Figure 1. Best Track analysis of Hurricane Danielle .1
Light Red=Category 1-2 Hurricane
Dark Red=Category 3-5 Hurricane
Hurricane Danielle was the third hurricane of the 2004 Atlantic Hurricane Season, which formed in the far eastern Atlantic Ocean. Danielle briefly threatened the Azores, but remained safely out in the Atlantic, away from any landmasses.
Danielle developed—like Charley—from a vigorous tropical wave that emerged off the coast of Africa during the highly active “Cape Verde Season.” During the morning of 13 August, the tropical wave developed into Tropical Depression Four just south of the Cape Verde Islands in the extreme Eastern Atlantic2.
Tropical Depression Four continued on its westward track at about 15 mph, and became Tropical Storm Danielle at 11 PM EDT on 13 August. Around that time, she rounded the base of a subtropical ridge to her east, and a large trough to her west, and began a turn towards the northwest. Between 14 and 18 August, Danielle slowly curled around to the west-northwest, and then the north, and finally the northeast—towards the Azores in the northeastern Atlantic. Between 14 and 15 August, Danielle underwent a phase of rapid intensification, jumping from a low-end 45 kt (50 mph) Tropical Storm, to a high end 80 kt (90 mph) Category 1 Hurricane in a period of 24 hours. This rapid change in intensity is also reflected in Danielle’s sudden loss of surface pressure, which dropped from 1004 mb* to 978 mb, a loss of 26 mb during that same 24 hour period.
On 16 August, Danielle reached her peak intensity of 95 kts (105 mph) in the Eastern Atlantic well away from any landmasses. Increasing wind shear from the approaching trough to the west began shredding thunderstorms from the center of circulation, and Danielle began a steady decrease in intensity in the extreme eastern Atlantic Ocean. At 12 UTC (8 AM EDT) on 18 August, Danielle was downgraded to a Tropical Storm a little less than 1000 miles southwest of the Azores. About 48 hours later at 18 UTC on 20 August, Danielle lost Tropical Storm status as her surface winds decreased to below 34 kt (39 mph).
Tropical Depression Danielle continued weaken as she moved over progressively cooler waters in the northeast Atlantic. By 24 August, Danielle had become a small swirl of spotty clouds, void of any thunderstorm activity,3 and three days later, the remnant low had completely dissipated over the cool waters of the central Atlantic.
*Millibar, which has the same value as a hectopascal (hPA) is a widely accepted measurement for atmospheric pressure. Average Sea Level Pressure (SLP) is 1013.325 mb, or 29.92 inches of mercury.
Data, Images and Animations
+Explore and analyze gridded data of the hurricane using the GES-DISC Interactive Online Visualization and Analysis Infrastructure (Giovanni)
+Use Mirador to obtain data provided by the GES DISC DAAC for a hurricane event.
+View animations and images of Hurricane Danielle in the 2004 Past Hurricane Archive.
| || |
MODIS Terra RGB using the MOD02HKM product. This image is of the swath data from Aug 17 at 1300 hrs. More images like this and parameters animation created from other datasets can be seen in our Archive Image Gallery for hurricane Danielle
1. Image courtesy of the NOAA coastal Services Center Http://hurricane.csc.noaa.gov/hurricanes
2. Stewart, Stacy. “Tropical Depression Four Discussion Number 1.” 13 August 2004. http://www.nhc.noaa.gov/archive/2004/dis/al042004.discus.001.shtml? (24 July 2006).
3. Avila, Lixion. “Tropical Depression Danielle Discussion Number 33.” 21 August 2004. http://www.nhc.noaa.gov/archive/2004/dis/al042004.discus.033.shtml? (24 July 2006).