Figure 1. Best track analysis of Hurricane Maria, which briefly attained major hurricane status in the Central Atlantic Ocean near the island of Bermuda. The hatched lines represent where Maria was still a formidable weather feature, despite having lost all tropical characteristics .1
Light Red=Category 1-2 Hurricane
Dark Red=Category 3-5 Hurricane
Maria was yet another early-season tropical cyclone, that briefly became a major hurricane late on 5 September. Even though she reached Category 3 status, Maria remained well out to sea and was not responsible for any damages or casualties2.
Maria began as a vigorous tropical wave that emerged off the western coast of Africa between 27 and 28 August. The wave axis—from roughly 14N 20W southward to around 5N 21W—featured strong thunderstorms along its entire length. By 30 August the convection along the wave axis had begun consolidating, as an area of low level cyclonic rotation began to develop near 12N 36W. At 11AM EDT on September 1, the Hurricane Center designated this area of disturbed weather Tropical Depression 14.3 The next morning, enough convection had developed around the low level center to categorize it as tropical storm Maria. On average, the Atlantic Basin sees 10 tropical storms between June and November, but barely four months into the season, a thirteenth named storm had already developed.
Maria then began a slow, but steady intensification as she progressed in a northwestward path towards Bermuda. Early on 4 September, Maria became the fifth hurricane of the 2005 season, and began to swing around to the north, and eventually the northeast4. In a region of low vertical speed shear (the increase in wind speeds from the surface to roughly 40,000 feet) and Sea Surface Temperatures (SSTs) around 29C, Maria continued to intensify in the middle of the Atlantic Ocean. Late on 5 September, Maria became a major hurricane, with maximum surface wind speeds near 115 mph5.
Maria, however, was headed towards no man’s land (so to speak), where SSTs averaged less than 22C and where upper level wind shear began tearing her apart. Just 12 hours after being classified as a Category 3 Hurricane, Maria had weakened to a Tropical Storm; and she became extratropical—i.e., loosing tropical characteristics by converting energy production from the release of latent heat in water to drawing energy out of the atmosphere—a short while later.
Damage and Casualties
Even though Maria briefly became a Category 3 hurricane, no reports of damage or deaths were directly correlated to the storm. Maria remained over 100 miles from the remote island of Bermuda on her closest approach, and was only a threat to marine interests.
Satellites like the MODerate resolution Imaging Spectroradiometer (MODIS) observing platform on board both the Terra and Aura spacecraft, Tropical Rainfall Measuring Mission (TRMM) instrument, and the Ozone Monitoring Unit (OMI) captured numerous snapshots of Hurricane Maria as she plowed her way northeastward towards Iceland and Norway.
Effective Surface Reflectivity is a useful parameter to track the progression of large, synoptic-scale weather features such as blizzards or hurricanes because clouds with high moisture contents (100 to 1000 g/m2) have very high reflectivities. Likewise, clouds with very little moisture content have very low reflectivities. The OMI instrument can measure various parameters from ozone concentration, to surface reflectivity, and captured images of Maria as she reached her zenith in intensity.
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MODIS Aqua RGB using the MOD02HKM product. This image is of the swath data from Sept 08 at 1640 hrs. More images like this and parameters animation created from other datasets can be seen in our Archive Image Gallery for hurricane Maria
1. Image courtesy of the NOAA coastal Services Center Http://hurricane.csc.noaa.gov/hurricanes
2.Blake, Eric S; Pasch, Richard J. “Tropical Cyclone Report: Hurricane Maria.” 8 February 2006. http://www.nhc.noaa.gov/pdf/TCR-AL142005_Maria.pdf (7 July 2006).
3. Avila, Lixion; “Tropical Depression Fourteen Discussion Number 1.” 1 September 2005. http://www.nhc.noaa.gov/archive/2005/dis/al142005.discus.001.shtml? (7 July 2006).
4. Stewart, Stacy. “Hurricane Maria Discussion Number 12.” 4 September 2005. http://www.nhc.noaa.gov/archive/2005/dis/al142005.discus.012.shtml? (7 July 2006).
5.Knabb, Richard. “Hurricane Maria Advisory Number 19.” 5 September 2005. http://www.nhc.noaa.gov/archive/2005/pub/al142005.public.019.shtml? (7 July 2006).