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: 1899 - 1849

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

1899. K8eCane
wake me up when september ends
Member Since: Posts: Comments:
Has the center of Danielle relocated to 16.6N/48.5W look at Ir shortwave loop floater??
Member Since: Posts: Comments:
1897. XStormX
Quoting KEEPEROFTHEGATE:
ALERT ATCF MIL 96X XXX 100824180000
2010082418
13.0 334.6
14.7 328.2
100
13.0 334.7
250100
1008250100
1
WTNT21 KNGU 250100
MSGID/GENADMIN/NAVMARFCSTCEN NORFOLK VA//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/1. FORMATION OF A TROPICAL CYCLONE IS POSSIBLE WITHIN 100NM
EITHER SIDE OF A LINE FROM 13.0N 25.4W TO 14.7N 31.8W OVER THE
NEXT 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF A NUMBERED
TROPICAL CYCLONE WARNING AT THIS TIME.
2. A 1050 ZULU ASCAT PASS SOUTH OF THE CAPE VERDE ISLANDS
SHOWS AN ELONGATED AREA OF CYCLONIC CIRCULATION. CURRENT REGIONAL
MODELS ARE SHOWING INTENSIFICATION OF THIS LOW OVER THE
NEXT 24HRS. THIS, IN CONJUNCTION WITH WARM SEA SURFACE TEMPERATURES
OF 86 TO 88 DEGREES FAHRENHEIT SHOULD HELP TO ENHANCE THE DEVELOPMENT
OF THIS TROPICAL FEATURE.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO A WARNING OR ALLOWED TO
EXPIRE BY 260100Z AUG 2010.//
can you send the link?
Member Since: Posts: Comments:
The official intensity seems a bit conservative for 96L.

Member Since: Posts: Comments:
Quoting Krycek1984:
Regardless of his forecasting abilities or lack thereof, I find JB's writing style (LACK THEREOF) to be difficult to follow. Maybe he should take a remedial communications/writing class before he blogs so much.
That's one of the problems with blogging, no editors, fact checkers etc. A lot of stuff would look a lot different if it went through that process.
Member Since: September 9, 2007 Posts: 36 Comments: 4687
Oh, the GFS does not like the North East US very much....
Member Since: Posts: Comments:
Here are all the NGPS models....



Member Since: Posts: Comments:
1891. KEEPEROFTHEGATE (Mod)
Quoting StormW:


Thanks Keeper!
ur welcome
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting will45:



lol ya brat :-)


Lol. SmileyCentral.com
Member Since: Posts: Comments:
1889. Walnut
Quoting tropicfreak:


And didn't TD 2 make landfall in TX or in MX?


Mexico
Member Since: Posts: Comments:
00z Dynamic for 96L
Member Since: Posts: Comments:
1887. JLPR2
Quoting Stormchaser2007:
00z Dynamic



Bermuda seems to be in a pickle there. :\
Member Since: September 4, 2007 Posts: 7 Comments: 8514
Hey everyone! I would suggest to all tropic lovers to visit hurricanetrack at 9pm eastern (NOW). They are showing a live broadcast about the tropics and the newest models.

http://www.ustream.tv/channel/hurricanetrack-com
Member Since: Posts: Comments:
1883. Levi32
Quoting tropicfreak:


IMO Danielle still has a little ways to go before she can clear the dry air, and i must add that i think it could pass very dangerously close to the leeward islands.



Notice how Danielle looks like a half-moon in that picture. That's how badly the dry air is attacking her west side right now, and why she almost died last night, but she will come back, slowly.

Member Since: Posts: Comments:
Quoting Thundercloud01221991:


plus just because Alex did not make landfall in US it was very close to the US as a cat 2


And didn't TD 2 make landfall in TX or in MX?
Member Since: Posts: Comments:
AL, 96, 2010082500, 03, SHIP, 0, 136N, 267W, 30, 0, , 0, , 0, 0, 0, 0,
AL, 96, 2010082500, 03, SHIP, 12, 141N, 300W, 36, 0, , 0, , 0, 0, 0, 0,
AL, 96, 2010082500, 03, SHIP, 24, 151N, 335W, 43, 0, , 0, , 0, 0, 0, 0,
AL, 96, 2010082500, 03, SHIP, 36, 159N, 366W, 51, 0, , 0, , 0, 0, 0, 0,
AL, 96, 2010082500, 03, SHIP, 48, 167N, 395W, 58, 0, , 0, , 0, 0, 0, 0,
AL, 96, 2010082500, 03, SHIP, 60, 175N, 422W, 67, 0, , 0, , 0, 0, 0, 0,
AL, 96, 2010082500, 03, SHIP, 72, 182N, 445W, 72, 0, , 0, , 0, 0, 0, 0,
AL, 96, 2010082500, 03, SHIP, 84, 186N, 470W, 76, 0, , 0, , 0, 0, 0, 0,
AL, 96, 2010082500, 03, SHIP, 96, 189N, 496W, 75, 0, , 0, , 0, 0, 0, 0,
AL, 96, 2010082500, 03, SHIP, 108, 199N, 523W, 77, 0, , 0, , 0, 0, 0, 0,
AL, 96, 2010082500, 03, SHIP, 120, 213N, 550W, 78, 0, , 0, , 0, 0, 0, 0,
AL
Member Since: Posts: Comments:
Do any models develop the GOM system? Thanks.
Member Since: Posts: Comments:
Here is just the GFDL and NGPS Models.....

Member Since: Posts: Comments:
1878. Levi32
Quoting jonelu:

agreed. Just watch yer video...you da bomb! Totally educational and well presented. Im a fan now and will check yer blog every day.


Thank you :)
Member Since: Posts: Comments:
Hello All, just wondering what time EDT does the FSU model page update with the 00z run.
Member Since: Posts: Comments:
1875. Ossqss
Model tinker tool if interested. Model selection on right, options bottom and layovers very bottom. L8R

http://weather.myfoxtampabay.com/maps/WTVT/custom/kml/06-googlemaps.html
Member Since: Posts: Comments:
1874. XStormX
i don't mean any disrespect about him, i'm just curious, has anyone heard from him before?
Member Since: Posts: Comments:
1873. KEEPEROFTHEGATE (Mod)
250100Z AUG 10
FM NAVMARFCSTCEN NORFOLK VA
TO WEATHER
BT
UNCLAS
MSGID/NLMC/OVLY2/0087/AUG
OVLY/TCFA/250100Z8/AUG/1OF1/TCFA AL9610/METOC
LINE/2//G/130000N4/0252400W3/144200N1/0314800W6
LINE/2//G/143600N4/0250000W7/112400N8/0255400W6
LINE/2//G/112400N8/0255400W6/130600N0/0321800W4
LINE/2//G/130600N0/0321800W4/161800N6/0312400W0
LINE/2//G/161800N6/0312400W0/143600N4/0250000W7
TEXT/20//G/101800N0/0283600W9/TCFA AL9610
TEXT/20//G/091800N8/0283600W9/VALID UNTIL 260100Z
TEXT/20//G/081800N7/0283600W9/WINDS: 20-25 KTS
TEXT/20//G/071800N6/0283600W9/MVG: WNW AT 15 KNOTS
ENDAT
BT
#0001
NNNN

Member Since: July 15, 2006 Posts: 169 Comments: 53296
StormW... With Danielles current heading is it going inside the NHC cone? TIA
Member Since: Posts: Comments:
1871. KEEPEROFTHEGATE (Mod)
ALERT ATCF MIL 96X XXX 100824180000
2010082418
13.0 334.6
14.7 328.2
100
13.0 334.7
250100
1008250100
1
WTNT21 KNGU 250100
MSGID/GENADMIN/NAVMARFCSTCEN NORFOLK VA//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/1. FORMATION OF A TROPICAL CYCLONE IS POSSIBLE WITHIN 100NM
EITHER SIDE OF A LINE FROM 13.0N 25.4W TO 14.7N 31.8W OVER THE
NEXT 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF A NUMBERED
TROPICAL CYCLONE WARNING AT THIS TIME.
2. A 1050 ZULU ASCAT PASS SOUTH OF THE CAPE VERDE ISLANDS
SHOWS AN ELONGATED AREA OF CYCLONIC CIRCULATION. CURRENT REGIONAL
MODELS ARE SHOWING INTENSIFICATION OF THIS LOW OVER THE
NEXT 24HRS. THIS, IN CONJUNCTION WITH WARM SEA SURFACE TEMPERATURES
OF 86 TO 88 DEGREES FAHRENHEIT SHOULD HELP TO ENHANCE THE DEVELOPMENT
OF THIS TROPICAL FEATURE.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO A WARNING OR ALLOWED TO
EXPIRE BY 260100Z AUG 2010.//
Member Since: July 15, 2006 Posts: 169 Comments: 53296
1870. jonelu
Quoting Levi32:
Danielle is pretty much in line with the forecast points right now.

agreed. Just watch yer video...you da bomb! Totally educational and well presented. Im a fan now and will check yer blog every day.
Member Since: Posts: Comments:


IMO Danielle still has a little ways to go before she can clear the dry air, and i must add that i think it could pass very dangerously close to the leeward islands.

Member Since: Posts: Comments:
00z Dynamic

Member Since: Posts: Comments:
Do any models develop the GOM system? Thanks.
Member Since: Posts: Comments:
1866. XStormX
Quoting StormW:


Hard to say...the 18Z on Danielle sort of fits what I have in my forecast, however I think at the moment, Danielle will be east of the U.S. Will be interesting to see. Earl, is to early to tell, and I am not banking right now on a sharp re-curve. After that, right now I'm not looking for too much re-curving after that. IF the pattern evolves the way I'm thinking, I would look for more LT's beginning mid to late in the first week of Sept.

As far as the number of storms it shows, consider it a possible pre-game show.

Storm, what do you think of that guy on hear, Steve haywood or something like that? Is he for real or a joke?
Member Since: Posts: Comments:
1865. will45
Quoting AtHomeInTX:
Someone's eating my posts again. Hope the GFS is wrong. Might have to send something express mail to N.C. after I'm done with it this weekend. :)



lol ya brat :-)
Member Since: July 18, 2009 Posts: 1 Comments: 994
1864. Dakster
Thanks Levi! Now it makes sense...
Member Since: Posts: Comments:
1863. Levi32
Danielle is pretty much in line with the forecast points right now.
Member Since: Posts: Comments:
Here are just the BAM models.....the BAMS shows a hook back toward the West at the end. Probably because of a weaker storm at the end.

Member Since: Posts: Comments:
1861. Levi32
Quoting Dakster:


What does LT's stand for?

I only know it as Lieutenant...


Long-Track storms.
Member Since: Posts: Comments:
1860. Levi32
1798. StormW 4:34 PM AKDT on August 24, 2010

Yeah....scary pattern still in store for sure. September should be no picnic. The GFS has really been lighting up the last few days.
Member Since: Posts: Comments:
1859. Dakster
Quoting StormW:


Hard to say...the 18Z on Danielle sort of fits what I have in my forecast, however I think at the moment, Danielle will be east of the U.S. Will be interesting to see. Earl, is to early to tell, and I am not banking right now on a sharp re-curve. After that, right now I'm not looking for too much re-curving after that. IF the pattern evolves the way I'm thinking, I would look for more LT's beginning mid to late in the first week of Sept.

As far as the number of storms it shows, consider it a possible pre-game show.


What does LT's stand for?

I only know it as Lieutenant...
Member Since: Posts: Comments:
Someone's eating my posts again. Hope the GFS is wrong. Might have to send something express mail to N.C. after I'm done with it this weekend. :)
Member Since: Posts: Comments:
Do any models develop the GOM system? Thanks.
Member Since: Posts: Comments:
Quoting tropicfreak:


TS Bonnie and Hurricane charley in 04 made landfall in the same state in fact within a 24 hour window


I guess I was so focused on Charlie, I forgot about that. That was a year I would like to forget!
Member Since: Posts: Comments:
1847.

Yep looks like it. I expect more organization tomorrow with Danielle. I could easily see this being a powerful cyclone in a few days if nothing unexpected happens.
Member Since: Posts: Comments:
Quoting philliesrock:
Looks like Danielle is taking a wobble north right now.


I completely disagree :)

It looks like it's heading to the west.

-Snow
Member Since: Posts: Comments:
Quoting tropicfreak:


Bonnie made landfall on the US even though it was a total joke.


plus just because Alex did not make landfall in US it was very close to the US as a cat 2
Member Since: Posts: Comments:
Regardless of his forecasting abilities or lack thereof, I find JB's writing style (LACK THEREOF) to be difficult to follow. Maybe he should take a remedial communications/writing class before he blogs so much.
Member Since: Posts: Comments:
1849. Skyepony (Mod)
I think the NASA DC-8 data today is part of the Pre-Depression Investigation of Cloud-Systems in the Tropics, atleast that's what the data page says.. Link
Member Since: Posts: Comments:

Viewing: 1899 - 1849

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

Partly Cloudy
74 °F
Partly Cloudy