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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2799. smuldy
Quoting LongGlassTube:


Although it appears that Danielle has finally started to turn a little to the north she has ignored the models for quite some time now. It is totally possible for not only a Bermuda hit but also New Foundland. I guess for some anything besides a US impact is a fish.
wow--i was being sarcastic because someone declared everyone clear of all CV storms this season; it is WAY too far out to rule out a hit from future Earl, Danielle will likely effect Bermuda and after that anywhere from jersey to eastern canada needs to watch carefully, if the sarcasm there didn't come across i don't know that it ever can especially given danielle is at 50w now without having turned-jeesh
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2797. BigToe
OK Ladies and Gentlemen,

Love to lurk the blog but after the french toast comments, I had to go to the kitchen and MAKE FRENCH TOAST. I will now slip back into the shadows and enjoy the ride.
Big Toe lurks
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2796. pottery
Quoting traumaboyy:


Thank you Sir....Has been an Interesting night but Quiet for now...30 more minutes....Don't talk too loud you will wake them up!!

(whispers...ok)
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Quoting IKE:
IF.....it follows the center line of the track it would pass at least 150 miles east of Bermuda. IF it does they will come out okay with Danielle. The 34 knot winds extend 90 miles to her NW right now.


For what its worth, Ike does say "IF" in his observations, I don't see him saying anything in definites, his observations have been very good so far.
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well i have sat long enough hoping... well 2 years now and I just have to vent here.

WISHCASTER - NO

HONEST AMERICAN TRYING TO SURVIVE - YES

Why can't a storm hit somewhere? Last year I watched wind shear and SAL tear up every freakin storm, now I have to sit here and watch this "extremely active" season produce a bunch of crap that just stirs up the water and don't do anything but get me excited. Why can't I get a storm? I would settle for a Cat3, Katrina was nice, but that was too long with no power for everyone in the area and people turned to shootin each other over stupid crap.

There Vent Done!

Now to cover up the kitty poo in the dirt... I NEVER wish for ones self being to be hurt and I know what it's like to lose everything you've worked for all your life, try living in Oklahoma where you get about a 10second warning to grab your life and get to shelter, atleast Hurricane you have a bit more notice, at the rate the models are doing a good job this year you would have almost a 2 week notice, some companies can build you an entire house in 2 weeks! I'm an insurance adjuster, so with destruction comes a paycheck, one that I have been chasing all over the US this year and last running after ice storms, hail storms, etc. just to make a paycheck. Why can't i just go to one area and work and be able to put food back on the table!!

I'm sure this will torque a few of you out there, but not all of us out here have the perfect 9-5er and well, someone has to do the job............

ya'll have a good day, the knowledge and experience I've learned on here from you "greats" has been awesome this year!
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hey ike look what i found for 96L


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2791. pottery
Quoting Tazmanian:



dont you guys evere follow the track from the nhc or do you guys this like yelling fish


yes this will hit Bermuda so there for no fish

LOL.
OK.
I believe you.
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Quoting IKE:


I haven't said fish this morning.


No, neither have or will I.
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Quoting pottery:
Greetings, Traumaboyy.
It is always great to see you.
It means that all is quiet in your line of work at the moment.
Good thing....


Thank you Sir....Has been an Interesting night but Quiet for now...30 more minutes....Don't talk too loud you will wake them up!!
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2788. pottery
Quoting DestinJeff:
The first image below is from the NHC, that government body that is ridiculously inaccurate with their forecast of Danielle. Note the the dashed line that is to the southwest of the 50W/20N intercept in Advisory #1:

(click image to enlarge)

Now look at this image, also from the NHC, from today at 5am. Note the location of the orange circle with the black dot in it, which also is located to the southwest of the 50W/20N intercept.


Now, please, can we all stipulate that the NHC has pretty much nailed the track for Danielle? The images above may even be considered the peer-reviewed, scientific evidence often called for on the blog to support an opinion.

You mean..... they got it RIGHT???
GASP!
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Quoting pottery:

You think it will impact Bermuda, Taz?



dont you guys evere follow the track from the nhc or do you guys this like yelling fish


yes this will hit Bermuda so there for no fish
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Quoting IKE:


I haven't said fish this morning.



ok am this wakeing up
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Quoting pottery:
Good Morning.
It's a Cloudy one again here. Surprise!!
Another Wave approaches.

Danielle has Problems, and is going to miss Bermuda. That's good.
The wave just coming off Africa is another Monster.

Will it? Wont it??
Stay Tuned, Frustrated, Dumbfounded and in Awe!
It's Tropical Weather, aint it??


"Like" lol. Good morning Pottery.
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2783. pottery
Quoting Tazmanian:



this is a Bermuda hit so there for no fish

You think it will impact Bermuda, Taz?
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Blog is munching posts again?
Member Since: August 23, 2008 Posts: 7 Comments: 5300
2780. IKE
Quoting Tazmanian:



this is a Bermuda hit so there for no fish


I haven't said fish this morning.
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2779. pottery
Greetings, Traumaboyy.
It is always great to see you.
It means that all is quiet in your line of work at the moment.
Good thing....
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Quoting LongGlassTube:


Although it appears that Danielle has finally started to turn a little to the north she has ignored the models for quite some time now. It is totally possible for not only a Bermuda hit but also New Foundland. I guess for some anything besides a US impact is a fish.


Respectfully, do you know that danielle is nearly exactly at where the models predicted she would be on the 6z run of August 22nd. She is an area of very limited data and so far for a mid oceanic storm - the models have performed quite well - of course this is my opinion. Also, recurvature (and the point of) is often one of the hardest things to accurately forecast, at least thats what I have been told.
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Quoting IKE:


Good morning!




this is a Bermuda hit so there for no fish
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2775. IKE
NHC needs to upgrade 96L.
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2774. pottery
Quoting DestinJeff:
I tell you what, if some of the things I am looking at verifies then September will be one to remember from Brownsville to Brunswick, Corpus Christie to Cape Cod, New Orleans to New York....

The pattern is such that it is inevitable:

We are all doom.


AACCKKK!!
It's the picture of the Peruvian Andes again!
What can it mean?
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2773. CATMAN5
Only the NOGAPS holds the ridge for as long as 6 days allowing Danielle to get near 32N, 68W. Others models open the ridge and the systems only gets to 62W.
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Quoting pottery:
Good Morning.
It's a Cloudy one again here. Surprise!!
Another Wave approaches.

Danielle has Problems, and is going to miss Bermuda. That's good.
The wave just coming off Africa is another Monster.

Will it? Wont it??
Stay Tuned, Frustrated, Dumbfounded and in Awe!
It's Tropical Weather, aint it??


LOL...Good Morning Sir!!
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Quoting TropicalBruce:
Danielle and Earl-to-be continue to be right on target as far as fish storm status is concerned with the possible exception of Bermuda. Earl-to-be will likely follow Danielle's path in general. With September fast approaching and the troughs from Canada into the U.S. already starting to become stronger, it appears as if Cape Verde storms will translate into fish storms at this time.

It may be a different story for storms which develop in the Caribbean, but that's something to worry about later in the season.


They are?
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2770. IKE
You should change your screen name to....thechart
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2769. pottery
Good Morning.
It's a Cloudy one again here. Surprise!!
Another Wave approaches.

Danielle has Problems, and is going to miss Bermuda. That's good.
The wave just coming off Africa is another Monster.

Will it? Wont it??
Stay Tuned, Frustrated, Dumbfounded and in Awe!
It's Tropical Weather, aint it??
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Quoting LongGlassTube:


Although it appears that Danielle has finally started to turn a little to the north she has ignored the models for quite some time now. It is totally possible for not only a Bermuda hit but also New Foundland. I guess for some anything besides a US impact is a fish.


Poor Fish!!
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Quoting smuldy:
c'mon, be brave, tell us the wave off over west africa and the one that will next develop off to its east in 1200 hours will be fish storms too-especially since this blog knows saying so makes it happen and models can never be wrong since danielle totally missed bermuda and turned at 40w!


Although it appears that Danielle has finally started to turn a little to the north she has ignored the models for quite some time now. It is totally possible for not only a Bermuda hit but also New Foundland. I guess for some anything besides a US impact is a fish.
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off her path.
Member Since: August 17, 2010 Posts: 3 Comments: 1561
2764. smuldy
Quoting TropicalBruce:
Danielle and Earl-to-be continue to be right on target as far as fish storm status is concerned with the possible exception of Bermuda. Earl-to-be will likely follow Danielle's path in general. With September fast approaching and the troughs from Canada into the U.S. already starting to become stronger, it appears as if Cape Verde storms will translate into fish storms at this time.

It may be a different story for storms which develop in the Caribbean, but that's something to worry about later in the season.
c'mon, be brave, tell us the wave off over west africa and the one that will next develop off to its east in 1200 hours will be fish storms too-especially since this blog knows saying so makes it happen and models can never be wrong since danielle totally missed bermuda and turned at 40w!
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I suspect TD 7 will come to be by 11am or even sooner based on what is evident on the vis sat this morning qkst I would think will show a closed circulation. May even see Earl by 11am??
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Quoting TropicalBruce:
Danielle and Earl-to-be continue to be right on target as far as fish storm status is concerned with the possible exception of Bermuda. Earl-to-be will likely follow Danielle's path in general. With September fast approaching and the troughs from Canada into the U.S. already starting to become stronger, it appears as if Cape Verde storms will translate into fish storms at this time.

It may be a different story for storms which develop in the Caribbean, but that's something to worry about later in the season.


96L is well north of where Danielle was at this same longitude. What that means in future track? Don't know.
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2760. surfmom
dog was on a mission this morning - guess she knows more rain is on the way for SWFL, wanted the long walk b/4 the weather got nasty.

Morning to all
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Quoting aquak9:
G'morning gentlemen, all around the world. G'morning ladies, if there's any lurking.

Nothing to add, will sit quietly and sip coffee. Nod m'head and chuckle on occasion.

Contemplatin'.
5:30 am and this lady Met is awake :D
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Quoting TropicalBruce:
Danielle and Earl-to-be continue to be right on target as far as fish storm status is concerned with the possible exception of Bermuda. Earl-to-be will likely follow Danielle's path in general. With September fast approaching and the troughs from Canada into the U.S. already starting to become stronger, it appears as if Cape Verde storms will translate into fish storms at this time.

It may be a different story for storms which develop in the Caribbean, but that's something to worry about later in the season.


While that 18z run indicated all kinds of future activity in the upcoming days, the last 2 runs have toned down considerably. Thats nothing in stone for sure but its at least encouraging.
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Good Morning Everyone and yes the french toast does sound good and must have the coffee
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Danielle and Earl-to-be continue to be right on target as far as fish storm status is concerned with the possible exception of Bermuda. Earl-to-be will likely follow Danielle's path in general. With September fast approaching and the troughs from Canada into the U.S. already starting to become stronger, it appears as if Cape Verde storms will translate into fish storms at this time.

It may be a different story for storms which develop in the Caribbean, but that's something to worry about later in the season.
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Have a good one, Aqua.

--



Still a bit patchy underneath the convection, but considering it is only a Category 1 for the moment. Still struggling with the elements a bit and looks like that'll mostly be the case the way through.

--

You start to get this eerie feeling after Colin, now maybe Danielle, possibly Earl if the models are close.

Possibly then Fiona. Lots of ifs, but:

It seems Bermuda's year up 'til now (if it transpires; I'm aware of Alex and Mexico, but they don't have a parade of storms seemingly coming round for coffee. Given their internal troubles as of late, that's a small blessing).

However, the wishcasters will be disappointed about nothing going up for a vacation on the Eastern Seaboard.

No rain for the streets of New York City
Member Since: August 23, 2008 Posts: 7 Comments: 5300
2754. WxLogic
Good Morning...
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Good morning from the Alamo City...severe thunderstorms yesterday afternoon in San Antonio...60 mph winds!
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Quoting barotropic:


The 6Z gfs appears to continue to indicate recurvature but it also continues to show a very slow moving storm. In nearly three days as the storm moves to the east of Bermuda (hopefully), she moves only about 6 degrees north in nearly 3 days. What that may do is prevent the weakness from closing between the ridging and allow Earl (if he developes), to gain latitude. Either way it seem a pretty big hole is going to be chewed in the atlantic ridge with such a slow moving storm. This may be good news with the heart of the season upon us. Atleast for the SE seaboard IMO.


Of course a storm moving thru the caribbean may be a different story and be a big problem
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2750. IKE
Quoting aquak9:
wish I could spend the day here, but alas, duties call.

Be kind to each other. Go in peace, carry on.


Have a nice day aqua!
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2749. aquak9
wish I could spend the day here, but alas, duties call.

Be kind to each other. Go in peace, carry on.
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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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