Danielle a hurricane; TD 7 forming off coast of Africa

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

Share this Blog
2
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 299 - 249

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68Blog Index

I don't get why we can't have proper building codes in the US to withstand hurricanes. Hurricanes happen all the time in Japan but don't entail the kind of destruction that happens here.

What prevents proper building of houses so that hurricanes aren't nearly such a threat? Corruption? Cheapness? I don't get it. There's no reason a Cat 2 should be blowing off roofs if a house is built to code. And there's no reason someone shouldn't expect their house to be totaled if they live near enough the sea to get a storm surge.
Member Since: Posts: Comments:
Thanks Storm. When you say folks in are in for a rude awakening, do you mean folks in Florida?
Member Since: Posts: Comments:
Hi storm, don't think you answered my question or I didn't see it. Would this in the GOM affect TX if it was to develop?
Member Since: Posts: Comments:
Link

GFS out to 132 hrs much further west so far on this run
Member Since: Posts: Comments:
Quoting StormW:


If you click on my handle, it will take you to my forecast.

As far as the coming months, folks are in for a rude awakening I feel.



Why do you feel that? Would it be good or bad? I would love to see a season bust. That would mean no one lost their homes, possesions, jobs, or, more importantly, their loved ones.
Member Since: Posts: Comments:
Quoting StormW:


So? I can respect that, and I can respect anyone who has one, cause it's a lot of hard work...I was working toward my meteorological degree, but circumstances with my son, required me to withdraw and take care of his medical needs..., but ya don't need a degree to forecast Hurricanes and tropical storms, or don't you read and comprehend my blog?


I do read your blog. And I always look forward to your posts. Lately though, your reponses to people have come off rather defensive and pissy.

You bash the NHC, you bash PH.D's. You talk down to people who disagree with you. You can let your work speak for itself.

I do think it's in poor taste to come into Dr. Masters blog and make comments like (paraphrasing) "Dr. Masters obviously read my blog..." and ridiculing the Ph.D designation he worked hard to achieve. You may not mean to come off that way, but you do (lately anyway).


Member Since: Posts: Comments:
291. Relix
StormW: Don't listen to some of the people here, especially being annoying with the Ph.D. Wake up call guys, not everyone with a PhD is perfect and flawless. StormW is probably the best forecaster and the one with more experience here in this blog aside from Dr. Masters himself. He knows his stuff much better than anyone here, and I am sure he's better forecasting than many people with the fabled PhD.
Member Since: August 3, 2006 Posts: 0 Comments: 2648
Quoting Hurricanes101:


that was over 4 hours ago, look at 96L since then


Link
Member Since: June 29, 2009 Posts: 13 Comments: 5300
Quoting jrweatherman:
I don't give a crap about the PHD stuff. All I am looking at is the track and model forecast.

Basically the NHC uses a blend of the models to create a forecast track.

On Advisory #1 at 72 hours their forecast point is 16.6N 46.7W. That would be at 5pm today.

At the 11:00 Advisory the current position is 17.5N 47.5W. They were within a stones throw of the position 72 hours out. So far, the models and the NHC have done a pretty good job.

Having said that, will the forecast track continue to validate? I have no idea. That is why we have Dr. M and StormW to give us their opinions and forecasts.
shouldn't she have been a major right now. Danielle looks like it may not even be a hurricane currently. I didn't see anyone forecast that even as late as last night.
Member Since: Posts: Comments:
Quoting BobinTampa:


the writer of this blog has a Ph.D. Not good enough??
Goes to prove my DDD's point. Dr Jeff had experience and an inquisitive mind before he got his Phd. Those guys are a rare treasure. If I were King and Emperor of The World I would require experience in the field before anyone could enter an advanced degree program. JMAO (just my arrogant opinion)
Member Since: Posts: Comments:
Quoting jrweatherman:
I don't give a crap about the PHD stuff. All I am looking at is the track and model forecast.

Basically the NHC uses a blend of the models to create a forecast track.

On Advisory #1 at 72 hours their forecast point is 16.6N 46.7W. That would be at 5pm today.

At the 11:00 Advisory the current position is 17.5N 47.5W. They were within a stones throw of the position 72 hours out. So far, the models and the NHC have done a pretty good job.

Having said that, will the forecast track continue to validate? I have no idea. That is why we have Dr. M and StormW to give us their opinions and forecasts.


Well PHD's provide those tracks and advisories that you love so much.
Member Since: Posts: Comments:
Quoting Clearwater1:
Quoting KerryInNOLA:
Every freaking storm that comes along has you guys playing scientist and predicting contrary to the pros. Just sit back and leave the driving to the NHC. Oh, and wipe the egg off your face, it might have salmonella

But that's the point of a blog like this. Right or wrong, us arm chair mets like to predict. Why ya care?

It is one thing to predict with a rational and another to simply love seeing the destruction wrought by hurricanes when they hit land. It appears to me and and Kerry that a lot of people on here simply want a hurricane to hit land and wishcast it that way while for those of us who have our lives turned upside down that sucks.

If it's close or you really see something the models or NHC is missing or you want to speculate based on some event outside of NHC's window because they are not allowed to speculate that's all good.
Wishing or trying to make it seem like a storm is going/going to go west enough to hit CONUS rather than on it's high confidence forecast track on here is your choice but it may really irritate the people who would be affected if it did. Thats why..
Member Since: Posts: Comments:
Quoting StormW:


So? I can respect that, and I can respect anyone who has one, cause it's a lot of hard work...I was working toward my meteorological degree, but circumstances with my son, required me to withdraw and take care of his medical needs..., but ya don't need a degree to forecast Hurricanes and tropical storms, or don't you read and comprehend my blog?


If you want to get paid you do. I believe that is the main difference. But as far as a weather blog it doesn't matter.
Member Since: Posts: Comments:
Storm,

good afternoon. what are your predictions for Earl? Trough re curving it to sea? Or a weaker system being steered by the High?

These troughs are incredible! just one after another!

Nothing lasts forever is my inside feeling. My fear is that a few of these storms in the coming months will get near Florida.
Member Since: Posts: Comments:
Quoting DestinJeff:


are you posting using the Cliche`-O-Matic 3000?


What?
Member Since: Posts: Comments:
Quoting AllStar17:



1. SHOWERS AND THUNDERSTORMS CONTINUE TO BECOME BETTER ORGANIZED IN
ASSOCIATION WITH AN AREA OF LOW PRESSURE PASSING ABOUT 100 MILES
SOUTH OF THE CAPE VERDE ISLANDS...AND IT APPEARS THAT A TROPICAL
DEPRESSION COULD BE FORMING. IF THIS TREND CONTINUES... ADVISORIES
ON THIS SYSTEM COULD BE INITIATED AS EARLY AS LATER THIS MORNING.
THERE IS A HIGH CHANCE...90 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES
WEST-NORTHWESTWARD AT NEAR 15 MPH. LOCALLY HEAVY SHOWERS AND
STRONG GUSTY WINDS ARE POSSIBLE OVER PORTIONS OF THE CAPE VERDE
ISLANDS TODAY...AND INTERESTS IN THOSE ISLANDS SHOULD MONITOR THE
PROGRESS OF THIS SYSTEM.


that was over 4 hours ago, look at 96L since then
Member Since: Posts: Comments:
I don't give a crap about the PHD stuff. All I am looking at is the track and model forecast.

Basically the NHC uses a blend of the models to create a forecast track.

On Advisory #1 at 72 hours their forecast point is 16.6N 46.7W. That would be at 5pm today.

At the 11:00 Advisory the current position is 17.5N 47.5W. They were within a stones throw of the position 72 hours out. So far, the models and the NHC have done a pretty good job.

Having said that, will the forecast track continue to validate? I have no idea. That is why we have Dr. M and StormW to give us their opinions and forecasts.
Member Since: Posts: Comments:
Quoting reedzone:
My first run on Danielle, it took a while because I wanted to see how long the westward movement would occur. I believe she will turn around 55W.

Photobucket


Reed-I feel it is possible for Danielle to hit the mid to southern part of Florida, of course I am just a lowly nurse...so take that for what it aint worth.
Member Since: Posts: Comments:
Shen beat me to it so I took mine down.
Member Since: Posts: Comments:
Quoting Hurricanes101:
what happened to 96L?

looks like it fell apart



1. SHOWERS AND THUNDERSTORMS CONTINUE TO BECOME BETTER ORGANIZED IN
ASSOCIATION WITH AN AREA OF LOW PRESSURE PASSING ABOUT 100 MILES
SOUTH OF THE CAPE VERDE ISLANDS...AND IT APPEARS THAT A TROPICAL
DEPRESSION COULD BE FORMING. IF THIS TREND CONTINUES... ADVISORIES
ON THIS SYSTEM COULD BE INITIATED AS EARLY AS LATER THIS MORNING.
THERE IS A HIGH CHANCE...90 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES
WEST-NORTHWESTWARD AT NEAR 15 MPH. LOCALLY HEAVY SHOWERS AND
STRONG GUSTY WINDS ARE POSSIBLE OVER PORTIONS OF THE CAPE VERDE
ISLANDS TODAY...AND INTERESTS IN THOSE ISLANDS SHOULD MONITOR THE
PROGRESS OF THIS SYSTEM.
Member Since: June 29, 2009 Posts: 13 Comments: 5300
Quoting Skyepony:


It feels like it here. Yesterday the wind, ring around the moon lastnight. Today~ overcast & the windows are still fogged up. FL should disrupt it but still a good chance of some weather dragging up the east coast the next few days. I think how bad only depends on if it drags the coast or gets off shore a little where the east coast misses out. The way it's lingering in the gulf I'm leaning toward dragging up the coast.


I was somewhat suprised the UKMET Office called for tropical development off the east coast. Last I looked at some cyclone phase did not show that. Guess it is possible.

NEW TROPICAL STORM FORECAST TO DEVELOP AFTER 12 HOURS
FORECAST POSITION AT T+ 12 : 34.5N 74.9W
Member Since: Posts: Comments:
Quoting Hurricanes101:
what happened to 96L?

looks like it fell apart


????
Member Since: June 29, 2009 Posts: 13 Comments: 5300

Member Since: June 29, 2009 Posts: 13 Comments: 5300
Does anyone know what the pressure tendacy is in the gulf?
Member Since: Posts: Comments:
My first run on Danielle, it took a while because I wanted to see how long the westward movement would occur. I believe she will turn around 55W.

Photobucket
Member Since: Posts: Comments:
.
Member Since: Posts: Comments:
what happened to 96L?

looks like it fell apart
Member Since: Posts: Comments:
My ample gut tells me that the CV season will be active, but no CV storms will make it across the entire Atlantic. I'm more concerned with landfall from a storm that first becomes a TD in the Caribbean or closer. Likely after Oct.1
Member Since: Posts: Comments:
wow Danielle is either now a weak TS or a TD now pre-TD7 moves west for the next 3-4 day

anyway Ihave to run out so BBL
Member Since: Posts: Comments:
261. RMCF
Are the models developing this front after it hits the tropical wave in the Caribbean.
Member Since: Posts: Comments:
06L/H/D/C1
MARK
16.81N/47.77W

Member Since: Posts: Comments:
Quoting southernstorm:


sorry u didnt learn anything!


I was talking about how a person acts, not the education part.



Member Since: Posts: Comments:
Quoting Skyepony:


It feels like it here. Yesterday the wind, ring around the moon lastnight. Today~ overcast & the windows are still fogged up. FL should disrupt it but still a good chance of some weather dragging up the east coast the next few days. I think how bad only depends on if it drags the coast or gets off shore a little where the east coast misses out. The way it's lingering in the gulf I'm leaning toward dragging up the coast.
a day or so ago, the gfs run predicted a storm forming off the coast of FL (albit for labor day) and heading towards the state or FL. Maybe it's happening. The GFS did predict danienlle 2 weeks ago, according to Masters.
Member Since: Posts: Comments:
Quoting StormW:
A lot of "hobbyists" keep saying it will go further west than what the NHC says. Have you ever seen the inside of the Center? It is 23rd century. They are the pros with the degrees, brains and large salaries to boot. They are doing their jobs giving us cutting edge forecasts. We are allowed to discuss and debate, this is
America, but remember they wear the pants.


Oh geez...here we go with the Ph.d stuff again...may I gag now or later?


BS= we all know what. MS= more of same. Phd= piles higher and deeper.

My DDD (dear departed dad) used to say experience + inquisitive mind can substitute for education fairly well. The opposite is less true.
Member Since: Posts: Comments:
Quoting StormChaser81:


I know a lot of stupid PHD's, book smarts are not everything, got to know how to use them in real life.


If the only thing you got out of school between your masters and phd, you might want to go back again.
Member Since: Posts: Comments:
Thanks StormW-----. I really do appreciate your updates, they are always very thorough. Also thank you for your "help" in the past seasons, especially with hurricane Ike.
Member Since: Posts: Comments:
click on fronts and look to the S of the front... several little spinners in the GOM, and it is still very, very wet here in WC coast of FL.
Link
Member Since: Posts: Comments:
Quoting StormW:
HURRICANE DANIELLE SYNOPSIS AUGUST 24, 2010 ISSUED 11:50 A.M.


Great update. Thanks, StormW.
Member Since: Posts: Comments:
Quoting BobinTampa:


the writer of this blog has a Ph.D. Not good enough??


Yeah, seems a lot of rudeness going on in here today, and a lot of fluffing feathers.
Member Since: Posts: Comments:

Viewing: 299 - 249

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Overcast
62 °F
Overcast