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

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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

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BEGIN
NHC_ATCF
invest_ep942012.invest
FSTDA
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201208101814
NONE
NOTIFY=ATRP
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EP, 94, 2012081018, , BEST, 0, 170N, 1025W, 25, 1005, DB
Member Since: Posts: Comments:
Quoting mcluvincane:


Not a troll by no means, i was just trying to live up the blog. Seems a bit down to me lately.
I'm ok with you.........
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Quoting PalmBeachWeather:
I give everyone benefit of the doubt..We have all said things we regret saying. Sometimes you eat the bear, and sometimes the bear eats you.... That's the way it is


Not a troll by no means, i was just trying to live up the blog. Seems a bit down to me lately.
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Quoting kwgirl:
Did you know that he helped in the prison, Fort Jefferson, with the yellow fever epidemic when the Doctor at the fort died? That's how he got his pardon, I was told. Pardoned to go work in Panama.
This was the place in the Keys, right? Think I read a Nnevada Barr novel set there....
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Quoting ParanoidAndroid:


Well I've been lurking so far all season but I just had to login here to POOF! this troll. Life is just a tad bit better now.
I give everyone benefit of the doubt..We have all said things we regret saying. Sometimes you eat the bear, and sometimes the bear eats you.... That's the way it is
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Threat for spinup tornadoes in my area today:

MESOSCALE DISCUSSION 1734
NWS STORM PREDICTION CENTER NORMAN OK
0103 PM CDT FRI AUG 10 2012

AREAS AFFECTED...PARTS OF SERN NEW ENGLAND

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 101803Z - 101930Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...TRENDS ARE BEING MONITORED FOR THE POSSIBILITY OF AN
INCREASING SEVERE THREAT...WHICH CURRENTLY APPEARS A BIT
MARGINAL...BUT COULD REQUIRE A WATCH WITHIN THE NEXT HOUR OR TWO.

DISCUSSION...A DISTINCT CYCLONIC VORTICITY CENTER AND ASSOCIATED
40-50 KT 500 MB JET STREAK...EMBEDDED WITHIN BROAD SOUTHWESTERLY
FLOW EAST OF THE LOWER GREAT LAKES CYCLONE...CONTINUES NORTHEASTWARD
ACROSS THE LONG ISLAND AREA AT AROUND 25-30 KT. A CLUSTER OF
VIGOROUS CONVECTION ACCOMPANIES THIS FEATURE...SUPPORTED BY LIFT OF
HIGH MOISTURE CONTENT AIR /CHARACTERIZED BY PRECIPITABLE WATER IN
EXCESS OF 2 INCHES...SURFACE DEW POINTS ABOVE 70/ WHICH EXTENDS IN A
CORRIDOR NEAR...BUT SLOWLY BEGINNING TO SHIFT EAST OF ATLANTIC
COASTAL AREAS.

AS THE MID-LEVEL CIRCULATION MIGRATES TOWARD EASTERN
MASSACHUSETTS/THE CAPE COD AREA...BETWEEN NOW AND 21-22Z...THE
CLUSTER OF STORMS WILL OVERSPREAD MUCH OF SOUTHEASTERN NEW ENGLAND.
GIVEN THE MOIST PROFILES WITH WEAK LAPSE RATES...HEAVY RAINFALL
APPEARS THE PRIMARY SEVERE THREAT...BUT EMBEDDED SUPERCELLS WITH
SOME POTENTIAL FOR TORNADOES MAY NOT BE COMPLETELY OUT OF THE
QUESTION. THIS THREAT LARGELY HINGES ON THE STRENGTH OF THE
SOUTHERLY LEVEL-LEVEL FLOW AND ASSOCIATED NEAR SURFACE VERTICAL
SHEAR. LOW-LEVEL HODOGRAPHS CURRENTLY APPEAR SOMEWHAT WEAK...BUT
MODEST STRENGTHENING AT WINDS AT 850 MB IS FORECAST ACROSS PARTS OF
RHODE ISLAND/EASTERN MASSACHUSETTS DURING THE NEXT FEW HOURS.

..KERR/CORFIDI.. 08/10/2012

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Quoting waveRoller:


Love it.

thanks!


Did you read his memories on Katrina? Impressive.
http://28storms.com/about/
(Scroll down)
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561. SLU
10/1745 UTC 17.1N 21.5W TOO WEAK 93L
10/1745 UTC 13.8N 51.1W T1.5/1.5 07L
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Any thoughts on the W. Caribbean blobbage? Looks nice 'n wet, but I didn't see any good outflow on it as of sat pic a few minutes ago. I'd just like to know where we think that's headed -- assuming it can hang together.
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Quoting mcluvincane:
Just kidding lmao!! I knew i would get that kinda response lol. You guys are nuts. Hell, i waiting on the big one. I'm here till the end


Well I've been lurking so far all season but I just had to login here to POOF! this troll. Life is just a tad bit better now.
Member Since: Posts: Comments:


It's trying to get a little more convective organization, but still a long way to go.
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I respect what you are saying and I am sure you know more about weather and tropical systems than I do but to call this season a bust? If el nino does develop quicker than storm totals will be less but looking at the season still ahead and having 3 landfalls (2 florida and 1 Yucatan), I would say recurves have not happened that much. Also, the high weakening? It could not be that weak if Ernesto and TD 7 are going west. The high is stronger this year than the previous three years. There are probably going to be some recurves in any season regardless of a strong high or not. I would not count this season out yet. The most active part of the season and dangerous is still yet to come especially home grown storms. The caribbean and the gulf are very warm and trade winds near normal. Is it possible this hurricane season could be a bust? Yeah, it's possible but it's also possible to have an average active or even above active season. If anyone disagrees with me, please prove me wrong.
Member Since: July 12, 2010 Posts: 0 Comments: 1133
Quoting Tribucanes:
NHC, come on keep it real, Ernesto is a TS now without a doubt imo. Looking for the NHC to come out with the statement that Ernesto did the rare feat of making the crossover. Ernesto never changed entities, COC didn't die, it simply relocated.


It's a tough call, but I can relate to NHC's thinking on it. The LLC was truly disrupted as expected, becoming quite diffuse to point I couldn't identify a coherent, trackable center from sat imagery and obs which remains the NHC's criteria for cross-basin continuity... although a somewhat broad circulation in "low level" wind field via MX observations, such as between Mexico City and Acapulco has been apparent... At any rate a new LLC is trying to form now along / off the coast - ha, past day the strong convection bursting out along MX's SW coast in response has been calling out, "Hey Erny, look we found another warm water source, come on over!"...

LOL, I did get a kick outta NHC's change in outlook on the probability the mid-upper vortex would survive the trek across to either regenerate or reform another TC, as many of us pointed out since about last Sunday via GFS forecast analysis - I thought might had a chance to retain it's name had it made a shorter, less disruptive trip across, say dropping more SW-ward to re-emerge... Anyway, we all know the now 70% chance development originated directly from Ernesto, more clearly so than the Alma / Arthur connection in 2008.

Later friends...
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Be back later...
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Largo.........It seems like your little quadrant of Florida has been getting hammered with the storms lately... It seems like here in Palm Beach county we get the same thing... Many say it is because of Lake Okeechobee.......Not sure, but we sure do get our share of bad storms here
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wow the whole east coast is gonna get the heavy rains in the forecast
Member Since: August 6, 2011 Posts: 4 Comments: 42264
Quoting wunderkidcayman:

hey I did not say is more likely I said is moving that means I just looked at it on WV and its moving N

and currently TD7 has a very weak anticyclone on it I'm thinking it will move into the caribbean and a bigger one will be provided when it reaches

these TUTTs have a tendency to change against forcast sometimes




I think conditions will be good enough for it to be alive and some slight strengthening maybe 5-10kt higher

and plus things change nothing is really as we expect anymore

I guess so...
E.I. Debby and Ernesto...

I only expect it to be a 45 Mph TS when it reaches the islands... and 50 Mph TOPS in the central caribbean... Once it reaches the Western caribbean, 65-70 is possible :)
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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...


Kidding, I've been tracking storms way to long to call it this early. I did that one year and Opal was at my front door a week later
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539
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look guys I am not expecting conditions to be perfect but just good enough
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Member Since: August 6, 2011 Posts: 4 Comments: 42264
Quoting HurricaneDean07:

No shield to protect you tonight...
..lol..shields being serviced lol
Member Since: August 6, 2011 Posts: 4 Comments: 42264
Quoting jeffs713:

Actually, the ULL in the Western Caribbean is more likely to push west, since there is a trough coming to the east coast. Also, TD7 already has an anticyclone. But the TUTT isn't forecast to do much except create shear.

hey I did not say is more likely I said is moving that means I just looked at it on WV and its moving N

and currently TD7 has a very weak anticyclone on it I'm thinking it will move into the caribbean and a bigger one will be provided when it reaches

these TUTTs have a tendency to change against forcast sometimes


Quoting HurricaneDean07:


I think conditions will be good enough for it to be alive and some slight strengthening maybe 5-10kt higher

and plus things change nothing is really as we expect anymore
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Quoting LargoFl:
....................................yep its going to be a wild weekend here alright, starting early too

No shield to protect you tonight...
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Quoting Grothar:
I've been listening to this guy for years. It is a nice link.




Link





Love it.

thanks!
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....................................yep its going to be a wild weekend here alright, starting early too
Member Since: August 6, 2011 Posts: 4 Comments: 42264
I'm just glad it's Friday
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Quoting mcluvincane:
Just kidding lmao!! I knew i would get that kinda response lol. You guys are nuts. Hell, i waiting on the big one. I'm here till the end

Really?
Are you really kidding?
Or are you just "Kidding" because you got bashed for calling this season a "Bust" by about 7 People...
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lol!
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...was boomers east of me, high dark clouds too but they moved on..looks like someone else is getting the storms and lightning
Member Since: August 6, 2011 Posts: 4 Comments: 42264
Quoting MississippiWx:
Well, looks like mcluvin accomplished his/her goal of riling up/trolling the blog. Look at all the responses. Lol.

534.
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Quoting mcluvincane:
Just kidding lmao!! I knew i would get that kinda response lol. You guys are nuts. Hell, i waiting on the big one. I'm here till the end


im mcluvin it....
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I think Mcluvincane is just being an attention whore, to get everyone to quote him/her...
Comments:
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Sarcasm Flag: Partially ON
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Quoting mcluvincane:
Just kidding lmao!! I knew i would get that kinda response lol. You guys are nuts. Hell, i waiting on the big one. I'm here till the end
Yea right
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Quoting wxchaser97:

Todays date: August 10th, still lots of time left and the wave train is getting into full swing. We aren't even in peak season yet. Rethink that and don't give up of forget about this hurricane season.
Not to mention there wasn't much going on until Irene entered the picture last year, which is 10 days from now and after that the Tropics stayed active and didn't end until November. 2009 which was also an El Nino didn't end until November. So still plenty of time and I wouldn't doubt we have 3 tropical systems simultaneously spinning at one time.
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Quoting mcluvincane:
One can almost hear a faint voice coming from the fat lady on the hurricane season, guess she's looking at the euro and GFS lol. The conus will more than likely be spared yet once again from a strong hurricane, something i think will be a trend for a few more years which is a good thing. I was hoping for a tropical system to help out with the drought but that just ain't going to happen with this set up. The door was open for a CONUS strike but now has quickly shut. The strong high has broken down allowing for recurvature to happen. The trade winds in the Caribbean are way to high to allow a storm to develope. El nino will be arriving soon also (officially), it's already here if u ask me but that will more than likely put the final nail in this years hurricane season. Putting away my tracking charts, deleting my tracking software and I'm done this year.



have fun digging them out for the season in a few weeks
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unless system is organized enough and northward to feel the pull north, hard to see a trough picking this up. I see your point but the high above too strong
Member Since: July 12, 2010 Posts: 0 Comments: 1133
Well, looks like mcluvin accomplished his/her goal of riling up/trolling the blog. Look at all the responses. Lol.
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Dude........?
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Quoting mcluvincane:
One can almost hear a faint voice coming from the fat lady on the hurricane season, guess she's looking at the euro and GFS lol. The conus will more than likely be spared yet once again from a strong hurricane, something i think will be a trend for a few more years which is a good thing. I was hoping for a tropical system to help out with the drought but that just ain't going to happen with this set up. The door was open for a CONUS strike but now has quickly shut. The strong high has broken down allowing for recurvature to happen. The trade winds in the Caribbean are way to high to allow a storm to develope. El nino will be arriving soon also (officially), it's already here if u ask me but that will more than likely put the final nail in this years hurricane season. Putting away my tracking charts, deleting my tracking software and I'm done this year.
I guess they want you to get the hell out of Dodge.... LOL... Matt Dillon would say the same
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Quoting dfwstormwatch:
Link

Yaaaaa about your "El Nino" have fun sitting on the sidelines why we enjoy our above average season

slightly* above average season
still more enjoyable than a 2006-09 season :)
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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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