Danielle a hurricane; TD 7 forming off coast of Africa

By: Dr. Jeff Masters , 2:18 PM GMT on August 24, 2010

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Hurricane Danielle has stopped intensifying and is now looking a bit ragged this morning, but remains a respectable Category 1 hurricane with 80 mph winds. The intensity of Danielle's heavy thunderstorms has waned in the past few hours, and the organization of the storm is less impressive. This is probably due do strong upper-level winds out of the west that are creating a moderate 10 - 20 knots of wind shear, and injecting some of the dry air from the Saharan Air Layer (SAL) that surrounds Danielle. Danielle is over warm 28°C water, but is far from any land areas.


Figure 1. Morning satellite image of Tropical Storm Danielle (left side of image) and the forming Tropical Depression Seven (right side of image.)

Forecast for Danielle
A powerful trough of low pressure over the mid-Atlantic Ocean will begin to pull Danielle more to the northwest by Wednesday, keeping Danielle well to the east of Bermuda. Most of the models predict that this trough will be strong enough to fully recurve Danielle out to sea. It is possible that Danielle could eventually threaten Newfoundland, Canada, but it currently does not appear that any other land areas will be at risk from this storm. History suggests that a storm in Danielle's current location has only a 20% chance of making landfall on the U.S. East Coast. If Danielle passes east of Bermuda, as forecast, these percentages drop to less than 5%. As far as intensity goes, it is looking unlikely that Danielle will attain major hurricane status (115+ mph winds.) There is enough dry air and wind shear affecting the storm today that it will take several days for the storm to recover its strength, making it less likely the storm can hit Category 3.

The formation of Danielle is remarkable in this it was successfully forecast by the GFS model nearly two weeks in advance. The ECMWF and NOGAPS models also did a good job of predicting Danielle's formation a week in advance. The models are getting better and better each year at forecasting genesis of tropical cyclones, though a successful 1-week forecast of genesis is still a rarity. For example, none of the models foresaw the development of 96L until just 3 - 4 days ago.


Figure 2. Plot showing historically the percent chance of a tropical cyclone in a given location impacting the U.S. East Coast. For storms in Danielle's current position (orange hurricane symbol), about 20% of them go on to hit the U.S. East Coast. For storms in 96L's current location (red circle with a "?" in it), the odds are also 20%. Image credit: Bob Hart, Florida State University.

96L (soon to be Tropical Depression Seven)
Satellite images suggests that a tropical wave (96L) that emerged off the coast of Africa yesterday morning has developed a closed circulation, low-level spiral bands, and an increasing amount of heavy thunderstorms. While this morning's ASCAT pass does not show a clear closed circulation, satellite estimates of 96L's strength support calling this a 30 mph tropical depression. It is likely that this storm will be designated Tropical Depression Seven later today. 96L is already bringing heavy rain and strong, gusty winds to the southern Cape Verde Islands. Winds were sustained at 26 mph at Mindelo in the northwest Cape Verde Islands this morning, and 24 mph at Praia, the station closest to the center of 96L. Both stations were reporting widespread dust, due to strong winds blowing Saharan dust from the coast of Africa. However, water vapor satellite images show that only a modest amount of dry air is accompanying this dust, and dry air is currently not a major detriment to 96L. Wind shear is about 10 - 20 knots, and sea surface temperatures are warm, 28°C.

Forecast for 96L/Tropical Depression Seven
Wind shear is predicted to remain low, 5 - 10 knots, for the next four days. SSTs will cool a bit to 27°C by Thursday, but this is still above the 26.5°C threshold for hurricane development. Dry air will probably be the main inhibiting factor for 96L. Most of the intensity forecast models bring 96L to hurricane strength by four days from now, and this is a reasonable forecast. 96L should become Tropical Storm Earl later today or on Wednesday, and will probably bring sustained winds of 40 mph to the southernmost Cape Verdes Islands tonight and Wednesday.

The long range fate of 96L remains unclear. The storm is being steering by the same ridge of high pressure steering Danielle, and will initially follow a track similar to Danielle. 96L may encounter the cold waters stirred up by Danielle at times this week, inhibiting development. As 96L approaches the central Atlantic five days from now, the storm will encounter the same mid-Atlantic trough that will be steering Danielle, and 96L should turn more to the northwest. It is unclear at this point whether this trough will be strong enough to fully recurve 96L out to sea, east of Bermuda. This will, in part, depend upon how strong Danielle gets. A stronger Danielle is likely to create more of a break in the ridge of high pressure steering 96L, encouraging the storm to turn north and recurve out to sea. A weaker Danielle will make 96L more likely to miss recurvature, and follow a track to the west or west-northwest towards the U.S. East Coast early next week. History suggests that a storm in 96L's current location has only a 20% chance of making landfall on the U.S. East Coast.

When will the Caribbean and Gulf of Mexico get active?
The large scale atmospheric circulation over the Caribbean and Gulf of Mexico currently features relatively dry, stable, sinking air. This is due, in part, to the Madden-Julian oscillation (MJO). The Madden-Julian oscillation is a pattern of enhanced rainfall that travels along the Equator from west to east. The pattern has a wet phase with large-scale rising air and enhanced thunderstorm activity, followed by a dry phase with large-scale sinking air and suppressed thunderstorm activity. Each cycle lasts approximately 30 - 60 days. When the Madden-Julian oscillation is in its wet phase over a hurricane-prone region, the chances for tropical storm activity are greatly increased. The latest MJO forecast from the GFS model calls for the wet phase of the MJO to move into the Caribbean during the first week of September. However, keep in mind that forecasts of MJO activity 1 - 2 weeks in advance are not very skillful. The GFS model forecast of MJO activity made two weeks ago did fairly well for the first week, but poorly for the second week of the forecast.

Tropical Storm Frank spares Mexico
Over in the Eastern Pacific, Tropical Storm Frank has moved away the coast far enough from the Mexican coast to no longer pose a heavy rainfall threat, and all tropical storm warnings have been dropped.

"Hurricane Haven" airing again this afternoon
Tune into another airing of my live Internet radio show, "Hurricane Haven", at 4pm EDT today. Listeners will be able to call in and ask questions. The call in number is 415-983-2634, or you can post a question in the comments area on my blog during the show. You can also email the questions to me today before the show: jmasters@wunderground.com. Be sure to include "Hurricane Haven question" in the subject line. I'll focus on Danielle, Earl, and Frank, and discuss the possibilities of a hyperactive Atlantic hurricane period coming during the first week of September.

Today's show will be 30 - 45 minutes, and you can tune in at http://www.wunderground.com/wxradio/wubroadcast.h tml. The show will be recorded and stored as a podcast.

Jeff Masters

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Quoting TXEER:


I'm sorry Amanda but y'all don't sound too bright!

The only good thing about IKE was my wife and I snuggled up in the laundry room on a mnattress and drank two bottles of very expensive red wine...figured if I was going out it would be in style.

I'm ready this time though...bought an $8,000 22,000 BTU natural gas generator...I will not go without electric and AC for 13 days ever again!
Amen. I sat for three days waiting for Frances to leave. Then another nine waiting for the electricity to turn back on. The wind and rain were fun for awhile but soon turned into pure hell.
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Quoting traumaboyy:


come on by and grab a cup in the morning....will still be here manning the lighthouse till sunup


sounds good man. :) figger it'll be a while till i go to sleep, anywho... tomorrow's gonna be a long day.
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2497. JLPR2
Quoting serialteg:


finally we see some systems starting to knock our door...


Looks like we are set for some close calls, I do hope they turn out to be close calls and not anything worse. :|
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2496. will45
Quoting txsweetpea:

Thanks


u r welcome
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Quoting TXEER:


I'm ready this time though...bought an $8,000 22,000 BTU natural gas generator...I will not go without electric and AC for 13 days ever again!


we really need a facebook-style "likes this" button for our blog :)
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Quoting will45:


would be Thursday im thinking

Thanks
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2492. smuldy
Quoting F4PHANTOM:
Anyone believing this garbage?
depends on what garbage you speak of
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2491. TXEER
Quoting Amanda44:
Back to TXEER, I am in Sugar Land, although I used to live in Kingwood. I was living in Humble during Alicia. If you were here during Ike.. didn't you find it just a little exciting at the very least?

The sounds the storm makes at night.. sounds like a giant walking around on your roof? (I have no idea what made that sound) and the sound that was coming down the chimney and the weird clanking and the sound of trees cracking? We thought several times the roof was just going to lift right off. It was all just so exciting.. of course we made a party out of it..the whole family all holed up in one house. (27 of us) My brother lives down in Clear Lake and nephew goes to school at UTMB in Galveston. Of course my dad nearly killed all of us running the generator IN THE HOUSE with all the windows and doors closed! (he's getting old.. guess he wasn't thinking..)



I'm sorry Amanda but y'all don't sound too bright!

The only good thing about IKE was my wife and I snuggled up in the laundry room on a mnattress and drank two bottles of very expensive red wine...figured if I was going out it would be in style.

I'm ready this time though...bought an $8,000 22,000 BTU natural gas generator...I will not go without electric and AC for 13 days ever again!
Member Since: Posts: Comments:
2490. will45
Quoting F4PHANTOM:
Anyone believing this garbage?


not me ha ha
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Danielle is starting to look very impressive on satellite imagery again... the CDO is parked right over the center, there is good outflow on every side except the west, and it seems to have completely eliminated the dry air.

Tropical Floater IR4 Imagery Loop

I'm willing to bet this will be back up to a cat 2 in relatively short order.
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Quoting serialteg:


New Periphery album is the best i've heard since the latest Faceless.



Got to wake up at 5am for a full day of work... so I'll have my "coffee" tomorrow morning, probably a Monster energy drink (green one) or the Lost. :D With some wunderground blogging, to boot, before i head out into the world.


come on by and grab a cup in the morning....will still be here manning the lighthouse till sunup
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2487. will45
I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. SUCCEEDING DAY OUTLOOK.....NEGATIVE.
3. REMARKS: THE NASA DC-8 WILL FLY AN 8-HR RESEARCH
MISSION IN THE GULF OF MEXICO TODAY AT 38,000 FT.
TAKEOFF TIME IS 24/1400Z.
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2486. xcool
ChrisDcat5Storm yep.i'm used 3 Satellite Imagery .GOES-East 4 km VIS/IR2 Floater 1

Infrared Channel 2 Loop


Shortwave Albedo
Member Since: September 26, 2009 Posts: 2 Comments: 15670
Quoting JLPR2:


Hiya!
Saludos desde el área norte! XD


finally we see some systems starting to knock our door...
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Quoting weatherman566:


There might be a low that forms from a stationary front in the Gulf, but nothing significant will develop from it.

Houston looks fine for the next 10 days.

The blobs the forecasters look at are tropical waves. These waves sometimes produce an area of low pressure. If these waves look promising....in other words, they have potential to develop, the National Hurricane Center will designate the wave as an invest. They number it 90-99 for invests, and label it L for Atlantic.

And, really, you shouldn't hope for storms hitting your area. They hurt the economy. Mmmkay?


Thank you very much for the info. I know I shouldn't wish for the storms.. actually cost me thousands of dollars in damage to my house, but still I can't help it.. inside of me.. I just love the excitement.

Sorry for the interruption in all the scientific talk, won't bother yall again. Just was curious about those invests and the new blobs. :)
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Quoting fatlady99:


Indeed. As much as possible.


New Periphery album is the best i've heard since the latest Faceless.

Quoting traumaboyy:
Fresh coffee.....Who needs a cup??


Got to wake up at 5am for a full day of work... so I'll have my "coffee" tomorrow morning, probably a Monster energy drink (green one) or the Lost. :D With some wunderground blogging, to boot, before i head out into the world.
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2480. will45
Quoting txsweetpea:
Are the HH scheduled to go out tomorrow? Maybe?


would be Thursday im thinking
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2473. CaicosRetiredSailor 4:52 AM GMT on August 25, 2010

seems to me she continues to go further south than they are thinking

just looked back at the 11pm 2 days ago and the NHC had her crossing 50W between 21N and 22N
Member Since: March 10, 2010 Posts: 1 Comments: 7677
2478. JLPR2
Quoting serialteg:

JLPR ... compañero... desde ponce, saludos


Hiya!
Saludos desde el área norte! XD
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Are the HH scheduled to go out tomorrow? Maybe?
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Quoting xcool:
Danielle move wnw at 15mph


didnt u say west earlyer?
Member Since: Posts: Comments:
Back to TXEER, I am in Sugar Land, although I used to live in Kingwood. I was living in Humble during Alicia. If you were here during Ike.. didn't you find it just a little exciting at the very least?

The sounds the storm makes at night.. sounds like a giant walking around on your roof? (I have no idea what made that sound) and the sound that was coming down the chimney and the weird clanking and the sound of trees cracking? We thought several times the roof was just going to lift right off. It was all just so exciting.. of course we made a party out of it..the whole family all holed up in one house. (27 of us) My brother lives down in Clear Lake and nephew goes to school at UTMB in Galveston. Of course my dad nearly killed all of us running the generator IN THE HOUSE with all the windows and doors closed! (he's getting old.. guess he wasn't thinking..)

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2474. will45
tropicalamanda?
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Eye passes 50 W
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2472. xcool
lol
Member Since: September 26, 2009 Posts: 2 Comments: 15670
2471. will45
Quoting F4PHANTOM:
YES!!!!! RUN for the hills



lolololol
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2469. xcool
Danielle move wnw at 15mph
Member Since: September 26, 2009 Posts: 2 Comments: 15670
2468. will45
that name Amanda does that ring a bell to anyone else?
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will the GOM get active or will be the Atlantic for most of the season this year???
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Quoting serialteg:


you like meshuggah too?


Indeed. As much as possible.
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2465. xcool


WOW HMM

UPDATE
Member Since: September 26, 2009 Posts: 2 Comments: 15670
Fresh coffee.....Who needs a cup??
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Quoting Amanda44:
Hello weather peeps! I am new here and have been reading this blog because yall all seem to be weather rocket scientists to me. I have lived in Houston TX all my life.. been through Alicia, and Ike...and this may sound crazy but I ALWAYS wish for a hurricane every year to come here! Even after living for 2 weeks with no power in the heat after Ike.. I still am ready for another one to blow through here.

Here is my question.. I don't understand any of the lingo or know what any of the blobby looking maps with various looking blobs and squiggly lines mean, so can any of you tell me if you think any of these lovely blobs that you all are talking about have a chance of coming to my town (Houston)for a visit?

Also why do they call them "invests"? Why do they call some of the colored blobs invests and others not? I got all excited about that new yellow blob in the GOM (see I can learn some lingo) but wondered how come it wasn't an "invest".

Love a good storm and hoping for one to come my way! I know I am not supposed to admit that though!! Not PC!

Back to your regularly scheduled weather mumbo jumbo talk! (no offense.. just wish I knew what yall were talking about!)


There might be a low that forms from a stationary front in the Gulf, but nothing significant will develop from it.

Houston looks fine for the next 10 days.

The blobs the forecasters look at are tropical waves. These waves sometimes produce an area of low pressure. If these waves look promising....in other words, they have potential to develop, the National Hurricane Center will designate the wave as an invest. They number it 90-99 for invests, and label it L for Atlantic.

And, really, you shouldn't hope for storms hitting your area. They hurt the economy. Mmmkay?
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2461. xcool


Member Since: September 26, 2009 Posts: 2 Comments: 15670
Quoting jason2010xxxx:
WATCH OUT IF YOU LIVE IN CAPE CODE.


They are perfectly aligned.... this scenario looks unreal!
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2459. TXEER
Quoting serialteg:


you like meshuggah too?



there's quite a few around here who share her nutty enthusiasm... ;)

JLPR ... compañero... desde ponce, saludos


IKE was enough for me...been there and done that!!
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Have to give the GFS credit this year. 500mb anomalies were forecast along the east coast some time ago, followed by a mean trough position over the great lakes. One happened, lets see about #2, looking at surface maps, may be a pattern change in store soon.

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Quoting fatlady99:


You are one mashugganah schmagehgie. I'm just sayin'....!


you like meshuggah too?

Quoting TXEER:


I live in Kingwood..and...dude you are NUTZ!!


there's quite a few around here who share her nutty enthusiasm... ;)

JLPR ... compañero... desde ponce, saludos
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If that massive weakness is in place that the GFS has been advertising for over a week the only threat will be Bermuda. The EC will be in the all clear. Nothing is going to hit the US EC until that gap is bridged. Looks like right now Bermuda could get a 1 2 punch.
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2455. xcool


Gulf of Mexico
Member Since: September 26, 2009 Posts: 2 Comments: 15670
2453. will45
96L got Bermuda on this run also
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I am seeing an upper level low just north of danielle. Does anyone have a thought on how this will affect her? TIA
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GFS takes all 3 systems out to sea

but Danielle and "Earl" do impact Bermuda
Member Since: March 10, 2010 Posts: 1 Comments: 7677
Good Night, I will be returning on Wednesday for new updates on Danielle and soon to be Earl. See ya.
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2449. xcool
Tropical Cyclone Formation Alert

96L
Member Since: September 26, 2009 Posts: 2 Comments: 15670

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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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