and Bain its fair game and no one peeps about it.

Actually, the nonsense is posted uncited "research" as fact, then being indignant when asked for citations or verification. Also, it is complete nonsense to post political attacks and questionable information on a WEATHER BLOG.
Member Since: December 31, 1969 Posts: Comments:
694. LargoFl
7:17 PM GMT on August 10, 2012
Quoting washingtonian115:
We had some very heavy rain this morning.I'm talking about torrential.When I drove through rock creek park today the water was still unsettled and rather high.In some parts you can't tell because it's humid outside.It's threatening to storm again to.The clouds have been ominous,and it's also been windy.
..the whole east coast is getting it, some real badly too
Member Since: December 31, 1969 Posts: Comments:
693. HuracanTaino
7:17 PM GMT on August 10, 2012
Quoting PalmBeachWeather:
My suggestion to you after the last hour ..........Sssshhhhh. Just an opinion
or I could say the same about the other "guy" but this aint the place or the forum for politics...
Member Since: December 31, 1969 Posts: Comments:
692. WunderAlertBot (Admin)
7:16 PM GMT on August 10, 2012
JeffMasters has created a new entry.
691. SouthTampa
7:16 PM GMT on August 10, 2012
Quoting LargoFl:
.....................................GT we are surrounded lol...first few raindrops starting to fall here by me
Big downpour here at ACH.
Member Since: December 31, 1969 Posts: Comments:
689. LargoFl
7:16 PM GMT on August 10, 2012
Quoting Hurricane1956:
Very interesting,it seems that all the action this Hurricane Season will be in the Caribbean??,to close for comfort!!!!,for us here in South Florida.
..yes i think the NWS said back in march..for us to be on the lookout this season for the local storms that form near us
Member Since: December 31, 1969 Posts: Comments:
688. SSideBrac
7:16 PM GMT on August 10, 2012
Quoting PalmBeachWeather:
SS, Where are you?


Cayman Islands - Cayman Brac - Yes - another one from Cayman
Member Since: December 31, 1969 Posts: Comments:
687. VAbeachhurricanes
7:15 PM GMT on August 10, 2012
Quoting CajunCrawfishhunter:


Maybe because this is a weather blog not a politics blog.. just saying...


Right, and no one ever talks about anything other than weather here.

Anyway, here is the big picture:


07L dealing with a lot of dry air to its north and west. A nice slow moving cold front is draped along the eastern CONUS. And a surface trough south of Cuba is being enhanced by the divergence that is being created by a TUTT of to its NE.
Member Since: December 31, 1969 Posts: Comments:
686. washingtonian115
7:15 PM GMT on August 10, 2012
We had some very heavy rain this morning.I'm talking about torrential.When I drove through rock creek park today the water was still unsettled and rather high.In some parts you can't tell because it's humid outside.It's threatening to storm again to.The clouds have been ominous,and it's also been windy.
Member Since: December 31, 1969 Posts: Comments:
685. xtremeweathertracker
7:15 PM GMT on August 10, 2012
My forecast of TD7....NOT OFFICIAL!!!
img src="Photobucket">
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684. PalmBeachWeather
7:14 PM GMT on August 10, 2012
Quoting SSideBrac:


Whoops - checks all my body parts, heart beat etc - fine so far - but TY for tip
SS, Where are you?
Member Since: December 31, 1969 Posts: Comments:
683. LargoFl
7:14 PM GMT on August 10, 2012
Quoting HondosGirl:
It's rumbling up again here in Northwest Florida. Expecting today's third round of heavy rain and lighting to arrive shortly.
..stay safe up there ..lots of lightning today with these storms, went outside before and I cant remember the sun being THIS hot before, and ive been here for a long time, the strong heat and ALOT of humidty..the storms are strong, and possibly dangerous today
Member Since: December 31, 1969 Posts: Comments:
682. MississippiWx
7:14 PM GMT on August 10, 2012
Quoting kmanislander:
An interesting race is developing between a ULL digging down from the N of TD7 and the depression itself trying to scoot to the West underneath it before it can impart too much shear over the circulation. At the present forward speed TD7 may win that race.

See WV loop here


Yeah, I was mentioning that last night during the night shift. It's often difficult for models to predict the movement of TUTTs accurately. They are often times to quick with moving them.
Member Since: December 31, 1969 Posts: Comments:
681. SSideBrac
7:14 PM GMT on August 10, 2012
Quoting PalmBeachWeather:
Last year "they" were saying they were excellent to eat... Now I have heard "please be careful eating them"


Whoops - checks all my body parts, heart beat etc - fine so far - but TY for tip
Member Since: December 31, 1969 Posts: Comments:
680. LargoFl
7:12 PM GMT on August 10, 2012
Quoting Abacosurf:
From 2 pm discussion.

What the heck does the last sentence mean.....LOl


A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 86W/87W FROM 25N
INTO COASTAL HONDURAS MOVING THROUGH THE YUCATAN CHANNEL.
THE WAVE IS MOVING OUT OF AND AWAY FROM THE AREA OF THE WESTERN
ATLANTIC OCEAN-TO-SOUTHEASTERN GULF OF MEXICO-TO WESTERN
CARIBBEAN SEA UPPER LEVEL TROUGH. IT IS DIFFICULT TO ASSOCIATE
ANY CONVECTIVE PRECIPITATION THAT JUST ACCOMPANIES ONLY THE
TROPICAL WAVE
..looks like it means they see rain but its all around the wave but its hard to tell if the rains are WITH the wave
Member Since: December 31, 1969 Posts: Comments:
679. kmanislander
7:12 PM GMT on August 10, 2012
An interesting race is developing between a ULL digging down from the N of TD7 and the depression itself trying to scoot to the West underneath it before it can impart too much shear over the circulation. At the present forward speed TD7 may win that race.

See WV loop here
Member Since: December 31, 1969 Posts: Comments:
678. HondosGirl
7:12 PM GMT on August 10, 2012
It's rumbling up again here in Northwest Florida. Expecting today's third round of heavy rain and lighting to arrive shortly.
Member Since: December 31, 1969 Posts: Comments:
676. Abacosurf
7:11 PM GMT on August 10, 2012
Quoting Hurricane1956:
I just wondering is a low is trying to form south of Western Cuba,you can see a define spin in that area, a lot of moisture around,maybe another Invest?,the way things are going in the tropics now,it will not surprise me to see something developing south of Cuba,I remember a couple of days ago,the CMC model having a system forming in that area and moving North,it dosen't show it anymore but at one point it did.Will see!!
Actually a tiny spin there and just SSE of key west.
Member Since: December 31, 1969 Posts: Comments:
675. Hurricane1956
7:11 PM GMT on August 10, 2012
Quoting LargoFl:
..ive been watching that for days now, its a tropical wave that stalled there for what seems like a week now, there IS a watch for it there..still purple so far
Very interesting,it seems that all the action this Hurricane Season will be in the Caribbean??,to close for comfort!!!!,for us here in South Florida.
Member Since: December 31, 1969 Posts: Comments:
674. SSideBrac
7:11 PM GMT on August 10, 2012
Time to sit back - shrug off any prevailing "Caribbean blob phobia" and observe, identify, assess and act(as required).
Member Since: December 31, 1969 Posts: Comments:

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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather

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