Figure 1. Hurricane Irene’s path looping around the Atlantic Ocean.1
Light Red=Category 1-2 Hurricane
Dark Red=Category 3-5 Hurricane
Irene was the second named storm during the month of August and meandered aimlessly around the Atlantic Ocean for over two weeks, but even with her longevity, no reports of damages were associated with Irene.
Irene developed from a large tropical wave that emerged off the west coast of Africa at rather high latitude (around 14N) between 30 September and 1 August. By moving off the African coast in such a high position, the wave dumped itself into cooler waters, averaging less than 26C. Nonetheless, the wave managed to organize enough to be classified as a Tropical Depression on 4 August 20051.
A sudden loss of convection was noticed on Satellite imagery on 5 August as Irene veered northwestward into cooler eastern Atlantic waters, with SSTs hovering around 25C. Even with this sudden loss of convection and organization, satellite and Dvorak classifications (the Dvorak technique is a system used to estimate tropical cyclone intensity by using Visible and Infrared Satellite data) continued to show Tropical Depression Nine with 30 kt surface winds. As Tropical Depression Nine continued on its northwestward track, convection once again began to fire around the low level center, and the disturbance was classified as Tropical Storm Irene early on 7 August. Irene was the earliest Ninth named storm in recorded history, surpassing the old record by an astonishing 13 days2.
Even though Irene was slowly making her way towards warmer SSTs, she weakened to a Tropical Depression during the morning of 8 August, and remained a depression until late on 10 August as she neared 25N. Irene, now in a more favorable environment, began to strengthen once more, and became a hurricane late on 14 August over 350 miles east of Cape Hatteras, NC3.
Irene continued her slow intensification until 16 August when she reached her peak intensity with 100 mph surface winds 300 miles northeast of Bermuda. Afterwards, increasingly cooler waters and strengthening upper level shear began to dismantle Irene’s structure, and she weakened to a Tropical Storm at 5PM EDT on 17 August. Her forward motion began to increase, and by 18 August, Irene was racing northeastward at over 30 mph towards Greenland.
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 or WHOM to obtain data provided by the GES DISC DAAC for a hurricane event.
+View animations and images of Hurricane Irene in the 2005 Past Hurricane Archive.
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MODIS Terra RGB using the MOD02HKM product. This image is of the swath data from Aug 12 at 1525 hrs. More images like this and parameters animation created from other datasets can be seen in our Archive Image Gallery for hurricane Irene
1. Image courtesy of the NOAA coastal Services Center Http://hurricane.csc.noaa.gov/hurricanes
2. Stewart, Stacy. “Tropical Cyclone Report: Hurricane Irene” 20 January 2006. http://www.nhc.noaa.gov/pdf/TCR-AL092005_Irene.pdf (10 July 2006).
3.Franklin, James. “Tropical Storm Irene Discussion Number 12.” 7 August 2005. http://www.nhc.noaa.gov/archive/2005/dis/al092005.discus.012.shtml? (10 July 2006).
4. Franklin, James. “Hurricane Irene Advisory Number 42.” 14 August 2005. http://www.nhc.noaa.gov/archive/2005/pub/al092005.public.042.shtml? (10 July 2006).